How To Improve Health After A Hip Replacement

Abstracts Oktober 2014 DOS Kongressen 2014 Radisson Blu Scandinavia Hotel 22.-24. oktober www.ortopaedi.dk DOS Kongressen 2014 1

DOS Bulletin Udgiver Dansk Ortopædisk Selskab Lyngskrænten 17 2840 Holte Ansvarshavende redaktør Steen Lund Jensen E-mail: editor@ortopaedi.dk Sekretariatsleder Gitte Eggers Web-page www.ortopaedi.dk Redaktion og annoncer Sekretariatsleder Gitte Eggers Lyngskrænten 17 2840 Holte E-mail: office@ortopaedi.dk Layout & Tryk Kandrups Bogtrykkeri Tlf. 3543 6000 E-mail: tryk@kandrup.dk www.kandrup.dk Betingelser for optagelse i DOS Alle læger med dansk autorisation kan optages i Dansk Ortopædisk Selskab. Anmodning om indmeldelse i DOS kan kun ske via hjemmesiden: www.ortopaedi.dk Aktiver linket Bliv medlem og udfyld ansøgningen sammen med oplysninger om personlige data. DOS Bestyrelse Se hele bestyrelsen side 249. ISSN 0902-8633 Næste BULLETIN Deadline: uge 32, 07.08.2015 Udkommer: uge 39, 28.09.2015 2 DOS Abstracts

Indhold Floorplan....................................... 4 Liste over udstillere................................. 5 Kort over udstillingsareal.............................. 6 Dag til dag programmer............................... 7 Videnskabelige sessioner............................. 13 Session 1: Hip................................. 13 Session 2: Sportstrauma........................... 15 Session 3: Hand/wrist............................. 17 Postersession I................................. 19 Postersession II................................ 21 Postersession III................................ 23 Session 4: Foot/ankle............................. 25 Session 5: Shoulder/elbow.......................... 27 Session 6: Tumor............................... 29 Session 7: Knee................................ 31 Session 8a: Experimental + Session 8b: Sportstrauma.......................... 33 Session 9: Trauma............................... 35 Session 10a: Hip/knee + Session 10b: Trauma.............................. 37 Session 11: Spine............................... 39 Session 12: Pediatrics............................. 41 Session 13: Foredragskonkurrence..................... 43 Posterudstilling................................ 45 Abstracts...................................... 53 DOS Kongressen 2014 3

Floorplan Capital Ballroom Reykjavik Stockholm Copenhagen Helsinki Oslo Capital Foyer Casino Ballroom Scandinavian Foyer Stairs to lobby, restaurants & bars Denmark Iceland Sweden Finland Scandinavian Ballroom 4 DOS Abstracts

Udstillere Firma Stand nr. Areal 3M Health Care A/S 1 3 ArjoHunteligh A/S 2 3 Arthrex Danmark A/S 3 24 Bauerefeind Nordic AB 4 3 Bayer HealthCare A/S 5 3 B. Braun Medical A/S 6 5 Biomet Danmark ApS 7 18 BK Medical 8 3 DePuySynthes 9 10 DJO Nordic 10 5 Episurf Medical AB 11 6 Fischer Medical ApS 12 3 Globus Medical Danmark 13 3 JHInova AB 14 3 Karl Storz Endoskopi Danmark A/S 15 5 KCI Medical ApS 16 3 KEBOMED A/S 17 3 Linvatec Denmark 18 5 Maquet Danmark A/S 19 3 Meda A/S 20 3 medi Danmark ApS 21 3 Medtronic Danmark A/S 22 3 Mobelife NV 23 3 Mærsk-Andersen A/S 24 5 Mölnlycke Health Care ApS 25 3 NOVAX A/S 26 3 Ortos A/S 27 3 Ossano Scandinavia ApS 28 5 Ortotech 29 5 Protesekompagniet A/S 30 12 Sahva 31 9 SECMA 32 3 Simonsen & Weel 33 12 Smith&Nephew A/S - ArthroCare 34 9 Stryker Danmark A/S 35 20 Swemacimaging 36 8 Swemac Orthopaedics ApS 37 3 Swemacosmedic A/S 38 5 Tornier Scandinavia A/S 39 3 Viking MedicalScandinavia ApS 40 6 Zimmer Danmark 41 18 Ôssur Nordic AB 42 3 10 DOS Bulletin DOS Kongressen 2014 5

10 30 15 Udstilling 23 Kaffebord 12 Scandinavian Ballroom 13 Køkken 3 Denmark 18 24 14 38 7 Iceland 20 37 11 35 4 Sweden 33 8 16 Toilet 17 27 9 Toilet 21 31 22 26 5 39 32 42 Finland 36 25 1 2 19 29 6 28 Norway Trappe 34 Kaffebord 40 41 6 DOS Abstracts DOS Kongressen 2014 11

Dagsprogram Onsdag d. 23. 22. oktober 2013 2014 Lokale: 09:00-10:30 DOS Session Symposium: 1 (Hip) Reykjavik Collesfrakturer 09:00-10.30 Session 2 (Sportstrauma) Stockholm/ 09:00 10.00 Session 1 (Sports) Stockholm/ Copenhagen Copenhagen 09:00-10:30 Session 3 (Hand/wrist) Helsinki/Oslo 10:00 10:30 Professorforelæsning: 09:00-10:30 DOS Uffe Symposium: Jørgensen Stockholm/ Casino Ballroom Klinisk dokumentation og Copenhagen indførelse af nye implantater 09:00 10:30 Session 2 (Hip 1) Helsinki/Oslo 10:30-11:00 Kaffe i udstillingen 10:30-11:00 Kaffe i udstillingen 11:00-12:00 Postersession I Reykjavik 11:00-12:00 Postersession I II Reykjavik Stockholm/Copenhagen Postersession III Stockholm/Copenhagen Helsinki/Oslo Postersession III Helsinki/Oslo 11:00-12:00 DOS Symposium: Casino Ballroom 12:00-13:00 Frokost Nationale i udstillingen Kliniske Retningslinjer Håndledsnære underarmsbrud 13:00-14:30 Møde i fagområderne 12:00-13:00 Fagområde: Frokost i udstillingen DSHK Reykjavik 12:15-12:45 Håndkirurgisk Frokostsymposium: Selskab Stockholm Casino Ballroom Dansk Össur Ortopædisk Traumeselskab Copenhagen SAKS Dr. Kristleifur Kristjánsson Helsinki Fod/ankelselskabet Ensuring results after cartilage Oslo Børneortopædisk injuries in the knee Selskab Directors Ortopædisk Onkologi/ Sarkomgruppen 2620(26.etage) Ledende overlæger Chairmans DOS Kongressen 2014 13 7

Dagsprogram Onsdag d. 22. oktober 2014, fortsat Lokale: Lokale: 14:30 09:00 13:00-10:30 14:30 15:00 Møde Session Kaffe i fagområderne udstillingen 1 (Hip) Fagområde: Reykjavik Lokale: 15:00 09:00-10.30 17.30 Møde Session Fod/ankelselskabet i fagområderne 2 (Sportstrauma) (fortsat) samt: Stockholm/ Lillebror Ryginteressegruppen Dansk Selskab for Håndkirurgi Copenhagen Executive Stockholm Skulder/albueselskabet Dansk Ortopædisk Traumeselskab Lillebror Reykjavik 09:00-10:30 Session DSHK 3 (Hand/wrist) Helsinki/Oslo Casino Ballroom 17:30 18.30 Velkomst Børneortopædisk og Posterwalk Selskab Capital Directors Foyer 09:00-10:30 DOS Dansk Symposium: selskab for skulder og albuekirurgi Casino Ballroom Oslo 18:00 21:00 Danske Ortopædisk Klinisk Ortopæders dokumentation Onkologi/knogleog Organisation og (DOO) Directors indførelse bløddelstumorer af nye implantater Chairmans 18.30 20:30 YODA SAKS Holdes Helsinki i Islands 10:30-11:00 Ledende Kaffe i udstillingen overlæger Brygges 2620 (26.etage) Kulturhus 11:00 14:30-15:00 12:00 Postersession Kaffe i udstillingen I Postersession II Reykjavik Stockholm/Copenhagen 15:00-17.30 Møde Postersession i fagområderne III (fortsat) samt: Helsinki/Oslo Ryginteressegruppen Copenhagen 11:00-12:00 DOS Symposium: Casino Ballroom 17:30-18.30 Velkomst Nationale og Kliniske Posterwalk Retningslinjer Capital Foyer Håndledsnære underarmsbrud 18:00 -? Danske Ortopæders Organisation Chairmans 12:00-13:00 Frokost i udstillingen 18:30-19:30 Arbejdsgruppen for danske infektions- 12:15-12:45 Interesserede Frokostsymposium: Ortopædkirurger Casino Ballroom Helsinki Össur 18.30-20:00 YODA Dr. Kristleifur Kristjánsson Ensuring results after cartilage injuries in the knee Holdes i Islands Brygges Kulturhus 8 DOS Abstracts DOS Kongressen 2014 13

Dagsprogram Torsdag 24. 23. oktober 2013 2014 Lokale 09:00 10:30 DOS Symposium: Reykjavik 08:00-09:30 DOS Nationale Symposium kliniske (infektion): retningslinjer Reykjavik Orthopaedic for udvalgte skulderlidelser Infections in Denmark. Status and perspectives Session 3 (Knee) Stockholm/Copenhagen 08:30-09:30 DOS Symposium (uddannelse): Stockholm/Copenhagen Session Ortopædkirurgisk 4 (Trauma 1) uddannelse: Helsinki/Oslo Et blik ind i fremtiden 10:30 11:00 Kaffe i udstillingen 08:30-09:30 DOS Symposium (forskning): Helsinki/Oslo 11:00 12:00 DOS Power Honorary og sample Lecture: size estimering Reykjavik Flemming Bro 09:30-10.30 Session Implementering 4 (Foot/ankle) af ny viden og Reykjavik kliniske retningslinjer Session 5 (Shoulder/elbow) Stockholm/Copenhagen DOS Symposium: Stockholm/Copenhagen Session Fase IV 6 målbeskrivelserne (Tumor) Helsinki/Oslo hvor langt er vi kommet? 10:30-11:00 Kaffe i udstillingen Session 5 (Experimentel) Helsinki/Oslo 11:00-12:00 DOS Honorary Lecture: Stockholm/Copenhagen 12:00 12:30 Frokost v/professor i udstillingen Ove Furnes Helsinki/Oslo The influence of learning 12:30 13:00 Frokostsymposium: curve on clinical outcome Arthrex A/S: Stockholm/ 12:00-13:00 Frokost i udstillingen Copenhagen Graftlink ACL Reconstruction 12:15-12:45 Frokostsymposium: using The Flipcutter Technique: Casino Ballroom Arthrex Pearls and A/S: early results Priv.-Doz. Dr. Dr. Phil. Max J. Kääb Rotator cuff reconstruction: bridging gaps DOS Kongressen 2014 17 9

Dagsprogram Torsdag 23. oktober 2014, fortsat Lokale: 13:00 13.30 Frokost i udstillingen (fortsat) 13:00 08:00-14.30 09:30 Session DOS Symposium 7 (Knee) (infektion): Reykjavik 13:30 15:00 Session Orthopaedic 6 (Sports/Shoulder) Infections in Reykjavik Session Denmark. 8a 7 (Spine) Status (Experimental) and perspectives Stockholm/Copenhagen Session 8 (Pediatrics) Helsinki/Oslo 08:30-09:30 DOS Session Symposium 8b (Sportstrauma) (uddannelse): Stockholm/Copenhagen 15:00 15.30 Ortopædkirurgisk Kaffe i udstillingen uddannelse: Session Et blik ind 9 (Trauma) i fremtiden Helsinki/Oslo 15:30 17:30 Generalforsamling i DOS Stockholm/Copenhagen/ 08:30 14:30-15.00 09:30 DOS Kaffe Symposium i udstillingen (forskning): Helsinki/Oslo Power og sample size estimering 15:00 19:00-17:00 19:30 Generalforsamling Gallamiddag, Velkomst i DOS Stockholm/Copenhagen/ Casino Ballroom 09:30-10.30 Session 4 (Foot/ankle) Helsinki/Oslo Reykjavik 19:30 -? Gallamiddag Capital Ballroom 18:30-19:00 Session Gallamiddag, 5 (Shoulder/elbow) Velkomst Casino Stockholm/Copenhagen Ballroom 19:00 -? Session Gallamiddag 6 (Tumor) Capital Helsinki/Oslo Ballroom 10:30-11:00 Kaffe i udstillingen 11:00-12:00 DOS Honorary Lecture: Stockholm/Copenhagen v/professor Ove Furnes Helsinki/Oslo The influence of learning curve on clinical outcome 12:00-13:00 Frokost i udstillingen 12:15-12:45 Frokostsymposium: Casino Ballroom Arthrex A/S: Priv.-Doz. Dr. Dr. Phil. Max J. Kääb Rotator cuff reconstruction: bridging gaps 10 DOS Abstracts DOS Kongressen 2014 17

Dagsprogram Fredag 25. 24. oktober 2013 2014 Lokale: 09:00-10.30 Session 9: 10a (Hip/knee) 2) Reykjavik Session 10: (Tumor/pediatrics) Stockholm/Copenhagen Session 11: 10b (Trauma) 2) Helsinki/Oslo Reykjavik 10:30 11:00 Session Kaffe i udstillingen 11 (Spine) Stockholm/Copenhagen 11:00 12:00 Guildal Session forelæsning: 12 (Pediatrics) Reykjavik Helsinki/Oslo Thomas P. Rüedi 10:30-11:00 Professorforelæsninger: The Evolution Fracture Surgery Anders in the 20th Troelsen Century Reykjavik The perfect treatment by hip Session and knee 12: arthroplasty (hand) Stockholm/Copenhagen Session how far 13: to (Foot/ankle) the promised land? Helsinki/Oslo 12:00 13:00 Niels Frokost Wedderkopp i udstillingen Stockholm/ Injuries in childhood, are Copenhagen 12:00 12:30 Debatmøde: traumas the Proteseinfektioner tip of the iceberg? Directors 13:00 14:30 Torben Session Bæk 14 Hansen (Foredragskonkurrence) Total joint arthroplasty of the trapeziometacarpal joint Helsinki/Oslo Reykjavik/Stockholm/ Copenhagen/Helsinki/ Oslo 11:00-11:30 Kaffe i udstillingen 14:30 15:30 Uddelinger: Stockholm/ 11:30-12:30 Guildal forelæsning: Stockholm/ Copenhagen/Helsinki/ Professor Tim Davis Helsinki/ Oslo Oslo DOS Degenerative Fonden diseases Guildal of the Fonden hand Vindere af foredrag og posterkonkurrence 12:30-13:30 Frokost i udstillingen 15:30 16:00 Kaffe og Adjourn Capital Foyer DOS Kongressen 2014 11 21

Dagsprogram Fredag 24. oktober 2014, fortsat Lokale: 13:30 09:00-15:00 10.30 Session 13 10a (Hip/knee) Stockholm/Copenhagen Reykjavik (Foredragskonkurrence) Helsinki/ Oslo Session 10b (Trauma) Reykjavik 15:00-16:00 Uddelinger: Stockholm/Copenhagen Session DOS 11 Fonden (Spine) Helsinki/Oslo Stockholm/Copenhagen Guildal Fonden Session Vindere 12 (Pediatrics) af foredrag og Helsinki/Oslo posterkonkurrence 10:30-11:00 Professorforelæsninger: 16:00-16:30 Anders Kaffe Troelsen Capital Reykjavik Foyeren The perfect treatment by hip and knee arthroplasty how far to the promised land? Niels Wedderkopp Stockholm/ Injuries in childhood, are Copenhagen traumas the tip of the iceberg? Torben Bæk Hansen Total joint arthroplasty of the trapeziometacarpal joint Helsinki/Oslo 11:00-11:30 Kaffe i udstillingen 11:30-12:30 Guildal forelæsning: Stockholm/ Copenhagen Professor Tim Davis Helsinki/ Oslo Degenerative diseases of the hand 12:30-13:30 Frokost i udstillingen 12 DOS Abstracts DOS Kongressen 2014 21

Session 1: Hip Sports/ Onsdag den 22. oktober arthroscopy 09:00 10:30 Lokale: Onsdag Reykjavik den 23. oktober 09:00 10:00 Chairmen: lokale: Stockholm/Copenhagen Nanna Sillesen Hylleholt / Mogens Berg Laursen 1. Chairmen: Prosthetic Kristoffer Joint Infection Barfod/Martin (PJI): Bacterial Lind Identification with Heat Flow Detection in Sonication Fluid of Removed Total hip or knee Arthroplasty (THA/TKA) Christen 1. The Ravn, influence Michael of Kemp, early Per weight-bearing Kjærsgaard-Andersen, after Søren non-operative Overgaard treatment of acute Achilles tendon rupture on biomechanical properties of 2. the Revision plantar-flexor risk of cementless muscle-tendon metal-on-metal complex. A blinded, total hip randomized, arthroplasty controlled trial. is influenced by component brand Claus Jesper Varnum, Bencke, Alma Kristoffer B. Pedersen, W Barfod, Mäkelä Hanne Keijo, Bloch Leif Lauridsen, Ivar Havelin, Christian Johan Kärrholm, Dippmann, Søren Lars Ebskov, Overgaard Anders Troelsen 3. 2. Regional Reconstruction differences of the between medial patellofemoral US and Europe ligament in radiological in adolescents osteoarthritis with open and growth self assessed plates quality of life in patients undergoing Total Hip Ditte Replacement Enderlein, Torsten (THR) Nielsen, surgery Peter Faunø, Svend Erik Christiansen, Martin Kirill Lind Gromov, Meridith Greene, Nanna Sillesen, Peter Gebuhr, Anders Troelsen, Henrik Malchau 3. Traction related complications during hip arthroscopy. 4. Lone The Frandsen, true incidence RN, Bent Lund, of prosthetic M.D, Svend joint Erik Christiansen, infection after M.D, 32,896 Torsten Grønbech primary total Nielsen, hip PT, arthroplasties: Martin Lind, Prof. A prospective M.D cohort study Per Hviid Gundtoft, Søren Overgaard, Henrik Carl Schønheyder, Jens Kjølseth Møller, 4. ACL Per reconstruction Kjærsgaard-Andersen, in children. Alma Becic Results Pedersen from the Danish Registry for Knee Ligament Reconstruction 5. Peter Comparison Faunø, Lene of Wagner, outcomes Martin and Lind complications of hip arthroscopy for mixed hip disorders in adolescents versus adults: a prospective cohort study 5. Outcome after posterior cruciate ligament (PCL) reconstruction. Manoj Bjarne Ramachandran, Mygind-Klavsen, Pramod Svend Erik Achan, Christiansen, Martin Gottliebsen, Bent Lund, Peter Bjarne Faunø, Møller- Mads Madsen Uldum Roesgaard, Martin Lind 92 DOS Bulletin DOS Kongressen 2014 2013 13 89

6. 6. Clinical Higher outcome UHMWPE after wear PCL rate support in cementless bracing compared treatment with for cemented patients with cups acute with posterior the Saturne cruciate Dual-Mobility ligament injury system. Sinan Steffan Said, Tabori Martin Jensen, Lind, Morten Torsten Homilius, Grønbech Christina Nielsen, Frølich, Christina Torben Mikkelsen, Bæk Hansen, Bjørn Engstrøm Maiken Stilling 7. 7. A Early validation morbidity study after of aseptic the Danish revision Knee hip arthroplasty Ligament Reconstruction in Denmark. A Registry. 2 year nationwide study. Lene Martin Rahr-Wagner, Lindberg-Larsen, Theis Thillemann, Christoffer Martin Calov Lind, Jørgensen Alma Pedersen, Torben Bæk Hansen, Søren Solgaard, Henrik Kehlet 8. Patient reported outcome are strongly associated by lower limb loading 8. Promising pattern, mechanical migration Pattern strength, at 1 and year functional follow-up performance of the short in Primoris ACLpatients Femoral Stem a cross-sectional study. Anders Mogens Holsgaard-Larsen, Berg Laursen, Janus Carsten Duus Jensen, Christiansen, Per Aagaard Gordon Blunn, Poul Torben Nielsen 9. Fast-track pathway for reduction of dislocated Hip Arthroplasty reduces surgical delay and length of stay Kirill Gromov, Fatin Willendrup, Henrik Palm, Anders Troelsen, Henrik Husted 10. Re-revision rates following revision of cemented and cementless primary hip arthroplasty Kirill Gromov, Alma Pedersen, Søren Overgaard, Peter Gebuhr, Henrik Malchau, Anders Troelsen 11. Can hip surgeons code periprosthetic joint infection? A cross-sectional study of data validity in the Danish National Patient Registry. Jeppe Lange, Alma B. Pedersen, Anders Troelsen, Kjeld Søballe 12. No association between pseudotumors, high serum metal-ion levels and metal hypersensitivity in large-head metal-on-metal total hip arthroplasty at 5-7-year follow-up Mette Holm Hjorth, Maiken Stilling, Kjeld Søballe, Lars Hans Bolvig, Inger Mechlenburg, Stig Storgaard Jakobsen 14 90 DOS Bulletin Abstracts DOS Kongressen 2014 93

Session 2: Sportstrauma Hip 1 Ondag Onsdag den den 22. 23. oktober 09:00 10:30 Lokale: lokale: Stockholm/Copenhagen Helsinki/Oslo Chairmen: Morten Stig Storgaard Boesen Morten Jakobsen/Per / Michael Kjærsgaard-Andersen Rindom Krogsgaard 13. Is the use of oral contraceptives associated with operatively treated anterior 9. Microbiologic cruciate ligament diagnosis injury? based A case-control implant sonication study from in hip the and Danish knee Registry arthroplasty of Knee revision Ligament surgery Reconstruction Lene Christen Rahr-Wagner, Ravn, Michael Theis Kemp, Thillemann, Per Kjærsgaard-Andersen, Frank Menhert, Alma Søren Pedersen, Overgaard Martin Lind 10. A Randomized controlled Radiostereometric study comparing a 14. novel Limited porous Osteochondral titanium construct Repair to by a a porous Biomimetic coated Collagen surface Scaffold in cementless to total Three knee Years arthroplasty Clinical and Radiological Follow-Up - One Bjørn Nikolaj Christensen, Sebastian Casper Winther, Foldager, Claus Niels Lindkær Christian Jensen, Jensen, Thomas Cody Lind, Bünger, Claus Martin Munk Lind Jensen, Henrik Schrøder, Michael Mørk Petersen 15. 11. One-year The revision follow-up risk of after 28480 ACL primary reconstruction total hip replacements surgeon or physical (THR) in therapist patients? younger than 55 years of age. Results from the Nordic Arthroplasty Wieland Register Nielsen, Association Kirsten Bettina (NARA) Jensen, Jonathan Jetsmark Bjerre, Peder Ina Klement Alma B. Jensen, Pedersen, Michael Frank R. Mehnert, Krogsgaard Ove Furnes, Leif Havelin, Johan Kärrholm, Søren Overgaard 16. The association between patient-reported outcomes and physical outcome 12. What measures do patients in Danish perceive patients as important one year preoperative after anterior information cruciate in ligament total hip- reconstruction and knee arthroplasty? Jonathan Jonas Vestergård Comins, Bettina Iversen, Jensen, Henrik Ina Husted, Wieland Mira Nielsen, Jørgensen, Volkert Anders Siersma, Troelsen Michael Krogsgaard 13. Fall-related readmissions after fast-track total hip and knee arthroplasty, Previous cause knee-injury of concern and or consequence low knee function of success? score increase risk of 17. future Christoffer knee Jørgensen, injury in adolescent Henrik Kehlet female football Mikkel Bek Clausen, Lars Tang, Mette Kreutzfeldt Zebis, Peter Krustrup, Per Hölmich, 14. Factors Kristian Influencing Thorborg Health-related Quality of Life after Total Hip Replacement - a comparison of data from the Swedish and the Danish Hip Arthroplasty Registers Max Gordon, Aksel Paulsen, Søren Overgaard, Göran Garellick, Alma B Pedersen, Ola Rolfson 94 DOS Bulletin DOS Kongressen 2014 2013 15 91

15. 18. Patient Significant compliance role on and rotatory findings stability of hip of pain, the elevated anterolateral metal ligament ion levels in and ACL revision insufficient surgery knees during a centrally mandated recall of patients with Metal-on-Metal Mette Tavlo, Salameh articulations. Eljaja, Jørgen Tranum-Jensen, Volkert Siersma, Michael Malchau Rindom Erik, Krogsgaard Peter Gebuhr, Kristian Otte, Tommy Korsgaard Larsen, Anders Troelsen 19. Redislocation after conservative treatment of primary patellar dislocations Treatment of a displaced femoral neck fracture cemented vs un- 16. cemented Bo Kaewkongnok, femoral Anders stem Bøvling, total hip Celia arthroplasty Møllenborg, Bjarke Viberg, Lars Blønd Michelle Fog Andersen, Thomas Jakobsen, Anne Soon Bensen, Niels Krarup 20. Do ACL patients suffer from comorbidity and is there any association Neck between narrowing comorbidity and BMC and after the resurfacing, risk of ACL 2 revision year result surgery? from a A ran- na- 17. domised tionwide study population-based case-cohort study of 13,443 ACL reconstructed That Pham, patients Jeannette Penny Minh Lene Rahr-Wagner, Theis Thillemann, Martin Lind, Alma Pedersen 18. No association between serum metal-ions and implant fixation in large-head 21. Autologous metal-metal Dual Tissue THA. Transplantation A 5 year RSA study for Osteochondral repair - Mette One Year Holm Clinical Hjorth, Kjeld and Radiological Søballe, Stig Storgaard Follow-Up Jakobsen, Nina D Lorenzen, Inger Bjørn Mechlenburg, Christensen, Maiken Casper Stilling Foldager, Martin Lind 19. 22. Can Posterior the need cruciate for Arthroscopy ligament be reconstruction predicted in Patients in skeletal undergoing immature Periacetabular children; a case Osteotomy? series of six patients. Charlotte Ole Gade Hartig-Andreasen, Sørensen, Peter Faunø, Anders Svend Troelsen, Erik Christiansen, Theis Muncholm Martin Thillemann, Lind John Gelineck, Kjeld Søballe 23. Testing basic competency in knee arthroscopy using a virtual reality simulator: Exploring reliability and validity Mads Emil Jacobsen, Morten Jon Andersen, Claus Ol Hansen, Lars Konge 24. Treatment of posterior cruciate ligament tear combined with postero-lateral instability in skeletal immature children. Ole Gade Sørensen, Peter Faunø, Svend Erik Christiansen, Martin Lind 16 92 DOS Bulletin Abstracts DOS Kongressen 2014 95

Session Postersession 3: Hand/wrist I Ondag Onsdag den den 22. 23. oktober 09:00 11:00 10:30 12:00 Lokale: lokale: Helsinki/Oslo Reykjavik Chairmen: Jesper Jeannette O. Schønnemann Østergaard Penny/Ole / Pernille Leicht Ovesen 25. Increased migration and more revisions of MOTEC compared with ELECTRA 139. No cups. increased A 2-year risk of RSA elevated study of metal trapeziometacarpal ions and pseudotumour prostheses formation when Stilling, using Torben modular Bæk-Hansen neck-stems bilaterally Maiken Peter Revald, Claus Varnum, Poulsen Thomas K., Per Kjærsgaard-Andersen 26. High early revision rate in a new cemented polyethylene cup in trapeziometacarpal 140. Body composition total joint preoperatively arthroplasty has no impact on clinical outcome Knak, after Torben hip arthroplasty Bæk Hansen - A cohort study of 102 patients 1year af- Jens ter surgery 27. Anette Test-retest Liljensøe, reliability Jens Ole Laursen, of Antonovsky s Kjeld Søballe, 13-item Inger Mechlenburg Sense of Coherence scale in patients with hand-related injures Alice 141. Ørts 3 year Hansen, Follow-up Hanne Kaae of a Long-term Kristensen, Ragnhild Registry-based Cederlund, Multicenter Hans Tromborg study on Vitamin E Diffused Polyethylene in Total Hip Replacement 28. Nanna Skin H. tear Sillesen, correlates Meridith to E. the Greene, degree Audrey of K. contracture Nebergall, Anders when Troelsen, treated Peter for Dupuytrens Gebuhr, Henrik contracture Malchau with Xiapex Christian Fagernæs, Susanne Mallet 142. Effect of early progressive resistance training compared to home 29. based Long-term exercise effect after of fast surgery track for total thumb hip in replacement. palm in adolescent A randomised cerebral controlled palsy patients. trial. Hans Lone Tromborg, Ramer Mikkelsen, Alice Ørts Inger Mechlenburg, Kjeld Søballe, Søren Mikkelsen, Thomas Bandholm, Mette Krintel Petersen 30. Short term results of the Maestro Total Wrist Arthroplasty for primary 143. and 3 revision months arthroplasty home-training by a standardized program improves Allan walking Ibsen distance Søensen, and Peter knee Axelsson extension strength in old patients 1-7 years after surgery with dual-mobility THA following femoral neck fracture. 31. Christina Trapezium Frølich, resection Inger Mechlenburg, vs. cemented Sara cup Birch, revision Lone in Lundager, cup failures Torben of the Bæk trapeziometacarpal Hansen, Maiken Stilling total joint prostheses of the thumb Jens Knak, Torben Bæk Hansen 144. Preoperative planning in cementless total hip arthroplasty - Accuracy of digital templating Mikkel Krüger Jensen, Søren Solgaard 96 DOS Bulletin DOS Kongressen 2014 2013 17 93

145. 32. Xiapex Timing of (collagenase preoperative clostridium prophylactic histolyticum) antibiotics for treatment knee arthroplastiestients with A quality recurrence-dupuytren s study after the introduction contracture of 1 the year WHO follow-up checklist of pa- with Søren a standard Larsen, Karina time-out Liv Hansen, before Tune skin Ipsen, incision. Jens Lauritsen Arne Svensson, Lars Peter Jorn 33. Long - term results of total joint arthroplasties with Elektra prothesis in No trapeziometacarpal correlations between osteoarhritis radiological angles and self-assessed 146. Quality Barbara of Kulinski Life in patients with Hip Dysplasia at 2-13 years of follow up after periacetabular osteotomy Sara 34. Birch, Equally Anette good Liljensøe, methods Charlotte for determination Hartig-Andreasen, of bone Kjeld quality Søballe, of the Inger trapezium Mechlenburg Kamille Breddam Mosegaard, Nadja Bouteldja, Maiken Stilling, Torben Bæk 151. Hansen Collateral Ligament Reconstruction of the Chronic Thumb Injury with Biotenodesis Screw Fixation Robert 35. Complication Gvozdenovic, rates Michel following Boeckstyns volar plating of distal radius fractures in relation to fracture pattern and surgeon experience. 154. Andreas Erythropoietin Qvist Christensen, elicits Nina a dose-dependent Madsen, Erik Valen, osteogenic Casper Bindzus effect Foldager on human mesenchymal stem cells Jan 36. Duedal Short Rölfing, term result Anette of Baatrup, a stable Maik modified Stiehler, Brunelli Helle Lysdahl, 360 degree Cody Bünger technique for reconstruction of scapho-lunate ligament. 155. Allan The Ibsen influence Sørensen, of Jonny hemostatic Andersson agents on bone healing after sternotomy in a porcine model Rikke Falsig Vestergaard, Annemarie Brüel, Jesper Skovhus THomsen, Ellen Margrethe Hauge, Kjeld Søballe, John Michael Hasenkam 18 94 DOS Bulletin Abstracts DOS Kongressen 2014 97

Postersession III Onsdag den 22. 23. oktober 11:00 12:00 Lokale: lokale: Reykjavik Stockholm/Copenhagen Chairmen: Morten Henrik Eckardt/Lars Bøgehøj / Henrik Konradsen Morville Schroeder 139. One-year evaluation: Is there effect of 8 weeks supervised progressive 158. Results resistance after training plate removal after in unicompartmental midshaft clavicle knee fracture arthroplasty? Focus on coexsisting soft-tissue shoulder injuries. surgery: Peter Ban Ilija, Bo Jørgensen, Poulsen Heidi, Søren Troelsen Bie Bogh, Anders Signe Kierkegaard, Henrik Sørensen, Kjeld Søballe, Inger Mechlenburg 159. Early experiences with the DHS blade in treating femoral neck 140. fractures Is gait velocity and gait quality associated with hip muscle strength in Rasmus hip osteoarthritis Stokholm, Lise patients Hellegaard, scheduled Steffen for Skov total Jensen hip arthroplasty? Signe Rosenlund, Dennis Brandborg Nielsen, Søren Overgaard, Carsten Jensen, Anders 160. Holsgaard-Larsen Retrospective review of radiographic referral, interpretation and treatment plan in a Danish emergency department in comparison to an 141. international Objectively benchmark. measured physical activity reference data obtained from Mohamed a Dutch Shalaby, population Wajeha with Malik, a three-axial Christine Hilbrandt, accelerometer Valentina Makolli, Thomas Signe HoueKierkegaard, Inger Mechlenburg, Bernd Grimm, Ide Heyligers, Rachel Senden 161. Feasibility of progressive strength training immediately after hip 142. fracture Validation surgery. of intraoperative reported angle measurements in periactabular Lise Kronborg, osteotomy Thomas Bandholm, Henrik Palm, Henrik Kehlet, Morten Tange Sepp Kristensen de Raedt, Inger Mechlenburg, Maiken Stilling, Marleen de Bruijne, Lone Rømer, Kjeld Søballe 167. Surgery for Kyphoscoliosis in Parkinson s Disease 143. Ebbe Safety Stender of Hansen, Vitamin Dharmendra E infused Singh, high wall Cody liners Bünger for routine use in primary THA: Single center, short term follow-up of 767 cases Nanna 168. The Sillesen physical Hylleholt, and Christopher mental outcome Barr J., of Peter 100 patients Gebuhr, Henrik having Malchau, a Percutaneous Husted, Vertebroplasty Troelsen Anders because of pathological vertebral fractures. Henrik Søren Lykke Lorentzen, Rikke Rousing, Stephan Hummel 144. Acetabular dysplasia increases risk for malpositioning of the acetabular component in Total Hip Arthroplasty (THA) Kirill Gromov, Meridith Greene, Christopher Barr, Peter Gebuhr, Henrik Malchau, Anders Troelsen 98 DOS Bulletin DOS Kongressen 2014 2013 19 95

172. 145. Artificial High frequency Meniscal of scaffold cystic pseudotumors Implantation and in large-head Meniscal metal-onmetal total hip arthroplasty at 5-7 years follow-up. Allograft Transplantation. Martin Mette Rathcke, Holm Hjorth Peter, Lavard, Niels Egund, Michael Inger Krogsgaard Mechlenburg, Stig Storgaard Jakobsen, Kjeld Søballe, Maiken Stilling 173. Does bony hip morphology affect the outcome of treatment for patients 146. Radiologic with adductor-related and histologic groin appearance pain? Long of metal-bone term results interphase of a ran-idomised failed tibial controlled component trial. in total knee arthroplasty. A retrieval study. Per Tue Hölmich, Smith Jørgensen, Kristian Thomas Thorborg, Lind, Per Henrik Nyvold, Schrøder, Jakob Eva Klit, Balslev Michael Bachmann Nielsen, Anders Troelsen 147. Hip arthroplasty with the Primoris stem Bone remodelling 174. around Custom-made a short femoral orthotics neck stem decrease medial foot loading during drop jump Janus and Duus single-leg Christiansen, squat Lauersen in individuals Mogens with Berg, patellofemoral Gordon Blunn, pain Poul Torben Michael NielsenRathleff, Camilla Richter, Jesper Bencke, Thomas Bandholm, Per Hölmich, Kristian Thorborg 148. Prevalence of kidney dysfunction at elective total hip arthroplasty 175. operations. DHAR the Danish Hip Arthroscopy Register Bent Helene Lund, Berg-Nielsen, Søren Winge, Morten Otto Kraemer, Boye Petersen, Svend Erik Mette Christiansen, Brimnes Martin Damholt, LindSøren Solgaard 149. Average cyst volume per cyst-patient decreases over a 10-year period after periacetabular osteotomy Inger Mechlenburg, Jens R. Nyengaard, John Gelineck, Kjeld Søballe 20 96 DOS Bulletin Abstracts DOS Kongressen 2014 99

Postersession IIII Onsdag den 22. 23. oktober 11:00 12:00 Lokale: lokale: Stockholm/Copenhagen Helsinki/Oslo Chairmen: Thomas Peter Holmberg Jakobsen Jørgensen/Stig / Kjeld Søballe Brorson Hansen 154. Pain distribution in primary care patients with hip osteoarthritis a 176. descriptive Tendon study and skeletal muscle matrix gene expression and functional Erik responses Poulsen, Søren to immobilization Overgaard, Jacob and Toft rehabilitation Vestergaard, in Henrik young Wulff males: Christensen, Effect of Jan growth Hartvigsen hormone administration Anders Ploug Boesen, Kasper Dideriksen, Peter Schjerling, Christian Couppe, 155. Michael The Kjaer, effect Henning of periacetabular Langberg osteotomy (PAO) on the clinical outcome in patients with retroverted acetabulum - a prospective cohort study 181. Comparison of Two Humeral Head Resurfacing Implants. 2 year Results of Schmiegelow, a Randomized Bjarke Controlled Løvbjerg Clinical Viberg, Ole Trial Ovesen, Søren Overgaard Victoria Inger Mechlenburg, Thomas Klebe, Kaj Døssing, Kjeld Søballe, Maiken Stilling 156. Evaluation of bone mineral density and bone markers in femoral amputees 182. Clinical prior implications to osseointegrated of positive implant cultures surgery in revision shoulder arthroplasty Lessmann Hansen, Peter Holmberg Jørgensen, Kjeld Søballe, Klaus Kjær Rehne Petersen, Thomas Falstie-Jensen, Maiken Stilling Janne Ovesen, Viggo S. Johannsen 157. 184. Amputation Construct validity after failed and responsiveness knee arthroplasty of functional measures used Tinne subjects B Gottfriedsen following Tinne an outpatient Brandt Gottfriedsen, prosthetic Anders rehabilitation Odgaard program Anders Odgaard, after a major Henrik lower M Schrøder limb amputation Henrik Morville Schrøder Kajsa Lindberg, Joanne Boelskifte, Jimmy Johansson, Mie Rinaldo, Morten Tange 158. Kristensen Acceptable agreement between Inertia-based Measurement Unit and Optical Motion Capture System applied in quantitative measurement 185. of Pneumococcal physical function sepsis-induced in patientssymmetrical Peripheral Gangrene Inger Taj Haubuf, Mechlenburg, Klaus Kjær Peter Petersen, Bo Jørgensen, Kurt Fuursted, Henrik Alex Sørensen, Lund Laursen, Dennis Johnny B Nielsen, Keller Bernd Grimm, Kjeld Søballe 186. Ultrasound guided core needle biopsy of peripheral nerve sheath 159. tumors. Intervertebral A retrospective disc degenerative study. changes after intradiscal injection Damgaard of TNF-α Jacob, in a Hauge porcine Hansen model Bjarne, Holmberg Jørgensen Peter, Keller Johnny, Kang, Hellfritzch Haisheng Michel, Li, Kresten Baad-Hansen Rickers, Thomas Steffen Ringgaard, Lin Xie, Cody Ran Bünger 100 DOS Bulletin DOS Kongressen 2014 2013 21 97

187. 160. Local A month Recurrence of heavy Rate resistance after Surgical exercise Excision increases of Desmoid the amount Fibro-omatosis. Collagen XIV in the endomysium close to the human MTJ Elinborg Jens Rithamer Mortensen, Jakobsen, Thea Hovgaard, Abigail Mackey, Michael Mørk Andreas Petersen Knudsen, Manuel Koch, Michael Kjaer, Michael Rindom Krogsgaard 188. Persistent wound drainage after tumor resection and endoprosthetic 161. reconstruction Pharmacokinetics the of proximal vancomycin femurin porcine bone obtained by microdialysis Horstmann, Werner Hettwer, Tomas Grum-Schwensen, Michael Mørk Pe- Peter tersen Mats Bue, Hanne Birke-Sørensen, Theis Muncholm Thillemann, Kjeld Søballe, Mikkel Tøttrup 190. Testing A New Type Of Osteosynthesis And After Care In Treatment 162. Of Collagen Antebrachium types and Fractures distribution in Children, at the human Preliminary myotendinous Result Of junction (MTJ) Case-Control Study. A Prospectiv Ture Jens Karbo, Rithamer Stig Sonne-Holm, Jakobsen, Abigail Christian Mackey, Wong Andreas Knudsen, Manuel Koch, Michael Kjaer, Michael Rindom Krogsgaard 191. Normal distribution of seating balance for healthy Danish children Line 163. Kjeldgaard Can gait Pedersen, deviation Ahmed index Abdul-Hussein be used effectively Abood, Ole for Rahbek, the evaluation Bjarne Møller-Madsen of gait pathology in total hip arthroplasty? An explorative randomized trial 192. Carsten Hamstring Jensen, lengthening Signe Rosenlund, in CP Dennis patients B. Nielsen, by needle Søren tenotomy Overgaard, is safe Anders Lauge Holsgaard-Larsen Østergaard, Gert Rahbek Andersen 164. Validation and inter-tester reliability of a tri-axial accelerometerbased classification of daily activities Marianne Tjur, Kenneth Juul Laugesen, Kamilla Nygaard Jensen, Mads Grosmann Svendsen, Inger Mechlenburg, Signe Kierkegaard 22 98 DOS Bulletin Abstracts DOS Kongressen 2014 101

Postersession Session 3: Knee III Onsdag Torsdag den den 22. 24. oktober 11:00 09:00 12:00 10:30 Lokale: lokale: Helsinki/Oslo Stockholm/Copenhagen Chairmen: Jeannette Poul Torben Ø. Nielsen/Henrik Penny / Anders Schröder Troelsen 165. Does an intensive alcohol cessation intervention at the time of fracture 20. Does surgery safe-zones induce spontaneous for alignment smoking and component cessation? position - The Scand- exist in Ankle primary study TKA? Erika Morten Wernheden, Grove Thomsen, Marianne Henrik Aalykke, Husted, Bolette Thor Bechsgaard, Pedersen, Julie Anders W. Troelsen M. Egholm, Hanne Tønnesen 21. Is fast-track total knee arthroplasty safe regarding manipulation 166. for unacceptable Compression knee in Anklefracture flexion? Treatment, the CAT-study Rikke Christian Winge, Wied, Stig Morten Sonne-Holm, Grove Thomsen, Camilla Ryge Lis Myhrmann,, Hans Gottlieb, Lotte Lasse Skov Bayer Jensen, Henrik Husted, Anders Troelsen 167. Characteristics of non-participants in orthopaedic research A study 22. Similar of patients Fixation undergoing but Increased ankle fracture Stress-Shielding surgery and of an declining I-Beam participatiopared with in a randomized Finned Tibial clinical Component trial Stem Design. A Randomized RSA com- Marianne and DXA Aalykke, Study with Erika 5 Wernheden, years Follow-up. Bolette Pedersen, Julie Weber Melchior Egholm, Maiken Hanne Stilling, Tønnesen Claus Fink Jepsen, Lone Rømer, Ole Rahbek, Kjeld Søballe, Frank Madsen 168. Early Complications of Ankle Fractures Following Treatment with Ilizarov 23. Absence External of Fixator tourniquet or Open does Reduction not affect Internal fixation Fixation and stability of cemented Roslund TKA:, a Matilda randomised Svenning, controlled Michael trial Brix, using Morten RSA Schultz Larsen Josefin Ashir Ejaz, Anders C. Laursen, Andreas Kappel, Sten Rasmussen, Mogens B. Laursen, Poul Knee T. Joint Nielsen Loading Indices Before and 3 Months after Arthroscopic 174. Partial Medial Meniscectomy Jonas 24. A B. questionnaire Thorlund, Mark survey W. Creaby, regarding Martin the Englund, Danish Nis activity Nissen, on L. axis Stefan corrective osteotomy Anders Holsgaard-Larsen (ACO) in treatment of uni-compartmental knee os- Lohmander, teoarthritis 177. Toke Outcome Kirchberg and Nilsson, risk of Andreas revision Kappel, after Anders shoulder Christian replacement Laursen, in Poul patients Torben with Nielsen osteoarthritis: 1,209 cases from the Danish Shoulder Arthroplasty Registry Jeppe Rasmussen, Anne Polk, Anne Kathrine Belling Sørensen, Bo Sanderhoff Olsen, Stig Brorson 102 DOS Bulletin DOS Kongressen 2014 2013 23 99

25. 181. Early Biomechanical full weight-bearing symmetry in open-wedge of a hip joint altered high tibia by valgus Perthes osteotomy: Remel A randomized, Salmingo, Tina controlled Skytte, Marie RSA trial Sand with Traberg, 2 years Kaj-Åge follow-up Henneberg, Klaus disease Anders Hindsø, Christian Laursen, Wong Thomas Lind-Hansen, Mogens Berg Laursen, Poul Torben Nielsen 184. The EOS imaging system: Workflow and radiation dose in scoliosis 26. examinations Similar and good fixation of cementless and cemented Oxford Partial Bo Knee Mussmann, Tibial Trays Stig Jespersen, at 2 years Trine follow-up. Torfing A Randomized RSA Study. Maiken Stilling, Frank Madsen, Claus Fink Jepsen, Kjeld Søballe, Per Wagner Kristensen, 185. Stand-alone Anders Odgaard XLIF; 22 Consecutive patients with degenerative scoliosis and foraminal stenosis a 2 year follow-up 27. Emil How Hansen does strength training influence knee joint pain shortly following total knee arthroplasty? Thomas 186. Early Bandholm, surgical Kristian stabilization Thorborg, of rib Troels fractures Haxholdt using Lunn, a minimally Henrik Kehlet, invasive procedure: Linding Jakobsen a pilot study Thomas Kiran Anderson, Jesper Ravn, Henrik Eckardt 28. Early outcome after aseptic revision total knee arthroplasty in Denmark. 192. A Ewings sarcoma 2 year nationwide of the study. calcaneus treated by limb sparing surgery Martin with calcanectomy Lindberg-Larsen, and Christoffer reconstruction Calov Jørgensen, with a composite Torben Bæk of Hansen, allograft Søren Solgaard, and a vascularised Anders Odgaard, osteocutaneous Henrik Kehletfibula graft. Werner Hettwer, Lisa Toft Jensen, Michael Mørk Petersen 29. Current trends of TKA fixation and cruciate ligament retention: Are surgeons on track? Erik Malchau, Kirill Gromov, Henrik Husted, Henriks Malchau, Anders Troelsen 30. Tourniquet induced ischemia and changes in metabolism during TKA: a randomised controlled trial using microdialysis Ashir Ejaz, Anders C. Laursen, Andreas Kappel, Poul T. Nielsen, Sten Rasmussen 24 100 DOS Abstracts Bulletin DOS Kongressen 2014 103

Session 4: Foot/ankle Trauma 1 Torsdag den 23. 24. oktober 09:30 09:00 10:30 Lokale: lokale: Reykjavik Helsinki/Oslo Chairmen: Jørgen Lonnie Baas Froberg/Frank / Johnny Frøkjær Damborg 37. Postoperative oxygenation and metabolism of the soft tissue covering 31. total Does ankle choice replacement of treatment of midshaft clavicle fractures affect early Frank return Linde, to work? Niels Christian Jensen, Kristian Kibak Nielsen, Hanne Birke- Sørensen Ban Ilija, Gromov Kirill, Troelsen Anders 38. 32. Completeness Feasibility of and implant-tracking data validity in the in orthopaedic Danish Achilles surgery: Tendon High Rupture completeness and minimal time consumption. Database Michael Heidi Poulsen, Bilde Kuhlman, Kirill Gromov, Anders Peter Troelsen, Gebuhr, Kristoffer Anders Barfod Troelsen 39. 33. Survival Virtual-reality of 308 total simulation ankle for replacement. the assessment A 1-14 of years skills in follow-up. hip fracture Niels surgery Chr. Jensen Poul Pedersen, Henrik Palm, Lars Konge 40. Five year survival rate of STAR ankle replacement Johnny 34. Breakage Frøkjær, Lasse at the Petersen proximal screw in long Gamma 3 titanium intramedullary femoral nail 41. Nikolaj No correlation Sode, Lonnie between Froberg, Michael Bone cyst Brix volume and clinical symptoms in patients with ankle replacement Ellen 35. Hamborg-Petersen, Anamnestic medicine Trine errors Torfing, among Janni Jensen, hip fracture Johnny patients Frøkjær can be reduced by a pharmacist / pharmaconomist 42. Morten Clinical B. Andersen, outcome Sanne in 308 H. total Johansen, ankle Marianne replacement. K. Jensen, A 1-14 Lise J. years Nørregaard, follow-up. Susanne D. Olsson, Henrik Palm Kristian Kibak Nielsen, Niels Christian Jensen, Claus Sundstrup, Frank Linde 36. Ilizarov salvage procedure following failed osteosynthesis of the 43. patella Functional rehabilitation of patients with acute Achilles tendon rupture: Tine A Nymark, meta-analysis Lars Schjøtz, of current Ole Skovevidence. Kristoffer Weisskirchner Barfod, Troels Mark-Christensen, Thomas Kallemose, Anders 37. Healing Troelsenand morbidity in femoral and tibial non-unions when using reamer-irrigator-aspirator system Søren Kjær Petersen, Morten Schultz Larsen 104 DOS Bulletin DOS Kongressen 2013 2014 101 25

38. 44. Preoperative Severely reduced CT scan functional of tibial diaphyseal outcome at fractures mean 9 year distal follow-up to the isthmuter influences complications treatment associated with acute Achilles tendon rupture af- Paulius Kristoffer Nekrasas, Weisskirchner Juozas Petruskevicius, Barfod, Thor Søren Magnus Kold Sveen, Ann Ganestam, Lars Bo Ebskov, Marko Nabergoj, Anders Troelsen 39. Health related quality of life after severe trauma comparison of EQ-5D with norm scores 15 years after injury Thomas Laursen, Morten Wad, Sidsel Fruergaard, Claus Falck Larsen, Benny Dahl 40. Complications after osteosynthesis of distal radius fractures using a volar locking-plate Roland Knudsen 41. Urinary tract infections and complications among hip fracture patients treated within a multimodal rehabilitation concept Pia Søe Jensen, Nicolai Bang Foss, Ulrich Stab Jensen, Dorthe Gaby Bove, Henrik Palm, Henrik Kehlet 26 102 DOS Abstracts Bulletin DOS Kongressen 2014 105

Session 5: Shoulder/elbow Experimental Torsdag den 23. 24. oktober 09:30 11:00 10:30 12:00 Lokale: lokale: Stockholm/Copenhagen Helsinki/Oslo Chairmen: Theis Casper Tillemann Bindzus / Foldager/Martin Steen Lund Jensen Lind 45. Physiotherapy improves patient reported shoulder function and health 42. status Vancomycin patients is superior with subacromial to active/passive impingement immunization syndrome against Filip Staphylococcus Holst Storgaard, aureus Christina periprosthetic Gravgaard Pedersen, osteomyelitis Majbritt in Lykke ratsjensen, Steen Lund Niels Jensen H. Søe, Nina Vendel-Jensen, Asger Lundorff Jensen, Janne Koch, Steen Seier Poulsen, Helle Krogh Johansen 46. Persistent pain after shoulder replacement: A nationwide questionnaire 43. Leukocyte-depletion study. in PRP decreases the proliferative effects of Karen human Toftdahl chondrocytes Bjørnholdt, Birgitte Brandsborg, Kjeld Søballe, Lone Nikolajsen Morten Lykke Olesen, Martin Lind, Helle Lysdahl, Casper Bindzus Foldager 47. Pitfalls in the self-management of pain after outpatient surgery: An exploratory 44. Local Delivery analysisof Anticancer Drug to Treat Primary Breast Cancer Karen and Bone Toftdahl Metastasis Bjørnholdt, Lone Dragnes Brix, Lone Nikolajsen Ming Sun, Miao Wang, Muwan Chen, Frederik Dagnaes-Hansen, Michael Robert 48. Horsman, Frozen Cody shoulder Eric Bünger - appearance in the electron microscope Mads Okholm, Abigail Mackey, Klaus Qvortrup, Jens Jakobsen, Thomas Hansen, Michael 45. The Krogsgaard concentration of cefuroxime in cortical and cancellous bone can be detected by use of microdialysis a methodological study 49. Mikkel Anatomical Tøttrup, changes Hanne Birke in the Sørensen, aging sternoclavicular Tore Forsingdal Hardlei, joint Kurt Fuursted, Martin Kjeld Søballe Wyman Ratchke, Jørgen Tranum-Jensen, Michael R. Krogsgaard 50. 46. Latissimus Systematized Dorsi Water Tendon Content Transfer Calculation for Irreparable in Cartilage Posterosuperior Using T1- Rotator mapping Cuff MR Tears. Estimations. A retrospective Design of study a Mathematical of 38 Cases Model. Magnús Juan Manuel Pétur Bjarnason Shiguetomi-Medina, Obinah, Theis Jose Muncholm Luis Ramirez-GL, Thillemann, Ole Janne Rahbek, Ovesen, Hans Brian Stødkilde-Jørgensen, Elmengaard, Hans Bjarne Viggo Møller-Madsen Skjeldborg Johannsen 51. 47. Revision Erythropoietin total elbow exerts arthroplasty its osteogenic using effect the linked on mesenchymal Coonrad-Morrey stromal cells via pleiotropic cell-surface receptors and intracellular signaling implant. Hans pathways Viggo Skjeldborg Johannsen, Janne Ovesen Jan H. Duedal Rölfing, Anette Baatrup, Maik Stiehler, Jonas Jensen, Helle Lysdahl, Cody Bünger 106 DOS Bulletin DOS Kongressen 2013 2014 103 27

48. 52. Preparation Complications of platelet-rich and revision plasma surgery (PRP) of the changes reverse the shoulder composition arthroplasty white blood cells in platelet-rich plasma of Morten Janne Ovesen, Lykke Olesen, Thomas Martin Falstie Lind, Jensen, Helle Hans Lysdahl, Viggo Casper Skjeldborg Bindzus Johannsen Foldager 49. Lactic-acid based polymers used for delivery of drugs to the boneimplant interface may impair implant fixation and bone formation Mette Sørensen, Jørgen Baas, Jeppe Barckman, Joan E. Bechtold, Kjeld Søballe 28 104 DOS Abstracts Bulletin DOS Kongressen 2014 107

Session 6: Tumor Sports/Shoulder Torsdag den 23. 24. oktober 09:30 13:30 10:30 15:00 Lokale: lokale: Helsinki/Oslo Reykjavik Chairmen: Werner Ilija Ban/Uffe Herbert Jørgensen Hettwer / Jørgen Peter Holmberg Jørgensen 53. 50. Excess Failed mortality Osteochondral in soft Repair tissue by sarcoma MayoRegen patients: Scaffolds a Danish in population-based with Ostochondritis study Dissecans Patients Katja Christensen Maretty-Nielsen, Bjørn Borsøe, Ninna Aggerholm-Pedersen, Foldager Casper Bindzus, Johnny Eric Keller, Bünger Akmal Cody, Safwat, Lind Steen Martin Baerentzen, Alma Pedersen 54. 51. Prognostic 2 years follow-up preoperative after parameters TruFit implantation for survival for in full patients thickness treated cartilage joint defects replacement in the surgery knee. for extremity bone metastases by Michala Lars Konradsen, Skovlund Michael Sørensen, R. Krogsgaard Klaus Hindsø, Kristine Grubbe Gregersen, Michael Mørk Petersen 52. Incidence and clinical presentation of groin injuries in sub-elite male 55. soccer YKL-40 protein expression in osteosarcoma tumor tissue Andrea Per Hölmich, Thorn, Kristian Lise Thorborg, Hanne Christiansen, Dehlendorff, Søren Daugaard, Kim Krogsgaard, Michael Christian Mørk Petersen Gluud 56. 53. Survival High injury of osteosarcoma incidence in adolescent patients diagnosed female soccer: in East The Denmark influence and of treated weekly at soccer Rigshospitalet exposure from and playing 2000-2010. level Andrea Mikkel Thorn, Bek Clausen, Søren Daugaard, Mette Zebis, Michael Merete Mørk Møller, Petersen Per Hölmich, Niels Wedderkopp, Kristian Thornorg 57. Pre-treatment biomarkers as prognosticators for mortality in patients 54. Identification with localized soft the tissue femoral sarcoma attachment point for medial patellofemoral Maretty-Nielsen, ligament (MPFL) Ninna Aggerholm-Pedersen, reconstruction without Johnny Keller, the use Alma of Pedersen, fluoros- Katja Steen copy Baerentzen, - A cadaver Akmal study Safwat Claus Ol Hansen, Mikkel Attrup, Per Hölmich 58. Markedly reduced mortality following a major non-traumatic lower limb 55. amputation Increased medial foot-loading during drop jump and single leg squat Morten in individuals Tange Kristensen, with patellofemoral Gitte Holm, Michael pain a Krasheninnikoff, cross-sectional Peter study Gebuhr Michael Rathleff, Camilla Richter, Jesper Bencke, Thomas Bandholm, Per Hölmich, Kristian Thorborg 108 DOS Bulletin DOS Kongressen 2013 2014 105 29

56. 59. Patient Tumor characteristics, reported outcome, patient revision reported rate symptoms and reason and for suspected revision following and final diagnosis resurfacing for hemiarthroplasty 64 sarcoma patients in patients referred diagnosed to a sarcoma with center osteoarthritis: after surgery/biopsy 837 operations in non-specialist reported to institutions. the Danish Shoulder Arthroplasty Heidi Buvarp Registry. Dyrop, Peter Vedsted, Katja Maretty-Nielsen, Bjarne Hauge Hansen, Jeppe Peter Rasmussen, Holmberg Jørgensen, Anne Polk, Johnny Sørensen Keller Anne Kathrine, Stig Brorson, Bo S Olsen, 57. 60. Implant Factors survival predicting after the total basic elbow amputee arthroplasty: mobility outcome A retrospective in patients study with a of major 324 procedures non-traumatic performed lower limb from amputation. 1980 to 2008 Hans Morten Christian Tange Plaschke, Kristensen, Theis Anni Thillemann, Østergaard Stig Nielsen, Brorson, Ulla Bo Olsen Madsen Topp, Peter Gebuhr 58. The effective analgesic dose of dexamethasone after outpatient shoulder surgery: a randomized, blinded trial. Karen Toftdahl Bjørnholdt, Peter Nørgaard Mønsted, Lone Nikolajsen, Kjeld Søballe 59. Primary total elbow arthroplasty in complex fractures of the distal humerus: a retrospective study of 24 consecutive cases Brian Weng Sørensen, Stig Brorson, Bo Sanderhoff Olsen 60. Short term reults after arthroscopic resection of synovial plicae in the radiohumeral joint: a case series of 68 procedures. Jens Brahe Pedersen 30 106 DOS Abstracts Bulletin DOS Kongressen 2014 109

Session 7: Knee Spine Torsdag den 23. 24. oktober 13:00 13:30 14:30 15:00 Lokale: lokale: Reykjavik Stockholm/Copenhagen Chairmen: Jakob Thomas Klit Andersen / Frank Madsen /Martin Gehrchen 61. Feasibility and safety of intensive weight loss before total knee replacement 61. Dural in tears obese influence patients: on A length randomized of admission controlled and trial outcome in spinal Anette surgery Liljensøe, Jens Ole Laursen, Henning Bliddal, Kjeld Søballe, Inger Mechlenburg Randi Holm, Dorte Clemmensen, Mikkel Andersen 62. Efficacy Intervertebral of preoperative disc degeneration progressive followed resistance by training interference on postoperativplate functional nutritional capacity pathway and in adolescent muscle strength porcine in models patients undergoing of end- total Ran knee Kang, arthroplasty Haisheng Li, Steffen Ringgaard, Kresten Rickers, Lin Xie, Cody Eric Birgit Bünger Skoffer, Thomas Maribo, Inger Mechlenburg, Per Møller Hansen, Kjeld Søballe, Ulrik Dalgas 63. Short-Term Mortality and Morbidity after Surgical Treatment of 63. Fixed EOS Spinal imaging Deformities. assessing Two-Years lower limb Experience alignment in and 102 implant Adult Patients positioning Tanvir after Bari, Total Martin Knee Gehrchen, Arthroplasty Sven Karstensen, (TKA) Sidsel Fruergaard, Benny Dahl, Kirill Gromov, Viktor Hansen, Dov Goldvasser, Orhun Muratoglu, Henrik Malchau, Anders 64. TLIF Troelsen surgery results in slightly higher risk of neurogenic leg pain 2 years after surgery compared to standard instrumented posterolateral 64. fusion. Early Results progressive from strength a randomized training clinical to enhance trial. recovery after fasttrack Kristian total Høy, knee Blazej arthroplasty. Grycel, Thomas A randomized Andersen, Peter controlled Helmig, trial Ebbe Stender Hansen, Cody Linding Bünger Jakobsen, Henrik Kehlet, Henrik Husted, Janne Petersen, Thomas Thomas Bandholm 65. A Comparison of the Tokuhashi Revised and the Tomita Scoring Systems Bone in a remodelling prospective of Cohort the of of the Patients tibia after with Metastatic total knee arthroplastry Epidural Spinal 65. with Cord uncemented Compression tibia (MESCC) implants Mikikel Søren Schmidt Rathsach Morgen Andersen, Nikolaj Winther, Thomas Lind, Henrik Schrøder, Michael Mörk Petersen 66. Implementing DaneSpine 66. Karen Similar Højmark, polyethylene Ane Simony, wear Carsten of Ernst, cementless Mikkel Andersen and cemented Oxford Partial Knee s at 2 years follow-up. A Randomized RSA Study Maiken Stilling, Anders Odgaard, Claus Fink Jepsen, Kjeld Søballe, Per Wagner Kristensen, Frank Madsen 110 DOS Bulletin DOS Kongressen 2013 2014 107 31

67. Vertebroplasty Does knee awareness for treating differ painful between vertebral knees in body bilateral fractures, simultaneous in patients TKA? with Predictors multipel of myeloma high knee awareness. Ane Katrine Simony, Abildgaard Mikkel Østerheden Nielsen, Morten Andersen, Grove Niels Thomsen, Abildgaard, Roshan Marius Latifi, Gaurilcikas Thomas Kallemose, Henrik Husted, Anders Troelsen 68. Long term outcome and health care utilizations following surgical treatment 68. Evaluation of adult of peri-implant spine deformity bone mineral density changes after femoral osseointegrated Sharma, Thomas prosthesis Andersen, Cody surgery Eric Bunger, Rikke Soegaard Shallu Rehne Lessmann Hansen, Peter Holmberg Jørgensen, Kjeld Søballe, Klaus Kjær 69. Petersen, Moderate Maiken to Almost Stilling Perfect Inter- and Intrarater Agreement in Assessment of Adult Spinal Deformity using the SRS-Schwab Classification 69. Functional capacity is associated with both extensor and flexor Dennis strength Hallager in patients Nielsen scheduled for total knee arthroplasty: a cross-sectional study 70. Birgit 3D Skoffer, correction Ulrik Dalgas, by novel Inger growth Mechlenburg, instrumentation Kjeld Søballe, in severe Thomas deformities of the immature spinal Maribo Cody 70. Eric Does Bünger, knee awareness Barbara Jensen, differ Haisheng between Li, Ebbe different Stender TKA Hansen, designs? Haolin A Sun, matched, case-control, Hoy cross-sectional study. Kristian Morten Grove Thomsen, Roshan Latifi, Thomas Kallemose, Henrik Husted, Anders 71. Troelsen Physical and mental outcome of 500 patients with spinal stenosis operated by decompression alone. Rikke 71. Rousing, Composition Frederik of Busch, The Knee Henrik Index, Grønvall a novel three-dimensional biomechanical index for knee joint load, in subjects with mild to moderate knee osteoarthritis Brian Clausen, Thomas Andriacchi, Dennis Brandborg Nielsen, Ewa Roos, Anders Holsgaard-Larsen 72. Pelvic movement strategies and leg extension power in patients with end-stage medial knee osteoarthritis: A cross-sectional study Signe Kierkegaard, Peter Bo Jørgensen, Ulrik Dalgas, Kjeld Søballe, Inger Mechlenburg 32 108 DOS Abstracts Bulletin DOS Kongressen 2014 111

Session 8a: 8: Pediatrics Experimental + Session Torsdag den 24. oktober 8b: Sportstrauma 13:30 15:00 Torsdag lokale: Helsinki/Oslo den 23. oktober 13:00 14:30 Lokale: Chairmen: Stockholm/Copenhagen Martin Gottliebsen/Keld Daubjerg Chairmen: Jan Duedal Rölfing / Martin Lind 71. Physical and mental outcome of 500 patients with spinal stenosis 73. operated The Göttingen by decompression Mini-Pig alone. (GMP) as an Animal Model for Articular Cartilage Rikke Rousing, Repair Frederik Busch, Henrik Grønvall Bjørn Christensen, Casper Foldager, Morten Olesen, Jan Rölfing, Steffen Ringgaard, 72. Is Radio Martin Freqency Lind Ablation (RFA) Epiphysiodesis Safe for Joint Articular Cartilage? 74. Juan Collagen Manuel type Shiguetomi-Medina, IV in Articular Ahmed Cartilage Abood, Damage Ole Rahbek, and Repair Hans Stødkilde- Casper Jørgensen, Bindzus Bjarne Foldager, Møller-Madsen Wei Seong Toh, Bjørn Borsøe Christensen, Martin Lind, Andreas H. Gomoll, Myron Spector 73. Acetabular index 6 months after reduction of late presenting hip 75. luxation Reduced predicts force risk development of secondary in rat surgery soleus for muscle residual after dysplasia exposure of to the Botulinum hip Neurotoxin A Sofie Louise Gjessing, Klingenberg, Ole Rahbek, Klaus Hindsø, Juan Andreas Manuel Balslev-Clausen Shiguetomi, Ole B. Nielsen, Bjarne Møller-Madsen 74. Identification of non-accidential injury in children in a Danish Emergency 76. Inhibition Room of Micromotion induced Osteolysis in a Sheep Hip Arthroplasty Helen Latifi, Bodil Model Moltesen, Christian Wong Thomas Jakobsen, Søren Kold, Juan Shiguetomi-Medina, Jørgen Baas, Kjeld Søballe, 75. Precise Ole Rahbek and feasible measurements of lateral calcaneal lengthening osteotomies by radiostereometric analysis (RSA) 77. Polina Sheep Martinkevich, model reflecting Ole Rahbek, glucocorticoid Kjeld Søballe, induced Bjarne osteoporosis Møller-Madsen, in postmenopausal Maiken Stilling women Christina Møller Andreasen, Ming Ding, Søren Overgaard, Peter Bollen, Thomas Levin 76. Calcaneal Andersen lengthening osteotomy for pes planovalgus using artificial bone graft material. Avoiding donor site morbidity 78. Martin Micromotion Gottliebsen, Induced Line Kjeldgaard Osteolysis Pedersen, in a Sheep Ivan Hip Hvid, Arthroplasty Michael Davidsen, Model Ole Thomas Rahbek, Jakobsen, Bjarne Møller-Madsen Søren Kold, Jørgen Baas, Kjeld Søballe, Ole Rahbek 112 DOS Bulletin DOS Kongressen 2013 2014 109 33

77. 79. Effectiveness Vancomycin is of superior reversible to Plectasin total epiphysiodesis against Staphyloccus using eight-plates. aureus periprosthetic retrospective osteomyelitis clinical study. in rats. A Silas Niels Hinsch H. Søe, Gylvin, Nina Martin Vendel-Jensen, Gottliebsen, Asger Christian Lundorff-Jensen, Wong Janne Koch, Steen Sejer Poulsen, Helle Krogh Johansen 78. Early experience with a follow-up programme, CPOP for children with 80. Cerebral Human chondrocytes Palsy. cultivated on modified polystyrene conserve Kirsten their chondrogenic Nordbye-Nielsen, phenotype Ole Rahbek, in Bjarne vitro Møller-Madsen Natasja Leth Jørgensen, Dang Le, Casper Foldager, Martin Lind, Helle Lysdahl 79. 11 years follow-up of congenital hip joint dislocation treated by Ludloffs 81. Tunnel Approach malpositioning in knee ligament reconstructions Denmark Jesper 2005-12 Holbeck-Brendel, Line Kjeldgaard Pedersen, Ole Rahbek, Michel Bach Hellfritzsch, Thomas Hansen, Peter Dalsgaard Kim Lyngby Nielsen, Mikkelsen, Bjarne Michael Møller-Madsen Rindom Krogsgaard 80. 82. Adaptation One-year follow-up and Validation in the of Danish a Danish Knee-ligament Translation Reconstruction of CPCHILD Questionnaire Register (DKRR) can be increased to 90 % Peter Jonathan Buxbom, Bjerre, Derek Peder Curtis, Klement, Stig Sonne-Holm, Bo Sparsø, Michael Christian Krogsgaard Wong 81. 83. Operative Normative treatment profiles for of hip elbow strength fractures and flexibility in pediatric in elite population: footballers timing of surgical treatment influence the rate of reoperation and Does post Andrea operative Mosler, complications? Kay Crossley, Kristian Thorborg, Adam Weir, Andreas Serner, Per Pernille Hölmich Bovbjerg, Zaid Al-Aubaidi 82. 84. Physeal Complications injuries after of the kneeligament distal humerus reconstruction lessons from in Denmark the Danish 2005- Patient 2012 Insurance as reported Association. to The Patient Compensation Association (PCA) Andreas Thomas Balslev-Clausen, Hansen, Kim Lyngby Steffen Mikkelsen, Volkvardsen, Michael Stig Rindom Sonne-Holm, Krogsgaard Jens Krogh Christoffersen, Christian Wong 34 110 DOS Abstracts Bulletin DOS Kongressen 2014 113

Session 9: Trauma Hip 2 Torsdag Fredag den 23. 25. oktober 13:00 09:00 14:30 10:30 Lokale: lokale: Helsinki/Oslo Reykjavik Chairmen: Peter Thomas Toft Jakobsen/Søren Tengberg / Søren Solgaard Kold 85. Orthogeriatric collaborative improves 30 day mortality and quality of 83. care Analysis after hip of 484 fracture retrieved in the Metal-on-Poly elderly: a nationwide Total Hip cohort Arthroplasty study liners: Kjær Prevalence Kristensen, of Theis Non-Concentric Muncholm Thillemann, Loading, Concentric Kjeld Søballe, Loading Søren and Paaske Im- Pia Johnsen pingement Nanna H. Sillesen, Leah Elson, Shannon L. C. Rowell, Young Min Kwon, Henrik 86. Malchau, Tranexamic Orhun Muratoglu Acid (TA) Reduces Overall Blood Loss in Unstable Trochanteric Fractures Treated with Intramedullary Nailing (IMN) Peter 84. Does Toft Tengberg, reduced movement Henrik Palm, restrictions Nicolai Foss, and Thomas use of Kallemose, assistive devices Anders Troelsen affect rehabilitation outcome after total hip replacement? A non-randomized, controlled study in 365 patients with six week follow up. 87. Lone Validation Ramer Mikkelsen, of fracture Mette treatment Krintel Petersen, codes Kjeld from Søballe, the Danish Søren National Mikkelsen, Patient Inger Mechlenburg Registry: Implications for The Danish Fracture Database Morten Jon Andersen, Michael Kuhlman, Michael Brix, Kirill Gromov, Anders Troelsen 85. Whole blood metal ion level in two populations of metal on metal hip arthroplasty and one standard total hip arthroplasty (THA) 88. Martin Sensitivity Schou, Jeannette and specificity Penny, Jens-Erik of CT and Varmarken, MRI imaging Søren in Overgaard occult hip fractures Martin 86. Incidence Haubro, Camilla of pseudotumor Stougaard, Trine large Torfing, diameter Søren head Overgaard metal on metal hip arthroplasty, resurfacing hip arthroplasty and standard hip arthroplasty 89. using Inter-rater magnetisc reliability resonance and imaging agreement (MRI) of the 6-minute walk test in females Martin Schou, with hip Jeannette fractures Penny, Jens-Erik Varmarken, Trine Torfing, Søren Overgaard Arnholtz Overgaard, Camilla Marie Larsen, Morten Tange Kristensen Jan 90. 87. Surgical Risk for delay revision increases of cementless early mortality stemmed for metal-on-metal patients with proximal total femoral hip arthroplasty fractures. (THA) A study from The Danish Fracture Database (MoM) Collaborators. Claus Varnum, Alma B. Pedersen, Mäkelä Keijo, Johan Kärrholm, Leif I. Havelin, Anne Søren Marie Overgaard Nyholm, KIrill Gromov, Henrik Palm, Michael Brix, Thomas Kallemose, Anders Troelsen 114 DOS Bulletin DOS Kongressen 2013 2014 111 35

88. 91. A Surgical novel program delay and for manual early mortality measurement in patients of acetabular with distal angles femoral with improved fracturesintra- and inter-rater reliability Sepp Bozo de Jian, Raedt, Thomas Marleen Kallemose, de Bruijne, Henrik Inger Palm, Mechlenburg, Michael Brix, Maiken Anders Stilling, Troelsen, Lone Kirill Rømer, Gromov Kjeld Søballe 89. 92. MoM RSA-measured ion analyses; rotation a comparison across SHS-treated of full blood trochanteric versus serum fractures and two - different is the anti-rotation laboratoriesscrew obsolete? Morten Maiken Bøgehøj, Stilling, Torben Ole Ovesen, Bæk-Hansen, Søren Overgaard Bøvling Søren, Steffen Jacobsen, Kim Holck, Henrik Palm 90. Acetabular & Femoral BMD around a Large Diameter Head, Standard and 93. Resurfacing Patient safe THA. pain 2 Year management Results of acute hip fracture patients requires focus Penny, on Ole the Ovesen, kidney Jens-Erik function Varmarken, Søren Overgaard Jeannette Morten Baltzer Andersen, Beata Malmqvist, Henrik Palm 91. Patient matched implant (PMI) in reconstruction of severe acetabular 94. bone Complications loss and pelvic and discontinuity Functional Outcome after total after hip Locking arthroplasty. Plate Fixation Anne of Distal Mette Tibial Stausholm, Fractures Jens Stürup, in the Poul Region Torben of Nielsen Southern Denmark 2007-2011 92. Silje 15-years Kleven, Ellen in risk Hamborg of cardiovascular Petersen, Bjarke events Viberg, and Ole Skov bleeding in total hip and knee replacement patients receiving thromboprophylaxis in routine clinical 95. A review practice: of a deep nationwide wound infection Danish cohort after study hip-fracture of 83,756 surgery osteoarthritis Frederik patients Stensbirk, Henrik Palm B. Pedersen Alma, Mehnert Frank, Sorensen Henrik Toft, Emmeluth Claus, Overgaard 96. Nailing Soren, Johnsen of unstable Soren trochanteric Paaske fractures with and without circumferential wires a study with focus on complications and reoperations 93. within Total two Hip years. Artroplasty (THA) following Open Reduction and Internal Fixation Lasse Birkelund, (ORIF) of Michael acetabular Brix, Ilija fractures. Ban, Henrik A case-kontrol Palm, Anders Troelsen study Jesper Høeg Vinther, Søren Overgaard, Ole Ovesen 36 112 DOS Abstracts Bulletin DOS Kongressen 2014 115

Session 10a: 10: Tumor/ Hip/knee + Session Pediatrics 10b: Trauma Fredag Fredag den den 24. 25. oktober oktober 09:00 09:00 10:30 Lokale: lokale: Reykjavik Stockholm/Copenhagen Chairmen: Kiril Thomas Gromov Baad-Hansen/Bjarne / Claus EmmeluthMøller-Madsen 97. Risk of readmission, reoperation and mortality within 90 days of total 94. The hip Prevalence and knee arthroplasty and Prognostic in fast-track Impact of Comorbidity departments in in Soft Denmark Tissue from Sarcoma: 2005 A to Population-Based 2011 Cohort Study Eva Katja Natalia Maretty-Nielsen, Glassou, Alma Ninna Becic Aggerholm-Pedersen, Torben Bæk Akmal Hansen Safwat, Steen Baerentzen, Alma Pedersen, Johnny Keller 98. Low Occurrence of Thromboembolic Events After Routine Use of Tranexamic 95. Predictors Acid for in Hip functional and Knee outcome Arthroplasty and health related quality of life Rune following Vinther limb Madsen, sparing Christian surgery Skovgaard for soft-tissue Nielsen, Thomas sarcomas Kallemose, Henrik Husted, Casper Anders Sæbye, Troelsen Hanna Maria Fuglø, Tine Nymark, Akmal Safwat, Michael Mørk Petersen, Johnny Keller 99. The use of a primary knee prosthesis as articulating spacer in twostage 96. Influence revision of of infected the Extent knee of arthroplasty. Surgery on Patient Survival after Total Rasmus Joint Replacement Juul, Jesper Fabrin, because Klaus of Poulsen, Metastatic Jeannette Bone Østergaard Disease Penny Michala Skovlund Sørensen, Kristine Grubbe Gregersen, Hindsø Klaus, Petersen 100. Michael Arthrodesis Mørk of the knee after failed knee arthroplasty Tinne Brandt Gottfriedsen, Anders Odgaard Anders Odgaard, Henrik M Schrøder Henrik 97. Local Morville recurrence Schrøderrate of Giant Cell Tumors of Bone Peter Horstmann, Michael Mørk Petersen 101. Can low knee awareness and higher function after primary TKA be predicted? 98. Adaptive A cross-sectional bone remodeling study of the of 316 femoral patients bone 1 after to 4 tumor years resection arthroplastry with an uncemented proximally hydroxyapatite coat- after surgery. Morten ed GMRS Grove stem. Thomsen, Roshan Latifi, Thomas Kallemose, Henrik Husted, Anders Troelsen Mikkel Rathsach Andersen, Michael Mørk Petersen 116 DOS Bulletin DOS Kongressen 2013 2014 113 37

99. 102. Through Does knee awareness amputation and associated functional with outcome high differ risk of between reamputatioes of bilateral simultaneous total knee arthroplasty (BSTKA) and unila- kne- Nikolaj teral total Sode, knee Steen arthroplasty Vigh Buch, Troels (UTKA)? Riis, Søren A cross-sectional, Kring, Annette matched, Sylvest, Benn case Duus control study. Roshan Latifi, Morten G. Thomsen, Thomas Kallemose, Henrik Husted, Anders 100. Troelsen Clinical outcome after treatment of paediatric elbow fracture; a comparison of supracondylar, lateral condyl and medial epicondyl fractures; 103. is Hip physiotherapy fractures: Can mandatory Thrombelastography adjuvant treatment? (TEG) on admission predict overall Bovbjerg, blood Zaid loss Al-Aubaidi Pernille Peter Toft Tengberg, Henrik Palm, Nicolai Foss, Jakob Stensballe, Thomas 101. Kallemose, Can the Anders Ottawa Troelsen Ankle Rules be applied in children with ankle injury? A prospective MRI study. Mikael 104. Hofsli, Validation Trine Torfing, of the Zaid Danish Al-Aubaidi version of the Quick-DASH questionnaire. 102. Jesper The Ougaard proportion Schønnemann of distal fibula Salter Harris type I epiphyseal fracture in the pediatric population with acute ankle injury. A prospective MRI 105. study. Primary brachial plexus reconstructon outcomes in 12 consecutive Mikael patients Hofsli, with Trine traumatic Torfing, Zaid brachial Al-Aubaidi plexus injury, treated at the National Center for Brachial Plexus Injuries in Odense between 2010 and 2013. 103. Jerzy Pitfalls Stiasny, in Anders the treatment Lorentsen, Peter of pediatric Birkelandsupracondylar fractures of the humerus a partial root core analysis of 101 cases from the Danish Patient 106. Osseointegrated Insurance prosthesis for the trans-femoral amputees. Steffen Peter Holmberg Folkvardsen Jørgensen, Steffen Folkvardsen, Klaus Kjær Petersen, Andreas Jens Baslev-Clausen Ulrik Petersen, Andreas Rene Baslev-Clausen, Lessmann Hansen Jens Krogh Christoffersen Jens Krogh Christoffersen, Stig Sonne Holm Stig Sonne Holm, Christian Wong Christian Wong 107. Preoperative in-cast intermittent pneumatic compression of malleolar Outcome fracturesof distal tibial physeal fractures; a comparison of 104. Triplane, Jesper Schønnemann, Tillaux and medial Rasmus malleolus Buck Bendtson SH-III and IV fractures. A retrospective study. Helene 108. Retrospective Højsgaard Jensen, study Sidsel of Hald fifth Rahlf, metatarsal Niels Wicbech fractures. Pedersen, Zaid Al- Aubaidi Jesper Høeg Vinther, Fanny Olsen 38 114 DOS Abstracts Bulletin DOS Kongressen 2014 117

Session 11: Spine Trauma 2 Fredag den 24. 25. oktober 09:00 10:30 Lokale: lokale: Stockholm/Copenhagen Helsinki/Oslo Chairmen: Mikkel Michael Østerheden Brix/Juozas Andersen Petruskevicius / Søren Eiskjær 109. A modification of the Tokuhashi Revised score improves prognostic precision 105. Level in patients of supervision with metastatic in fracture-related spinal cord surgery compression. in Denmark. Experience Schmidt from Morgen, centres Martin participating Gehrchen, in Sebastian the DFDB Bjørck, (Danish Claus Fracture Falck Larsen, Data- Søren Svend base) Aage collaboration. Engelholm, Benny Dahl Morten Jon Andersen, Kirill Gromov, Michael Brix, Anders Troelsen, DFDB Collaborators Reliability and validity of the Danish version of SRS 22r 110. Ane Simony, Karen Højmark Hansen, Leah Carreon, Mikkel Østerheden Andersen 106. Routine blood tests indicate increased mortality risk in lower limb amputation patients 111. Steen Self-reported Vigh Buch, Nikolaj scoliosis Sode, is Troels not a Riis, valid Søren method Kring, for Annette estimating Sylvest, concordance Rønnow Duus rates of Adolescent Idiopathic Scoliosis in a Danish twin po- Benn pulation Mikkel 107. Andersen, High patient Kirsten volume O. Kyvik is associated, Karsten Thomsen with increased, Ane Simony 30-day mortality after hip fracture. 112. Pia Kjær Investigating Kristensen, Theis human Muncholm VANGL1, Thillemann, as a candidate Søren Paaske gene for Johnsen adolescent idiopathic scoliosis Malene 108. External Rask Andersen, versus Ane internal Simony, fixation Lars Allan of intra-articular Larsen distal tibial fractures - A systematic critical review 113. Peter Does Ivan Andersen, obesity delay Bjarke time Løvbjerg of surgery Viberg, Morten for Lumbar Schultz Disc Larsen Herniation, and does it influence surgical outcome in 832 patients treated with discectomy. 109. Over- og undertriage ved modtagelse af multitraumatiserede patienter Rousing, - En sammenligning Ane Simony, Henrik af to Grønvall, triagesystemer Karen Højmark, Stefan Hummel, Rikke Mikkel Torben Østerheden Stryhn, Morten Andersen Schultz Larsen 114. 110. Moderate Patient volume Precision in hip of the fracture Tokuhashi units Revised associated Score and with the increased Bauer Modified length of Score hospital in Patients stay and with increased Metastatic surgical Spinal delay. Cord Compression. Søren Pia Kjær Schmidt Kristensen, Morgen, Theis Martin Muncholm Gehrchen, Thillemann, Dennis Søren Hallager Paaske Nielsen, Johnsen Claus Falck Larsen, Svend Aage Engelholm, Benny Dahl 118 DOS Bulletin DOS Kongressen 2013 2014 115 39

111. 115. Demographic Morbidity and and mortality short-term of complex outcome spine changes surgery: within a 10 prospective years of a cohort multimodal study fast-track in 679 patients hip fracture validating program the SAVES system in a European Morten population Tange Kristensen, Henrik Palm Sven Karstensen, Tanvir Bari, Martin Gehrchen, John Street, Benny Dahl 112. Venous thrombosis following fractures below the knee, a nationwide 116. cohort Clinical study correlation of the SRS-Schwab Classification with HRQOL Liv measures Riisager in Wahlsten, a prospective Henrik Eckardt, non-us cohort Gunnar of Hilmar ASD Gislason, patientsjonas Bjerring Olesen, Dennis Christian Hallager Torp-Pedersen Nielsen, Lars Valentin Hansen, Casper Rokkjær Dragsted, Martin Gehrchen, Benny Dahl 113. The management of anticoagulant therapy in hip fracture patients in 117. Denmark Providence Nighttime Bracing in adolescent idiopathic scoliosis Peter Ane Toft Simony, Tengberg, Inge Beuschau Nicolai Bang, Lena Foss, Quisth Henrik, Mikkel Palm, Anders Østerheden Troelsen Andersen, Stig Mindedahl Jespersen 114. Reliability of a Scoring System for Measurement of Implant Position 118. after Is the Internal surgical Fixation outcome of Undisplaced for lumbar disc Femoral herniations Neck Fractures related to the Marie-Louise duration of Lervad symptoms? Bartholin, Kolja Weber, Rune Dueholm Bech, Henrik Palm, Bjarke Christian Viberg, Støttrup, Morten Carsten Schultz Ernst, Larsen Dorte Clemmensen, Alexander Isenberg-Jørgensen, Randi Holm, Mikkel Østerheden Andersen 115. Reoperation rates on proximal femoral fractures Pernille 119. Does Nygaard loss Vedel, of follow-up Troels Riis, bias Annette patient-related Sylvest, Henrik outcome Løvendahl measures Jørgensen, of Benn spine Duus surgery performed at the Sector for Spine Surgery and Research, Region of Southern Denmark. Karen Højmark, Christian Støttrup, Mikkel Østerheden Andersen 40 116 DOS Abstracts Bulletin DOS Kongressen 2014 119

Session 12: Pediatrics Hand Fredag den 24. 25. oktober 09:00 11:00 10:30 12:00 Lokale: lokale: Helsinki/Oslo Stockholm/Copenhagen Chairmen: Christian Maiken Stilling/Anders Wong / Ole Rahbek Lorentzen 120. Micro dose acquisition in Leg length Discrepancy using the EOS imaging 116. Satisfaction system with Upper Extremity Surgery in Individuals with Tetraplegia Jensen, Bo Mussmann, Niels Wisbech, Zaid Al-Aubaidi, Trine Torfing Janni Hanne Gregersen, Mille Lybæk, Inger Lauge Johannesen, Pernille Leicht, Ulla Vig 121. Nissen, Reliability Fin Biering-Sørensen of Instrumented gait analysis in children with spastic cerebral palsy Helle 117. Mätzke Xiapex Rasmussen, (collagenase Dennis clostridium Brandborg histolyticum) Nielsen, Niels Wisbech treatment Pedersen, of patients Overgaard, with Dupuytren s Anders Holsgaard-Larsen contracture 1 year follow-up Søren Søren Larsen, Karina Liv Hansen, Tune Ipsen, Jens Lauritsen 122. Reliability and validation of the Oxford Ankle Foot Questionnaire (OxAFQ) 118. High in 82 revision Danish rates patients with aged the metal 5 to 16 on years metal Motec trapeziometacarpal Martinkevich, total arthroplasty Bjarne Møller-Madsen, Martin Gottliebsen, Line Kjeldgaard Polina Pedersen, Janni Kjærgaard Ole Rahbek Thillemann, Theis Muncholm Thillemann, Bo Munk, Karsten Krøner 123. The revised FLACC behavioural pain scale: Translation, reliability and 119. validation Compensation for pain claims assessment from the in children use of an with arterial cerebral tourniquet palsy during Line limb Kjeldgaard surgery Pedersen, in Denmark Ole in Rahbek, the years Lone 1998 Nikolajsen, -2010 Bjarne Møller-Madsen Lasse E. Rasmussen, Søren Larsen, Kim L Mikkelsen 124. Danish Translation and adaptation of Gait Outcomes Assessment List, 120. GOAL Questionnaire, Tendon Gene Therapy a by patient Electroporation reported holds priority Potential based outcome to Modify measure Flexor Tendon Healing Kirsten Sys Hasslund, Nordbye-Nielsen, Hanne Gissel, Unni Carl Narayanan, Christian Ole Danielsen, Rahbek, Bjarne Mette Møller-Madsen Koefoed, Lars Aagaard, Kjeld Søballe 125. Skeletal Healing after Periacetabular Osteotomy Measured by RSA - 121. Preliminary Amputation Results of a spastic, paralysed arm after a stroke, prosthetic Peter supply Buxbom, and functional Stig Sonne-Holm, outcome. Christian Wong Pernille Leicht, Ellen Thomsen Rasmussen, Lisbeth Villemoes Sørensen, Stig Jensen 120 DOS Bulletin DOS Kongressen 2013 2014 117 41

122. 126. Treatment Measuring of the proximal effect of interphalangeal treatment on joint gait quality fractures in children by the pins with and cerebral rubbers palsy traction a retrospective system - a follow studyup Jessica Anders Agneta Holsgaard-Larsen, Nilsson, Hans-Eric Rasmus Rosberg Skov Sørensen, Carsten Jensen, Dennis Brandborg Nielsen, Annie Gam-Pedersen, Niels Wisbech Pedersen 123. Small Joint Arthroscopy in Hands - technique and clinical uses in RA 127. patients Complex regional pain syndrome (CRPS) in children - treatment Charlotte with peripheral Schultz, Martin nerve catheter Andersen, Vendel Jensen Ninna, Niels H. Søe, Henning Bliddah Søren Bødtker, Søren Anker Pedersen, Lene Larsen, Vibeke Rosenkvist, Svandhild Ivarsslaten, Mai Pedersen 128. Are pain thresholds in children influenced by orthopedic surgery? - A prospective study Line Kjeldgaard Pedersen, Polina Martinkevich, Ole Rahbek, Lone Nikolajsen, Bjarne Møller-Madsen 129. Treatment of clubfoot: Comparing surgical correction and the Ponseti Method A comparative study Mette Tavlo, Lise Karlsmark, Klaus Hindsø 130. Children and adolescents admitted to the level 1 trauma centre at Odense University Hospital 2002-2011. Rasmus Hviid Larsen, Danny Stefan Ekström, Jens Martin Lauritsen, Christian Færgemann 131. Outcome after resection of tarsal coalition in children Ahmed Abdul-Hussein Abood, Ole Rahbek, Bjarne Møller-Madsen 42 118 DOS Abstracts Bulletin DOS Kongressen 2014 121

Session 13: Foot/ankle Fredag den 25. oktober Foredragskonkurrence 11:00 12:00 Fredag lokale: den Helsinki/Oslo 24. oktober 13:30 15:00 Lokale: Chairmen: Stockholm/Copenhagen/Helsinki/Oslo Jeannette Østergaard Penny/Lasse Danborg Chairmen: Casper Foldager / Søren Overgaard 124. Dynamic non-operative treatment of acute Achilles tendon rupture: 132. Preparation The influence of of the early femoral weight-bearing bone cavity on clinical for cementless outcome. stems: A blinded, randomized, Broaching versus Compaction. controlled trial. A 5 year randomized RSA and DXA study of Kristoffer 40 bilateral W Barfod, 1-stage Jesper operations Bencke, Hanne Bloch Lauridsen, Ilija Ban, Lars Ebskov, Mette Anders Holm Troelsen Hjorth, Maiken Stilling, Kjeld Søballe, Poul Torben Nielsen, Poul Hedevang Christensen, Søren Kold 125. High volume injection, autologous conditioned plasma and placebo treatment 133. Bone autograft in patients versus with recombinant chronic Achilles human tendinopathy BMP-2 (rhbmp-2) A single at bone blinded docking-site prospective in study tibial bone transport. A randomized clinical trial (RCT). Anders Ploug Boesen, Morten Boesen, Rudi Hansen, Peter Malliaras, Otto Chan, Søren Henning Kold, Langberg Martin Lind, Susanne Jølck, Knud Christensen 134. 126. Pharmacokinetics Modified Lapidus of arthrodesis Cefuroxime in Plantar Bone, Subcutaneous plating and compression Tissue and Plasma screw Retrospective Comparison of evaluation Continuous of versus fusion Short-term rate and IM-1 Infusion angle correction Mikkel Tøttrup, Mats Bue, Kurt Fuursted, Tore Forsingdal Hardlei, Kjeld Søballe, Hanne Kim Hegnet Birke-Sørensen Andersen, Anna Kathrine Pramming, Jens Kurt Johansen, Jeannette Østergaard Penny 135. Methylprednisolone reduce pain and decrease knee swelling in the first 127. 24 Surgical hours after treatment fast-track of lesser-toe-mtp Oxford unicompartmental joint instability: knee arthroplasty Plantar plate repair using a plantar approach. Søren Anna Rytter, Kathrine Maiken Pramming, Stilling, Jens Stig Kurt Munk, Johansen, Torben Bæk Kim Hansen Hegnet Andersen, Jeanette Østergaard Penny 136. Physical activity and return to work after fast-track total hip replacement 128. Development with or without and validation supervised of rehabilitation. a novel ultrasonographic Results from method a randomized for evaluation controlled of Achilles trial. tendon elongation after rupture Lone Kristoffer Ramer W Mikkelsen, Barfod, Anja Inger Falck Mechlenburg, Riecke, Anders Kjeld Søballe, Boesen, Lene Philip Bastrup Hansen, Jørgensen, Jens Friedrich Maier, Thomas Bandholm, Anders Annemette Troelsen Krintel Petersen 122 DOS Bulletin DOS Kongressen 2013 2014 119 43

129. 137. Achilles Preoperative Tendon embolization ruptures treatment in surgical and treatment complications: of spinal A metastases: review single-blind, randomized controlled clinical trial of efficacy in systematic Christina decreasing Holm, intraoperative Pernilla Eliassonblood loss Caroline Clausen, Benny Dahl, Susanne C Frevert, Lars Valentin, Michael B Nielsen, 130. Lars Complications Lönn after acute Achilles tendon rupture. A registry study of 324 patients from the Danish Patient Insurance Association Thor-Magnus 138. HA-coating Sveen, may Kristoffer decrease W. Barfod, screw Lars migration Ebskov, in Anders the femoral Troelsenhead following hip fracture surgery a double blinded RSA study 131. Henrik Prospective Palm, Kim Holck, comparative Steffen Jacobsen, study comparing Søren Bøvling, the results Torben of Bæk-Hansen, proximal crescentic Maiken Stilling osteotomies and open wedge osteotomies to patients with severe hallux valgus Jens Ulrik Wester, Niels Herold, Palle Bo Hansen, Johnny Frøkjær 44 120 DOS Abstracts Bulletin DOS Kongressen 2014 123

Posterudstilling Session 14: Fra onsdag den 22. oktober Foredragskonkurrence 10:30 lokale: Capital Foyer Fredag den 25. oktober postere udvalgt til posterpræsentation listes også side 13:00 14:30 19-24 98-103 lokale: Stockholm/Copenhagen/Helsinki/Oslo 139. One-year evaluation: Is there effect of 8 weeks supervised progressive resistance training after unicompartmental knee arthroplasty? Chairmen: Ole Rahbek/Steen Lund Jensen Peter Bo Jørgensen, Søren Bie Bogh, Signe Kierkegaard, Henrik Sørensen, Kjeld Søballe, Inger Mechlenburg 132. Prognostic Factors in 1065 Adult Non-Metastatic Soft Tissue Sarcoma: a Population-Based Cohort Study 140. Is gait velocity and gait quality associated with hip muscle strength Katja Maretty-Nielsen, Ninna Aggerholm-Pedersen, Akmal Safwat, Peter Holmberg Jørgensen, Alma Pedersen, Johnny Keller in hip osteoarthritis patients scheduled for total hip arthroplasty? Signe Rosenlund, Dennis Brandborg Nielsen, Søren Overgaard, Carsten Jensen, Anders Holsgaard-Larsen 133. Radiostereometric analysis (RSA) of two MoM cups, 2 year results from a randomized clinical trail (RCT) 141. Objectively measured physical activity reference data obtained Jeannette Penny, Ming Ding, Ole Ovesen, Jens Erik Varmarken, Søren Overgaard from a Dutch population with a three-axial accelerometer Signe Kierkegaard, Inger Mechlenburg, Bernd Grimm, Ide Heyligers, Rachel Senden 134. Preoperative effects of progressive individualized explosive-type resistance training in patients with osteoarthritis scheduled for total hip 142. Validation of intraoperative reported angle measurements in periactabular osteotomy arthroplasty (THA) -a prospective randomized controlled trial (RCT) Andreas E B Hermann, Anders Holsgaard-Larsen, Bo Zerahn, Steen Mejdahl, Sepp De Raedt, Inger Mechlenburg, Maiken Stilling, Marleen de Bruijne, Lone Søren Overgaard Rømer, Kjeld Søballe 135. Is 8 weeks supervised early progressive resistance training after 143. Safety of Vitamin E infused high wall liners for routine use in primary THA: Single center, short term follow-up of 767 cases unicompartmental knee arthroplasty more effective than home based exercise? Nanna Sillesen Hylleholt, Christopher Barr J., Peter Gebuhr, Henrik Malchau, Peter Bo Jørgensen, Søren Bie Bogh, Kjeld Søballe, Henrik Sørensen, Anders Odgaard, Inger Henrik Husted, Troelsen Anders Mechlenburg 144. Acetabular dysplasia increases risk for malpositioning of the acetabular component in Total Hip Arthroplasty (THA) 136. 3 Year Multicenter RSA evaluation of vitamin E diffused highly cross-linked polyethylene liners and acetabular cup stability Kirill Gromov, Meridith Greene, Christopher Barr, Peter Gebuhr, Henrik Malchau, Nanna H. Sillesen, Audrey Nebergall, Poul T. Nielsen, Mogens B. Laursen, Anders Anders Troelsen Troelsen, Henrik Malchau 124 DOS Bulletin DOS Kongressen 2013 2014 121 45

137. 145. Collagen High frequency conduit vs. of cystic microsurgical pseudotumors neurorrhaphy in large-head Two year metal-onmetal of a prospective total hip arthroplasty blinded clinical at 5-7 and years electrophysiological follow-up. multicenter follow up RCT Mette Holm Hjorth, Niels Egund, Inger Mechlenburg, Stig Storgaard Jakobsen, Michel Kjeld Søballe, E.H. Boeckstyns, Maiken Stilling Allan Ibsen Sørensen, Joaquin Fores Vineta, Birgitta Rosén, Xavier Navarro, Christian Krarup 146. Radiologic and histologic appearance of metal-bone interphase in 138. failed Cup tibial design component is an important in total factor knee arthroplasty. in survival of A trapeziometacarpal retrieval study. total Tue Smith joint trapezium Jørgensen, Thomas components. Lind, Henrik Schrøder, Eva Balslev Haider Ghalib Majeed, Torben Bæk Hansen 147. Hip arthroplasty with the Primoris stem Bone remodelling around a short femoral neck stem Janus Duus Christiansen, Lauersen Mogens Berg, Gordon Blunn, Poul Torben Nielsen 148. Prevalence of kidney dysfunction at elective total hip arthroplasty operations. Helene Berg-Nielsen, Morten Boye Petersen, Mette Brimnes Damholt, Søren Solgaard 149. Average cyst volume per cyst-patient decreases over a 10-year period after periacetabular osteotomy Inger Mechlenburg, Jens R. Nyengaard, John Gelineck, Kjeld Søballe 150. Outcome of Two-stage revision of chronic infections in hip joint replacement in Denmark 2003-2008. Jeppe Lange, Alma B. Pedersen, Anders Troelsen, Kjeld Søballe 151. No dislocations after primary total hip arthroplasty with the AVANTAGE dual mobility cup in Garden Type 3/4 hip fracture patients with dementia: A retrospective study of 26 procedures. Anders Elneff Graversen, Mathias Bjerring Ho, Stig Storgaard Jakobsen, Andrey Kovalev, Pia Kjær Kristensen, Theis Muncholm Thillemann 152. DHAR 1-year results of Hip Arthroscopy in Adolescents Bent Lund, Søren Winge, Otto Kraemer, Torsten Grønbech Nielsen, Martin Carøe Lind 46 122 DOS Abstracts Bulletin DOS Kongressen 2014 125

Posterudstilling 153. Cementless Metaphyseal Sleeves without Stem in Revision Total Knee Arthroplasty David Gøttsche, Thomas Lind, Thorbjørn Christiansen, Henrik Morville Schrøder Fra onsdag den 23. oktober 154. 10:30 Pain distribution in primary care patients with hip osteoarthritis a lokale: descriptive Capital study Foyer Erik Poulsen, Søren Overgaard, Jacob Toft Vestergaard, Henrik Wulff Christensen, (postere Jan Hartvigsen udvalgt til posterpræsentation listes også side 78-83 ) 155. 139. The No effect increased of periacetabular risk of elevated osteotomy metal ions (PAO) and pseudotumour on the clinical formation when in patients using modular with retroverted neck-stems acetabulum bilaterally- a prospective cohort outcome study Peter Revald, Claus Varnum, Poulsen Thomas K., Per Kjærsgaard-Andersen Victoria Schmiegelow, Bjarke Løvbjerg Viberg, Ole Ovesen, Søren Overgaard 140. Body composition preoperatively has no impact on clinical outcome Evaluation after hip arthroplasty of bone mineral - A cohort density study and bone of 102 markers patients in 1year femoral af- 156. amputees ter surgery prior to osseointegrated implant surgery Rehne Anette Lessmann Liljensøe, Hansen, Jens Ole Peter Laursen, Holmberg Kjeld Søballe, Jørgensen, Inger Kjeld Mechlenburg Søballe, Klaus Kjær Petersen, Maiken Stilling 141. 3 year Follow-up of a Long-term Registry-based Multicenter study 157. on Vitamin Amputation E Diffused after Polyethylene failed knee arthroplasty in Total Hip Replacement Tinne Nanna B Gottfriedsen H. Sillesen, Meridith Tinne Brandt E. Greene, Gottfriedsen, Audrey K. Anders Nebergall, Odgaard Anders Anders Troelsen, Odgaard, Gebuhr, Henrik Henrik M Schrøder Malchau Henrik Morville Peter Schrøder 158. 142. Acceptable Effect of early agreement progressive between resistance Inertia-based training Measurement compared to home Unit and based Optical exercise Motion after Capture fast track System total applied hip replacement. in quantitative A randomised measurement controlled of physical trial. function in patients Inger Lone Mechlenburg, Ramer Mikkelsen, Peter Bo Inger Jørgensen, Mechlenburg, Henrik Sørensen, Kjeld Søballe, Dennis Søren B Nielsen, Mikkelsen, Bernd Grimm, Thomas Kjeld Bandholm, Søballe Mette Krintel Petersen 159. 143. Intervertebral 3 months home-training disc degenerative by a changes standardized after program intradiscal improves injection walking of TNF-α distance in a porcine and knee model extension strength in old patients 1-7 years Ran after Kang, surgery Haisheng with Li, dual-mobility Kresten Rickers, THA Steffen following Ringgaard, femoral Lin Xie, neck Cody fracture. Bünger Christina Frølich, Inger Mechlenburg, Sara Birch, Lone Lundager, Torben Bæk 160. Hansen, A month Maiken of Stilling heavy resistance exercise increases the amount of Collagen XIV in the endomysium close to the human MTJ Jens 144. Rithamer Preoperative Jakobsen, planning Abigail in Mackey, cementless Andreas total Knudsen, hip arthroplasty Manuel Koch, - Michaecuracy Kjaer, of Michael digital templating Rindom Krogsgaard Ac- Mikkel Krüger Jensen, Søren Solgaard 126 DOS Bulletin DOS Kongressen 2013 2014 123 47

145. 161. Timing Pharmacokinetics of preoperative of vancomycin prophylactic in porcine antibiotics bone for obtained knee arthroplastiescrodialysis A quality study after the introduction of the WHO checklist by mi- with Mats a standard Bue, Hanne time-out Birke-Sørensen, before Theis skin Muncholm incision. Thillemann, Kjeld Søballe, Arne Mikkel Svensson, TøttrupLars Peter Jorn 146. 162. No Collagen correlations types and between distribution radiological at the human angles myotendinous and self-assessed junction (MTJ) of Life in patients with Hip Dysplasia at 2-13 years of follow up Quality after Jens periacetabular Rithamer Jakobsen, osteotomy Abigail Mackey, Andreas Knudsen, Manuel Koch, Michael Birch, Kjaer, Anette Michael Liljensøe, Rindom Krogsgaard Charlotte Hartig-Andreasen, Kjeld Søballe, Inger Sara Mechlenburg 163. Can gait deviation index be used efectively for the evaluation of 147. gait Removal pathology of in mobilisation total hip arthroplasty? restrictions following An explorative primary randomized THR does not trial increase risk of early dislocation. Kirill Carsten Gromov, Jensen, Anders Signe Troelsen, Rosenlund, Kristian Dennis Stahl B. Otte, Nielsen, Thue Søren Ørsnes, Overgaard, Henrik Husted Anders Holsgaard-Larsen 148. Block-step asymmetry 5 years after large-head MOM THA is related 164. to Validation lower muscle and inter-tester mass and leg reliability power on of the a tri-axial implant side. accelerometerbased Holm classification Hjorth, Maiken of daily Stilling, activities Nina D Lorenzen, Stig Storgaard Jakobsen, Mette Kjeld Marianne Søballe, Tjur, Inger Kenneth Mechlenburg Juul Laugesen, Kamilla Nygaard Jensen, Mads Grosmann Svendsen, Inger Mechlenburg, Signe Kierkegaard 149. No clinical important increase in perioperative bleeding during total 165. hip replacement Does an intensive users alcohol of serotonergic cessation antidepressants intervention at the time of Annie fracture Primdahl, surgery Frank induce Damborg, spontaneous Tine Nymark, smoking Michael cessation? Dall, Jesper - Hallas The Scand- Ankle study 150. Erika Initial Wernheden, Hip Model Marianne Aalykke, Bolette Pedersen, Julie W. M. Egholm, Hanne Tønnesen Skytte, Lars Pilgaard Mikkelsen, Stig Sonne-Holm, Christian Wong, Tina 151. 166. Collateral Compression Ligament in Anklefracture Reconstruction Treatment, of the the Chronic CAT-study Thumb Injury with Rikke Biotenodesis Winge, Stig Sonne-Holm, Screw Fixation Camilla Ryge, Hans Gottlieb, Lasse Bayer Robert Gvozdenovic, Michel Boeckstyns 167. Characteristics of non-participants in orthopaedic research A 152. study Partial of patients Scaphoid undergoing Implant (APSI). ankle fracture A Seven surgery Years Follow-up and declining participation Vendel, in Lene a randomized Jensen, Niels clinical H. Søe Søe, triallars B. Dahlin Nina Marianne Aalykke, Erika Wernheden, Bolette Pedersen, Julie Weber Melchior 153. Egholm, Volar Hanne dislocation Tønnesen of the second and third carpometacarpal joint following a soccer tackle -a case story of a missed diagnosis in a 15 year old 168. boy. Early Complications of Ankle Fractures Following Treatment with Anne Ilizarov Mørup-Petersen, External Fixator Camilla or Ryge, Open Dorte Reduction Engelund Internal Fixation Josefin Roslund, Matilda Svenning, Michael Brix, Morten Schultz Larsen 48 124 DOS Abstracts Bulletin DOS Kongressen 2014 127

169. 154. The Erythropoietin epidemiology elicits of acute a dose-dependent Achilles tendon osteogenic ruptures in effect the south on human mesenchymal area in the stem period cells 2004-2013 Copenhagen Ann Jan Ganestam, Duedal Rölfing, Anders Anette Troelsen, Baatrup, Kristoffer Maik W. Stiehler, Barfod Helle Lysdahl, Cody Bünger 170. 155. Regional The influence Differences of hemostatic in Number agents of Meniscal on bone healing Procedures after in sternotomy in a porcine model Denmark Kristoffer Rikke Falsig Borbjerg Vestergaard, Hare, Jesper Annemarie Høeg Brüel, Vinther, Jesper L Stefan Skovhus Lohmander, THomsen, Jonas Ellen Bloch Margrethe Hauge, Kjeld Søballe, John Michael Thorlund Hasenkam 171. 156. Differences Topographical in MACI microstructures Patient Characteristics increase proliferation in European of Countries primary chondrocytes in vitro. human Casper Natasja Bindzus Leth Jørgensen, Foldager, Martin Anna Lind Nielsen, Ole Zoffman Andersen, Morten Foss, Martin Lind, Helle Lysdahl 172. PROM in the referral of patients to knee arthroscopy Peter 157. Christian Dental Pulp Siesing, Stem Claus Cells Hjorth Seeded Jensen, on Thomas Modified Lind, Polycaprolactone Anders Odgaard Scaffolds Promotes Osteogenic Differentiation in Vitro 173. Jonas Diagnosis Jensen, Helle and Lysdahl, treatment David of Kristian chronic Evar exertional Kraft, Jan compartment Rölfing, Cody Bünger syndrome - a proposition for an algorithm based on case series of patients treated 158. Results at Sports after Medicine plate removal Division, in midshaft Department clavicle of Orthopaedic fracture surgery: Surgery, Focus Viborg on coexsisting Regional Hospital, soft-tissue Denmark shoulder injuries. Peter Ban Ilija, Birk, Poulsen Steffen Heidi, Skov Jensen, Troelsen Bente Anders Overgaard Hansen, Janni Stroem 174. 159. Knee Early Joint experiences Loading Indices with the Before DHS and blade 3 Months in treating after Arthroscopic femoral neck Partial fractures Medial Meniscectomy Jonas Rasmus B. Thorlund, Stokholm, Mark Lise W. Hellegaard, Creaby, Martin Steffen Englund, Skov Jensen Nis Nissen, L. Stefan Lohmander, Anders Holsgaard-Larsen 160. Retrospective review of radiographic referral, interpretation and 175. treatment Inter-tester plan in reliability a Danish of emergency four tests department measuring muscle in comparison strength to in an the international shoulder using benchmark. a handheld dynamometer Mikkel Mohamed Bek Clausen, Shalaby, Peter Wajeha Andreas Malik, Christine Rothe, Jens Hilbrandt, Langermann, Valentina Per Makolli, Hölmich, Thomas Kristian Houe Thorborg 176. 161. Osseointegrated Feasibility of progressive (OI) Prothesis strength for Upper training Limb immediately Amputees. after hip Klaus fracture Kjær Petersen, surgery. Peter Holmberg Jørgensen Lise Kronborg, Thomas Bandholm, Henrik Palm, Henrik Kehlet, Morten Tange Kristensen 118 DOS Bulletin DOS Kongressen 2013 2014 125 49

162. 177. Severe Outcome fractures and risk after of Segway revision related after shoulder accidents replacement in an amusement in patients with osteoarthritis: 1,209 cases from the Danish Shoulder Ar- park Morten throplasty Knudsen, Registry Svend-Erik Heiselberg, Ole Brink Jeppe Rasmussen, Anne Polk, Anne Kathrine Belling Sørensen, Bo Sanderhoff 163. Olsen, Tibia Stig intramedullary Brorson nailing - comparison of physical activity and pain with or without secondary surgery Katrine 178. Mri Borum, imaging Peter Toquer and pathology Jessen of avascular necrosis in the proximal pole of the scaphoid bone after fracture 164. Britt Tibia Mejer, intramedullary Niels Søe, Nina Vendel nailing Jensen, - secondary Katalin surgery Kiss, Lone - Larsen, rate, indications Lars B. Dahlin contexts. and Katrine Borum, Toquer Jessen Peter 179. Early experience with bone scan SPECT CT in assessing adolescents 165. with Complication complex problems rates in unstable the foot trochanteric and ankle region fractures when type of osteosynthesis Ole Rahbek, Deborah is dictated M Eastwood, by the Marina preference Easty, of Lorenzo the surgeon Biassoni Eske Brand, Jakob Klit 180. Supramelleolar tibial osteotomy without fibular osteotomy, allowing immediate Surgery for weightbearing, Kyphoscoliosis is in safe. Parkinson s Disease 167. Ebbe Ida Marie Stender Rahbek, Hansen, Gert Dharmendra Rahbek Andersen Singh, Cody Bünger 168. 181. The Biomechanical physical and symmetry mental outcome of a hip of joint 100 altered patients by having Perthes a Percutaneous Remel Salmingo, Vertebroplasty Tina Skytte, because Marie of Sand pathological Traberg, Kaj-Åge vertebral Henneberg fractures., Klaus disease Søren Hindsø, Lykke Christian Lorentzen, WongRikke Rousing, Stephan Hummel 169. 182. Evaluation The postoperative of stratified rehabilitation surgical intervention of lumbar disk based patients on the in Aarhus the Region of Tumor Southern Algorithm Denmark Spinal Miao Rune Wang, Tendal Cody Paulsen, Eric Bünger, Erik Bergholdt, Kristian Mikkel Høy, Peter Østerheden Helmig, Ebbe Andersen, Stender Rikke Hansen, Rousing Haisheng Li 170. 183. The Can epidemiology older patients of survive surgically 8 hours treated spine spinal reconstruction fractures in Eastern surgery Denmark for degenerative scoliosis? Thomas Jens Egebjærg Pensbo-Madsen, Rye Svendsson, Kiran Anderson, Valancius Corrado Kestutis Lucantoni, Santhana Rambabu, Martin Gehrchen, Benny Dahl 184. The EOS imaging system: Workflow and radiation dose in scoliosis 171. examinations Satisfactory Curve Correction Using Ultra Low Profile Segmental Pedicle Bo Mussmann, Screw Implant Stig Jespersen, in AIS Trine Torfing Martin Gehrchen, Jonas Walbom, Lars Valentin Hansen, Benny Dahl 185. Stand-alone XLIF; 22 Consecutive patients with degenerative scoliosis and foraminal stenosis a 2 year follow-up Emil Hansen 50 126 DOS Abstracts Bulletin DOS Kongressen 2014 119

186. 172. Early Artificial surgical Meniscal stabilization scaffold of rib Implantation fractures using and Meniscal a minimally Allograft invasive Transplantation. procedure: a pilot study Kiran Martin Anderson, Rathcke, Jesper Peter Ravn, Lavard, Henrik Michael Eckardt Krogsgaard 187. 173. Open Does showering bony hip morphology of external ring affect fixators the outcome in combination of treatment with occlusive patients pin with care. adductor-related A prospective study groin of pain? infection Long rate. term results of a ran- for Mykola domised Horodyskyy, controlled Søren trial. Kold, Pernille Bønneland, Anne Mette Pedersen, Juozas Per Hölmich, Petruskevicius Kristian Thorborg, Per Nyvold, Jakob Klit, Michael Bachmann Nielsen, Anders Troelsen 188. 1-year follow up after a 3 months training program mean 3 years after 174. THA Custom-made following a orthotics femoral neck decrease fracture medial foot loading during drop Christina jump and Frölich, single-leg Inger Mechlenburg, squat in individuals Sara Birch with, Lone patellofemoral Lundager, Torben pain Baek- Hansen, Michael Maiken Rathleff, Stilling Camilla Richter, Jesper Bencke, Thomas Bandholm, Per Hölmich, Kristian Thorborg 189. Coagulant preventing drugs in patients with hip fractures Bjarke 175. Viberg, DHAR Lasse the Enkebølle Danish Hip Rasmussen Arthroscopy Register Bent Lund, Søren Winge, Otto Kraemer, Svend Erik Christiansen, Martin Lind 190. Impact of timing of soft tissue coverage and antibiotics in outcome 176. of Tendon open tibial and skeletal 2 fractures muscle matrix gene expression and functional Ulrik responses Kähler Olesen, to immobilization Rasmus Juul, Christian and rehabilitation Bonde, Claus in young Moser, males: Henrik Eckardt Effect of growth hormone administration 191. Anders Intraoperative Ploug Boesen, 3D Kasper imaging Dideriksen, is useful Peter in Schjerling, the operative Christian treatment Couppe, of Michael Kjaer, calcaneal Henning fractures Langberg displaced Marianne Vestergaard Lind, Henrik Eckardt 177. Outcomes of acute fixation of chondral lesions following patellofemoral Ewings sarcoma dislocationof the calcaneus treated by limb sparing surgery 192. with Knud calcanectomy Gade Freund, Lene and Guldberg reconstruction Hansen, with Peter a Kraglund composite Jacobsen of an allograft and a vascularised osteocutaneous fibula graft. Werner 178. Trochleaplasty Hettwer, Lisa Toft in Jensen, the treatment Michael Mørk of severe Petersen patellofemoral instability 193. Peter Pathway Lavard, Anette Leading Hollm To Kourakis, Lower Limb Michael Amputation Rindom Krogsgaard a Danish national registry study Pia 179. Søe Incidence Jensen, Klaus of Kirketerp-Møller, arthroscopy-identified Nasrin Faqir, cartilage Janne Petersen, injuries Ingrid of the Poulsen, and Ove proportion Andersen leading to repair procedures A nationwide Danish co- knee hort study 1996-2011 194. Anil Mor, Clinical Miriam outcome Grijota, after Mette CT-guided Nørgaard, Jonas radiofrequency Munthe, Martin ablation Lind, Alma of osteoicic Pedersen osteoma. Long-term follow up in 52 patients. Be- Morten Knudsen, Andreas Riishede, Arne Lücke, John Gelineck, Johnny Keller, Thomas Baad-Hansen 130 DOS Bulletin DOS Kongressen 2013 2014 127 51

180. 195. The Extended influence Antibiotic of Patellar Prophylaxis and Trochlear is associated lesions on with the Low results Rate of of anteromedial Infection after tibia Tumor tubercle Resection osteotomy and Endoprosthetic Reconstruction involving Kiilerich the Proximal Andresen, Femur Jens Kristinsson Andreas Werner H. Hettwer, Thea B. Hovgaard, Peter Horstmann, Thomas A. Grum- 181. Schwensen, Comparison Michael of M. Two Petersen Humeral Head Resurfacing Implants. 2 year Results of a Randomized Controlled Clinical Trial Inger Mechlenburg, Thomas Klebe, Kaj Døssing, Kjeld Søballe, Maiken Stilling 182. Clinical implications of positive cultures in revision shoulder arthroplasty Thomas Falstie-Jensen, Janne Ovesen, Viggo S. Johannsen 183. Translation and validation of Western Ontario Osteoarthritis of the Shoulder Index (WOOS) The Danish Version Jeppe Rasmussen, John Jakobsen, Stig Brorson, Bo S Olsen 184. Construct validity and responsiveness of functional measures used in subjects following an outpatient prosthetic rehabilitation program after a major lower limb amputation Kajsa Lindberg, Joanne Boelskifte, Jimmy Johansson, Mie Rinaldo, Morten Tange Kristensen 185. Pneumococcal sepsis-induced Symmetrical Peripheral Gangrene Taj Haubuf, Klaus Kjær Petersen, Kurt Fuursted, Alex Lund Laursen, Johnny Keller 186. Ultrasound guided core needle biopsy of peripheral nerve sheath tumors. A retrospective study. Damgaard Jacob, Hauge Hansen Bjarne, Holmberg Jørgensen Peter, Keller Johnny, Hellfritzch Michel, Baad-Hansen Thomas 187. Local Recurrence Rate after Surgical Excision of Desmoid Fibromatosis. Elinborg Mortensen, Thea Hovgaard, Michael Mørk Petersen 188. Persistent wound drainage after tumor resection and endoprosthetic reconstruction the proximal femur Peter Horstmann, Werner Hettwer, Tomas Grum-Schwensen, Michael Mørk Petersen 52 128 DOS Abstracts Bulletin DOS Kongressen 2014 131

Abstracts DOS Kongressen 2014 53

Prosthetic Joint Infection (PJI): Bacterial Identification with Heat Flow Detection in Sonication Fluid of Removed Total hip or knee Arthroplasty (THA/TKA) 1. Christen Ravn, Michael Kemp, Per Kjærsgaard-Andersen, Søren Overgaard Orthopaedic Research Unit, University of Southern Denmark; Department of Clinical Microbiology, Odense University Hospital; Department of Orthopaedic Surgery, Vejle Hospital; Department of Orthopaedic Surgery and Traumatology, Odense University Hospital Background: In PJI a delay of 5-10 days after surgery is frequent before bacterial diagnosis by conventional culture methods. Introduction of sonication for biofilm dislodgement of removed implants have increased the sensitivity of PJIdiagnostics as compared to culture of biopsies (Trampuz et al. NEJM, 2007). Microcalorimetry can demonstrate microbial growth in small fluid samples as measured by heat flow (µw), and may even give a more rapid diagnosis than simple culture. Purpose / Aim of Study: To compare microcalorimetry with culture of sonication fluid for bacterial detection, and to evaluate the time to detection (TTD) of bacterial presence by microcalorimetry. Materials and Methods: We analyzed prosthetic components removed during joint revision for deep infection (Dinf) or aseptic loosening (Asl) of THA and TKA. The prostheses were individually sonicated before aerobic and anaerobic culture, and checked for positive growth (>20 colonies/ml) twice daily. Furthermore sonication fluid (SF) was analyzed with microcalorimetry (TA Instruments) for 48 hours. TTD (hours) was defined as time to reach a detection limit of 10 µw. Findings / Results: In 111 revisions of THA (70) and TKA (41) indications were resp. Dinf (49) and Asl (62). Sonication fluid was found culture positive in 50 cases, whereas microcalorimetry was positive in only 35 (sensitivity 0.70 / specificity 0.93) with a mean TTD of 9.4 hours (range 1.5-29.4). Bacterial findings of microcalorimetry appears as species (no./mean TTD): S.aureus (9/6.4), E.faecalis (7/8.2), streptococcus sp. (4/12.3), E.coli (1/12.7), and coagulase neg. staph. (13/14.3). Bacteria not found incl. CNS (3), P.acnes (2) and streptococc sp. (2). Conclusions: Microcalorimetry of sonication fluid demonstrated good specificity, but rather low sensitivity. A bacterial diagnosis was rapidly found (mean 9.4 hr) by heat flow detection. 54 DOS Abstracts

Revision risk of cementless metal-on-metal total hip arthroplasty is influenced by component brand Claus Varnum, Alma B. Pedersen, Mäkelä Keijo, Leif Ivar Havelin, Johan Kärrholm, Søren Overgaard 2. Orthopaedic department, Vejle Hospital; Department of clinical epidemiology, Aarhus University Hospital; Department of Orthopaedics and Traumatology, Turku University Hospital, Finland; The Norwegian Arthroplasty Register, Department of Orthopedic Surgery, Haukeland University Hospital, Bergen, Norway; Institute of Clinical Sciences, Department of Orthopaedics, Sahlgrenska University Hospital, Gothenburg, Sweden; Department of Orthopaedic Surgery and Traumatology, Odense University Hospital Background: There are several concerns for the use of metal-on-metal (MoM) bearings in total hip arthroplasty (THA) especially for certain brands of MoM components due to increased revision rates. Purpose / Aim of Study: We aimed to investigate the 6-year revision risk of cementless stemmed MoM THAs in a population-based follow-up study from the Nordic Arthroplasty Registry Association (NARA). Materials and Methods: In the NARA database, we identified 85,371 cementless stemmed primary THAs operated from 2002 to 2010. Metal-on- polyethylene (MoP) THA was used as reference, and only patients operated with MoM or MoP bearings were included. In total, 32,678 patients were included. At 6 years follow-up, the adjusted relative risk (arr) for any revision with 95% confidence intervals (CI) was assessed by the use of regression with the pseudovalue approach and modelled with death as competing risk. Findings / Results: 11,567 patients (35%) had MoM and 21,111 (65%) had MoP THAs. The arr of any revision for MoM was 1.49 (CI: 1.30-1.71). For different brands of acetabular cups in MoM THA, higher RR of any revision was found for the ASR cup (n=759; arr 6.38, CI: 4.99-8.15), the Conserve Plus cup (n=478; arr 1.70, CI: 1.14-2.54), and other cups (n=351; arr 2.38, CI: 1.45-3.92). No difference in RR of any revision was found for the Recap, M2a, Pinnacle, Birmingham, and Durom cups compared to MoP THA. After exclusion of the 759 patients having the ASR acetabular component, the arr of any revision was 1.12 (CI: 0.97-1.30) for MoM compared to MoP THA. Conclusions: The arr of any revision at 6 years follow- up was 49% higher for MoM compared to MoP THA. After exclusion of the ASR cup, the arr of any revision was 12% higher for MoM THA although this was not significant. Based on recent reports, we may expect increasing revision rates of MoM THAs with longer follow-up. DOS Kongressen 2014 55

Regional differences between US and Europe in radiological osteoarthritis and self assessed quality of life in patients undergoing Total Hip Replacement (THR) surgery 3. Kirill Gromov, Meridith Greene, Nanna Sillesen, Peter Gebuhr, Anders Troelsen, Henrik Malchau Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Harris Orthopaedic Laboratory, Massachusetts General Hospital Background: Precise indications for THR remain unclear and regional differences might exist in selecting patients for surgery. Purpose / Aim of Study: In this study we investigate radiological grade of OA and self-reported quality of life in patients undergoing THR in US and Europe Materials and Methods: There are 909 patients from 16 centers in the USA and Europe enrolled into a prospective 10year outcome study. All patients were operated using an uncemented RingLoc or Regenerex cup and a Biomet stem of surgeons choice. Recorded patient demographics included age, gender, BMI and Charnley score. Preoperative grade of OA was recorded using Tönnis classification as well as JSW. Self reported survey data included pain visual analogue scale (VAS), EQ-5D, SF36, Harris Hip, and UCLA scores that were recorded preoperatively and at 1 year follow up. Findings / Results: Patients in US were significantly younger (61.4vs 64.2; p<0.001) and had a higher BMI (29.9vs 27.4; p<0.001). More patients with mild Tonnis OA grade underwent surgery in US compared to Europe (5.3% vs 2.2%, p=0.046). Patients in the US had significantly higher pain VAS (6 vs 5; p=0.004) and significantly lower SF-36 Physical Function (29.7 vs 33.9; p=0.003), while having significantly higher EQ VAS scores (78 vs 66; p<0.001) preoperatively. Conclusions: Patient demographics and disease severity according to radiological OA grade and self- reported survey scores vary between United States and Europe. This knowledge can be used in the interpretation of US and European based studies on outcome following THR. 56 DOS Abstracts

The true incidence of prosthetic joint infection after 32,896 primary total hip arthroplasties: A prospective cohort study 4. Per Hviid Gundtoft, Søren Overgaard, Henrik Carl Schønheyder, Jens Kjølseth Møller, Per Kjærsgaard-Andersen, Alma Becic Pedersen Orthopedic, Kolding Hospital and Odense University Hospital; Orthopaedic Surgery and Traumatology, Odense University Hospital; Clinical Microbiology, Aalborg University Hospital; Clinical Epidemiology, Aarhus University Hospital Background: The risk of prosthetic joint infection in patients with total hip arthroplasty (THA) is often underestimated when based on registry data. Purpose / Aim of Study: The purpose of this study was to estimate the true incidence of prosthetic joint infection in THA using multiple data sources. Materials and Methods: The Danish Hip Arthroplasty Register (DHR) was searched for primary THAs performed between January 1, 2005 and December 31, 2011 in the Danish provinces Jutland and Funen. The DHR and the Danish National Register of Patients (NRP) were searched to identify first revisions following a primary THA. The revisions were classified as due to prosthetic joint infection or to causes other than infection using an algorithm incorporating intraoperative cultures, aspirations of joint fluid, plasma C- reactive protein, prior use of antibiotics, and clinical findings described in the medical record. We calculated the cumulative incidences. Findings / Results: A total of 32,896 primary THAs were identified. Of these, first time revisions were reported to the DHR and/or NRP for 1,546. The 1-year cumulative incidences of prosthetic joint infection were 0.51 % [CI 0.44; 0.59] and 0.48 % [0.41; 0.56] for the DHR and NRP, respectively; while, the 5-year cumulative incidences were 0.64 % [0.51; 0.79] and 0.57 % [0.45; 0.71], respectively. The corresponding 1- and 5-year cumulative incidences estimated by the algorithm were 0.86 % [0.77; 0.97] and 1.03 % [0.87; 1.22], respectively. Thus, the true incidence of prosthetic joint infection in primary THA was approximately 40 % higher compared with the national registers when using additional data. Conclusions: The true incidence of prosthetic joint infection in primary THA is significantly higher than reported by the Danish national registers and can be estimated using multiple clinical and paraclinical data. DOS Kongressen 2014 57

Comparison of outcomes and complications of hip arthroscopy for mixed hip disorders in adolescents versus adults: a prospective cohort study 5. Manoj Ramachandran, Pramod Achan, Martin Gottliebsen, Bjarne Møller- Madsen Department of Paediatric Orthopaedics, Barts and The London Children s Hospital, Whitechapel Road, Whitechapel, London, England ; Department of Children s Orthopaedics, Aarhus University Hospital Background: The current literature indicates that hip arthroscopy is safe in both adolescents and adults with good early outcomes. There are no available studies however that directly compare the outcomes of this procedure for mixed indications between these two groups. Purpose / Aim of Study: This was a prospective cohort study of 102 consecutive supine hip arthroscopies in 96 patients (48 adolescent (<18) hips, mean age 13.9 years and 54 adult (>18 hips), mean age 33.8 years) at a tertiary referral paediatric and adult university hospital followed-up for a minimum of two years. Materials and Methods: At two-year follow-up, the Modified Harris Hip Score improved from a mean of 55.3 to 87.5 (p<0.05) in the adolescent group and from 58.7 to 86.9 (p<0.05) in the adult group while the Non-Arthritic Hip Score improved from 57.1 to 86.7 (p<0.05) in the adolescent group and from 61.4 to 87.4 (p<0.05) in the adult group. There was no statistical significance difference in outcome between the two groups at 2 years. With respect to complications, there were 3 transient pudendal nerve palsies that resolved spontaneously in the adolescent group by 4 weeks. No cases of proximal femoral physeal growth disturbance or osteonecrosis were seen at final follow-up. Findings / Results: This study confirms that hip arthroscopy for mixed indications leads to good early outcomes with low complication rates in adolescent and adult patients. The incidence of pudendal nerve palsy in the adolescent group is however noted and is of concern. Advances in hip arthroscopy for adolescent hip disorders should focus on reducing or eliminating the side effects of traction. Conclusions: Hip arthroscopy, although effective in adolescents and adults in the short-term for mixed indications, has a higher incidence of pudendal nerve palsy in adolescents. 58 DOS Abstracts

Higher UHMWPE wear rate in cementless compared with cemented cups with the Saturne Dual-Mobility system. Steffan Tabori Jensen, Morten Homilius, Christina Frølich, Torben Bæk Hansen, Maiken Stilling Ortopædkirurgisk, Hospitalsenheden Vest 6. Background: Displaced medial femoral neck fracture (FNF) may be treated with primary arthroplasty. Dual-mobility articulations have advantages on stability and range of motion, however polyethylene (PE) wear on two articulating sides might lead to excessive wear. Purpose / Aim of Study: To investigate PE wear rate of primary DM cups in patients with acute FNF Materials and Methods: From 2005-2011, 414 consecutive patients were operated with Saturne DM cups, 28mm femoral metal heads, UHMWPE. Cementless cups were coated with hydroxyapatite (HA). 239 cups were cemented and 175 were press-fit by choice of the surgeon. In 2012, at minimum 1-year follow-up, 155 patients were dead and the remaining 259 were invited for clinical follow-up. 80 patients were evaluated with standard radiographs for analysis of cup placement, 2D wear and wear rate (PolyWare software 3D Pro). Mean age at time of surgery was 80 (range 30-98) years. Findings / Results: At a mean follow-up of 3.5 (1.4 7.7) years the mean 2D wear was 0.82 (sd 0.38, 0.3-2.2) mm and 2D wear rate was 0.29 (sd 0.21, 0.1-1.2). Wear rate of 0.35 (sd 0.22) in cementless cups were higher (p=0.045) than 0.16 (sd 0.07) in cemented cups. Patients with cementless cups were younger (78 vs. 81 years, p=0.005). Mean cup inclination was 44 (26-65) degrees and mean cup anteversion 17 (-12-47). There was no correlation between cup inclination and wear (p>0.34) and no difference in wear between gender (p>0.33). There was no correlation between age at time of surgery and wear (p>0.06). Cup inclination was similar (p=0.13) for cemented and cementless cups. Conclusions: At short term follow-up, we found a higher wear rate in cementless HA coated cups compared with cemented cups. In general mean 2D wear and wear rate in these old and low demand patients was high and above the osteolysis threshold (0.1mm). DOS Kongressen 2014 59

Early morbidity after aseptic revision hip arthroplasty in Denmark. A 2 year nationwide study. Martin Lindberg-Larsen, Christoffer Calov Jørgensen, Torben Bæk Hansen, Søren Solgaard, Henrik Kehlet 7. Section of Surgical Pathophysiology and The Lundbeck Centre for Fast-track Hip and Knee Arthroplasty, Rigshospitalet, Copenhagen University, Denmark; Department of Orthopaedic Surgery and The Lundbeck Centre for Fast-track Hip and Knee Arthroplasty, Holstebro Regional Hospital, Holstebro, Denmark Background: Limited data exist on early morbidity after revision total hip arthroplasty (RTHA). Purpose / Aim of Study: To describe early morbidity after aseptic RTHA and relate the morbidity to the extent of the revision procedure. Materials and Methods: All aseptic RTHA procedures from 2009 to 2011 were analysed using the Danish National Patient Registry with additional information from the Danish Hip Arthroplasty Registry. The procedures were divided into total revisions, acetabular cup revisions, femoral stem revisions and partial revisions. All readmissions and in- hospital complications were analyzed based upon detailed evaluation of patient records and causes were divided into surgical and medical complications. Findings / Results: 1553 procedures were performed in 40 centres. The mean age was 70.4 years (range: 25-98) and median length of hospital stay (LOS) 5 days (interquartile range, IQR: 3-7). Within 90 days postoperatively the readmission rate was 18.3% and mortality rate 1.4%. The 90-day reoperation rate was 6.1%, dislocation rate 7.0% and infection rate 3.0%. Of all readmissions, 63.9% were due to surgical complications vs. 36.1% medical complications. The duration of surgery, bone loss, intraoperative complications and LOS indicated that the total revisions and femoral stem revisions represented the most complex surgery, but there were no differences in early morbidity across the surgical subgroups. Conclusions: Aseptic RTHA was performed with LOS of 5 days and without differences in early morbidity across revision subgroups despite major differences surgical extent. All types of RTHA were associated with increased early morbidity compared to primary hip arthroplasty. The results from this study suggest that future focus should be held on the surgical technique as well as the perioperative set-up according to the fast-track methodology. 60 DOS Abstracts

Promising migration Pattern at 1 year follow-up of the short Primoris Femoral Stem Mogens Berg Laursen, Janus Duus Christiansen, Gordon Blunn, Poul Torben Nielsen 8. Northern Ortopaedic Division, Aalborg University Hospital; University College London, RNOHT, Stanmore, United Kingdom Background: In order to save proximal bone stock in primary total hip arthroplasty (THA), short femoral stems are introduced. Purpose / Aim of Study: Designed for perfect fit within the femoral neck, the Primoris femoral stem has been released for clinical studies in coherence with the stepwise introduction of new implants. This is the preliminary report of the Radio Stereometric Analysis (RSA) results after 1 year follow-up (FU). Materials and Methods: We carried out a prospective cohort study of 52 patients scheduled for surgery with the femoral neck-preserving Primoris stem. Migration was analyzed by RSA, and the Harris hip score, UCLA activity score, WOMAC, EQ5D health questionnaire and Oxford Hip scores were recorded. Findings / Results: 2 patients were excluded intra-operatively and 1 patient was revised due to aseptic loosening after 3 months, leaving 47 patients for analysis. Further 2 patients were excluded from the RSA analysis due to technical problems. RSA showed minor micromotion of the stem: Mean subsidence was 0.35 mm (precision: 0.10 ) and mean rotation around the longitudinal axis was 0.10º (precision: 0.64) after 1 year. Conclusions: The stems showed very small migration as it is characteristic for stable uncemented implants. If they stay stable until the 2 year FU, we will go on with a multi center study. DOS Kongressen 2014 61

Fast-track pathway for reduction of dislocated Hip Arthroplasty reduces surgical delay and length of stay Kirill Gromov, Fatin Willendrup, Henrik Palm, Anders Troelsen, Henrik Husted Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre 9. Background: Dislocation is one of the most common complications following hip arthroplasty. Delay until reduction leads to pain and discomfort for the patient and can potentially increase risk for complications. Purpose / Aim of Study: In this study we investigated the safety aspect of a fast-track pathway for dislocated hip arthroplasties and evaluated its effect on surgical delay and Length of Stay (LOS) Materials and Methods: 402 consecutive and unselected dislocations (253 patients) were admitted at our institution between 05-10-2010 and 09-31- 2013. Fast track pathway for early reduction was introduced on 01.01.2012. Fast track patients with clinically suspected dislocation (no radiographic verification) were moved directly to post anesthesia care unit (PACU) and then straight to the OR (operating room). Dislocation was confirmed under fluoroscopy and reduced under general anesthesia. Surgical delay (hours), LOS (hours), perioperative complications and complications during hospital stay were recorded. Dislocation status for fast-track patients (confirmed vs unconfirmed by fluoroscopy) was recorded as well Findings / Results: Both surgical delay (2.5 vs 4.1; p<0.001) and LOS (26.0 vs 30.5; p<0.05) were significantly reduced in patients admitted through fasttrack pathway compared to regular pathway. Perioperative complications (1.6% vs 3.7%) and complications during stay (11.2% vs 15.4%) were also reduced, however insignificantly. Only 1 case admitted through fast-track pathway had a fracture instead of a dislocation; no fast-track patients with suspected dislocation had no dislocations Conclusions: Fast-track pathway for reduction of dislocated hip arthroplasty results in decreased surgical delay as well as LOS, without increasing perioperative complications or complications during hospital stay 62 DOS Abstracts

Re-revision rates following revision of cemented and cementless primary hip arthroplasty 10. Kirill Gromov, Alma Pedersen, Søren Overgaard, Peter Gebuhr, Henrik Malchau, Anders Troelsen Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Department of Clinical Epidemiology, Aarhus University Hospital; 3Department of Orthopaedic Surgery, Traumatology and Clinical Institute, Odense University Hospital; Orthopaedic Department, Massachusetts General Hospital Background: Increased use of cementless technique for primary THA in most parts of the world can lead to changes in reoperation patterns, ie indications for revision, and potentially influence the survival of revision arthroplasty. Purpose / Aim of Study: In this registry-based study we wanted to investigate the role, primary femoral fixation plays in survival of revision arthroplasty. Materials and Methods: Primary THA s with cemented (n=1889) and uncemented (n=805) femoral component that subsequently sustained 1st revision of femoral component were identified from the Danish Hip Registry. Survival of 1st revision THA, with 2nd revision of the femur as outcome, was evaluated using cox regression analyses to calculate adjusted hazard ratios (HR). Patient demographics, time until revision, indications for revision and femoral bone defects at the time of 1st revision were also recorded. Findings / Results: Adjusted HR for 2nd revision due to any reason of cementless compared with cemented primary THA with 1st revision was 1.36; 95%CI (1.02-1.83). 71.6% of cemented primary THAs were revised due to aseptic loosening; while 46.1% of cementless primary THAs were revised due to femoral fracture. 3.6% of revisions on cemented primary THAs were performed <1 year after index surgery, compared to 37.1% of revisions on cementless THA s when only looking at revisions performed due to aseptic loosening. Conclusions: We found significantly increased risk of 2nd revision after 1st revision performed on primary cementless THA compared to cemented THA considering all causes for revision. Different indications for 1st revision could potentially explain inferior survival of revision performed on cementless THA. Our data suggest that increased use of cementless fixation in primary THA might lead to inferior survivorship of 1st revision THA. DOS Kongressen 2014 63

Can hip surgeons code periprosthetic joint infection? A cross-sectional study of data validity in the Danish National Patient Registry. 11. Jeppe Lange, Alma B. Pedersen, Anders Troelsen, Kjeld Søballe Lundbeckfoundation Centre for Fast-track Hip and Knee Surgery, Tage- Hansens Gade 2, 8000 Aarhus, Den, Department of Orthopaedic Surgery, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus, Den; Department of Clinical Epidemiology, Aarhus University Hospital, Olof Palmes Allé 43-45, 8200 Aarhus, Denmark; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Kettegaard Allé 30, 2650 Hvidovre Denmark Background: The Danish National Patient Registry (DNPR) collects data for all patients in Denmark. The DNPR is a potential high quality research database, however, validity of data on prosthetic joint infection (PJI) is unknown. Purpose / Aim of Study: To evaluate the positive predictive value (PPV) of diagnosis and procedure codes associated with hip PJI. Materials and Methods: We identified patients in the DNPR from 2003-2008 in Aarhus, Aalborg, Silkeborg, Viborg, Hvidovre, Vejle, Gentofte, Hørsholm, Hillerød, Helsingør, and Frederikssund with a primary and secondary ICD10 discharge diagnosis of T84.5. As we aim to validate only hip joint affections, we combined T84.5 with a hip joint noninfectious-specific (NIS) or infectiousspecific (IS) procedure code. Medical records of all identified patients (n= 236) were reviewed by one of the authors. Findings / Results: 190 of the 236 patients were confirmed as having a hip PJI according to a priori defined criteria, corresponding to an overall PPV of 81%. This means that the T84.5 diagnosis code truly correlates with hip PJI in 81% of the patients coded with the investigated combination in the DNRP. The PPV of the T84.5 diagnosis code in combination alone with a hip NIS procedure code was 69%, while T84.5 in combination alone with a hip IS procedure codes was 87%. Conclusions: T84.5 is the sole discharge diagnosis regarding PJI. The PPV of T84.5 in the DNRP is currently not satisfactory. Data on PJI obtained from administrative registries are a valuable source of information, but should be used with caution in medical research. We urge hip surgeons to be meticulous in their onward coding practice, to increase the PPV of the T84.5 code to enable valid research in a field where absolute number of PJI is low, making clinical epidemiologic research on register data a valuable source of future knowledge. 64 DOS Abstracts

No association between pseudotumors, high serum metal-ion levels and metal hypersensitivity in largehead metal-on-metal total hip arthroplasty at 5-7- year follow-up 12. Mette Holm Hjorth, Maiken Stilling, Kjeld Søballe, Lars Hans Bolvig, Inger Mechlenburg, Stig Storgaard Jakobsen Department of Orthopaedics, Aarhus University Hospital; Department of Radiology, Aarhus University Hospital Background: The relationship between metal wear debris, pseudotumor formation and metal hypersensitivity is complex and not completely understood. Purpose / Aim of Study: The purpose of this study was to assess the prevalence of pseudotumor formation in a consecutive series of metal-on-metal (MoM) total hip arthroplasty (THA) and to investigate its relationship to serum metal-ion levels and hypersensitivity to metal. Materials and Methods: Forty-one patients (31 males), mean age 52 (28-68) years, with a total of 49 large-head MoM THA participated in a 5-7-year follow-up study. Patients underwent ultrasonography (US), serum metal-ion concentrations were measured, metal allergy (patch test) and atopic dermatitis were evaluated, and the patients completed the questionnaires of the Oxford Hip Score (OHS), Harris Hip Score (HHS) and the Short-Form Health Survey (SF- 36). Findings / Results: Pseudotumors were found in eight patients, but they were asymptomatic and their serum metal-ion levels were similar to those observed in patients with no pseudotumors (p>0.36). The capsule- stem distance of mean 8.6 mm (SD 3.82, 95% CI: 5.40-11.79) was wider (p=0.02) in patients with pseudotumours than in patients without pseudotumors of mean 5.6 mm (SD 2.89, 95% CI: 4.68-6.58). Positive patch test reactions were seen in three patients (two to nickel and one to iron). Higher serum metal-ion levels of chromium and cobalt were significantly correlated with steeper cup inclination and smaller femoral head sizes, and were associated with female gender (p<0.04). Conclusions: We found no association between pseudotumor formation, serum metal-ion levels, metal patch test reactivity, and atopic dermatitis. However, clinicians should be aware of asymptomatic pseudotumors, and we advise further exploration into the mechanisms involved in the pathogenesis of pseudotumors. DOS Kongressen 2014 65

Is the use of oral contraceptives associated with operatively treated anterior cruciate ligament injury? A case-control study from the Danish Registry of Knee Ligament Reconstruction 13. Lene Rahr-Wagner, Theis Thillemann, Frank Menhert, Alma Pedersen, Martin Lind department of ortopaedic surgery, Aalborg University Hospital; department of clinical epidemiology, Aarhus University Hospital; department of ortopaedic surgery, sports medicine, Aarhus University Hospital Background: The incidence of anterior cruciate ligament (ACL) injuries is 2-9 times higher in women than in men. Additionally, in vitro studies have demonstrated that ACL is an estrogen target tissue, and some studies have therefore suggested a protective association between oral contraceptives (OC) and the likelihood of sustaining ACL injury. Purpose / Aim of Study: The aim was to test the hypothesis of a protective association between OC use and the likelihood of sustaining operatively treated ACL injury. Materials and Methods: The study population included 4,497 female cases with an operatively treated ACL injury registered in the Danish Registry of Knee Ligament Reconstruction for the 2005-2011 period and 8,858 age-matched controls with no ACL injury. The study evaluated exposure to OC use at the time of ACL injury and in the five previous years (ever user) or no OC use (never user). Ever users were further classified as either new users, long-term users or recent users. Finally, a dose-response analysis of OC use was performed. We used conditional logistic regression to calculate the relative risk (RR) with a 95% confidence interval (CI) of sustaining operatively treated ACL injury according to OC use. Findings / Results: The adjusted RR associating OC with ACL injury was 0.82 (95% CI: 0.75 to 0.90) between ever users and never users. Furthermore, we found a decreased relative risk (RR) of sustaining ACL injury of 0.80 (95% CI: 0.74 to 0.91) in long-term users and 0.81 (95% CI: 0.72 to 0.89) in recent users. Additionally, we found a trend towards a dose-response association. Using OC for more than four years did not seem to alter the likelihood of sustaining operatively treated ACL injury. Conclusions: This indicates a protective association between OC use and the likelihood of sustaining operatively treated ACL injury. 66 DOS Abstracts

Limited Osteochondral Repair by a Biomimetic Collagen Scaffold - One to Three Years Clinical and Radiological Follow-Up 14. Bjørn Christensen, Casper Foldager, Niels Christian Jensen, Cody Bünger, Martin Lind Orthopedic Research Laboratory, Aarhus University Hospital; Department of Orthopedic Surgery, Aarhus University Hospital; Division of Sports trauma, Aarhus University Hospital Background: Osteochondral injuries are therapeutically challenging and no gold standard treatment has been established. Cell-free, layered scaffolds are a new treatment option for these defects. Purpose / Aim of Study: The aim of this study was to evaluate the osteochondral repair in patients treated with The MaioRegen scaffold, a cell-free biomimetic scaffold. It has previously been shown to induce clinical subchondral bone and articular cartilage regeneration. Materials and Methods: Eleven patients with osteochondral defects in the knee (n=7) or in the talus (n=4) were enrolled. Patients filled out clinical evaluation questionnaires pre-op and at the final follow-up (2,5 years, range 1,9-3,1 years). The patients underwent pre-op MRI, and CT and MRI 1 (range 1-1,2 years) and 2,5 years post-op (range 1,9-3,1 years). The knee patients were evaluated using KOOS, IKDC and Tegner, the ankle patients using AOFAS Hindfoot and Tegners score. The cartilage and bone formation was evaluated using the MOCART score. Findings / Results: Three patients were re-operated and excluded due to treatment failure. CT: None of the patients had complete regeneration of the bone. 6/8 patients had no or very limited (<10%) bone formation. 1/8 had 20-30% bone filling and 1/8 had 40-50% bone filling. MRI: No improvement was found in the MOCART score at any time point. 5/6 patients experienced a clinical improvement, and one patient a worsening. The results were insignificant. Conclusions: Treatment of osteochondral defects with the MaioRegen scaffold resulted in incomplete cartilage- and limited subchondral bone repair at 1 and 2,5 year s follow-up. Three patients were excluded due to treatment failure. This study raises concerns about the biological repair potential of the MaioRegen implant. Long-term studies are needed to investigate if the clinical improvements are permanent. DOS Kongressen 2014 67

One-year follow-up after ACL reconstruction surgeon or physical therapist? 15. Ina Wieland Nielsen, Kirsten Bettina Jensen, Jonathan Jetsmark Bjerre, Peder Klement Jensen, Michael R. Krogsgaard Ergo- and Physical Therapy, Bispebjerg Hospital; Section for Sportstraumatology M51, Bispebjerg Hospital; Dept. of Orthopadic Surgery, Bispebjerg Hospital Background: One year follow-up after ACL reconstruction is traditionally done by orthopaedic surgeons, often the person who operated, which could lead to bias in the results. One year is also time for return to sports, and patients often request instruction for further rehabilitation. Purpose / Aim of Study: To replace surgeons with physical therapists (PTs) at one-year follow-up and evaluate if stability measures changed. Materials and Methods: Between 1.5.13 and 30.4.14 (P2) one- year follow-up of patients after ACL reconstruction were done by one of two specially trained PTs and only by a surgeon if problems were reported. Stability measures including Lachman-, drawer- and pivot-tests and anterior laxity with Rolimeter in both knees were performed. In addition 4 functional tests were done. The same stability measurements were performed by the surgeons in a previous period: 1.5.12 30.4.13 (P1), and results for the two periods were compared. Findings / Results: Rolimeter measures right/left were 5,63/5,79 mm in P1 and 6,96/7,07 mm in P2. Measures were significantly higher for both knees in P2 (t-test: p < 0,001). The difference between operated and non-operated knee in P1/P2 was 1,38/1,98 mm (p = 0,008). There were more positive drawer tests (p = 0,005) during P1, but no difference for Lachman and pivottests (p > 0,05). Standard rehabilitation plans (GOPs) had been sent to the local therapists following reconstruction, but the content of the actual rehabilitation varied and many patients asked for further instruction. Conclusions: Absolute measures and differences in Rolimeter measurements were higher during the period when PTs tested, indicating that PTs and surgeons might test differently. An advantage of PT follow-up is the possibility for further instructions, functional testing results and release of surgeons time. 68 DOS Abstracts

The association between patient-reported outcomes and physical outcome measures in Danish patients one year after anterior cruciate ligament reconstruction 16. Jonathan Comins, Bettina Jensen, Ina Wieland Nielsen, Volkert Siersma, Michael Krogsgaard Section for Sports Traumatology M51, Bispebjerg Hospital; 3Department of Occupational and Physical Therapy, Bispebjerg Hospital; Research Unit and Section of General Practice, Department of Public Health, University of Copenhagen Background: Patient-reported outcome measures (PROMs) fail to correlate with anterior laxity and functional performance tests in patients with anterior cruciate ligament (ACL) deficiency. A recent Korean study found that the IKDC PROM correlates significantly with laxity and functional performance in patients with ACL reconstruction. Purpose / Aim of Study: We assessed the degree of association between two different PROMs (KNEES-ACL and IKDC) and anterior laxity and standard functional performance tests in Danish patients one year post ACL reconstruction. Materials and Methods: Eighty-six patients who had undergone ACL reconstruction one year previously were retrospectively included. Patients completed KNEES-ACL and IKDC and a physical therapist applied tests of knee ligament laxity and a battery of standardized functional performance tests. Betweenknee differences were computed and Spearmans rho correlations were assessed between the seven subscales of KNEES, the IKDC total score, between-knee laxity values, and functional performance tests. Findings / Results: All KNEES subscores correlated highly significantly with the IKDC total score. KNEES ADL, Symptoms, and Slackness correlated highest with IKDC at between 0.67 and 0.78. Correlations between the other KNEES subscales and IKDC ranged from 0.36 to 0.57. There were low associations between laxity and functional performance. All KNEES subscales correlated highly significantly with one another. Conclusions: The IKDC and the KNEES-ACL do not correlate highly with physical outcome measures in Danish patients one year post ACL reconstruction. The IKDC correlates best with the constructs of ADL, Symptoms, and sensation of instability (Slackness) in the KNEES-ACL. This supports the notion that both PROMs and physical measures are necessary to assess surgical outcome in patients treated for ACL deficiency. DOS Kongressen 2014 69

PREVIOUS KNEE-INJURY AND LOW KNEE FUNCTION SCORE INCREASE THE RISK OF FUTURE KNEE INJURY IN ADOLESCENT FEMALE FOOTBALL 17. Mikkel Bek Clausen, Lars Tang, Mette Kreutzfeldt Zebis, Peter Krustrup, Per Hölmich, Kristian Thorborg School of Physiotherapy, Institute of Rehabilitation and Nutrition, Faculty of Health and Technology, Metropolitan University; Arthroscopic Centre Amager, SORC-C, Copenhagen University Hospital, Amager-Hvidovre, Denmark; Gait Analysis Laboratory, Copenhagen University Hospital, Hvidovre, Denmark; Department of Nutrition, Exercise and Sports (NEXS), Section of Human Physiology, Copenhagen Centre for Team Sport and Health, University of Copenhagen, Copenhagen, Denmark Background: Knee-injuries are common in adolescent female football. Severe knee-injuries can cause persistent symptoms, potentially forcing female players to retire from contact sport. Previous knee-injury is recognized as a risk factor for future knee-injuries in adult football, but evidence regarding adolescent female football is scarce and contains important methodological flaws. Purpose / Aim of Study: The primary aim of this study was to investigate the risk of sustaining future knee-injury in relation to previous knee-injuries. Secondly, low Knee Osteaoarthritis Outcome Score (KOOS) was investigated as a potential risk factor for future knee injuries. Materials and Methods: A population based sample of 326 girls (15-18 years) without knee-injury at baseline, participating in a Danish Football Association series during the spring 2012 season, was included. Self-reported data on previous knee-injury and KOOS- score were collected at baseline. Football-injuries and football-exposures were reported weekly by answers to standardised textmessage questions followed by individual injury-interviews. A priori, previous knee-injury and low KOOS-scores (< 80 points) were chosen as independent variables of interest in the primary and secondary risk-factor analyses. Findings / Results: 29 players sustained 34 time-loss knee-injuries. Adjusted for match/total ratio and playing-level, baseline report of previous knee-injury significantly increased the risk of time-loss knee-injury (RR: 3.65 95%CI 1.73-7.68; p<0.001). Low baseline-score in three KOOS sub-scales (ADL, Sport/rec and QOL) significantly increased the risk of time-loss knee-injury (RR: 2-5, p= 0.008-0.046). Conclusions: Previous knee-injury and KOOS subscale scores lower than 80 points in ADL, Sport/rec and QOL significantly increases the risk of sustaining a knee-injury in adolescent female football players. 70 DOS Abstracts

Significant role on rotatory stability of the anterolateral ligament in ACL insufficient knees Mette Tavlo, Salameh Eljaja, Jørgen Tranum-Jensen, Volkert Siersma, Michael Rindom Krogsgaard 18. Institut for Cellulær og Molekylær Medicin, Københavns Universitet; Afdeling for Idrætskirurgi, Bispebjerg Hospital; Forskningsenheden for Almen Praksis, Center for Sundhed og Samfund Background: Recent studies have described the anatomy of an anterolateral ligament (ALL) of the knee. This ligament has been linked to the Segond fracture that is patognomonic for tear of the anterior cruciate ligament (ACL). ALL is hypothesised to be important for the internal rotatory stability of the knee, but its mechanical effect has yet to be clarified. Purpose / Aim of Study: Our aim was to test the function of the ALL for rotatory and anterior-posterior (AP) stability in ACL insufficient and reconstructed knees and the effect of anatomical ALL reconstruction with a tendon. Materials and Methods: In 18 cadaver legs ALL was dissected. Function of ALL (+/- ALL) and of ALL reconstruction (reall) was tested with the ACL removed (-ACL) and reconstructed (+ACL) with following combinations: +ACL- ALL, +ACL+ALL, - ACL+ALL, -ACL-ALL, -ACL+reALL and +ACL+re-ALL. All combinations were tested with the knees in 0, 30, 60 and 90 degrees of flexion. AP stability was tested with a Rolimeter. Rotation of tibia was applied with 50 N internal and external and measured photographically from K-wires inserted in tibia and femur. Findings / Results: The ALL did not appear uniform, but was well defined in 78 %. ACL (+/-) had a significant effect on the AP stability but not on rotation. ALL (+/-) had significant effect on the rotatory stability (p = 0.0006), regardless of the condition of ACL, and on the AP stability in ACL insufficient knees (p = 0.023). The lost stability of ALL was regained when ALL was reconstructed. Conclusions: ALL is a major rotational stabilizer. If ALL is torn in connection with ACL rupture, reconstruction of ACL is not re-establishing rotatory stability. When ALL is reconstructed anatomically, rotatory instability is re- established. ALL reconstruction as supplement to ACL reconstruction might be considered in patients with a Segond fracture. DOS Kongressen 2014 71

Redislocation after conservative treatment of primary patellar dislocations 19. Bo Kaewkongnok, Anders Bøvling, Celia Møllenborg, Bjarke Viberg, Lars Blønd Orthopaedic Surgery, Køge; Orthopaedic Surgery and Traumatology, Odense University Hospital; Orthopaedic Surgery, Køge Background: Primary patellar dislocation should be treated conservatively using either a immobilizing brace or a plaster splint, except for cases with osteochondral fracture. No studies have yet focused on various treatment regimens in relation to the duration of immobilization. Purpose / Aim of Study: This study compares different conservative treatment regimes after primary patella dislocation measuring the rate of redislocation. Materials and Methods: Retrospective study comparing two cohorts from two hospitals, having two different conservative treatment protocols. The first regime consist of 2 weeks 30 degree locked brace and the second regime consist of 6 weeks brace with gradually increasing range of movements after two weeks. Patients under 30 years having first-time patellar dislocations were included. Redislocations, treatment regimens, type of rehabilitation and trochlea dysplasia and patella alta on radiographs were recorded. Findings / Results: 458 patients having 475 primary patella dislocations (230 females) with a median age of 17.0 years (IQR 14.9-20.5) were included. Redislocations (or surgery) were recorded for 132 patients with a median re-dislocation time of 347 days (IQR 170-704). X-ray images suited for measurement showed a dysplasia proportion of 72.9%. A logistic regression analysis showed that increasing age (OR 0.82, p<0.0001), instruction in VMO exercises (OR 0.31, p<0.048), and increasing Insall-Salvati index (OR 0.047,p<0.009) all were preventive of re-dislocations. None of the treatment regimes showed any statistical significant difference for preventing re-dislocations. Conclusions: We found no difference between the two conservative treatment protocols in respect to the rate of re-dislocation. Increasing age, instructions in VMO exercises and increasing Insall-Salvati index was found to be preventive for re-dislocation. 72 DOS Abstracts

Do ACL patients suffer from comorbidity and is there any association between comorbidity and the risk of ACL revision surgery? A nationwide population-based case-cohort study of 13,443 ACL reconstructed patients Lene Rahr-Wagner, Theis Thillemann, Martin Lind, Alma Pedersen 20. Department of Orthopaedic surgery, Aalborg University Hospital; Department of Clinical Epidemiology, Aarhus University Hospital Background: Anterior cruciate ligament (ACL) reconstructed patients are considered healthy individuals. However, information on comorbid disease is lacking. Purpose / Aim of Study: The aim of this study was to describe and compare comorbid conditions among ACL reconstructed patients and a matched cohort without ACL injury. Further, to evaluate the impact of comorbid diseases on the risk of ACL revision surgery. Materials and Methods: This case-cohort study included 13,443 unilateral primary ACL reconstructed patients from the Danish Knee Ligament Reconstruction Register (DKRR) matched on gender and age with a comparison cohort without ACL injury. Information on medical comorbid conditions was obtained from the Danish National Registry of Patient. The prevalence of all comorbid conditions was described for ACL reconstructed patients and the comparison cohort in terms of: 1) Charlson Comorbidity Index (CCI) 2) ICD-10 disease chapters, 3) more common chronic diseases in a younger population. Finally we assessed the risk of ACL revision surgery according to the comorbid conditions, using Cox regression analysis. Findings / Results: ACL reconstructed patients had generally a slightly lower prevalence of almost all ICD-10 classified comorbid disease groups compared to the comparison cohort without ACL injury. The percentage of CCI=0 was high in both groups. As expected most diseases increased slightly with rising age. Most of the comorbid conditions did not affect the risk of revision surgery. Conclusions: This study provides new information on comorbid conditions in ACL reconstructed patients, which has not previously been described. This study supports the hypothesis that ACL patients are generally healthy individuals. A large variety of diseases are present in the ACL reconstructed group, but with very low prevalence and a low CCI indicating a healthy cohort. DOS Kongressen 2014 73

Autologous Dual Tissue Transplantation for Osteochondral repair - One Year Clinical and Radiological Follow-Up 21. Bjørn Christensen, Casper Foldager, Martin Lind Orthopedic Research Laboratory, Aarhus University Hospital; Division of Sports trauma, Aarhus University Hospital Background: Articular cartilage has a very limited potential for spontaneous regeneration, due to the avascular nature of the tissue. Numerous treatment methods have been implemented, among them microfracture, ACI and mosaicplasty, but no Gold standard treatment has been established. Purpose / Aim of Study: To evaluate the use of Autologous Dual- Tissue Transplantation (ADTT): An easily applicable, low cost treatment option for articular cartilage repair. Materials and Methods: Eight patients (age 33 years, range: 24-45) suffering from osteochondral defects of the medial femoral condyle were enrolled. The injury area was debrided and the osteochondral defect was filled with autologous bone from the tibial tuberosity, to the level of the adjacent cartilage. Cartilage biopsies from the intercondylar notch, was chipped, and the cartilage chips were embedded in fibrin glue in the defect. The stability of the treatment was tested with 40 full range motions, and the incision was closed. The patients were evaluated pre- operatively and one year post-operatively using MRI, CT, and clinical scores (KOOS, IKDC and Tegner) Findings / Results: A significant improvement was found in the IKDC score (from 40,2 67,5, p=0,02), the Tegner score (2,8 4,6, p=0,01) and KOOS pain, symptoms, sport/rec and quality of life. The MOCART MRI score improved from 30 to 62,5 (p=0,0003). CT imaging showed very good defect filling, with an uneven bone surface. Conclusions: Treatment of osteochondral injuries in the knee with ADTT resulted in significant clinical and radiological improvements at one year. Despite the limited number of patients and the short-term follow-up, this study highlights ADTT as a promising treatment option for osteochondral injuries. 74 DOS Abstracts

Posterior cruciate ligament reconstruction in skeletal immature children; a case series of six patients. Ole Gade Sørensen, Peter Faunø, Svend Erik Christiansen, Martin Lind Orthopedics, University Hospital of Århus 22. Background: Rupture of the posterior cruciate ligament (PCL) is a rare knee injury in childen with open growth plates. So far only case studies have been reported in the literature. We present follow-up results of six patients with open physes treated with PCL reconstruction. Purpose / Aim of Study: To evaluate clinical outcome after PCL reconstruction in six skeletal immature patients. Materials and Methods: Between August 2006 and October 2010 six skeletal immature patients (one girl and five boys) were treated with PCL reconstruction. In 5 cases hamstring tendons autografts were used. One patient was reconstructed with use of a tibialis anterior tendon allograft. At time of surgery median age was 9 years (range 6 14). Median follow-up time after surgery was 50 months (range 41 90). Outcome was evaluated by KOOS and Tegner scores, Instrumented knee laxity and radiologic long axis leg length measurements. Findings / Results: Median KOOS score at follow up regarding symptoms, pain, ADL, Sport, and QOL were 79 (range 43 100), 89 (range 41 100), 99 (range 66 100), 70 (range 5 100), and 81 (range 19 94) respectively. Median Tegner score was 6 (range 4 7). Median side to side difference in laxity using KT1000 was 2 mm (range 1 5) at 25 degrees of flexion and 3 mm (range 3 6) at 70 degrees of flexion. No side to side difference in knee extension was found. In contrast a median difference of 8 degrees of flexion decrease was found. All but one patient had returned to sports at follow-up. One patient had a leg length discrepancy of 16 mm, the index knee being the longer. Conclusions: PCL reconstruction resulted in fair to good clinical outcome in skeletal immature children. DOS Kongressen 2014 75

Testing basic competency in knee arthroscopy using a virtual reality simulator: Exploring reliability and validity 23. Mads Emil Jacobsen, Morten Jon Andersen, Claus Ol Hansen, Lars Konge Center of Clinical Education, Copenhagen University Hospital Rigshospitalet, Denmark; Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre, Denmark; Arthroscopic Center Amager, Copenhagen University Hospital Amager, Denmark Background: Orthopedic residents are confronted with diagnostic arthroscopies early in their training. Arthroscopy differs from traditional open surgery and many residents feel less prepared for arthroscopic procedures. Virtual reality (VR) training and testing could ensure basic competency before proceeding to supervised operations in patients. Purpose / Aim of Study: The aim of this study was to create a reliable and valid simulation-based test for diagnostic knee arthroscopy. Materials and Methods: Twenty-six physicians (13 untrained novices and 13 experienced surgeons) performed a test consisting of five procedures on a VR knee arthroscopy simulator. Performance was evaluated by obtaining predefined metrics from the simulator for each procedure from which z-scores, describing inappropriate behavior, were calculated. Reliability was explored by calculating an Intra-class Correlation Coefficient. Validity was explored by comparing the performances of novices and experienced surgeons using independent samples t-tests. Using the contrasting groups method a pass/fail standard was set and its consequences explored. Findings / Results: One procedure was excluded from the final test due to lack of validity. Z-scores showed an inter-case reliability of 0.87 between the four procedures in the final test. A total z-score was 38.6 ± 27.3 for the novices and 0.0 ± 9.1 for the experienced surgeons (p < 0.0005). The pass/fail standard was set at a total z-score of 15.5 resulting in two of the novices passing the test and a single experienced surgeon failing. Conclusions: By combining four procedures on a VR arthroscopy simulator we were able to create a valid and reliable test of basic arthroscopic competency, and establish a credible pass/fail standard. The test could help assess and ensure basic competency of junior surgeons before supervised operations in patients. 76 DOS Abstracts

Treatment of posterior cruciate ligament tear combined with postero-lateral instability in skeletal immature children. 24. Ole Gade Sørensen, Peter Faunø, Svend Erik Christiansen, Martin Lind Orthopedics, University hospital of Århus Background: Tear of the posterior cruciate ligament (PCL) in combination with instability of the postero-lateral corner (PLC) is a very uncommon finding in children with open growth plates. We present follow- up results of three patients with open physes treated with PCL and PLC reconstruction. Purpose / Aim of Study: To evaluate clinical outcome after combined PCL and PLC reconstruction in three skeletal immature patients. Materials and Methods: Between July 2004 and December 2010 three skeletal immature patients were treated with combined PCL and PLC reconstruction. Age at time of surgery was 7, 7 and 9 years. At follow-up the three patients were 16, 15 and 13 years respectively. Outcome was evaluated by KOOS and Tegner scores, Instrumented knee laxity and radiologic long axis leg length measurements. Findings / Results: KOOS scores at follow up for patient# 1, regarding symptoms, pain, ADL, Sport, and QOL were 61, 64, 66, 15 and 38. Patient# 2 scores were 86, 100, 100, 100 and 100, whereas patient#3 scored 96, 94, 100, 95 and 81 respectively. Tegner score was 6, 9 and 6 for the three patients. Laxity measurement was only performed for patient#1 and patient#2 at follow-up. Side to side difference in laxity using KT1000 was 0 and 2 mm at 25 degrees of flexion and 1 and 8 mm at 70 degrees of flexion. Side to side difference in knee flexion was 15, 5 and 5 degrees. No difference in knee extension was found. At follow-up all three patients had returned to sports at a recreational level. Leg length discrepancy was found to be 11, 16 and 5 mm, the index knee being the longer in all three patients. Conclusions: Combined PCL and PLC reconstruction seems to result in variable clinical outcome in skeletal immature children and our data suggest a risk of growth disorder in these patients. DOS Kongressen 2014 77

Increased migration and more revisions of MOTEC compared with ELECTRA cups. A 2-year RSA study of trapeziometacarpal prostheses 25. Maiken Stilling, Torben Bæk-Hansen Department of Orthopaedics, Regional Hospital Holstebro, Hospital Unit West Background: Cup failure is a recognized problem in total trapeziometacarpal (TM) joint prosthesis. Several cup designs are available but clinical documentation is sparse. Cementless cups are inserted pressfit and depend on a primary mechanical and secondary osseous stability, which may be evaluated with radiostereometric analysis (RSA). Purpose / Aim of Study: To compare cup stability with two cementless screw cups and the possible relation to cup revision. Materials and Methods: 2 consecutive prospective patient cohorts, Eaton type 2-4, were operated with TM joint prostheses using two differently designed trapezium screw cups: the MOTEC cup with a collar (n=22), and the ELECTRA bimetal cup without a collar (n=22). Mean age was 60 (45-74) years. There were 31 female and 13 males. Model-based RSA was used to measure cup migration with respect to the trapezium, which was marked with 1mm tantalum beads during surgery. Stereoradiographs and DASH score was measured at baseline, 3 and 6 months, and 1 and 2 years postoperative. Findings / Results: At 2 years total translation of mean 2.32 (sd 2.4) mm with MOTEC cups (n=7) was higher (p=0.01) than mean 0.87 (sd 1.61) mm with ELECTRA cups (n=16). At 3 months total translation was higher in cups that were revised later on (p=0.03). There was a tendency for more subsidence with MOTEC cups (1.03 vs 0.22 mm; p=0.053). There was no significant cup migration between 1 and 2 years (p=0.62). However, at 2 years the revision rate in the MOTEC group was 41% (9/22), versus 0% (0/22) in the Elektra group (p= 0.02). There were no significant differences in clinical results between the two groups. Conclusions: The MOTEC trapeziometacarpal cup with a collar has higher implant migration and more revisions compared with the ELECTRA collarless bimetal cup at 2 years followup. Early migration was higher in cups that were later revised. 78 DOS Abstracts

High early revision rate in a new cemented polyethylene cup in trapeziometacarpal total joint arthroplasty 26. Jens Knak, Torben Bæk Hansen Department of Orthopaedics and The Orthopaedic Research Unit, Hospital Unit West, Holstebro Background: Trapeziometacarpal total joint arthroplasty may be used in treatment of trapeziometacarpal osteoarthritis preserving the length of the thumb and providing rapid rehabilitation and good grip strength. Unfortunately high revision rates have been reported, and new implant designs strive to reduce the revision rates. Purpose / Aim of Study: To evaluate the mid term results using a new cemented cup design with the Motec polyethylene trapezium cup in ball and socket trapeziometacarpal total joint arthroplasty. Materials and Methods: We did a prospective study in 58 patients, 11 males and 39 females, mean age 61 years (range 41-77) operated with a Motec polyethylene trapezium cup in the period december 2010 to November 2012. All patients were followed with DASH score, VAS and measurement of grip strength as well as radiological follow- up at 3, 12 and 24 months. Findings / Results: After a mean follow-up of 33 months (range 19-43) 8 patients had been revised due to early aseptic loosening or osteonecrosis, (14%), 2 patients due to recidivant luxation, 1 patient due to traumatic cup loosening and 1 patient due to deep infection. 5 of the 8 patients with aseptic loosening/ osteonecrosis were revised during the first 12 months. The clinical results in the remaining 47 patients were equivalent to other published series. Conclusions: The early revision rate due to aseptic loosening or osteonecrosis has been surprisingly high indicating a technical failure during cementing. We suspect heat induced bone necrosis to be a possible cause, and further studies are needed looking at the cementation technique in trapeziometacarpal total joint arthroplasty. DOS Kongressen 2014 79

Test-retest reliability of Antonovsky s 13-item Sense of Coherence scale in patients with hand-related injures 27. Alice Ørts Hansen, Hanne Kaae Kristensen, Ragnhild Cederlund, Hans Tromborg Department of Orthopedic, Odense University Hospital; Department of Rehabilitation, Odense University Hospital; Health Sciences, Lund University Background: Patients with identical hand injuries, who gets the same treatment and rehabilitation, recover differently from their injuries. It might be due to personal factors. Antonovsky developed a questionnaire measuring Sense of Coherence (SOC13) reflecting person s ability coping in a stressful situation. Studies have shown that patients with strong Sense of Coherence (SOC) get better functional outcome and satisfaction in daily activities after hand- and orthopaedic injuries compared to patients with weak SOC. Psychometric properties of SOC 13 have not been tested on patients with hand injuries. This is necessary before using SOC13 to predict outcome and plan rehabilitation. Purpose / Aim of Study: To report on distribution, stability and test-retest reliability of SOC13 in patients with hand-related injuries and explore associations between SOC13 and age, education level, gender and type of injury. Materials and Methods: The design was a survey with test- retest using selfadministered questionnaire. SOC13 and demographic data was collected before occupational therapy in an Outpatient Clinic from 170 patients with hand-related injuries aged 18 and older. SOC13 was completed after 14 days and 3 months. Findings / Results: 170 patients completed SOC13 at baseline (median score 71, range 30-91). Intra-class correlation coefficient (ICC) between baseline and 14 days was 0.87 (n=151), 3 months 0.82 (n=113). Weak correlations was found between SOC, age (r=0.17, p<0.03), education(r= 0.02, p<0.02). No correlation was found between SOC and gender or type of injury. Conclusions: SOC13 showed stability and reliability for patients with hand injuries before and 3 months after hand therapy. Age and education had a weak relationship with SOC without clinical relevance. SOC13 has potential to be a powerful tool measuring personal factors before hand therapy. 80 DOS Abstracts

Skin tear correlates to the degree of contracture when treated for Dupuytrens contracture with Xiapex Christian Fagernæs, Susanne Mallet 28. Orthopaedics, Køge Hospital Background: Xiapex is used in the treatment of Dupuytren s disease (DD). Xiapex is injected into the cord which the next day is manipulated to attempt rupture. No trial has explored the number of skin tear as an adverse effect (AE). Purpose / Aim of Study: The aim was to explore the joint level and the degree of contracture to the risk of the AE of skin tear. Materials and Methods: 105 cases (90 patients) with DD with DIP and/or PIP contracture from august 1st 2012 till april 1st 2014 were enrolled prospectively. Excisting skin defects were cause for exclusion. DIP and PIP contractures were treated with 0.25 ml and 0.20 ml of Xiapex.The degree of contracture was measured with a goniometer and skin tears were classified as yes/no. Findings / Results: 77 (73%) had the contracted cord at the level of the MCP joint and 28 (27%) at the level of the PIP joint. 59 (56%) got skin tear. The RR of skin tear is 1,5 for MCP level of >60 degrees compared to MCP level at 20-59 degrees (p=0,17). The RR of skin tear is 2,2 for PIP level of >60 degrees compared to PIP level at 20-59 degrees (p=0,04). The relative risk for skin tear is 1,1 (CI = (0.72; 1.58), p=0,74) for MCP level compared to PIP level. By logistic regression it is shown that the degree is the most important factor concerning skin tear with a higher risk in the >60 degree-group compared to the 20-59 degree-group with an odds ratio of 5.4 ((95%CI (1.4; 20.6), p=0.01). Conclusions: There is a higher risk of skin tear when the contracture is >60 degree and located at the level of the PIP joint. Overall the factor most important for higher risk of skin tear is the degree of the contracture more that the level. Focus on patients with contracture of more than 60 degrees is needed. A type of skin-softener could be helpful but should be explored. DOS Kongressen 2014 81

Long-term effect of surgery for thumb in palm in adolescent cerebral palsy patients. Hans Tromborg, Alice Ørts 29. Hand Surgery, Dept of Ortopaedic Surgery, Odense University Hospital; Department of Rehabilitation (Hand), Odense University Hospital Background: Cerebral palsy of the hand can be a seriously debilitating illness, especially hand activities demanding the use of two hands can be affected. The ability to open the hand to grip objects and bringing the fist finger into contact with the second finger (pinch key grip) are cornerstones of hand function. Purpose / Aim of Study: To evaluate the long-term effect of thumb surgery for thumb in palm spasticity in adolescent patients with cerebral palsy. Materials and Methods: Twenty six patients with cerebral palsy was surgically reconstructed with flexor carpi ulnaris (FCU) transferal to the extensor carpi radialis brevis (ECRB) and surgery to correct the thumb in palm deformity. Age 15(6) years (AVG (SD)). Hand opening was measured as the ability to grasp a wooden cylinder with contact to the web space between the first and the second finger. Two hand activities (THAc) were measured by awarding points for the use of two hands in pre-defined and standardized two hand activities (modified Sollerman hand test). Maximum possible points was 15. After surgery, the patients were treated with immobilization in a cast for eight weeks. All patients initially received highly specialized rehabilitation and afterwards guided therapy. Findings / Results: Patients increased hand opening from 4.6 (1.5) cm (AVG (SD)) preoperatively to 5.5 (1.3) cm (p<0.05) after half a year and increased points of THAc from 9.2 (4.1) points preoperatively to 11.8 (4.0) points (p<0.001) after half a year. Hand opening and THAc increased a little from 6 months to 18 months and therefore remained statistically significantly improved. Conclusions: In carefully selected adolescent children with cerebral palsy hand opening and two hand function can be improved by surgery and subsequent hand therapy. 82 DOS Abstracts

Short term results of the Maestro Total Wrist Arthroplasty for primary and revision arthroplasty Allan Ibsen Søensen, Peter Axelsson 30. Clinic of Hand Surgery, University Hospital Sahlgrenska Background: Wrist arthroplasties have been used for dekades with better results for the newer designs. Purpose / Aim of Study: The aim of this study is was to review our shortterm results of the Maestro prosthesis used for primary and revision wrist- arthroplasty. Materials and Methods: The Maestro implant is a modular total wrist joint prosthesis. The indications for it s use in this study were rheumatoid arthritis (RA), degenerative (OA) and posttraumatic arthritis (POA) and revision of former Wrist arthroplasty. The procedure was performed in 14 patients, 3 men and 11 women. Median age was 64 years (41-75). 10 RA, 3 OA and 1 POA patients were operated. Median follow-up was 13 month (range 12-25). Primary arthroplasty was performed in 11 patients and revision arthroplasty in 3 (2 KMI - and 1 Remotion prosthesis were removed). Cement was used in 4 cases. Additional Darrach procedures were performed in 4 cases. Findings / Results: Wrist extension and flexion was preoperatively 35/30 degrees and at follow-up 40/25. Radial/ulnar deviation was 10/30 degrees versus 10/25 postoperatively. Grip strength, in KgF, was preoperatively 8 (range 2-36) and at follow-up 18 (7-30). VAS pain (0-100 mm) was preoperatively at rest/activity; 30/65 mm and at follow-up; 2/4 mm. Minor radiographic osteolysis around one screw was seen in 2 of 14 cases at the last follow-up, but no signs of loosening were detected. Quick DASH and PRWE were preoperatively; 50 and 68 and at follow-up; 28 and 12. VAS satisfaction at latest followup was 98 mm (34-100).2 minor hematomas and 1 moderate hematoma were observed. No infections, dislocations or other early complications were encountered and no reoperations performed. Conclusions: In this small selected case series the Maestro Total Wrist Arthroplasty had a low complication rate and showed promising short-term results. DOS Kongressen 2014 83

Trapezium resection vs. cemented cup revision in cup failures of the trapeziometacarpal total joint prostheses of the thumb 31. Jens Knak, Torben Bæk Hansen Department of Orthopaedics and The Orthopaedic Research Unit, Hospital Unit West, Holstebro Background: Total joint prostheses may be used as treatment of trapeziometacarpal osteoarthritis of the thumb, but unfortunately a relatively high rate of loosing of the trapezium component has been observed. Revision may be performed as a cup revision or as a conversion into a trapeziectomy, but so far no studies have been made to compare these two treatment options. Purpose / Aim of Study: The primary aim of this study was to compare the outcome in patients with failure of the trapezium cup revised into a cemented cup or into a trapeziectomy. Materials and Methods: We did a follow up-study in 44 patients (with 49 operations) revised in the period 2004 until 2014. 13 patients were excluded because of a less than 12 months follow-up or declined to participate, and it left us with 36 hands/operations in 31 patients, respectively 23 trapezium resections and 13 cup to cemented cup revisions. Clinical measures were VAS-score, DASH, strength and movement of the thumb, and in all implants an AP and lateral radiograph. Findings / Results: We did not find any difference regarding VAS-, DASHscore, grip strength and movement of the thumb comparing. In the series of cup revision we found a re-revision rate of 4 out of 18 operations (22%). These 4 patients were revised into trapeziectomy. Conclusions: Cup revision into trapeziectomy gives a good functional result, and cup revision into a cemented new cup should be used in selected patients only due to a high risk of re-revision. 84 DOS Abstracts

Xiapex (collagenase clostridium histolyticum) treatment of patients with recurrence-dupuytren s contracture 1 year follow-up 32. Søren Larsen, Karina Liv Hansen, Tune Ipsen, Jens Lauritsen Unit for Hand Surgery, Department of Orthopaedic Surgery, Odense University Hospital Background: Dupuytren s contracture (DC) is a disorder that affect the palmar fascia where a pretendinous cord with time causes the finger to flex resulting in impaired hand function. Purpose / Aim of Study: The aim of this study was to evaluate the efficacy of Xiapex treatment of recurrence- DC at least 12 month after Xiapex injection. Materials and Methods: The study was a prospective study on consecutive series of patients with recurrent DC and flexion deformities of the metacarpophalangeal and/or proximal interphalangeal joint of >200 and a palpable cord. Our end points was reduction in contracture, improving hand function and patient satisfaction Findings / Results: 144 treatments were enrolled, 124 men and 20 women, mean age 66 years [36-85]. 91% of the treated fingers are the 4. and 5. finger. Treatment distribution MP/PIP joints were 45/55%. 49% had a skin-rupture after manipulation and 89% of these patients had a need for additional visit in our out-patient-clinic. Mean follow-up was 15 month [12-23]. At followup a mean reduction in contracture of 60/30% for MP/PIP-joint. Mean DASH pre-injection was 15 [0-61] and at 3 months follow-up 8 [0-39]. In 6 cases (7%) there had been a need for further treatment of Xiapex treated finger at 12 month (=unacceptable recurrence). At 12 months follow-up 44% of the patients were satisfied or very satisfied. Conclusions: Our results are acceptable and we find Xiapex a possible treatment option for recurrence-dc-patients with a palpable cord. The treatment is not as effective, has a higher recurrence-rate and lower patient satisfaction compared to Xiapex treatment of primary DC. DOS Kongressen 2014 85

Long - term results of total joint arthroplasties with Elektra prothesis in trapeziometacarpal osteoarhritis Barbara Kulinski 33. Hand Unit, Southern Jutland Hospital Background: The Elektra prothesis is a cementless prothesis used in trapeziometacarpal osteoarthritis.early follow-up studies showed fast recovery and good functional results.later studies with longer follow-up indicated severe problems with implant survival. Purpose / Aim of Study: To report our long-term results with the Elektra TMC prothesis Materials and Methods: Between 2005-2009 14 TMC joints in 13 patients (3 men,10 women) with a mean age of 52(range 40-73) years were operated using the Elektra prothesis.all patients were diagnosed with symptomatic and radiological TMC oeteoarthritis, Eaton- Littler stage 2 and 3.One hand surgeon performed all operations.clinical and radiological follow-up were performed at 3 weeks,12 weeks,52 weeks postoperatively.in 2014 two hand surgeons examined all implants still in place with radiographs, grip/pinch strength and patient perceived outcome. Blood samples were analysed for serum cobalt and chrome. Findings / Results: 4 implants(28%) had been revised because of dislocation of the neck 34 months(range 3-70)postoperatively.The necks were changed to longer ones,however in two patients the protheses later had to be removed. One patient had the prothesis removed after trauma. In two patients revision with trapezectomy was performed due to loose cup after 7 and 36 months. After mean follow-up of 93 months (range 60-108) 8 patients with 9 retaining implants (62%) were available for follow-up.radiographs showed no loosening, mean quickdash was12 (range 0-32 ),mean pinch strength was 6.5 (range 4-9)kg,mean grip strength was 30.6(range 20-42)kg.Mobility was excellent in all patients.2 patients had elevated serum cobalt and chrome values. Conclusions: We found a high revision rate but excellent functional result in the surviving protheses. Due to high revison rate the Elektra prothesis should be used in selected patients. 86 DOS Abstracts

Equally good methods for determination of bone quality of the trapezium Kamille Breddam Mosegaard, Nadja Bouteldja, Maiken Stilling, Torben Bæk Hansen 34. Department of Orthopaedics, Regional Hospital Holstebro, Hospital Unit West, Denmark; Department of Radiology, Regional Hospital Holstebro, Hospital Unit West, Denmark; Department of Orthopaedics, Regional Hospital Holstebro, Hospital Unit West, Denmark Background: High loosening rates of the trapezium component in total joint arthroplasty of the trapeziometacarpal joint may be caused by multiple independent factors, and one possible cause is poor bone mineral quality of the trapezium. However technical difficulties in measuring the bone mineral density (BMD) has been described due to the irregular and sclerotic bone contours. Purpose / Aim of Study: We wanted to compare the measurements of bone quality of the trapezium using DXA scan BMD with bone quality measurements using computed tomography (CT) and Houndsfield units (HU). Materials and Methods: We included 71 hands in 60 patients, 13 males and 47 females, mean age 59 years (43-77) diagnosed with Eaton Glickel stage II IV osteoarthritis. In all patients we measured the BMD of the trapezium with two different methods: DXA including the circumferential/cortical part of the bone or in the center of the trapezium alone. We also measured the BMD of the distal radius. All BMD measurements were compared to measurements of the bone quality using the HU. Findings / Results: In the trapezium the CT measured HU in the trapezium correlated with DXA measured BMD (r=0.49, p=0.000) of the trapezium (perimeter method) and with DXA measured BMD (r=0.55, p=0.000) in the trapezium (inner-circle method). DXA measured BMD of the trapezium (perimeter method) correlated (r=0.94, p=0.000) with DXA measured BMD of the trapezium (inner-circle method). In the radius the average CT measured HU in distal radius correlated with DXA measured BMD (r=0.67, p=0.000). Conclusions: The correlation between the two DXA measurement methods was excellent, and the easier inner-circle method may be preferred. We found a good correlation between measurements made by CT with HU and DXA BMD in both the distal radius and in the trapezium using the inner circle method, and both methods may be used. DOS Kongressen 2014 87

Complication rates following volar plating of distal radius fractures in relation to fracture pattern and surgeon experience. 35. Andreas Qvist Christensen, Nina Madsen, Erik Valen, Casper Bindzus Foldager Orthopedics, Randers Regional Hospital ; Radiology, Randers Regional Hospital Background: Fractures of the distal radius are among the most common injuries in orthopedics, accounting for up to 15% of all extremity fractures. Internal fixation using volar plating has become increasingly popular. Reported complication rates following volar plating vary widely (9-60%), but are unknown in the Danish population. Purpose / Aim of Study: To examine complication rates following volar plating of distal radius fractures in relation to fracture pattern and surgeon experience in patients operated at Randers Regional Hospital in 2011-2012. Materials and Methods: Patients with distal radius fractures surgically treated with volar plating in 2011 and 2012 at Randers Regional Hospital were enrolled in the study. Radiological classification was performed using the AO and Frykman. Clinical journals were reviewed for complications. Surgeons were categorized as resident, orthopedic surgeon or hand surgeon. Correlation between complications and surgeon experience or fracture classification was investigated using Spearman s correlation. Findings / Results: Seventy three patients were identified. Mean age 64yrs (18-91) with 81% females. Most common type was AO-27 A2.2 (25%) and Frykman type was II (47%). Seventeen different surgeons performed the procedures (9 residents, 7 consultants, and 1 hand surgeon). The complication rate was 31.5%. Revision surgery rate was 16.4% (12 pts). The most common complications were wrist pain and implant-related discomfort (61%). There was no correlation between complication rate and surgeon experience (P=0.49); fracture classification (OA P=0.72; Frykman P=0.18). Conclusions: We found a high complication rate of 31.5% following volar plating, which was not related to fracture classification or surgeon experience in the present cohort. 88 DOS Abstracts

Short term result of a stable modified Brunelli 360 degree technique for reconstruction of scapho-lunate ligament. 36. Allan Ibsen Sørensen, Jonny Andersson Clinic of Hand Surgery, University Hospital Sahlgrenska Background: Several techniques for reconstruction of the scapho-lunate ligament have been used during the years, but none of the techniques have full stability of the ligament. Purpose / Aim of Study: The aim of the study is to present short term result of a stable modified Brunelli 360 degree technique for reconstruction of scapho- lunate ligament. Materials and Methods: In the modified Brunelli technique a part of FCR tendon or Plantaris tendon were tunneled through scaphoideum as Brunelli described. Then the tendon graft is tunneled through lunate bone in AP direction and then passed along the volar capsule to tuberculum of the scaphoid bone and fixed with either suture at tuberculum or biocomposit screw in scaphoideum. Furthermore the graft is fixed in lunate bone with a biocomposit screw. Fourteen patients were operated and 2 patients twice, 13 men and 1 woman. Median age 39,8 years (19-52). Median values are used. Findings / Results: Median follow-up 15,6 month (2,8-36,5). Preoperative SL distance 5,7mm and at follow-up 2,7 mm. Dorsal/volar flexion preoperatively 94 (35-185) of normal wrist and at follow-up 77% (40-109), radial/ ulnar flexion 92% (35-193) versus 76% (35-133). Grip strength in KgF preop 40 (11-60) and at follow-up 42 (11-74). VAS pain (mm) preop at rest/activity 19/67 and at FU 0/43. Watsons test preop. positive in 10 of 11 cases and post. op positive in 2 of 15. DISI in 8 of 13 cases preoperatively compared with one positive of 13 post. op.. Quick DASH and PRWE preop. 41 and 55 and at followup 23 and 27. There were one superficial pin tract infection and one deep infection in the two patients who were re- operated due to instability. Conclusions: In this small series modified Brunelli 360 degree technique for reconstruction of scapho-lunate ligament seemed to have promising short term results with a stable fixation. DOS Kongressen 2014 89

Postoperative oxygenation and metabolism of the soft tissue covering total ankle replacement Frank Linde, Niels Christian Jensen, Kristian Kibak Nielsen, Hanne Birke-Sørensen 37. Department of Orthopaedics, University Hospital of Aarhus Background: Up to one third of total ankle replacements (TAR) are followed by wound healing complications. Even minor complications are potentially catastrophic as they may lead to loss of the prosthesis. Purpose / Aim of Study: The aim was to obtain knowledge regarding the oxygen pressure and the metabolism in the soft tissue after TAR. Materials and Methods: Fifteen TAR patients were included. Transcutaneous oxygen tension (tcpo2) was measured at both sides of the incision site preoperatively, 3 hours postoperatively and daily the following 6 days or until discharge from the hospital and finally at 3 weeks follow-ups. Microdialysis catheters were placed subcutaneously at both sides of the incision during the operation. Samples for analysis of the local metabolism were harvested each half hour for 3 hours after the operation and then every 2 hours during daytime Findings / Results: TcpO2 was normal the first 3 hours postoperatively. At the 2nd postoperative day it has dropped to median 20% of the preoperative values and stayed low until the 4th day. Day 6 it has increased to median 45%, and 3 weeks postoperatively it had reached a normal level. No sign of anaerobic metabolism was found, and none of the 15 patients developed skin complications. Conclusions: The oxygen tension in the soft tissue adjacent to the skin incision after TAR may be critical low during the 2nd to 4th day after operation. These data may serve as guide for timing and duration of interventions for optimization postoperative care after TAR and other major foot operations. 90 DOS Abstracts

Completeness and data validity in the Danish Achilles Tendon Rupture Database Michael Bilde Kuhlman, Anders Troelsen, Kristoffer Barfod 38. Orthopaedic surgery, Clinical Orthopaedic Research Hvidovre, Copenhagen University Hospital, Hvidovre, Denmark Background: Orthopaedic surgeons treat acute Achilles tendon rupture (ATR) differently as there is currently no consensus on the preferred treatment. Data from the Danish Achilles Tendon Rupture Database (DADB) can, for the first time, offer quality monitoring of treatment and may shed light on outcomes of different treatments provided that data are complete and valid. Purpose / Aim of Study: The aim of this study was to test the completeness and validity of data in DADB. Materials and Methods: DADB was established in April 2012. Currently, five Danish Orthopaedic Departments enter data such as general patient demographics and acute ATR treatment and outcome specifics. The study period was 1st of October 2012 to 30th of September 2013. Two primary outcome parameters were assessed: 1) Completeness of data was assessed using data generated at one institution. Data from DADB was compared to medical records. The proportion of patients with acute ATR registered in DADB was assessed. Eighty percent completeness was considered satisfactory. 2) Validity of data entered in to DADB was performed on the same dataset. Data from DADB was compared to medical records. Only complete (100%) agreement between DADB and medical records were considered valid. Findings / Results: Eighty-five patients were registered in DADB. Of these, 73 (86%) were males. Median age was 40.3 years (25-75% IQR: 35.0-51.9). Overall, 87.1% of data from DADB was consistent with medical records. The validity (consistency with medical records) of the individual parameters assessed range from 50.6-92.9%. Data completeness in DADB was 82.5%. Conclusions: In conclusion, this study shows that DADB offer satisfactory data completeness and validity for future purposes of quality monitoring and research. Improved data validity can be achieved through clarifying data parameter definitions. DOS Kongressen 2014 91

Survival of 308 total ankle replacement. A 1-14 years follow-up. Niels Chr. Jensen 39. Orthopaedic, University Hospital Aarhus Background: As total ankle replacement (TAR) becomes a white spread solution to degenerative ankle disease it is important to know the results after TAR. Purpose / Aim of Study: The aim of this study is to describe the failure pattern and the survival rate of the STAR TAR. Materials and Methods: It is a single center prospective study of 308 STAR TAR. 231 with osteoarthrosis (OA) and 77 had rheumatoid arthritis (RA) were done in a period from 1998 to the 1. of June 2012. Failure was defined as failure of one or more prosthetic component. Findings / Results: Twenty-five with OA and 17 with RA were failures. Fifteen OA and 4 RA were late failures where only the polyethylene component was broken or worn. Seven OA and 3 RA patients had a revision. Ten RA and 7 OA had an arthrodesis. One, 5 and 10 Year survival rate survival rate for OA was 0.97, 0,90 and 0,77 respectively. One, 5 and 10 year survival rate for RA was 0,90, 0,84 and 0,75. Conclusions: There is a relatively high early failure rate especially for the RA patients the late failures are dominated by failure of the polyethylene component. Despite the relatively high failure rate 223(97%) of 231 OA TAR is still in place and 67(87%) of 77 RA TAR is still in place. 92 DOS Abstracts

Five year survival rate of STAR ankle replacement Johnny Frøkjær, Lasse Petersen 40. Orthopedic department, foot & ankle section, Odense University Hospital; Orthopedic department, Odense University Hospital Background: Total ankle replacement has become a good alternative to arthrodesis in the treatment of ankle arthrosis in selected patients. Results have been variable, therefore we find it of interest to report our results. Purpose / Aim of Study: The aim of the study was to find our five year survival rate, for the STAR ankle replacement, at our institution. Materials and Methods: We evaluated the intermediate prosthesis survival rate of 200 STAR ankle replacements, inserted in 196 patients between 2004 and 2013 at our department. 109 were men and 87 women. Four patients were operated bilaterally. Surgical concept was to align the ankle during first surgical procedure, if there was any alignment. Patients were seen annually until at least six years after index surgery. We retrospectively evaluated the prosthesis survival, using our database, where data were continously registred at surgery and at follow up. Furthermore patient records were used, to exclude surgery at other hospitals. Revision was defined as removal or exchange of one or more components with the exception of incidental exchange of the polyethylene insert The surgical guide system was changed during this period Findings / Results: Ten patients had a revision performed, four of these were among the first ten patients operated - illustrating the steep learning curve. Additional three patients had the polyethylene liner exchanged. Using the above mentioned end point, 5 year survival rate for the STAR ankle replacement is 94% (95% CI-interval 0,89-0,99) Conclusions: We find the intermediate survival rate of the STAR ankle replacement excellent. Learning curve problems could only be detected for the first surgeon, while problems for next two surgeons were eliminated. We will continue to follow our patients, with regular controls, and will report further survival rates. DOS Kongressen 2014 93

No correlation between Bone cyst volume and clinical symptoms in patients with ankle replacement Ellen Hamborg-Petersen, Trine Torfing, Janni Jensen, Johnny Frøkjær Ortopædkirurgisk Afdeling, OUH; Radiologisk Afdeling, OUH 41. Background: Periprosthetic bone cysts are a known side effect following a total ankle replacement (TAR), possibly threatening the long-term survival of the implant. Purpose / Aim of Study: The primary purpose of this retrospective study was to investigate the correlation between AOFAS score, VAS score, function, age of implant and periprosthetic cyst volume after TAR. Materials and Methods: 40 consecutive patients with a Scandinavian Total Ankle Replacement were seen for a yearly control from 16.09.11-17.05.12. Forty- one ankles were evaluated, mean age was 61.6 years (40-79) and mean follow up time was 36 months (3-72). The replacements were radiologically evaluated for cysts using Weight- bearing Multi-Planar Reconstructed Fluoroscopic imaging followed by clinical tests measuring the patients AOFAS score, VAS score and function. Plots of the residual did not fulfill the normal distribution. For this reason all analyses were performed using non-parametric tests (Spearman rho). Findings / Results: No statistical significant correlation was found between the cyst volume and any of the variables: AOFAS score (rho=0.005, p=0.974, 95% CI:-0.307 to 0.316), VAS score (rho=0.137, p=0.399, 95% CI:-0.182 to 0.430), Function (rho=-0.062, p=0.706, 95% CI:-0.371 to 0.258) and ankle replacement age (rho=0.229, p= 0.149, 95% CI:-0.084 to 0.502). Conclusions: No correlation between total cyst volume and AOFAS score, VAS score and function was found. No correlation between age of TAR and total cyst volume was found. The significance of periprosthetic cysts in ankles is still not clear. All patients will be followed with regular controls in the future to observe further cyst development and aseptic loosening of the prosthesis. 94 DOS Abstracts

Clinical outcome in 308 total ankle replacement. A 1-14 years follow-up. Kristian Kibak Nielsen, Niels Christian Jensen, Claus Sundstrup, Frank Linde Section of foot and Ankle Surgery., University Hospital of Aarhus. Aarhus. Denmark. 42. Background: As total ankle replacement (TAR) becomes a generally accepted treatment for degenerative ankle disease, it is important to know the clinical outcome after TAR. Purpose / Aim of Study: The aim of this study is to describe the clinical outcome in STAR TAR Materials and Methods: This is a single centre prospective study of 308 STAR TAR, performed from 1998 to 1. June 2012. Two hundred and thirty one patients with osteoarthrosis (OA) and 77 with rheumatoid arthritis (RA). There was 197 TAR in OA patients and 56 TAR in RA patients who had the primary TAR in place and a complete standard scoring at follow up. The AOFAS hind foot score and retrospective VAS-score for pain was used for evaluation Findings / Results: In the RA group the preoperativ AOFAS hind foot score changed from 31 to a postoperative score of 73. In the OA group the score changed from preoperative 49, to a postoperative score of 75. All RA patients and 89% of the OA patients had a significant improvement in VAS pain score. Conclusions: Both RA and OA patients improves after TAR in both AOFAS hind foot score and VAS pain score. DOS Kongressen 2014 95

Functional rehabilitation of patients with acute Achilles tendon rupture: A meta-analysis of current evidence. 43. Kristoffer Weisskirchner Barfod, Troels Mark-Christensen, Thomas Kallemose, Anders Troelsen Department of Orthopedic Surgery, Clinical Orthopedic Research Hvidovre, Copenhagen University Hospital Hvidovre;, Physiotherapist at Fysiocenter Århus Background: The optimal treatment for acute Achilles tendon rupture (ATR) is continuously debated. Recent studies have proposed that the choice of either operative or non- operative treatment may not be as important as the following rehabilitation, suggesting that functional rehabilitation should be preferred over traditional immobilization. Purpose / Aim of Study: The purpose of this meta-analysis of randomized, controlled trials (RCT s) was to compare functional rehabilitation to immobilization in the rehabilitation of ATR. Materials and Methods: This meta-analysis was conducted using the databases: PubMed, Embase, Rehabilitation & Sports Medicine Source, Amed, Cinahl, Cochrane and PEDro using the search terms: Achilles tendon, rupture, mobilization and immobilization. Seven RCT s involving 427 participants were eligible for inclusion, with a total of 211 participants treated functionally and 216 treated with immobilization. Findings / Results: Re-rupture rate, other complications, strength, range of motion, duration of sick leave, return to sport and patient satisfaction was examined. There were no statistically significant differences between groups. A trend favoring functional rehabilitation was seen regarding the examined outcomes. Conclusions: Functional rehabilitation after acute Achilles tendon rupture does not increase the rate of re-rupture or other complications. There is a trend towards earlier return to work and a significant increased patient satisfaction using functional rehabilitation. The present literature is of low to average quality and the basic constructs of the examined treatment and study protocols vary considerably. Larger, randomized controlled trials using validated outcome measures are needed to confirm the findings. 96 DOS Abstracts

Severely reduced functional outcome at mean 9 year follow-up after complications associated with acute Achilles tendon rupture 44. Kristoffer Weisskirchner Barfod, Thor Magnus Sveen, Ann Ganestam, Lars Bo Ebskov, Marko Nabergoj, Anders Troelsen Orthopaedic surgery, Clinical Orthopaedic Research Hvidovre, Copenhagen University Hospital, Hvidovre, Denmark; Orthopaedic surgery, Copenhagen University Hospital, Køge Background: Treatment of acute Achilles tendon rupture is highly debated. In the pursuit of the best treatment severity of complications is important. Purpose / Aim of Study: To investigate the long term effect of deep infection, sural nerve injury and re-rupture in the treatment of acute Achilles tendon rupture. Materials and Methods: 324 patients made a claim to the Danish Patient Insurance in the period 1992 to 2010 due to a complication after acute Achilles tendon rupture. Of those 150 agreed to receive written information concerning the investigation and 98 patients (m/f = 63/35) returned the Achilles tendon Total Rupture Score (ATRS) and the Short Form-36 (SF- 36) questionnaires. Patients suffering from deep infection (n=8), Sural nerve injury (n=5) and rerupture (n=16) were invited to participate in a follow up investigation. Findings / Results: The mean follow up period was 8.9 years (3;21). Looking at the whole population a mean ATRS of 50 (SD 30) was found; in comparison healthy subjects have a median of 100 (94;100). The summary scores of SF- 36 were PCS = 42 (SD 12) and MCS = 52 (SD 11); in comparison healthy subjects have a mean of 50 for both scores. No differences were found comparing the subpopulations who suffered from a deep infection, injury to the Sural nerve or re-rupture. The physical evaluation investigating tendon length and heel-rise work revealed a statistically significant difference between the affected and the unaffected limb after re-rupture (p<0.01) but not after injury to the Sural nerve (n.s.) and deep infection (n.s.). Conclusions: The investigated patients who suffered from a complication after acute Achilles tendon rupture had a remarkable reduction of the ATRS and PCS at mean 9 year follow up. Patients suffering from re-rupture had a significant elongation of the tendon and reduction of strength in the affected limb. DOS Kongressen 2014 97

Physiotherapy improves patient reported shoulder function and health status in patients with subacromial impingement syndrome 45. Filip Holst Storgaard, Christina Gravgaard Pedersen, Majbritt Lykke Jensen, Steen Lund Jensen Physiotherapy, Aalborg University Hospital; Orthopaedic, Aalborg University Hospital Background: Physiotherapy may be as effective as surgery in the treatment of subacromial impingement syndrome (impingement). According to National Clinical Guidelines, patients with impingement should have recieved at least three months of physiotherapy before surgery is considered. Purpose / Aim of Study: To report the outcome of a standardized physiotherapy based treatment regimen for impingement. Materials and Methods: An orthopaedic shoulder specialist provisionally selects patients from referrals. The physiotherapist makes a final diagnosis of impingement based on clinical findings and radiographs, and initiates a 3-6 months rehabilitation program including rotator cuff strengthening, posture correction and scapula setting. Treatment efficacy is monitored by Oxford Shoulder Score (OSS) and EQ- 5D-5L, using web based software and email communication (Procordo). Findings / Results: The first year 222 patients (mean age 53 years, 121 males) were included for physiotherapy and patient reported outcome. Homebased response rates were 92% and 82% after 4 and 12 months. The mean OSS scores at inclusion, after 4 months and after 12 months were 30.3, 35.3 and 38.4 respectively (p<0.001). The corresponding EQ-5D-5L index values were 0.79, 0.82 and 0.86 (p<0.001). 31 had clinically unsatisfactory results, and were seen by shoulder surgeon (mean OSS improvement at 4 months -1.3 compared with 5.9 for those treated exclusively by physiotherapist); 24 had surgery. Conclusions: Patients with impingement managed by a physiotherapy regimen improve self- perceived shoulder function and health status. Improvement continues during the first year, even after formal physiotherapy is stopped. Only few patients need evaluation for surgery. Measuring patient reported outcome with a web based software and email is feasible and provide high response rates in this patient group. 98 DOS Abstracts

Persistent pain after shoulder replacement: A nationwide questionnaire study. 46. Karen Toftdahl Bjørnholdt, Birgitte Brandsborg, Kjeld Søballe, Lone Nikolajsen Department of Orthopaedic Surgery, Horsens Hospital; Department of Anaesthesiology, Aarhus University Hospital; Danish Pain Research Center/ Department of Anaesthesiology, Aarhus University Hospital Background: Persistent postsurgical pain is a well- recognized problem after various types of surgery such as amputation, thoracotomy and inguinal hernia repair. The prevalence of persistent pain, and to which degree it involves neuropathic pain, is highly dependent on the type of surgery. Persistent pain following shoulder replacement has not previously been investigated. Purpose / Aim of Study: This study aimed to investigate the prevalence, characteristics and risk factors of persistent pain 1-2 years after shoulder replacement surgery performed in Denmark. Materials and Methods: A questionnaire was sent to patients who had undergone primary shoulder replacement between April 2011 and April 2012, and whose operations had been reported to the Danish Shoulder Arthroplasty Register. Patients who had undergone reoperation or bilateral replacements were excluded. The outcome of persistent pain was defined as pain experienced daily or constantly within the last month at a level that interfered much or very much with daily activities. A multivariate logistic regression model was used to assess risk factors. Findings / Results: 538 patients were available for analysis. The prevalence of persistent pain was 22% (CI 18-25%), and the prevalence of neuropathic pain was 13% (CI 10-16%). Risk factors were pain intensity the first postoperative week, pain elsewhere, diagnosis of fracture, and previous osteosynthesis, but not age or sex. Also, prosthesis type and supplemental cuff reconstruction seemed to influence the risk of persistent pain, but these findings may have various explanations. Conclusions: Persistent pain occurs in a considerable amount of patients after shoulder replacement, and this study emphasizes the need to intensify early postoperative pain management and to further study patients at risk, so possible causes can be identified and treatment can be engaged. DOS Kongressen 2014 99

Pitfalls in the self-management of pain after outpatient surgery: An exploratory analysis Karen Toftdahl Bjørnholdt, Lone Dragnes Brix, Lone Nikolajsen 47. Department of Orthopaedic Surgery, Horsens Hospital; Department of Anaesthesiology, Horsens Hospital; Danish Pain Research Center/Department of Anaesthesiology, Aarhus University Hospital Background: Adequate pain treatment is important for postoperative recovery. Studies have shown that many outpatients fail to obtain adequate pain control at home, but knowledge of the extent of the problem and the pitfalls that occur is limited. Purpose / Aim of Study: We aimed to find possible problem areas in analgesic consumption after discharge, in order to direct future interventions to improve pain control. Materials and Methods: Data were obtained during a randomised clinical trial of dexamethasone involving outpatients undergoing minor arthroscopic shoulder surgery at Horsens Hospital. Patients received preoperative dexamethasone (40 mg, 8 mg, or placebo) and intraoperative local bupivacaine. In the recovery room, patients received fentanyl as needed and initiated the post-discharge regime of paracetamol around-the-clock and ibuprofen and morphine as needed. Patients recorded pain scores and analgesic use until the third postoperative day. Findings / Results: 75 patients were available for analysis. The average pain intensity was successfully kept <4 out of 10 in 27 patients. Undertreatment occurred, as 16 patients experienced days or nights with average pain intensity >7 out of 10. Moreover, 6 of these refrained from any rescue analgesics. Overtreatment also occurred, as 18 patients consumed morphine when their worst pain intensity was <4. Rescue doses between 0:00 and 6:00 a.m. were consumed by 32 patients. Some patients exceeded the maximal daily dose of paracetamol (n=7) and ibuprofen (n=14). Overdoses were mostly due to other brand names or strengths compared to patients usual medication. Conclusions: Problems in the self-management of pain after discharge include overdoses, under-/overtreatment, and nightly failures. Attention should be directed toward improving patient education and/or providing further assistance to patients after discharge. 100 DOS Abstracts

Frozen shoulder - appearance in the electron microscope 48. Mads Okholm, Abigail Mackey, Klaus Qvortrup, Jens Jakobsen, Thomas Hansen, Michael Krogsgaard Ortopædkirurgisk Afd. M, Bispebjerg Hospital; Institute of Sports Medicine Copenhagen, Bispebjerg Hospital; Core Facility for Integrated Microscopy, University of Copenhagen; Ortopædkirurgisk Afd., Idrætskirurgisk Enhed M51, Bispebjerg Hospital Background: Primary frozen shoulder (PFS) has been thoroughly described clinically as well as histologically. To our knowledge, only a single study has ever described the electron microscopic appearance of PFS capsule tissue, and no study has ever compared the different phases of the disease. Purpose / Aim of Study: To evaluate and describe capsular tissue appearance with the transmission electron microscope (TEM) in the 3 phases of PFS compared to controls. Materials and Methods: Tissue samples from PFS capsules were taken during arthroscopic capsular release. 8 samples were randomly selected from a larger pool of tissue samples these included two from each of the three phases and two from controls (patients with subacromial impingement syndrome). Samples were prepared for TEM, and two experienced observers evaluated the images on a Philips CM 100 TEM. Tissue cellularity, collagen architecture and fibril appearance was described. Findings / Results: In general, the collagenous tissue was very dense in all samples. Fibril diameter varied between 30 and 70 nm. In all phases, areas of cross-sectioned fibrils with irregular, hairy edges were seen. In the phase 1 frozen shoulder samples, an abundance of large, irregularly shaped fibroblasts with clearly dilated organelles (golgi apparatus, rough endoplasmic reticulum) and intracellular lipid inclusions was noted. In phase 2 the cellular abundance was still present, but without the same enlargement of cell size and organelles. In phase 3 the cellularity was clearly reduced, and fibroblasts were small and rounded with modest organelle size. Conclusions: In PFS, very active fibroblasts produce a densely packed collagenous tissue with many thick and irregular collagen fibrils. The morphology is phase-related: The earlier the phase, the larger, more irregularly shaped and dilated fibroblasts. DOS Kongressen 2014 101

Anatomical changes in the aging sternoclavicular joint Martin Wyman Ratchke, Jørgen Tranum-Jensen, Michael R. Krogsgaard 49. Section for Sportstraumatology M51, Bispebjerg Hospital; (1) Department of Cellular and Molecular Medicine, Copenhagen University Background: The prevalence of degenerative changes of the sternoclavicular joints (SCJ) is unknown. Some cases are so painful that surgical treatment is indicated. Degeneration of the intraarticular disc with a central hole and the cartilage on the clavicle is reported in cadaver studies, but in sternoclavicular arthroscopies we often find detachment of the disc from the anterior capsule and marked disintegration of the disc. Purpose / Aim of Study: To study the anatomy of the SCJ in detail and describe occurrence of conditions, that are potentially surgically accessible. Materials and Methods: Both SCJs from 39 formalin embalmed (age mean: 79, range: 59-96, 13 F/26 M) were frozen and divided frontally with a thin band saw, so both SCJs were opened through the centre of the disc. Examination of the joints was performed after the specimens had been thawed and stored in 30% ethanol. Findings / Results: We found a typical pattern: detachment of the disc inferior from the manubrium and from anterior and posterior capsule, in connection with thinning and fragmentation of the inferior part of the disc. Generally the disc was thickest superior and thinnest inferior. With inferior detachment we found a marked supero-medial instability of the medial clavicular end. In all cadavers but one there were cartilage changes on the clavicle and sternum. The manubrium joint surface was much smaller that the clavicular surface. Conclusions: The superior part of the clavicular cartilage is only in contact with the cartilage of manubrium during extensive elevation off the clavicle, e.g. in abduction of the arm. Therefore it is mainly the inferior part of the discus that is compressed between articular surfaces and subject to age related degenerative tearing. This disc pathology can be trimmed but not reinserted. If instability is symptomatic, the joint can be stabilized. 102 DOS Abstracts

Latissimus Dorsi Tendon Transfer for Irreparable Posterosuperior Rotator Cuff Tears. A retrospective study of 38 Cases 50. Magnús Pétur Bjarnason Obinah, Theis Muncholm Thillemann, Janne Ovesen, Brian Elmengaard, Hans Viggo Skjeldborg Johannsen Shoulder and Elbow Unit, Department of Orthopaedic Surgery, Aarhus University Hospital Background: Latissimus Dorsi Transfer (LDT) was proposed by Gerber in 1988 for treating irreparable posterosuperior rotator-cuff tears involving the supraspinatus and infraspinatus. These injuries can cause superior migration of the humeral head, which may lead to glenohumeral cartilage degeneration due to excentric wear, and ultimately cuff tear arthropathy. Purpose / Aim of Study: The aim of this retrospective study was to evaluate the 1-11 years results after LDT in a consecutive series of 38 cases. Materials and Methods: We included 38 LDT procedures in 38 patients treated in the period from 2003-2013. Pre- and peroperative information was collected by review of medical reports. The primary outcome was failure defined as graft rupture or revision surgery (shoulder arthroplasty). Secondary outcomes obtained at follow-up included range of motion (ROM), Constant score, Oxford Shoulder Score (OSS), simple shoulder value (SSV) and radiographic evaluation. Findings / Results: Mean follow-up was 76.5 months (19-137). Mean age at operation was 58,3 (49 69). Eight patients had revision surgery, with a median interval between index and revision surgery of 45 months (8 96). One patient had a graft-failure. The cumulative 5 year survival rate was 83,9% (95% CI: 67,5 92,4). At follow-up mean active flexion was 105º (95% CI: 85 126), abduction 102º (95% CI: 81 122) and external rotation 28º (95% CI: 21 34). Mean Constant score was 44 (95% CI: 37 50), mean OSS was 32 (95% CI: 28-37) and mean SSV was 50 (95% CI: 39 60). When asked if they would choose a LDT again if given the same preoperative circumstances; 90% answered yes. Conclusions: Latissimus Dorsi Transfer is a satisfactory treatment for irreparable posterosuperior rotator-cuff tears. At long term follow-up we found acceptable functional outcome and pain relief with good overall patient satisfaction. DOS Kongressen 2014 103

Revision total elbow arthroplasty using the linked Coonrad-Morrey implant. Hans Viggo Skjeldborg Johannsen, Janne Ovesen 51. Shoulder and Elbow Unit, Orthopaedic Dept, Aarhus University Hospital Background: Total elbow arthroplasty is not a common procedure, and reports on revision elbow arthroplasty are rare. Purpose / Aim of Study: The objective of the present study was to report our experience with revision elbow arthroplasty using a semiconstrained Coonrad- Morrey prosthesis and to review the functional outcome after revisions. Materials and Methods: From 2000 to 2010, 58 patients (58 elbows) had a revision elbow arthroplasty using a linked Coonrad-Morrey implant. Forty-five patients were revised because of aseptic loosening and 13 because of infection. There were 27 women and 31 men with a mean age 63 (range 35 to 83) years at the time of revision. Thirteen had died from unrelated causes at a mean of 38 months (range 16 to 61 months) post-operatively, in all except one patient the implant was in place. Five of the surviving 45 patients were unable to return for follow-up. Mean follow-up was 5,3 (range 1 to 12) years. Follow-up included Mayo Elbow Performance Score and Oxford Elbow core, radiographs and clinical examination. Findings / Results: Forty elbows in 40 patients had a full follow-up.the mean Oxford Elbow score was 26.8 (8 to 48). According to the Mayo Elbow Performance Score, 31 elbows had a satisfactory outcome (6 excellent, 8 good, 17 fair). The mean score was 70.5 (range 45 to 100). Eight of the 40 patients had been re-revised; five because of infection and three because of aseptic loosening. Complications included ulnar nerve palsy, intraoperative fracture, triceps failure, deep infection and aseptic loosening. Conclusions: Revision elbow arthroplasty is a technically challenging procedure and both the short term and long term complication rates sre high. A number of different surgical options should be considered and the treatment individualized. Satisfactory results can be achieved in most cases.there is a high incidence of progressive radiolucency and patients should be monitored closely. 104 DOS Abstracts

Complications and revision surgery of the reverse shoulder arthroplasty Janne Ovesen, Thomas Falstie Jensen, Hans Viggo Skjeldborg Johannsen Shoulder and Elbow Clinic. Department of Orthopaedic Surgery., Aarhus Universityhospital 52. Background: The indications for reverse total shoulder arthroplasty (RTSA) have expanded, but there is relatively limited knowledge regarding longterm results after revisions of the RTSA. Purpose / Aim of Study: To identify and understand the most common complications and reasons for failure in RTSA. Materials and Methods: Between 2003 and 2014, 37 patients with RTSA had revision surgery. Clinical and radiographic examinations were performed preoperatively, postoperatively and analyzed retrospectively. Revision was defined as a surgical intervention with exchange or removal of one or more components. Causes for revision were identified and the patients were reviewed with a mean of 56 months follow-up after the first intervention. Findings / Results: 37 patients with a mean age of 70.1 years (51 to 83), needed at least one additional intervention to treat a complication of RTSA. Additional interventions after RTSA were needed between the second day of the RTSA and 11 years thereafter, with mean of 21.4 months postoperatively. The most common causes for revision were infection (62.2%), prosthetic instability (24.3%), humeral loosening, fracture (5.4%), glenoid loosening (5.4%) and other reasons (2.7%). At follow-up 17 patients had retained a RTSA, 17 patients had undergone conversion to hemiartroplasty and 3 patients had chosen to keep the cementspacer. Previous surgery was found to be a potential cause of low-grade infection. Conclusions: The most frequent causes for revision of a failed RTSA were infection and instability. Previous failed surgery was a risk factor for revision RTSA, in particular failed treatment for fracture (hemiarthroplasty or osteosynthesis) and failed cuffrepair. Revision of RTSA may lead to several surgical procedures in the same patient. Preservation or replacement of the RTSA, allowing a functional shoulder, was in most cases possible. DOS Kongressen 2014 105

Excess mortality in soft tissue sarcoma patients: a Danish population-based study Katja Maretty-Nielsen, Ninna Aggerholm-Pedersen, Johnny Keller, Akmal Safwat, Steen Baerentzen, Alma Pedersen 53. Department of Experimental Clinical Oncology, Aarhus University Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Oncology, Aarhus University Hospital; Department of Pathology, Aarhus University Hospital; Department of Clinical Epidemiology, Aarhus University Hospital Background: To assess the excess mortality caused by soft tissue sarcoma (STS), sarcoma-specific estimates are often reported; however, these rely on precise and correct data on the cause of death, which can be difficult to acquire. Another, more precise, method is to assess the relative mortality, i.e., mortality in sarcoma patients compared to the general population. Purpose / Aim of Study: The aims of this study were to assess the relative mortality in STS patients, and to compare this with the sarcoma-specific mortality. Materials and Methods: We included 1246 patients treated for STS at the Aarhus Sarcoma Centre between 1979 and 2008, and 6230 individually ageand sex-matched individuals from the general population. The relative mortality was estimated as rates and rate ratios, using the Cox proportional hazard model. The sarcoma-specific mortality was compared to the corresponding relative mortality. Findings / Results: The overall 5- and 10-year relative mortality was 32.8% and 36.0% Overall, STS patients had a 4.4 times higher risk of dying within the first five years after diagnosis and a 1.6 times higher risk between five and ten years compared with the general comparison cohort. Patients with low-grade STS did not have increased mortality compared with the general population. The relative mortality was highest in younger patients and in patients without comorbidity. The overall 5- year sarcoma-specific mortality was underestimated by 3.1 percentage points compared to the relative mortality. Conclusions: Patients with low-grade STS did not have increased mortality compared with the general population. A tendency towards underestimating mortality due to STS was seen when sarcoma-specific mortality using death certificates was reported. 106 DOS Abstracts

Prognostic preoperative parameters for survival in patients treated by joint replacement surgery for extremity bone metastases 54. Michala Skovlund Sørensen, Klaus Hindsø, Kristine Grubbe Gregersen, Michael Mørk Petersen Ortopædkirurgisk klinik, Rigshospitalet Background: Estimation of patient survival is important when planning surgical treatment of metastatic bone disease (MBD) of the extremities. We have done a single centre study evaluating prognostic preoperative parameters for patient survival after joint replacement (JR) surgery in patients with MDB of the appendicular bones. Purpose / Aim of Study: To estimate prognostic preoperative parameters for patient survival, in patients receiving JR, due to MBD in the appendicular skeleton. Materials and Methods: We included 130 patients that received a JR due to MBD during the period Jan 03 to Dec 08 at the Department of Orthopaedic Surgery, Rigshospitalet, Copenhagen. The cohort was followed with regard for survival until death or marts 29th 11. The following data were registered: age, gender, pathological fracture/impending fracture, number of bony metastases, visceral metastases, erythrocyte sedimentation rate (SR), C reactive protein (CRP), haemoglobin (HGB), Karnofsky score, ASA score, and primary type of cancer. Statistics: Kaplan-Meier survival analysis with logrank test and Cox proportional hazard regression analysis. Findings / Results: The calculated probability of survival after surgery was 51% and 39% at 6 months and 1 years of follow-up. The median survival time was 7 (0.03 96) months. Univariate analysis showed that all preoperative parameters were statistical significant predictors for survival except gender and pathological fracture/impending fracture. Multivariate analysis showed that visceral metastasis, Karnofsky score < 7, ASA group 3 or 4, HGB < 8 and primary type of cancer remained statistical significant predictors of survival. Conclusions: We have been able to identify preoperative parameters that correlate to patient survival in patients operated on, with a JR, because of MDB in the appendicular skeleton. DOS Kongressen 2014 107

YKL-40 protein expression in osteosarcoma tumor tissue Andrea Thorn, Lise Hanne Christiansen, Søren Daugaard, Michael Mørk Petersen 55. Musculoskeletal Tumor Section, Department of Orthopedic Surgery, Rigshospitalet, University of Copenhagen, Denmark; Department of Pathology, Rigshospitalet, University of Copenhagen, Denmark Background: YKL-40 is a glycoprotein that has showed increased expression in several other types of cells such as cancer cells, macrophages and leukocytes, embryonic cells, fetal cells, and cartilage cells. Previous studies have shown that elevated serum concentrations of YKL-40 in patients with various types of cancer constitute an independent prognostic variable for both short recurrencefree interval and short overall survival. Purpose / Aim of Study: The aim of this study is to identify if ykl-40 can serve as a surrogate marker for prediction of the outcomes in patients with high-grade osteosarcoma. Materials and Methods: All patients diagnosed with a high-malignant osteosarcoma of the extremities, spine or trunk wall at the Department of Pathology, Rigshospitalet during the years 2000-2010 were identified (n=86). Of these 48 patients (mean age 26 (6-88) years, F/M= 29/19) met criteria for inclusion in the study based on data availability and biopsy sample size. The biopsies were analysed by immunohistochemical analysis in order to determent the degree of YKL-40 staining intensity in tumour tissue Findings / Results: All 48 biopsies were positive for YKL-40 staining with various staining intensities. If the mean staining intensity of 24% was used to divide the material, we found a better survival in patients with high staining intensity (p=0.05), and the 5 and 10 years survival was 80% for patients with a staining intensity over the mean intensity of 24% (n=15), and 48% and 43% respectively, for patients with an intensity below the mean (n=33) Conclusions: Data indicates that a higher YKL-40 expression is connected to a longer overall survival. 108 DOS Abstracts

Survival of osteosarcoma patients diagnosed in East Denmark and treated at Rigshospitalet from 2000-2010. 56. Andrea Thorn, Søren Daugaard, Michael Mørk Petersen Musculoskeletal Tumor Section, Department of Orthopedic Surgery, Rigshospitalet, University of Copenhagen, Denmark; Department of Pathology, Rigshospitalet, University of Copenhagen, Denmark Background: Osteosarcoma is the most common histological type of bone sarcomas. Purpose / Aim of Study: To examine the overall survival for all osteosarcoma patients diagnosed in East Denmark and treated at Rigshospitalet from 2000-2010. Materials and Methods: All patients diagnosed with a high-malignant osteosarcoma at the Department of Pathology, Rigshospitalet during the years 2000-2010 were identified (n=86). Sixteen patients were excluded because it was consultation biopsies from other hospitals and 9 patients were excluded because the diagnosis was later changed (chondrosarcoma/giant cell sarcoma/ osteoblastoma/myeloma/ desmoid fibromatose = 3/1/1/1/1), or was from before 2000 (n=2). A total of 61 patients (mean age 31 (6-88) years, F/ M=34/27) were then analyzed for survival. Survival data were obtained from the CPR register. Statistics: Kaplan Meier survival analysis and log-rank test. Findings / Results: The probability of 5 and 10-year survival for all patients (n=61) was 57% and 52% years respectively. The probability of survival in young individuals (age 20 years) was not different from patients aged >20 years (p=0.14) and no difference between sexes (p= 0.19) was found. In patients treated with preoperative chemotherapy (n=46) the survival was higher (p=0.002), if the degree of tumor cell necrosis was 90%. Both the probability of 5 and 10 years survival in patients with 90% necrosis (n=20) was 90%, while in patients with <90% necrosis (n=26) survival was 46% and 41% respectively. Conclusions: The overall survival for patients with high- malignant osteosarcoma in East Denmark is consistent with the international average overall survival for this patient group. DOS Kongressen 2014 109

Pre-treatment biomarkers as prognosticators for mortality in patients with localized soft tissue sarcoma 57. Katja Maretty-Nielsen, Ninna Aggerholm-Pedersen, Johnny Keller, Alma Pedersen, Steen Baerentzen, Akmal Safwat Department of Experimental Clinical Oncology, Aarhus University Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Clinical Epidemiology, Aarhus University Hospital; Department of Pathology, Aarhus University Hospital; Department of Oncology, Aarhus University Hospital Background: The existing literature on biomarkers and mortality in soft tissue sarcoma (STS) is limited in both number and size, lacking the data on important confounders. Purpose / Aim of Study: The aim of this study was to determine the prognostic value of pre-treatment biomarkers for mortality in a large population-based series of adult patients with localized STS. Materials and Methods: Pre-treatment levels of albumin, C-reactive protein (CRP), hemoglobin, neutrophil to lymphocyte ratio (NLR), and sodium were analysed in 614 consecutive STS patients treated at the Aarhus Sarcoma Centre between 1994 and 2008. The prognostic value of biomarkers on sarcoma-specific mortality was estimated as hazard ratios (HR) using Cox proportional hazard models adjusted for important confounders including age and comorbidity. Findings / Results: Hypoalbuminemia (HR 1.85 [95% CI 1.14-2.99]), anemia (HR 1.66 [95% CI 1.07-2.56]), and elevated NLR (HR 1.72 [95% CI 1.10-2.70]) were independently associated with a statistical significant increased mortality, while there where a clear tendency towards CRP (HR 1.46 [95% CI 0.98-2.19]) being associated as well. Patients with abnormal values in all important biomarkers had a significant additional risk of dying, compared to patients with only some abnormal values (HR 3.91 [95% CI 1.68-910]). The median survival was 95.8 months in patients with normal values compared to 30.7 and 7.2 in patients with only some abnormal values, and patients with abnormal values in all important biomarkers, respectively. Conclusions: Hypoalbuminemia, anemia, and elevated NLR were independent prognosticators for early death in patients with localized STS. The measurement of these can be used as an additional diagnostic tool to identify high-risk patients that could be candidates for possible intensive therapy. 110 DOS Abstracts

Markedly reduced mortality following a major non-traumatic lower limb amputation 58. Morten Tange Kristensen, Gitte Holm, Michael Krasheninnikoff, Peter Gebuhr Physical Medicine and Rehabilitation Research - Copenhagen, Depertments of Physiotherapy and Orthopa, Hvidovre University Hospital; Department of Orthopaedic Surgery, Hvidovre University Hospital Background: Historically high 30-days and 1-year mortality rates of respectively 30% and 54% were reported in a Danish 2009 consecutive series of 93 patients with a non-traumatic lower limb amputation. Purpose / Aim of Study: To evaluate if allocation of staff expertise and instituting an optimized program could reduce the number of these fatal events. Materials and Methods: A consecutive series of 129 amputations (median age of 75 (IQR, 65-84) years, 53% below knee (BKA) and 47% amputated at a higher level or bilateral (AKA), admitted to an orthopaedic ward. The program instigated within a 2-year period included standards for fluid and transfusion, supplemental oxygen when supine, pain management, early mobilization and physiotherapy, weekly multidisciplinary meetings, and monthly audits of standards. Findings / Results: Twenty (16%) and 48 (37%) patients respectively, died within 30-days and 1-year. Cox regression demonstrated that a patient from a nursing home (n=26) and/or an ASA-rating of 4 (n = 12) respectively, was 3 and 5 times more likely to die within 30 days, compared to a patient with an rating of 2 (n = 41), when adjusted for age, gender, cause of and amputation level. Length of stay was reduced with a mean of 6 days. Conclusions: Allocating people with expertise and instituting an optimized program seem to reduce the short and long-term mortality rates markedly in patients with a major lower limb amputation. DOS Kongressen 2014 111

Tumor characteristics, patient reported symptoms and suspected and final diagnosis for 64 sarcoma patients referred to a sarcoma center after surgery/ biopsy in non-specialist institutions. 59. Heidi Buvarp Dyrop, Peter Vedsted, Katja Maretty-Nielsen, Bjarne Hauge Hansen, Peter Holmberg Jørgensen, Johnny Keller Department of Experimental Clinical Oncology, Aarhus University Hospital; The Research Unit for General Practice, Aarhus University; Department of Orthopaedics, Sarcoma Centre of Aarhus University Hospital Background: Some sarcomas are referred after surgery on suspected benign tumors. This can affect patient prognosis and cause large re- excisions. Knowledge about diagnostic pathways of these patients is uncertain and must be reviewed. Purpose / Aim of Study: To investigate patient and tumor characteristics, patient reported symptoms, suspected and final diagnosis, and explore reasons for referral, in sarcoma patients referred after surgery in non-specialist institutions. Materials and Methods: Retrospective review of medical files. From a previous study on 258 sarcoma patients referred over 4 years, we identified 64 (24.8%) referred with a confirmed histological sarcoma. Medical files were reviewed for patient reported symptoms, suspected diagnosis and reasons for referral. Patient and tumor characteristics were previously collected. Findings / Results: 27 (42.2 %) tumors were low grade, 37 (57.8 %) high grade. Lipoma and fibroma/dermatofibroma were most reported suspected diagnoses. 7 patients were suspected of other malignancies due to location (breast, testicles, kidney). For 23 (35.9%) patients, initial presence of alarm symptoms were described in the referral text. 9 tumors were >5cm, 10 subfascial and 9 were both. 32 (50%) had superficial small tumors, of which 21 (65.6%) were suspected skin conditions. 8 (12.5%) of 64 patients stated that it was a second removal of a tumor in the same area. 3 patients reported changes in a tumor that had been present for years. Conclusions: 1/4 of sarcoma patients had surgery on suspected benign tumors. For 1/3, alarm symptoms had been reported, the remaining fell outside referral guidelines or alarm symptoms were not discovered. Sarcoma should be considered even in unusual or superficial locations, also when the tumor is <5 cm. Recurring benign tumors and changes in dormant tumors should cause reevaluation of diagnosis. 112 DOS Abstracts

Factors predicting the basic amputee mobility outcome in patients with a major non-traumatic lower limb amputation. 60. Morten Tange Kristensen, Anni Østergaard Nielsen, Ulla Madsen Topp, Peter Gebuhr Physical Medicine and Rehabilitation Research Copenhagen, Departments of Physiotherapy and Orthopa, Hvidovre University Hospital; Department og Physiotherapy, Hvidovre University Hospital; Department of Orthopaedic Surgery, Hvidovre University Hospital Background: Prosthetic fitting is the long term goal for most patients following a major lower limb amputation. However, this is not possible in every dysvascular amputee and not the primary focus of today s acute in-patient rehabilitation programmes. On the contrary, independence in transfers and wheelchair skills is considered mandatory for all, but knowledge regarding who achieve this, and factors influencing are limited. Purpose / Aim of Study: To examine factors predicting the basic amputee mobility outcome in an acute orthopaedic ward following a dysvascular major lower limb amputation. Materials and Methods: Ninety-one out of 103 (12 died in- hospital) consecutive patients (32 women and 59 men, 57 below knee and 34 above knee or bilateral index amputations) with a mean age of 71.6 (SD, 12) years, admitted from their own home. The outcome variables were independency in bedand bed to chair transfers, and indoor wheelchair manoeuvring. Findings / Results: Patients who achieved independency (n=64) stayed in the ward a mean of 23.2 (9.3) days as compared to 30.2 (20.2) for those not (30%). Multiple logistic regression revealed that a patient with no preamputation walking ability was 6 times more likely not to achieve independency in basic activities during admittance, while odds increased with 8% per each additional year a patient got older, when adjusted for gender, ASA-score, diabetes (n=39) and the final amputation level. Correspondingly, odds was 4 times (P=0.06) higher for patients who experienced a major revision or reamputation (n=19). Conclusions: The preamputation function and age were independent predictors of the in- hospital amputee mobility outcome, while having a reamputation also seem to influence. Clinicians, have the possibility to spot patients who may benefit from more intensive training, while number of reamputations should be reduced. DOS Kongressen 2014 113

Feasibility and safety of intensive weight loss before total knee replacement in obese patients: A randomized controlled trial 61. Anette Liljensøe, Jens Ole Laursen, Henning Bliddal, Kjeld Søballe, Inger Mechlenburg Department of Orthopedics, Aarhus University Hospital; The Parker Institute, Department of Rheumatology, Copenhagen University Hospital, Bispebjerg- Frederiksberg Background: Annually 8500 total knee replacements (TKR) are performed in Denmark. About 80% of this population is overweight or obese. The present material is part of a longitudinal randomized study. ClinicalTrial.gov: NCT01469403 Purpose / Aim of Study: To investigate whether it is feasible and safe to implement an intensive weight loss program in order to reduce preoperative body weight of obese patients before total knee replacement (TKR) surgery. Materials and Methods: We conducted a pragmatic, single- blind, singlecenter randomized study. Eligible patients were scheduled for TKR due to osteoarthritis (OA) of the knee and obesity (BMI > 30kg/m2). Participants were randomized to either a control group that followed the standard care or a weight loss group that followed a low-energy diet (810 kcal/day) 8 weeks before TKR. Outcomes were assessed before intervention for the weight loss group, and within 1 week preoperatively for both the weight loss group and the control group. Findings / Results: Included were 77 patients (weight loss group n=38; control group n=39), 71% were females, the mean age was 65 years (range 46-85), and the average BMI was 31. The average weight loss after 8 weeks was 10.7 kg. According to dual energy X-ray absorptiometry (DXA), the weight loss consisted of a 6.7 kg reduction in fat mass, a 3.0 kg reduction in lean body mass, and lean body mass increased by 2.3%. The intensive diets had few and mild adverse effects. Serious cardiac complications were found in two cases in the intervention group and in one case in the control group. All three patients later underwent TKR without complications. No perioperative complications were recorded in any group. Conclusions: Our results show that it is feasible and safe to implement a weight loss program shortly before TKR. 114 DOS Abstracts

Efficacy of preoperative progressive resistance training on postoperative functional capacity and muscle strength in patients undergoing total knee arthroplasty Birgit Skoffer, Thomas Maribo, Inger Mechlenburg, Per Møller Hansen, Kjeld Søballe, Ulrik Dalgas 62. Institute of Clinical Medicine and Department of Physical and Occupational Therapy, Aarhus University and Aarhus University Hospital; MarselisborgCentret, Danish Rehabilitation Research Centre; National Public Health and Quality Impro, Central Denmark Region, Aarhus and Aarhus University; Institute of Clinical Medicine and Orthopaedic Research Centre, Aarhus University and Aarhus University Hospital; Orthopaedic Department, Silkeborg Regional Hospital; Orthopaedic Research Centre, Aarhus University Hospital ; Section of Sport Science, Department of Public Health, Aarhus University Background: Reduced knee extensor muscle strength and associated impaired functional capacity is a common clinical finding in people with knee osteoarthritis. Furthermore, knee extensor muscle strength is a strong predictor of functional capacity one year after total knee arthroplasty (TKA). Purpose / Aim of Study: To investigate the efficacy of 4 weeks of preoperative and 4-week post-operative progressive resistance training (PRT) compared to 4 weeks of postoperative PRT alone in patients undergoing total knee arthroplasty. Outcomes were functional capacity, muscle strength and patient reported outcomes. Materials and Methods: In a single-blinded, clinical, randomized, controlled trial, 59 patients were randomized to 4 weeks of preoperative PRT (PRT group) or to a control group who lived as usual (control group). All patients performed 4 weeks of PRT after TKA. At 6 weeks before TKA, and at 6 weeks after TKA functional capacity, knee extensor and flexor muscle strength, patient reported functional capacity, health related quality of life, pain scores and medication was registered. Findings / Results: A significant group difference was found in favor of the PRT group for the 30sec-sit-to- stand test (3.5± 1.2 rep; p<0.01), the timedup-and-go test (-1.56± 0.64 sec.; p<0.05), in knee extensor muscle strength (19.3± 6.4 Nm; p<0.01) and in knee flexor muscle strength (16.0± 5.5 Nm, p<0.01) when evaluated 6 weeks after TKA. No differences were found between groups on patient reported outcomes except for the KOOS sport subscale (13.6± 6.6 p<0.05) favoring the PRT group. Conclusions: Preoperative PRT is an effective intervention improving postoperative functional capacity and muscle strength but not patient reported outcomes, without worsening pain or increasing medication in patients undergoing TKA. DOS Kongressen 2014 115

EOS imaging for assessing lower limb alignment and implant positioning after Total Knee Arthroplasty (TKA) 63. Kirill Gromov, Viktor Hansen, Dov Goldvasser, Orhun Muratoglu, Henrik Malchau, Anders Troelsen Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Harris Orthopaedic Laboratory, Massachusetts General Hospital Background: The lower limb axis and implant alignment are traditionally assessed to evaluate the success of primary TKA surgery. EOS imaging is a novel technology that can provide the surgeon with full body images, while exposing the patient to significantly lower radiation dosage Purpose / Aim of Study: In this study we seek to evaluate the precision of EOS imaging for measuring lower limb axes as well as implant alignment following primary TKA Materials and Methods: 32 patients that underwent TKA and had EOS radiography performed pre- and postoperatively were included in the study. Hip- Knee-Ankle (HKA) axis and tibiofemoral angle (TFA) was measured pre- and postoperatively. Tibial and femoral implant alignment was assessed in anteriorposterior (AP) and lateral plane in respect to anatomical as well as mechanical axis. Two readers each assessed all images with reassessment by one reader.. Intra- and inter-reader variability was assessed by the mean difference and 95% limits of agreement (LoA) Findings / Results: 95% LoA for postoperative HKA and TFA were +/- 0.41 and +/-0.80, respectively. 95% LoA for AP implant alignment in respect to the mechanical axes were all within +/-0.80 and within +/-1.47 in respect to anatomical axes. 95% LoA for tibial lateral implant alignment were within +/- 1.50 and within +/-3.65 for femoral lateral implant alignment. There were no systematic differences between observers. Mean difference and LoA for tibial component alignment in the AP plane in respect to the mechanical compared to anatomical axis was -0.18 +/-2.86 Conclusions: EOS imaging can be used for precise measurements of lower limb axis and implant alignment following primary TKA. This allows EOS imaging to be potentially implemented as a clinical tool for evaluation of results following TKA 116 DOS Abstracts

Early progressive strength training to enhance recovery after fast-track total knee arthroplasty. A randomized controlled trial 64. Thomas Linding Jakobsen, Henrik Kehlet, Henrik Husted, Janne Petersen, Thomas Bandholm Lundbeck Foundation Centre for Fast-track Hip and Knee Arthroplasty, Clinical Research Centre, Physi, Hvidovre Hospital, University of Copenhagen; Section for Surgical Pathophysiology 4074, Lundbeck Foundation Centre for Fasttrack Hip and Knee Ar, Rigshospitalet, University of Copenhagen; Department of Orthopaedic Surgery, Hvidovre Hospital, University of Copenhagen; Clinical Research Centre, Hvidovre Hospital, University of Copenhagen; Physical Medicine and Rehabilitation Research - Copenhagen (PMR-C), Department of Physical Therapy,, Hvidovre Hospital, University of Copenhagen Background: A pronounced loss of muscle strength and functional performance has been found after total knee arthroplasty (TKA). A rehabilitation modality known to increase muscle strength and functional performance over time - such as progressive strength training (PST) - seems rational to enhance recovery after TKA. However, the effect of rehabilitation with PST has not been investigated in a large assessor-blinded randomized controlled trial. Purpose / Aim of Study: To compare 7 weeks of supervised rehabilitation with or without PST commenced early after fast-track TKA on functional performance. Materials and Methods: Eighty-two patients with a unilateral primary TKA were randomized to 7 weeks of supervised rehabilitation with (PST-group) and without (CON-group) PST commenced early after fast-track TKA. The primary outcome was the maximal distance walked in 6 minutes (6- minute walk test). Secondary outcomes were lower limb strength and power, knee joint effusion and range of motion, knee pain and self-reported disability and quality of life. All outcome measures were assessed before (baseline) and 4, 8 and 26 weeks after TKA. Findings / Results: There was no statistically significant difference between the PST- and CON- group 8-week postoperatively (primary endpoint) for the 6-minute walk test (mean difference between groups: -11.3 meters, 95% confidence interval -45.4 to 22.7 meters; analysis of variance, p=0.51). There were no statistically significant or clinically meaningful differences between groups in change scores from baseline to any other time point for all secondary outcomes. Conclusions: Seven weeks of supervised rehabilitation with PST was not superior to 7 weeks of supervised rehabilitation without PST in improving functional performance, measured as the maximal walking distance in 6 minutes, at the primary endpoint 8 weeks after fast-track TKA. DOS Kongressen 2014 117

Bone remodelling of the of the tibia after total knee arthroplastry with uncemented tibia implants 65. Mikikel Rathsach Andersen, Nikolaj Winther, Thomas Lind, Henrik Schrøder, Michael Mörk Petersen Knæklinikken, Ortopædkirurgisk afdeling, Gentofte Hospital, Region Hovedstaden; Ortopædkirurgisk klinik U, Hovedortocenteret, Rigshospitalet, Region Hovedstaden Background: Loss of bone stock as a response to the bone trauma and postoperative immobilisation is a well known complication to joint replacement surgery. Purpose / Aim of Study: This study investigates the adaptive bone remodelling of the tibia, after total knee arthroplasty (TKA) with two uncemented total knee arthroplastries. Materials and Methods: We performed 1 year follow up of 54 patients (mean age 61,7 (38-70) years, 28/26=x/y, BMI 29,5) that received an uncemented TKA in a prospective randomised controlled trial, where the patients were randomised into two groups that recieved different tibial components. The TKAs were performed using the uncemented Zimmer Nexgen trabecular metal tibia implants with either a monoblock (A) or modular (B) polyethylene design. Measurements of bone mineral density (BMD) were done postoperatively and after 3, 6, and, 12 months. BMD was measured in 3 regions of interest (ROI) medially, laterally, and distally around the tibial component. Statistics: Paired and unpaired t-test (P< 0.05 were considered significant). Findings / Results: Significant changes in BMD after 12 months of follow-up was only seen in group A, where BMD decreased medially by 9.4% (p=0.002) and laterally by 6.7% (p=0.009). When comparing BMD changes between the groups after 12 months differences was found in the medial (p=0.01) and lateral (p=0.053) ROIs. Conclusions: A significantly different bone remodelling pattern of the proximal tibia was seen in the two groups with a higher degree of bone loss seen in knees that received the monoblock design. 118 DOS Abstracts

Similar polyethylene wear of cementless and cemented Oxford Partial Knee s at 2 years follow-up. A Randomized RSA Study 66. Maiken Stilling, Anders Odgaard, Claus Fink Jepsen, Kjeld Søballe, Per Wagner Kristensen, Frank Madsen Department of Orthopaedic Research, Aarhus University Hospital; Department of Orthopaedics, Copenhagen University Hospital Gentofte Background: Wear of polyethylene is a significant cause of revision surgery in partial knee replacement. The Oxford Partial Knee has a fully-congruent, mobile, polyethylene (PE) bearing designed to minimize wear. Well-functioning knees have low PE wear, but impingement or incongruous articulation may affect the wear rate. Cementless components are hydroxyapatite coated, which may risk higher polyethylene wear. Purpose / Aim of Study: To compare PE wear of cementless (CL) and cemented (C) Oxford Partial Knee s at 2 years by radiostereometric analysis (RSA). Materials and Methods: 80 patients (48 men) were randomly allocated to surgery with CL hydroxyapatite-coated (n=25) or C (n=55) Oxford Partial Knee s (Biomet Inc.) and UHMWPE at 2 hospital sites. Refobacin bone cement (Biomet Inc.) was used. Evaluations of PE wear (model-based RSA y-translation, weight bearing set-up) and clinical outcomes (OKS, AKSS) was performed between baseline and 2 years. Findings / Results: At 2 years followup mean PE wear of 0.43 (sd 0.98) mm in cementless knees was similar (p=0.10) to 0.11 (sd 1.08) mm in cemented knees. The wear rate including creep was 0.21 (sd 0.48) mm in cementless knees and 0.06 (sd 0.54) mm in cemented knees (p=0.10). PE wear did not correlate to age (p=0.45), OKS (p=0.54), pain in general (p=0.61), pain during work (p=0.50), side instability (p=0.67), knee axis (p=0.96), walking aids (p=0.50) or patient reported walking distance (p=0.27). At 2 years mean OKS was 40 (range 21-47) (p=0.53) with similar improvement from baseline (p=0.11). Satisfaction was high in both groups. No revisions. Conclusions: Cementless Oxford Partial Knee s had a tendency towards higher PE wear at 2 years followup, and all knees had higher wear rate than reported for well- functioning partial knees in the literature. Functional results were good and similar in both groups. DOS Kongressen 2014 119

Does knee awareness differ between knees in bilateral simultaneous TKA? Predictors of high knee awareness. Katrine Abildgaard Nielsen, Morten Grove Thomsen, Roshan Latifi, Thomas Kallemose, Henrik Husted, Anders Troelsen 67. Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Denmark Background: Low knee awareness during activities of daily living has become the primary goal when evaluating outcome after Total Knee Arthroplasty (TKA). However, it is still unclear how patient derived factors (e.g. knee alignment) influence postoperative knee awareness and functional outcome. The Forgotten Joint Score (FJS) evaluates to what extent the patient is aware of the artificial knee and thereby, whether the knee feels natural or not. Purpose / Aim of Study: To evaluate knee awareness of patients undergoing bilateral simultaneous TKA and to clarify the factors that predict a high or low score. Materials and Methods: This cross sectional study was conducted on 120 simultaneous bilateral TKAs (cemented CR AGC, Biomet) performed at our institution between 2008 and 2012 (2-6 years follow-up). All patients received 1 set of questionnaires (FJS and Oxford Knee Score (OKS)) for each knee. 99 patients (45 men, 54 women, mean age at operation 66,6 years) completed the survey and were eligible for analysis. Based on FJS scores patients knees were divided into two groups - best and worst knees. The FJS and OKS scores were compared between groups. Findings / Results: The absolute difference in FJS and OKS score between the knees within each patient was calculated, a non-parametric bootstrap was used to create a 95 % confidence interval (CI) for the median of these differences. The results was a median of 1 (CI: 0-4) for the FJS score and 1 (CI: 0-1) for the OKS score. A predictive model found that KL-score (p=0.006) and preoperative knee-alignment (p=0.017) had a significant effect on FJS score. Conclusions: Knee awareness and functional outcome did not differ significantly between the best and worst knee in patients undergoing bilateral simultaneous TKA. More severe preoperative varus alignment and more severe KLgrades predict lower knee awareness after TKA. 120 DOS Abstracts

Evaluation of peri-implant bone mineral density changes after femoral osseointegrated prosthesis surgery 68. Rehne Lessmann Hansen, Peter Holmberg Jørgensen, Kjeld Søballe, Klaus Kjær Petersen, Maiken Stilling Department of orthopaedic research, University Hospital of Aarhus; Department of orthopaedic surgery, University Hospital of Aarhus Background: Trans-femoral amputees have reduced bone mineral density (BMD) in the residual femur, hip and ipsilateral pelvis. Insertion of an osseointegrated (OI) prosthesis may affect the BMD additionally. Purpose / Aim of Study: To study the effects of unloading/loading and stress shielding after OI-prosthesis surgery. Materials and Methods: 20 patients (13 males) mean age 48 (range 30-66) years, were operated with an OI femoral implant in two stages. DXA scans were performed at baseline and at intervals of 3, 6, 9, 12, 18 months postoperatively. The first 9 months partial weight bearing (PW) was allowed, and after 9 months full weight bearing (FW) was encouraged. The femoral peri- implant bone was evaluated in 3 regions of interest (ROIs), proximally (Rp), medially (Rm) and laterally (Rl) to OI implant. Findings / Results: From baseline to 18 months follow-up total peri-prosthetic BMD was unchanged (p=0.44). However, during PW periprosthetic BMD decreased (p=0.005) 25% and during FW BMD increased (p=0.04) 17%. All 3 periprosthetic ROIs had a decrease in BMD (p<0.0007) during the PW rehabilitation period of 30%, 20% and 24% for Rp, Rm and Rl, respectively. During FW rehabilitation BMD increased (p<0.04) in Rp 19% and in Rm 14%, whereas the BMD in Rl was similar (p=0.06). However, baseline values were not reached at 18 months. Conclusions: Unloading, or less than full weight bearing, in the first 9 months after IO implantation causes pronounced stress-shielding and peri-implant BMD loss. Increased or full loading between 9 and 18 months increases BMD, but not to baseline values. Patients will be followed to investigate if direct femoral bone loading from the OI implant will result in continued BMD increase of the periimplant bone. DOS Kongressen 2014 121

Functional capacity is associated with both extensor and flexor strength in patients scheduled for total knee arthroplasty: a cross-sectional study 69. Birgit Skoffer, Ulrik Dalgas, Inger Mechlenburg, Kjeld Søballe, Thomas Maribo Institute of Clinical Medicine and Department of Physical and Occupational Therapy, Aarhus University and Aarhus University Hospital; Section of Sport Science, Department of Public Health, Aarhus University; Institute of Clinical Medicine and Orthopaedic Research Centre, Aarhus University and Aarhus University Hospital; Orthopaedic Research Centre, Aarhus University Hospital; MarselisborgCentret, Danish Rehabilitation Research Centre; National Public Health and Quality Impro, Central Denmark Region and Aarhus University Background: Impairment of the knee extensor muscle strength in patients with knee osteoarthritis (OA) is well documented. Furthermore, pain and reduced functional capacity in combination with radiographically confirmed severe OA are the main indications for total knee arthroplasty (TKA). Purpose / Aim of Study: To test in people scheduled for TKA if muscle strength would be 1) strongly associated with both objectively measured functional capacity and patient-reported measures; 2) more closely associated with lower extremity function when measured during concentric than during isometric contractions and; and 3) more strongly related to the 30-sec-sit-to-stand (30sSTS) test than to the timed-up-and- go (TUG) and walking tests. Materials and Methods: In fifty nine patients (70.4±6.8 years). Associations between muscle strength and objectively measured functional capacity and patient reported outcomes were calculated. Findings / Results: Both knee extensor and knee flexor strength were associated with functional capacity outcomes. Generally, the isokinetic knee flexor muscle strength was more strongly associated with functional capacity than the isometric knee flexor strength. Isokinetic and isometric knee extensor strength were of equal importance. The 30sSTS test was better than the TUG and the walking tests at determining muscle strength. Conclusions: Knee extensor and knee flexor muscle strength and functional capacity are generally associated. Focus on knee extensor and knee flexor muscle strength is of equal importance to improve or maintain functional capacity. Furthermore, the 30sSTS test was found to be the best proxy measure of muscle strength when more advanced equipment for measurement of muscle strength is not available. 122 DOS Abstracts

Does knee awareness differ between different TKA designs? A matched, case-control, cross-sectional study. 70. Morten Grove Thomsen, Roshan Latifi, Thomas Kallemose, Henrik Husted, Anders Troelsen Dept. of Orthopedic surgery, Copenhagen University Hospital of Hvidovre, Denmark Background: Low knee awareness after TKA has become the ultimate goal in trying to achieve a natural feeling knee that meet patient expectations. To accommodate this manufacturers of TKAs have developed new prosthetic designs that potentially could give patients a more natural feeling knee during activities. Purpose / Aim of Study: To compare the Forgotten Joint Score (FJS) and Oxford Knee Score (OKS) of patients treated with a previous generation standard CR TKA to the scores obtained by patients treated with a newer generation CR TKA or a mobile bearing CR TKA. Materials and Methods: We identified all patients receiving a new generation CR TKA or mobile bearing TKA at our institution between 2010 and 2012. These were matched to a population of patients receiving a standard CR TKA regarding age, gender, year of surgery, KL- grade and pre- and postoperative knee alignment. Patients were asked to complete the FJS and OKS questionnaires. Of the 316 patients completing the survey 64 standard CR TKAs to 45 new generation CR TKAs and 121 standard CR TKAs to 68 mobile bearing TKAs were matched. The FJS and OKS scores of the three TKA designs were compared. Findings / Results: When comparing the new generation CR TKAs to the standard CR TKAs we found statistically significant higher OKS and FJS scores (6 (p=0.04) and 16 (p=0.03) points respectively) for the new generation CR TKAs. When comparing the mobile bearing TKAs to the standard CR TKAs we found a statistically significant higher OKS score (3 points, p=0.04), and a higher FJS score (4 points, p=0.48) for the mobile bearing TKAs. Conclusions: Patients receiving the new generation CR and mobile bearing CR TKAs obtained higher FJS and OKS scores when compared to patients receiving a standard CR TKA, indicating that the use of these newer prosthetic designs facilitate less knee awareness and better function after TKA. DOS Kongressen 2014 123

Composition of The Knee Index, a novel threedimensional biomechanical index for knee joint load, in subjects with mild to moderate knee osteoarthritis 71. Brian Clausen, Thomas Andriacchi, Dennis Brandborg Nielsen, Ewa Roos, Anders Holsgaard-Larsen Department of Sports Science and Clinical Biomechanics, University of Southern Denmark; Department of Mechanical Engineering, Department of Orthopedic Surgery, Stanford University, Stanford, USA; Veterans Administration, Palo Alto; Department of Orthopaedics and Traumatology, Department of Clinical Research, Odense University Hospital, University of Southern Denmark Background: Knee joint load is an important factor associated with progression of knee osteoarthritis. To provide an overall understanding of knee joint loading, the Knee Index (KI) has been developed to include moments from all three planes (frontal, sagittal and transversal). However, before KI is used in clinical trials a biomechanical analysis identifying the respective contributions of the knee moments derived from the three planes is needed. Purpose / Aim of Study: The purpose of this study was therefor to investigate how the frontal, sagittal and transversal moments contribute to KI, a novel biomechanical index of joint load for the knee, in patients with mild to moderate knee osteoarthritis. Materials and Methods: The contribution of frontal, sagittal and transversal plane knee moments to KI was investigated in 24 subjects (13 women, age: 58 ± 7.6 years, BMI: 27.1 ± 3.0) with clinically diagnosed mild to moderate knee osteoarthritis according to the ACR criteria. Three dimensional gait analysis was performed. Subjects walked barefoot at self-selected walking speed. The first peak magnitude KI from all three planes were calculated using inverse dynamics. Findings / Results: Frontal plane kinematics contributed with 59.3% (SD 25.6) of KI while sagittal plane kinematics contributed with 40.5% (SD 26.1). A substantial inter-subject variation in the relative contribution of the flexion and extension moment components to KI was observed. Conclusions: Our findings support the notion that the primary contributor to KI is the frontal plane kinematics (i.e. the knee adduction moment), and secondarily the sagittal plane kinematics (i.e. the knee flexion moment). This holds promise for using KI in clinical trials since both frontal and sagittal knee joint moments have been suggested to be associated with the knee osteoarthritis disease progression. 124 DOS Abstracts

Pelvic movement strategies and leg extension power in patients with end-stage medial knee osteoarthritis: A cross-sectional study 72. Signe Kierkegaard, Peter Bo Jørgensen, Ulrik Dalgas, Kjeld Søballe, Inger Mechlenburg Orthopaedic Research, Aarhus University Hospital; Department of Sport Science, Aarhus University Background: While it is well-known that knee osteoarthritis (OA) and knee extensor muscle strength are associated, less is known about leg extension power although leg power is closely related to functional performance in elderly persons. Patients with medial knee OA use a variety of compensatory movement strategies to minimize the joint load in the affected leg. Little is known about these movement strategies of the pelvis during functional performance tests. Purpose / Aim of Study: The aim of the study was to investigate leg extension power and pelvic movements during walking, stair climbing and stepping in patients with end-stage medial knee OA and in healthy controls. Materials and Methods: 57 patients (mean age 65.6 years) scheduled for medial uni-compartmental knee arthroplasty (UKA) were included in the crosssectional study together with 29 age and gender matched controls. Leg extension power was tested in the Nottingham Leg Extension Power-Rig and pelvic movements were derived from an inertial sensor with gyroscope placed between the posterior superior iliac spines during walking, stair and step ascending and descending. Findings / Results: Both the affected and the contralateral leg of the patients were weaker than the matched control legs. Patients used a greater pelvic movement than controls during stair and step ascending and descending, which was especially evident during descending. Furthermore a significant inverse association between leg extension power and pelvic movements during stair and step descending was found in the patient group. Conclusions: Compared to controls, patients with medial knee OA use greater pelvic movements during advanced functional performance tests, especially during descending tasks. Further longitudinal studies are required to investigate pelvic movements after UKA. DOS Kongressen 2014 125

The Göttingen Mini-Pig (GMP) as an Animal Model for Articular Cartilage Repair Bjørn Christensen, Casper Foldager, Morten Olesen, Jan Rölfing, Steffen Ringgaard, Martin Lind 73. Ortopedic Research Laboratory, Aarhus University Hospital; Orthopedic Research Laboratory, Aarhus University Hospital; MR center, Aarhus University Hospital; Division of sports trauma, Aarhus University Hospital Background: Several animal models are available for preclinical testing of cartilage repair, but a cost-effective and predictable large animal model is needed to bridge the gap between in vitro studies and clinical studies. Ideally, the animal model should allow for testing of clinically relevant treatments and the biological response should be reproducible and comparable to humans. This allows for a reliable translation of results to clinical studies. Purpose / Aim of Study: This study aimed at verifying the GMP as a preclinical model for articular cartilage repair by testing several clinically available surgical treatment options and evaluation methods. Materials and Methods: Thirteen fully mature GMPs were used. The GMPs received bilateral trochlear osteochondral drill-hole defects or chondral defects (Ø 6mm). The defects were treated with one of the following: Matrix-induced autologous chondrocyte implantation (MACI), microfracture (MFx), autologous- dual-tissue transplantation (ADTT), autologous bone graft, autologous cartilage chips. Empty chondral and osteochondral defects were used as controls. MRI and CT were performed 3 and 6 month, histology was performed at 6 month postoperative. Findings / Results: The repair tissue varied in morphology from non-cartilaginous fibrous tissue to fibrocartilaginous tissue as seen on MRI, CT and histology at 6 month. The worst results were seen in the empty controls, the defects treated with autologous bone graft and defects treated with MFx. The best results were achieved with the MACI treatment. Conclusions: The outcomes of the applied treatments were consistent with the outcomes in clinical studies. The GMP model was easy to handle, cost-effective and provided predictable outcome. Based on this study, we conclude that the GMP is a viable animal model for articular cartilage research. 126 DOS Abstracts

Collagen type IV in Articular Cartilage Damage and Repair 74. Casper Bindzus Foldager, Wei Seong Toh, Bjørn Borsøe Christensen, Martin Lind, Andreas H. Gomoll, Myron Spector Orthopaedic Research Lab, Aarhus University Hospital; Faculty of Dentistry, National University of Singapore; Sports Trauma Clinic, Aarhus University Hospital; Cartilage Repair Center, Brigham & Women s Hospital; VA Tissue Engineering Lab, Harvard Medical School Background: Chondrocytes are surrounded by a thin layer of pericellular matrix (PCM). Collagen type IV (COL4) is present in the PCM of healthy chondrocytes. COL4 is composed of three of six different alpha-chains. Three of these alpha-chains contain angiogenesis inhibiting domains in alpha-1 (arresten), alpha-2 (canstatin), and alpha-3 (tumstatin), but their presence in cartilage is unknown. Purpose / Aim of Study: To identify the COL4 alpha-chains in cartilage and describe its distribution of in cartilage damage and repair. Materials and Methods: In vitro: Human chondrocytes from 6 patients were cultured in standard 21% oxygen and physiologic 1% oxygen for up to 6 days. Quantitative gene expression analysis (RT-qPCR) was performed to confirm the chondrogenic phenotype (Sox5, Sox6, Sox9) and to investigate the presence of the different COL4 alpha-chains 1-6. In vivo: Distribution of collagen type IV was investigated with immunohistochemistry in normal cartilage (human, n=5), damaged cartilage (human, n=5), clinically failed repair (human, n=11), cartilage repair with 6-month follow-up (minipig, n=11). Findings / Results: COL4 expression in normal chondrocytes consisted of alpha chain 1 and 2. In normal cartilage COL4 was restricted to the PCM. Damaged cartilage contained significantly less COL4 in the PCM compared with normal cartilage. In minipigs with fibrous repair matrix COL4 was found in the extracellular matrix (ECM) and not the PCM. In fibrocartilage COL4 was also seen in the PCM and the interterritorial matrix. In hyaline repair tissue COL4 was restricted to the PCM. In failed repair COL4 was found in the PCM of 0-75% of the cells depending on tissue morphology and treatment. Conclusions: COL4 in cartilage contain the angiogenesis inhibitors arresten and canstatin. The distribution of COL4 is changed in cartilage repair compared to normal cartilage. DOS Kongressen 2014 127

Reduced force development in rat soleus muscle after exposure to Botulinum Neurotoxin A Sofie Gjessing, Ole Rahbek, Juan Manuel Shiguetomi, Ole B. Nielsen, Bjarne Møller-Madsen 75. Dept. of Children s Orthopaedics, Aarhus University Hospital; Department of Biomedicine, Aarhus University Background: A fast force development at the beginning of a muscle contraction is an important functional aspect of locomotion such as gait. In both human and rat motor function this can be achieved by firing double pulses (doublets) with an inter-pulse interval (IPI) as short as 1.6 ms. We hypothesize that Botulinum Neurotoxin A (BoNT) reduces the ability of the neuromuscular junction to transmit doublets and therefore also reduces their potentiating effect on force development. Purpose / Aim of Study: We aimed to examine the effect of BoNT on force potentiation resulting from doublet stimulation in skeletal muscle. Materials and Methods: Experiments were performed on isolated soleus muscle with intact motor nerve from juvenile Wistar rats that had been given intramuscular injections of BoNT 1-4 days prior to ex vivo examinations of contractile force. Findings / Results: BoNT caused a progressive decline in nerve-stimulated tetanic force of the muscle preparations. In controls, nerve-stimulated doublets increased twitch force to ~200% of force of a single pulse when IPI was 2 ms and 230% for an interval of 4 ms. This potentiation was, however, attenuated by BoNT in a manner that depended on the reduction in nerve-stimulated force and the IPI. When tetanic force stimulated via the nerve was reduced to 0-39% of force produced by direct stimulation of the muscle fibres, force potentiation, resulting from nerve stimulation by doublets with an IPI of 2 ms, was significantly reduced (P<0.01, one-way ANOVA). No significant effects was observed at an IPI > 4 ms. Conclusions: Treatment with BoNT in vivo reduced the ability of the neuromuscular junction to transmit high-frequency doublets in skeletal muscle. This indicates that treatment with BoNT may interfere with motor function during locomotion, which could compromise gait. 128 DOS Abstracts

Inhibition of Micromotion induced Osteolysis in a Sheep Hip Arthroplasty Model Thomas Jakobsen, Søren Kold, Juan Shiguetomi-Medina, Jørgen Baas, Kjeld Søballe, Ole Rahbek 76. Ortopædkir. Forskningslab., Aarhus Universitets Hospital; Ortopædkir. afd., Aalborg Universitets Hospital; Ortopædkir. Forskningslab, Aarhus Universitets Hospital; Ortopæd. Afd., Aarhus Universitets Hospital Background: Aseptic loosening is the leading indication for revision surgery of a total hip replacement. It has previously been shown that early micromotion of a total hip replacement is associated with early aseptic loosening. One way to reduce the impact of the early micromotion on implant fixation could be with the use of bisphosphonates (BP). These compounds are strong inhibitors of bone resorption. Purpose / Aim of Study: The aim of this study was to investigate whether local treatment with BP would reduce bone resorption around an experimental implant subjected to micromotion. Materials and Methods: One micromotion implant were inserted into each medial femoral condyle in ten sheep. The micromotion device consists of an anchor bearing a PMMA implant and a PE plug. The 7.5 mm PMMA implant is placed exact-fit into a 7.5 mm bone cavity. During each gait cycle the PE plug will transfer load through the anchor and make the PMMA implant axially piston 0.5 mm. During surgery one of the femoral condyles were locally treated with 0.8 mg zoledronic acid. The other condyle served as control. Bone-implant specimens were harvested after 12 weeks of observation. Each specimen were embedded and vertically cut for histomorphometrical analysis. Findings / Results: Histological evaluation showed a fibrous capsule around both the control and BP implants. Histomorphometrical analysis showed that 97% of the surface on both control and BP implants were covered by fibrous tissue (p=0.7). However, the BP was able to preserve bone in a 1 mm zone around the implants (66% bone volume fraction for BP vs. 57% bone volume fraction for control, p = 0.02). Conclusions: This study indicates that local treatment with BP can not prevent the formation of a fibrous capsule around an implant subjected to micromotion. However, BP is able to reduce resorption of peri-prosthetic bone. DOS Kongressen 2014 129

Sheep model reflecting glucocorticoid induced osteoporosis in postmenopausal women Christina Møller Andreasen, Ming Ding, Søren Overgaard, Peter Bollen, Thomas Levin Andersen 77. Department of Ortopaedics & Traumatology O, Institute of Clinical Research, Odense University Hospital, University of Southern Denmark; Department of Orthopaedics & Traumatology O, Institute of Clinical Research, Odense University Hospital, University of Southern Denmark; Biomedicine Laboratory, University of Southern Denmark; Department of Clinical Cell Biology, Institute of Regional Health Services Research, Vejle-Lillebælt Hospital, University of Southern Denmark Background: Sheep are often used as models for human osteoporosis, but it has not been verified whether the bone remodelling of sheep is comparable to human. Purpose / Aim of Study: Here we investigate whether the bone loss in glucocorticoid treated ovariectomised sheep results from a similar bone remodelling defect as in osteoporotic postmenopausal women treated with glucocorticoids. Materials and Methods: Ten sheep were ovariectomised and treated with prednisolone for 7 months. Ten untreated sheep served as control. The bone structure, selected histomorphometric parameters and the serum level of bone biomarkers were evaluated. Findings / Results: Ovariectomy and glucocorticoid treatment induced a significant bone loss after 7 months. The extent of bone surfaces colonized by osteoclasts was unchanged, while the resorption marker CTX had a significant periodically elevation peaking after one month. The bone formation marker osteocalcin was consistently reduced after one week, and the extent of formative osteoid surfaces was almost undetectable after 7 months. The extent of reversal surfaces was significant increased after 1 month, covering almost 50% of the bone surfaces after 7 months. Most of these were arrested reversal surfaces without any neighbouring osteoclasts or osteoid surfaces, supporting that the bone formation and resorption were uncoupled during the reversal phase. The arrested reversal surfaces had a significantly reduced cell density and immunoreactivity for the osteoblastic markers runx2, osterix and SMA. Conclusions: In sheep the bone loss results from an uncoupling of the bone formation and resorption during the reversal phase, as described in osteoporotic postmenopausal women treated with glucocorticoids, making it a relevant preclinical model for studying orthopaedic implant and biomaterial research under osteoporotic conditions. 130 DOS Abstracts

Micromotion Induced Osteolysis in a Sheep Hip Arthroplasty Model Thomas Jakobsen, Søren Kold, Jørgen Baas, Kjeld Søballe, Ole Rahbek 78. Ortopædkir. Forskningslab., Aarhus Universitets Hospital; Ortopædkir. afd., Aalborg Universitets Hospital; Ortopædkir. Afd., Aarhus Universitets Hospital; Ortopæd. Afd., Aarhus Universitets Hospital Background: Aseptic implant loosening might occur when peri-prosthetic bone anchorage is replaced by a fibrous membrane. It could be that the first step in the osteolytic cascade is micromotion-induced formation of a fibrous membrane around the implant. Purpose / Aim of Study: The aim of this study was to investigate whether implants subjected to micromotion would be able to induce bone resorption and formation of a fibrous membrane without the presence of wear-debris particles. Materials and Methods: One micromotion implant (T12) were inserted into one of the medial femoral condyle in ten sheep. The micromotion device consists of an anchor bearing a PMMA implant and a PE plug. The 7.5 mm PMMA implant is placed exact-fit into a 7.5 mm bone cavity. During each gait cycle the PE plug will transfer load through the anchor and make the PMMA implant axially piston 0.5 mm. After 12 weeks of observation the bone specimens were harvested and a post- mortem control implant (T0) was inserted into the contra-lateral medial femoral condyle. Each specimen were embedded and cut for histomorphometrical analysis. Findings / Results: Histomorphometrical evaluation showed that the T12 implant surface was covered by fibrous tissue (93% for T12 vs. 0% for T0, p <0.001). The control implants were covered by lamellar bone (91% for T0 vs. 4 % for T12, p < 0.001). No difference was found with respect to the volume fraction of lamellar bone in a 1 mm zone around the implants (57% for T12 vs. 48% for T0, p = 0.2). Conclusions: This study indicates that micromotion alone is sufficient to induce osteolysis and a fibrous membrane around an implant. DOS Kongressen 2014 131

Vancomycin is superior to Plectasin against Staphyloccus aureus periprosthetic osteomyelitis in rats. 79. Niels H. Søe, Nina Vendel-Jensen, Asger Lundorff-Jensen, Janne Koch, Steen Sejer Poulsen, Helle Krogh Johansen Hand Section,Department of Orthopaedic, Gentofte University Hospital; Department of Anaesthesiology,Intensive care and Operations, Gentofte University Hospital; Faculty of Health and Medical Sciences, University of Copenhagen; Biomedical Department,Panum, Institute, University of Copenhagen; Department of Clinical Microbiology, Rigshospitalet, Denmark Background: Commonly used antibiotics cannot always control S. aureus associated infections in orthopaedic implants Purpose / Aim of Study: We investigated the ability of Vancomycin and Plectasin to eradicate S. aureus in a knee prosthesis model of osteomyelitis in rats. We compared Plectasin in a 20 and 40 mg concentration to Vancomycin 40 mg, all antibiotics were given i.p. daily. Plectasin is a peptide antibiotic with therapeutic potential from a saprophytic fungus. Materials and Methods: Thirty Sprague-Dawley rats had prosthesis inserted and divided into three groups (N=10) Vancomycin including 2 controls and two Plectasin groups (N= 10) 20 mg and (N= 10) 40 mg including 2 controls in each groups. All groups were infected with S. aureus MN8,ica+103 in the tibia and the femur marrow before insertion of the prosthesis. Control rats were given NaCl i.p. After two weeks, the rats were sacrificed and all specimens were analysed. Findings / Results: One rat in the 20 mg Plectasin group and four in the 40 mg Plectasin group died of anaphylactic shock (histamine release). The 20 and 40 mg Plectasin groups both showed a decrease of bacteria but it was not as efficiently eradicated as in the Vancomycin group. Conclusions: Plectasin treatment against S. aureus osteomyelitis reduced the infection. However, Plectasin released histamine strongly after one day and some of the rats died especially in the 40 mg group. In contrast, Vancomycin reduced the infection significantly in almost of the parameters. 132 DOS Abstracts

Human chondrocytes cultivated on modified polystyrene conserve their chondrogenic phenotype in vitro 80. Natasja Leth Jørgensen, Dang Le, Casper Foldager, Martin Lind, Helle Lysdahl Orthopaedic Research Laboratory, Aarhus University Hospital; Interdisciplinary Nanoscience Center, inano, Aarhus University; Sports Trauma Clinic, Aarhus University Hospital Background: Autologous articular chondrocytes tend to dedifferentiate under prolonged expansion culture ex vivo. Porous scaffolds have been widely used to guide cells and grow new tissue. Purpose / Aim of Study: In this study, we investigated the influence of precipitant induced porosity augmentation (PIPA) modified polystyrene surface on human chondrocytes (HCs) cultured in vitro. We hypothesized, that culturing HCs on 2D PIPA modified surfaces would conserve their phenotype. Materials and Methods: The modification of polystyrene was made by the technique precipitant induced porosity augmentation (PIPA). Polystyrene was immersed with 1,4 dioxane and ozone treated prior to cell seeding. HCs were enzymatically isolated from cartilage biopsies collected from the inter-condylar groove in the distal femur. Isolated chondrocytes were expanded to passage 1 (P1) in DMEM/F12 supplemented with 10% FCS, 5 ng/ml bfgf, 1 ng/ml TGFβ3, and 1:100 penicillin-streptomycin (P/S). Chondrocytes in P1 were then seeded on PIPA modified polystyrene surfaces or on traditional monolayer (on a plan polystyrene surface) with 10,000 cells/cm2 in DMEM/F12 supplemented with 10% FCS and 1:100 P/S. HCs were cultivated until P4 and samples were collected for quantitative RT-PCR at each passages P1-P4. Toluidine blue and collagen II stains were performed on P2 HCs cultivated in pellets, 1 106 cells/ ml, for 28 days. Findings / Results: The PIPA surface promoted chondrogenic differentiation of HCs compared with traditional monolayer culture evident by higher gene expression of COL II, and the differentiation indices COLII/COLI and AGG/COLI. HCs expanded on PIPA surfaces prior to pellet formation revealed a better chondrogenicity by more synthesis of proteoglycans and collagen II. Conclusions: Cultivation of HCs on the PIPA modified surface seems to conserve the chondrogenic phenotype. DOS Kongressen 2014 133

Tunnel malpositioning in knee ligament reconstructions Denmark 2005-12 Thomas Hansen, Kim Lyngby Mikkelsen, Michael Rindom Krogsgaard Section for Sportstraumatology M51, Bispebjerg Hospital;, The Patient Compensation Association 81. Background: Suboptimal positioning of tunnels is stated as the reason for cruciate ligament revision in 27 % of 1.866 operations reported to the Danish Kneeligament Reconstruction Register (DKRR) 2005-13. It is also the most common reason for compensation from The Patient Compensation Association (PCA) to patients after knee ligament reconstruction. Purpose / Aim of Study: To describe the characteristics of tunnel malpositioning in knee ligament reconstruction reported to PCA and to evaluate causes and possible means of prevention. Materials and Methods: From PCA patients with a reported complication 2005-2013 after knee ligament reconstruction were identified, and details in cases of tunnel malpositioning were studied. This was combined with information about the number of operations/year for each clinic (< 10, 10-50 and >50), if it was a public or private clinic and technique for femoral tunnel positioning. Findings / Results: 92 malpositions were accepted for compensation. Of 52 malpositions in femur, 38 were anterior and 12 were vertical. Of 29 malpositions in tibia, 9 were anterior, 7 posterior and 13 medial, some perforating the medial tibial plateau. Combined malposition in femur and tibia was seen in 11. The incidence of tunnel malpositioning was highest in clinics with < 10 reconstructions/year (2,26 %), medium in clinics with 10-50 reconstructions/year (0,69 %), and lowest in clinics with > 50/year (0,28 %) (p < 0,05). 73 femoral tunnels were placed by transtibial (TT) technique and 11 by anteromedial (AM) technique about 1/3 of all operations were done with AM technique and 2/3 with TT. Conclusions: If 27 % of revisions were caused by tunnel malpositioning, less than 21 % of these had been reported to PCA. AM technique was less frequently connected to malpositions than TT technique. Routine seemed to be the best prevention against tunnel malpositioning. 134 DOS Abstracts

One-year follow-up in the Danish Knee-ligament Reconstruction Register (DKRR) can be increased to 90 % 82. Jonathan Bjerre, Peder Klement, Bo Sparsø, Michael Krogsgaard Department of sports traumatology, Bispebjerg; Department of orthopedic surgery, Bispebjerg; Center of health, Region Hovedstaden Background: : The 1-year follow-up examination after ACL-reconstruction is a key quality parameter in DKKR. However, in the year report 2013 follow-up was reported for only 49,2 % (for Region Hovedstaden (RH) 45,6 %), which is a serious problem for the validity of the register. It has not been investigated why the reported follow-up is so low. The standard of >60% is based on the assumption that these patients are mobile and less motivated for follow-up. Purpose / Aim of Study: To evaluate: completeness of 1-year follow-up after ACL-reconstruction in 2012 in RH, reasons why it is incomplete, ways to increase completeness and whether the official standard of > 60 % is realistic. Materials and Methods: Patients who were registered with an intervention classified as KNGE45 or KNGE46 in 2012 the databases of 8 public and private hospitals in RH were identified, and their hospital files were studied. For patients who had no one-year follow-up it was checked if they had been invited. Data were compared with extracts from the DKRR. Findings / Results: Of 931 operated patients, 814 were registered in DKKR (87,4 %). The follow-up rate reported to DKRR was 34,9 % (range 0-68 %). The actual follow-up rate was 64 % (range 30 91 %). There were marked differences in the way follow-up was planned. Most important reasons for lacking follow-up were failure to report to DKRR, no standard strategy for follow-up, technical problems with DKRR and unclear courses due to other operations. Less than 10 % of patients refused to show up. Conclusions: A reported follow-up rate >90% is realistic if patents are invited at a reasonable time before follow-up, if they are re-invited once in case they don t show up and if hospitals report actual follow-ups. Technically, reporting should be easier and robust to IT evolution. DOS Kongressen 2014 135

Normative profiles for hip strength and flexibility in elite footballers 83. Andrea Mosler, Kay Crossley, Kristian Thorborg, Adam Weir, Andreas Serner, Per Hölmich Sports Groin Pain Center, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar;, University of Queensland; Sports Orthopedic Research Center - Copenhagen, Arthroscopic Center Amager; Sports Groin Pain Center & SORC-C, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar & Arthroscopic Ceneter Amager Background: Normative profiles for hip/groin strength and flexibility have not been established in footballers. Purpose / Aim of Study: The primary aim of this study was to determine these normative profiles. Materials and Methods: 345 males (18-40) years, playing professional football in the Qatar Stars League were evaluated. Strength was measured using a hand held dynamometer with an eccentric break test in side-lying for hip adduction (ADD) and abduction (ABD), and squeeze test in supine with 45 hip flexion. Flexibility measures included; hip internal rotation (IR) in both 90 flexion and prone, hip ABD in side-lying and bent knee fall out (BKFO). Demographic information was collected and the effect on the profiles was analysed. Pain on each testing procedure was recorded. Findings / Results: Normative values for strength were as follows (mean±sd); ADD non- dominant=3.2±0.6 Nm/kg, dominant=3.1±0.6 Nm/kg; ABD both legs= 2.4±0.4 Nm/kg; ADD:ABD ratios non- dominant=1.4±0.3, dominant=1.3±0.3; Squeeze test=3.2±0.8 N/kg. Flexibility; IR in flexion both legs=37±8, IR in prone non- dominant=36±8, dominant=37±8, ABD in side lying both legs=47±8, BKFO non- dominant= 13.5±4.1cm, dominant=13.7±4.1cm. Leg dominance and a past history of injury had no clinically relevant effect on the strength and flexibility profiles. However, pain on squeeze testing significantly reduced the score for that test (p 0.05). Conclusions: Clinicians can confidently compare the strength and flexibility profile with the non- injured leg when assessing a footballer with unilateral pain. Pain on testing resulted in lower squeeze values, but a past history of hip or groin injury did not affect these profiles. Future studies will examine the predictive value of these measures for injury. 136 DOS Abstracts

Complications after kneeligament reconstruction in Denmark 2005-2012 as reported to The Patient Compensation Association (PCA) 84. Thomas Hansen, Kim Lyngby Mikkelsen, Michael Rindom Krogsgaard Section for Sportstraumatology M51, Bispebjerg Hospital;, The Patient Compensation Association Background: The number and distribution of complications to kneeligament reconstruction is widely unknown, as many reports of complications origin from centers with selected patient groups. The Danish Kneeligament Reconstruction Register only report some types of complications, and the follow-up rate is quite low. Purpose / Aim of Study: To describe complications to kneeligament reconstruction in Denmark as reported to PCA, related to number of reconstructions. Materials and Methods: From PCA patients with a claimed complication after kneeligament reconstruction 2005-2012 were identified, excluding reconstruction of patellar ligaments. The files for each patient were studied, the complications were grouped and combined with information about rejection or compensation. Findings / Results: Total number of reconstructions was 22.321. From 493 claimed cases, 261 (=1,17 %) were recognized for a compensation (total 35.558.205 DKK = 136.238 DKK/complication = 1.593 DKK/reconstruction). The 8 most common complications (claimed/recognized/total compensation in DKK): Tunnel malpositioning (104/92/13.221.872), deep infection (97/66/5.771.059), nerve damage (59/39/8.328.102), unrecognized diagnosis typical undiagnosed multiligament injury (23/22/1.878.326), pain (46/18/1.022.676), arthrofibrosis (22/6/4.957.405), instrument failure (19/12/1.357.566), thromboembolic events (9/8/631.138). The 10 most expensive (6 tunnel malpositions) complications cost 15,8 mio DKK. Only six of 66 patients with infection had not received prophylactic antibiotics. Complications were not significantly more common in private (1,5 % of registered operations in DKRR) than in public (1,2 %) clinics, with individual variations. Conclusions: Tunnel malpositioning is the most common complication, whereas nerve damage and arthrofibrosis are the (relatively) most expensive complications. Thromboembolic complications were rare. DOS Kongressen 2014 137

Orthogeriatric collaborative improves 30 day mortality and quality of care after hip fracture in the elderly: a nationwide cohort study 85. Pia Kjær Kristensen, Theis Muncholm Thillemann, Kjeld Søballe, Søren Paaske Johnsen Department of Orthopaedics, Hospital Horsens; Orthopaedic surgery, University Hospital Aarhus; Orthopaedics, University Hospital Aarhus; Department of Clinical Epidemiology, University Hospital Aarhus Background: Orthogeriatric collaborative has been linked with better clinical outcomes for hip fracture in clinical trials, however little is known about the impact of orthogeriatrics on quality of care and clinical outcomes among patients with hip fracture in a routine setting. Purpose / Aim of Study: We examined the association between orthogeriatrics and 30-day mortality, quality of care, surgical delay and length of stay among patients with hip fracture. Materials and Methods: Using prospectively collected data from the Danish Multidisciplinary Hip Fracture Registry, we identified 12,065 patients 65 years who were admitted with a hip fracture between 1. March 2010 to 30. November 2011. The exposure was divided in two groups; Orthopaedic ward with geriatric or medical consultant service on request and orthogeriatric collaborative where the geriatrician is integrated into the orthopaedic team with nurses, physiotherapist and the orthopaedic surgeon. The primary outcome was 30-day mortality. Secondary outcome included quality of care assessed using six process indicators, surgical delay and length of stay. Data was analyzed using regression techniques while controlling for potential confounders. Findings / Results: The 30-day mortality was 9.4 % and 12.0 % for orthogeriatric and orthogeriatric ward. Admittance to an orthogeriatric ward was associated with decreased 30-day mortality (adjusted odds ratio = 0.69 (95% CI: 0.54-0.88)). Furthermore, patients had higher relative risk for systematic pain assessment, for receiving basic mobility assessment, for a post discharge rehabilitation program, for anti-osteoporotic medication and for prevention future fall accidents. Length of hospital stay and surgical delay were similar in the groups. Conclusions: Admittance to an orthogeriatric ward was associated with decreased mortality rates and improved quality of care. 138 DOS Abstracts

Tranexamic Acid (TA) Reduces Overall Blood Loss in Unstable Trochanteric Fractures Treated with Intramedullary Nailing (IMN) 86. Peter Toft Tengberg, Henrik Palm, Nicolai Foss, Thomas Kallemose, Anders Troelsen CORH, Hvidovre Hospital; Anesthesiologic dept, Hvidovre Hospital Background: Patients with unstable trochanteric fractures treated with intramedullary nailing (IMN) suffer a major overall blood loss. This is associated with risk of postoperative anemia resulting in increased morbidity, mortality and prolonged hospitalization. Tranexamic Acid (TA) has shown documented effect, with reduced blood loss, in other fields of orthopaedics, such as arthroplasty surgery. Purpose / Aim of Study: The aim of the study was to test if TA can reduce overall blood loss in patients with unstable trochanteric fractures treated with a short IMN. Materials and Methods: The study is a 2-arm, double blinded, randomized placebo controlled trial with two groups. The inclusion period was September 2011 to June 2014. Patients with unstable trochanteric fractures scheduled for a short IMN were eligible for inclusion. Patients in the intervention group were given a 1 g bolus of TA during initiation of anesthesia and 3 g of TA in 1 l of saline over 24 hours postoperatively. The placebo group was given a similar regime, without TA. 270 patients were approached for inclusion. Of these, 75 were included, with a final study group of 73 after 2 postoperative inclusions. Findings / Results: There were 51 (71%) women. Mean age was 77.3 (SD: 12.3). Mean blood loss in the intervention group (33 patients) was 1410,9 ml (1001,4) compared to a mean blood loss of 2100,4 (1152,6) in the placebo group (p=0.008, t-test). There were no cases of in-hospital, thromboembolic events in either group. Conclusions: We found a statistically significant reduction in the overall blood loss close to 700 ml for patients treated with TA. TA seems to be an effective blood saving strategy for this group of hip fracture patients and should be considered in future treatment regimens. Our data revealed no safety concerns. Further studies should focus on optimal timing and dose of TA. DOS Kongressen 2014 139

Validation of fracture treatment codes from the Danish National Patient Registry: Implications for The Danish Fracture Database 87. Morten Jon Andersen, Michael Kuhlman, Michael Brix, Kirill Gromov, Anders Troelsen Orthopaedic Surgery, Copenhagen University Hospital Hvidovre Background: More than 99% of all public discharges are recorded in the Danish National Patient Registry (NPR), however data have been proven to have a degree of uncertainty. The Danish Fracture Database (DFDB) was established with the goal of recording all fracture surgery in Denmark. With the growing amount of data in DFDB, a viable way of verifying completeness and validity is needed. Purpose / Aim of Study: The aim of this study was to validate the NPR treatment codes regarding fracture surgery to allow for continuous monitoring of DFDB data. Materials and Methods: At our institution the diagnosis and operation codes are reported directly from the operation-booking programme (OBP) to NPR. A list of 500 consecutive patients operated for fractures from January to April 2012 was created from the OBP. Patient charts and x-rays where reviewed by the authors. The treatment codes were considered correct when codes and the x- ray assessment matched exactly. The anatomic region of the diagnosis or operation was considered correct if the fracture or osteosynthesis was present in the region specified by the first four letters in the code. Findings / Results: In 16 cases x-rays were missing, 484 cases was analysed further. The overall validity of data was 86% (417/484). In 94% (454/484) the NPR diagnosis code was correct and the NPR anatomic region was correct in all but one case. In 91% (440/484) the operation code was correct and the anatomic region for the operation was correct in all but two cases. The correct side (left/right) was given in 99% (477/484) of cases. Conclusions: Diagnosis and operation codes regarding fracture surgery reported to the NPR showed very high validity. If the same data validity of data reported to NPR can be confirmed for other regions and hospitals in Denmark NPR data can serve as a way of verifying completeness and validity in DFDB. 140 DOS Abstracts

Sensitivity and specificity of CT and MRI imaging in occult hip fractures Martin Haubro, Camilla Stougaard, Trine Torfing, Søren Overgaard 88. Department of Orthopaedic Surgery and Traumatology, Odense University Hospital; Department of Radiology, Odense University Hospital Background: The incidence of occult hip fracture has been estimated to 2-10% using standard X-ray imaging. It has been stated that MRI is superior to CT in detecting occult fracture of the hip however this statement is based on case reports and non-controlled studies of few patients. Purpose / Aim of Study: To estimate sensitivity and specificity of CT and MRI examinations in patients with fractures of the proximal femur. To determine the interobserver agreement of the modalities among a senior consulting radiologist, a resident in radiology and a resident in orthopaedics surgery. Materials and Methods: 67 patients seen in the emergency room with hip pain after fall, inability to stand and a primary X-ray without fracture were evaluated with both CT and MRI. The images were analysed by a senior consulting musculoskeletal radiologist, a resident in radiology and a resident in orthopaedic surgery. Sensitivity and specificity were estimated with MRI as the golden standard. Kappa value was used to assess level of agreement in both MRI and CT finding. Findings / Results: 15 fractures of the proximal femur were found. Two fractures were not identified by CT and four changed fracture location. Among those, three patients underwent surgery. Sensitivity of CT was 0.87; 95% CI [0.60;0.98]. Kappa for interobserver agreement for CT were 0.46; 95% CI [0.23; 0.76] and 0.67; 95% CI [0.42; 0.90]. For MRI 0.67; 95% CI [0.43;0.91] and 0.69; 95% CI [0.45;0.92]. Conclusions: MRI was observed to have a higher diagnostic accuracy than CT in detecting occult fractures of the hip. Interobserver analysis showed high kappa values corresponding substantial agreement in both CT and MRI. DOS Kongressen 2014 141

Inter-rater reliability and agreement of the 6-minute walk test in females with hip fractures Jan Arnholtz Overgaard, Camilla Marie Larsen, Morten Tange Kristensen 89. Department of Rehabilitation and Physical Medicine and Rehabilitation Research - Copenhagen (PMR-C), Municipality of Lolland; Research Unit of Musculoskeletal Function and Physiotherapy, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark; Physical Medicine and Rehabilitation Research - Copenhagen (PMR-C), Departments of Physiotherapy and, Hvidovre University Hospital Background: The 6-minute walk test (6MWT) is widely used as a clinical outcome measure. However, the reliability and agreement of the 6MWT is unknown in individuals with hip fractures. Purpose / Aim of Study: To evaluate the relative inter-rater reliability and agreement of the 6MWT in individuals with hip fractures. Materials and Methods: Two senior physiotherapy students independently examined (randomized order) a convenient sample of 20 participants; their assessments were separated by two days, and testing followed instructions from the American Thoracic Society. Hip pain was assessed with the Verbal Ranking Scale. Findings / Results: Participants (all women) with a mean (SD) age of 78.1 ± 5.9 years performed the test within a mean of 31.5 ± 5.8 days post-surgery; 10 had a cervical and 10 a trochanteric fracture. Excellent inter-rater reliability; ICC2.1 = 0.92 (95% CI, 0.81-0.97) was found, and the standard error of measurement (SEM) and smallest real difference (SRD) were calculated as 21.4 meters and 59.4 meters, respectively. Bland-Altman plots revealed no significant difference (mean of 3.2 ± 31.5 meters, P = 0.83) between the two raters, and no heteroscedasticity was seen (r = -0.196, P = 0.41). On the contrary, participants walked a mean of 21.7 ± 22.6 meters longer, at the second trial (P = 0.002). Participants with moderate hip fracture- related pain walked a shorter distance than those with no or light pain during the first test (P = 0.04), while this was not the case during the second (P = 0.25). Conclusions: Excellent inter-rater reliability was found with a low level of measurement error, particularly for a group of participants with hip fractures, as a change of 22 meters can be considered a real change. The importance of measuring hip fracture-related pain during testing seems important when individuals with hip fracture perform the 6MWT. 142 DOS Abstracts

Surgical delay increases early mortality for patients with proximal femoral fractures. A study from The Danish Fracture Database Collaborators. 90. Anne Marie Nyholm, KIrill Gromov, Henrik Palm, Michael Brix, Thomas Kallemose, Anders Troelsen Department of Orthopaedics, Hvidovre Hospital Background: Surgical delay (SD) of proximal femoral fracture (PFF) is of interest as some studies show SD >24 or >48 hours to significantly increase mortality (MT), while others find no correlation. Purpose / Aim of Study: To show if a) SD or b) surgeon s experience (SE) increases MT rates for following PFF. Materials and Methods: We included trochanteric or femoral neck fractures (AO31A and 31B) from the Danish Fracture Database, excluding pathological and high-energy trauma fractures. Data included age, gender, American Society of Anesthesiologists (ASA) score, type of fracture and osteosynthesis, SE and SD. SE was defined as attending or above or below attending. SD was defined as hours (h) from radiological diagnostics until start of surgery. MT data was from The Civil Registration System. Multiple logistical regression analysis was used to calculate MT rates. Findings / Results: 3595 fractures were included: mean age 81.0 years, 70% were female and 49% were trochanteric fractures (AO31A). SD was <12h in 21%, <24h in 70%, <48h in 92% and <72h in 95% of cases. SE was Attending or above in 49% of all cases. MT was 10.8% at day 30 and 17.4% at day 90. SD >12h increased adjusted risk of 30-day MT (OR 1.43, p=0.02). SD >24h increased adjusted risk of 90-day MT (OR 1.24, p=0.03). SE below attending increased MT risk at both day 30 (OR 1.27, p=0.04) and day 90 (OR 1.28, p=0.01). Increasing age and ASA score, male gender and type of osteosynthesis significantly increased both 30-day and 90-day MT. Conclusions: In this study SD >12 h and SD >24 h significantly increased adjusted risk of MT at day 30 and day 90, respectively. The adjusted risk of both 30-day MT and 90-day mortality increased significantly when SE was below attending. The study findings challenge the departments to facilitate fast surgical treatment supported by attending orthopaedic surgeons. DOS Kongressen 2014 143

Surgical delay and early mortality in patients with distal femoral fractures Bozo Jian, Thomas Kallemose, Henrik Palm, Michael Brix, Anders Troelsen, Kirill Gromov Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre 91. Background: While fast surgical treatment of proximal femoral fractures is supported by previous studies and is encouraged by national clinical guideline in several countries, no consensus exists on optimal timing for surgical treatment of the equally frail patient group with distal femoral fractures. Purpose / Aim of Study: The purpose of this study was to investigate whether increased surgical delay (SD) in patients with distal femoral fractures is associated with risk for early mortality. Materials and Methods: 189 patients surgically treated for distal femoral fractures in 2008-2013 were identified at two university hospitals. Only patients > 50 years old were included for analysis (n=170). Recorded parameters included age, gender, American Society of Anesthesiologists (ASA) score, AO diagnosis, osteosynthesis type, presence of total knee arthroplasty (TKA) and SD (hours). SD was defined as time from admission to the hospital to beginning of surgery and divided into groups: <12h, <24h, <48h, <96h and >96h. 30 and 90 day mortality was recorded. Multiple logistical regression analysis was performed to calculate adjusted risk for 30-day and 90-day mortality. Findings / Results: Median age was 78, range (51-99). 80% were female, 96% were treated with plate fixation and 21% had a TKA at the fracture site. 7% were operated within 12 hours, 37% within 24 hours, 62% within 48 hours and 86% within 96 hours. 30- and 90-day mortality rate was 5% and 11%, respectively. Patients with surgical delay > 24 hours had a significantly increased 90- day mortality risk (OR 5.76; p=0.03) Conclusions: Delay of surgery > 24 hours for patients with distal femoral fractures is associated with increased risk for early mortality. This should be taken into consideration when planning surgery for this group of patients. 144 DOS Abstracts

RSA-measured rotation across SHS-treated trochanteric fractures - is the anti-rotation screw obsolete? 92. Maiken Stilling, Torben Bæk-Hansen, Bøvling Søren, Steffen Jacobsen, Kim Holck, Henrik Palm Department of Orhopaedics, Regional Hospital Holstebro, Hospital Unit West Background: Rotation across trochanteric fractures treated by a sliding hip screw (SHS) remains controversial, and measurement is difficult. Some surgeons add a so-called anti-rotation screw, but the indication is questionable. Purpose / Aim of Study: To investigate the amount of, and possible predictors for, rotation across SHS-treated stabile trochanteric fractures by use of RSA. Materials and Methods: 24 patients (21 female) at mean age 76 (56-91) years with SHS-treated stabile trochanteric fractures were followed postop, 1.5, 3 and 6 months after surgery with marker-based RSA and measurement of fracture migration between the femoral head/neck and the trochanter/shaft fragment. EGS- RSA was used to transfer the rotation axis in line with the sliding screw. Screw position within the femoral head was assessed into thirds as high/central/low in AP and posterior/central/anterior in LA post- operative radiographs. Findings / Results: No cut-outs or revisions were observed. Average rotation across the fracture around the sliding screw was 0.6 (sd 7.1) degrees, and rotation stopped at 6 weeks (p>0.24). 7 patients with non-central screw position (3 with a low AP screw position, 4 with an LA anterior or posterior screw position) had higher rotation compared with 17 patients with central screw placement in two planes (mean 5.3 (sd 4.5) vs. 1.5 (sd 7.1) degrees, p=0.01). Low positioned screws with mean rotation of 8.8 (sd 3.8) degrees had the most rotation (p=0.02). Other translations and rotations were not correlated with screw position. Conclusions: Overall rotation across the trochanteric fracture was small, but depended on SHS position, with most rotation following a low-positioned screw. If the SHS is correctly positioned in the central third of the femoral head in both AP and LA radiographs, adding an anti-rotation screw appears obsolete. DOS Kongressen 2014 145

Patient safe pain management of acute hip fracture patients requires focus on the kidney function Morten Baltzer Andersen, Beata Malmqvist, Henrik Palm 93. Department of Orthopaedic Surgery & The Hospital Pharmacy, Copenhagen University Hospital Hvidovre, Denmark; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Denmark Background: Standard medical treatment including painkillers are often used for hip fracture patients in Denmark. Painkillers and the frequent co-morbidity Chronic Kidney Disease (CKD) are a known as risk factors for the serious complication including Acute Kidney Injury (AKI). AKI are often reversible but increase mortality and hospitalization. Purpose / Aim of Study: The purpose was to identify the amount of CKD, AKI and use of painkillers among hip fracture patients. Materials and Methods: 202 consecutive hip fracture patients (71% female, mean age 78 (range 22-97)) admitted through the ER from Sept 2012 to March 2013 were included. Painkillers were defined as NSAID and/or Morphine, both included in our standard medicine package. The patient s upper and lower estimated Glomerular Filtration Rate (egfr) was recorded between admission and discharge. The stage of CKD was based on the patients highest egfr during hospitalization and the AKI definition was based on the egfr change by the RIFLE (R-risk, I-Injury, F- failure, L-loss, E-end stage) classification. Findings / Results: 91 (45%) patients had a normal kidney function, while it was reduced mildly in 69 (34%), moderately in 38 (20%), severe in 3 (1%) and a single patient had terminal renal insufficiency. AKI occurred in 20 cases (10%) and patients with reduced kidney function had four times greater risk of developing AKI (p=0.02). Among these cases, use of NSAID was not stopped in 8 and oral Morphine in 7 of the 20 patients after they had developed AKI. Conclusions: Use of standardized prescribed painkillers appear secure for 90% of hip fracture patients. However, as half of the patients have reduced kidney function and thereby increased risk of AKI, continued focus on kidney function seems necessary for increasing patient safety. 146 DOS Abstracts

Complications and Functional Outcome after Locking Plate Fixation of Distal Tibial Fractures in the Region of Southern Denmark 2007-2011 94. Silje Kleven, Ellen Hamborg Petersen, Bjarke Viberg, Ole Skov Dept. of Orthopaedic Surgery and Traumatology, Odense University Hospital Background: Distal tibia fractures often present a challenge for the orthopaedic surgeon and the best treatment remains controversial. Previous research on locking plates has shown promising results, but we do not know enough about complications and functional outcome Purpose / Aim of Study: To assess the rate of complication and the long-term functional outcome in patients with distal tibial fractures treated with a lowprofile locking plate Materials and Methods: A historical case-series of 70 patients with 71 distal tibial fractures treated with low-profile locking plate between January 2007 and April 2011 was retrieved. Patient-, injury- and treatment characteristics as well as information of post-operative complications were retrieved from electronic health records and patient interviews. Complications were classified as minor complications and major complications. Long-term functional outcome was assessed by EQ5D-5L, AOFAS score, and return to pre-injury job function through patient interview and examination Findings / Results: There were 32 43A, 5 43B and 34 43C- fractures, 12 open and 10 high-energy fractures. 49 cases (69%) experienced complications during the follow-up time, of which 34 were minor and 15 were major complications. The median (IQR) EQ5D-5L index was 0.76 (0.65-0.84), health VAS- score 80 (60-90), and AOFAS score 73 (60-87). Logistic regression analyses showed that smoking increased the risk of minor complications (OR 23, p<0.018). All other variables showed no statistical significance for minor or major complications. 33 % of working patients had not returned to work as a result of the fracture Conclusions: Our study suggests that treatment of distal tibial fractures with low-profile locking plates might have higher rates of complications and worse functional outcome than previously reported DOS Kongressen 2014 147

A review of deep wound infection after hip-fracture surgery Frederik Stensbirk, Henrik Palm 95. Orthopaedic Surgery, Copenhagen University Hospital Hvidovre Background: Deep wound infection is one the most severe and costly complications following hip-fracture surgery. The few previously published series have shown multiple re- operations, longer hospitalization, massive antibiotic treatment and increased mortality and morbidity. For improving results, surgeons should besides performing surgical debridement be aware, which organisms are responsible, the relevant antibiotics, and the consequences for patient and hospital. Purpose / Aim of Study: To investigate rate, bacteriology and antibiotic treatment of patients developing deep wound infection following hip-fracture surgery. Materials and Methods: 4189 consecutive hip fracture patients admitted and treated at our hospital from September 2002 to June 2013 were included. All patients were treated with arthroplasty, intramedullary nailing, dynamic hip screw or parallel screws/pins. Retrospectively, deep wound infections, bacteriology, antibiotic treatment, hospitalization, number of re-operations and 1-year mortality were investigated. Findings / Results: 73 patients reoperated due to deep wound infection were identified (1.7%). 80 positive bacterial cultures were identified. 45 displayed S. aureus (63%), 13 coag. neg. staph. (18%), 7 E. coli (10%), 15 distributed on 10 other bacteria, while 6 patients had negative bacteria cultures (8%). 17 cultures were resistant to cefuroxime (21%). 29 patients were treated with >3 antibiotics (40%). Hospitalization was 52 days. 37 patients were re-operated more than once (51%). Within the first year after re- operation 30 patients had died (41%). Conclusions: A deep wound infection rate at 1.7% is relatively low and comparable to previously published series, but when it occurs, consequences are devastating. Continuous focus on infection registration and optimal prophylactics and treatment is therefore important to improve outcome. 148 DOS Abstracts

Nailing of unstable trochanteric fractures with and without circumferential wires a study with focus on complications and reoperations within two years. 96. Lasse Birkelund, Michael Brix, Ilija Ban, Henrik Palm, Anders Troelsen Ortopædkirurgisk, Aabenraa Sygehus Background: Open reduction and circumferential wires have long been controversial in trochanteric fractures treated with an intramedullary nail (IMN) because of concerns about compromising the periosteal blood supply leading to bone necrosis. We hypothesize that wires may instead facilitate optimal implant position and fracture reduction Purpose / Aim of Study: To compare per- and postoperative results in patients with an unstable trochanteric fracture treated with IMN with or without wires, within 2 year from surgery Materials and Methods: 51 consecutive patients with trochanteric fractures treated with IMN and wires were identified in from two prospective databases. It was compared to, a by age and fracture subtype, matched control group of 51 patients treated with IMN without wires, selected in a third database. ASA, operation-time, bleeding, fracture reduction postoperative, tip-apex distance (TAD) and reoperations within two years were assessed from records and radiographs Findings / Results: Due to the match method, the 2 groups were alike regarding age and fracture classification. ASA and TAD was NS. Application of wires resulted in significantly longer operation time (p<0.001) and increased bleeding (p<0.001), but a superior reduction (p<0.001). 4/51 patients with wires were reoperated: 1 due to technical failure during osteosynthesis, 1 screw cut out, 1 new fracture after a fall and 1 hardware removal. 9/51 patients without wires were reoperated: 2 deep infections, 3 new fractures after a fall, 1 screw cut out, 1 nail removal and 2 non- unions Conclusions: It appears that open reduction and application of circumferential wires facilitates a superior fracture reduction, probably worth the increased bleeding and longer operation time. Future level-1 studies are warranted including outcome parameters such as mobilization and pain on short and longer term DOS Kongressen 2014 149

Risk of readmission, reoperation and mortality within 90 days of total hip and knee arthroplasty in fasttrack departments in Denmark from 2005 to 2011 97. Eva Natalia Glassou, Alma Becic Pedersen, Torben Bæk Hansen Department of Orthopedic Surgery, Regional Hospital West Jutland, Denmark; Department of Clinical Epidemiology, Aarhus University Hospital, Denmark Background: Fast track programs are widely adopted in the treatment of hip and knee arthroplasties. Several clinical studies have shown that fast track programs reduce adverse events. This study evaluates fast track programs in a population based cohort. Purpose / Aim of Study: The aim was to compare risk of readmission, reoperation and mortality within 90 days of surgery in orthopedic departments with well documented fast track arthroplasty programs with all other orthopedic departments in Denmark from 2005 to 2011. Materials and Methods: The Danish Hip and Knee Arthroplasty Registers were used to identify patients with primary total hip and knee arthroplasty. Information about readmission, reoperation and mortality was obtained from national databases. The fast track cohort consisted of departments participating in the Lundbeck Foundation Centre for Fast- track Hip and Knee Replacement. The national cohort consisted of all other departments. Cohorts were divided into 3 periods; 2005-2007, 2008-2009 and 2010-2011. Regression methods were used to calculate relative risk (RR) for adverse events adjusting for age, sex, type of fixation and co- morbidity. Findings / Results: 79,098 arthroplasties were included; 17,284 in the fast track cohort and 61,814 in the national cohort. Median length of stay (LOS) was less for the fast track cohort in all 3 periods (4/3/3 vs. 6/4/3 days). RR of readmission due to infection was higher in the fast track cohort in 2005-2007 (1.3, 95% CI 1.1-1.6). RR of readmission due to thrombo-embolic event was lower in the fast track cohort in 2010-2011 (0.7, CI 0.6-0.9). Conclusions: The general reduction in LOS indicates that fast track programs are widely implemented. Concurrently it seems that dedicated fast track departments are able to optimize the fast track program further without a rise in readmission, reoperation and mortality. 150 DOS Abstracts

Low Occurrence of Thromboembolic Events After Routine Use of Tranexamic Acid in Hip and Knee Arthroplasty 98. Rune Vinther Madsen, Christian Skovgaard Nielsen, Thomas Kallemose, Henrik Husted, Anders Troelsen CORH - Clinical Orthopaedic Research Hvidovre, Dept. of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Denmark Background: Tranexamic acid (TXA) has, for many years, been used to reduce bleeding in both elective and trauma patients. TXA s blood reducing effect is well documented. However, the still existing skepticism for routine use of TXA in elective hip and knee replacement surgeries is due to the lack of studies with larger cohorts providing documentation of the risk for thromboembolic complications after routine administration of TXA. Purpose / Aim of Study: The objective of this study was to investigate the occurrence of thromboembolic complications after routine use of TXA in hip and knee replacement surgeries. Materials and Methods: We identified all 3175 patients, who underwent surgery with hip or knee replacement at Hvidovre Hospital between November 2007 and March 2013. Data was then extracted from The Danish National Patient Registry focusing on post-operative thromboembolic complications, which were divided into subgroups (deep venous thrombosis, acute myocardial infarction and pulmonary embolism), occurring up to 90 days post-operatively. TXA, bolus i.v. 1 g, was administered pre-operatively, and patients were admitted in a well-documented fast-track set-up focusing on early mobilization. Findings / Results: Of the 3175 patients, 398 did not receive TXA during their hip or knee replacement surgery. Of the remaining 2777 patients, who all received TXA during their surgery, respectively 13 (=0.5%), 6 (=0.2%) and 8 (=0.3%) patients suffered from symptomatic deep venous thrombosis, pulmonary embolism or acute myocardial infarction within 90 days post-operatively. Conclusions: The findings suggest that routine use of TXA in hip and knee replacement surgeries is safe with a low occurrence of thromboembolic complications. However, other factors, such as early mobilization, may play a significant role in diminishing thromboembolic events. DOS Kongressen 2014 151

The use of a primary knee prosthesis as articulating spacer in two-stage revision of infected knee arthroplasty. 99. Rasmus Juul, Jesper Fabrin, Klaus Poulsen, Jeannette Østergaard Penny Department of Orthopaedic Surgery, Køge Hospital Background: Gold standard for treating chronic prosthetic infection is twostage revision. Traditional static spacers impair the rehabilitation whereas articulating spacers allow weight bearing and maintain joint movement. We created an articulating spacer using a new P.F.C. Sigma femoral component and a cemented tibial polyethylene insert (NFI spacer). Purpose / Aim of Study: The aim of this study is to report the infection control after two-stage revision using the NFI spacer. Materials and Methods: From December 2010 to March 2013 two-stage revision using NFI spacer was performed on 31 patients (32 knees), 18 women and 13 men, with an average age of 64 years. The patient s medical records were reviewed retrospectively. The diagnosis was verified from microbiologic examination of tissue cultures obtained at first-stage surgery. Successful result was considered when eradication of infection was achieved with two-stage revision using only one NFI spacer. Findings / Results: Nine patients were excluded because of negative tissue cultures and 1 patient due to prior surgery with static cement spacers. 2 patients died from unrelated medical reason and were lost to follow-up. 1 patient had bilateral NFI spacers. The left NFI spacer was excluded as the patient choose to have above knee amputation due to a tendency to luxation in the spacer. The remaining 19 patients (19 knees), mean time follow-up was 24 months, all had positive tissue cultures except one patient that had negative tissue culture but the intraoperative findings were obvious purulent. 3 patients (16 %) had recurrence of infection after second-stage surgery. 16 patient (84 %) required only one NFI spacer. Conclusions: Successful eradication of infection was achieved in 16 of 19 cases (84%) with infected TKA. This is comparable to others studies describing the use of articulation spacer. 152 DOS Abstracts

Arthrodesis of the knee after failed knee arthroplasty Tinne Brandt Gottfriedsen, Anders Odgaard, Henrik M Schrøder Henrik Morville Schrøder 100. Department of Orthopaedics, Copenhagen University Hospital Gentofte Background: Existing data on arthrodesis for failed knee arthroplasty is limited. Data from the Danish Knee Arthroplasty Register (DKR) suggests that only 74 arthrodeses have been performed since 1997. Purpose / Aim of Study: To identify the incidence and causes of arthrodesis after failed knee arthroplasty. Materials and Methods: Nationwide data was extracted from the Danish Hospital Episodes Statistics and DKR. Relevant patient notes were retrospectively reviewed. Findings / Results: We identified 89,545 primary knee arthroplasties performed in Denmark from 1997-2013. 153 arthroplasties were followed by arthrodesis corresponding to an overall crude incidence of 0.17%. Of these, 152 were performed for causes related to the knee arthroplasty corresponding to an incidence of 0.17% (range among regions, 0.07-0.28%, p=0.0002). Survival data will be presented. Mean age was 69.6 years (58.5-73.1, p=0.01). Mean time between primary knee arthroplasty and arthrodesis was 2.2 years (1.9-3.0, p=0.81). The patients underwent an average of 2.3 knee surgeries prior to arthrodesis (1.9-3.2, p=0.04). 57% of cases were assessed at a highly specialised hospital (22-100%, p<0.0001). Indications for arthrodesis included infection in 140 cases (92%), extensor mechanism disruption in 44 cases (29%), soft tissue deficiency in 22 cases (14%), bone loss in 11 cases (7%), pain in 9 cases (6%), periprosthetic fracture in 5 cases (3%) and chronic knee dislocation in one case (0.7%). In 74 cases (49%) there were at least two or more indications for arthrodesis. Conclusions: We found significantly more arthrodeses than reported to DKR. There was large variation in the incidence among Danish regions. The main causes of arthrodesis were infection and extensor mechanism disruption. Surgeons should consider new treatment options for these complications. DOS Kongressen 2014 153

Can low knee awareness and higher function after primary TKA be predicted? A cross-sectional study of 316 patients 1 to 4 years after surgery. 101. Morten Grove Thomsen, Roshan Latifi, Thomas Kallemose, Henrik Husted, Anders Troelsen Dept. of Orthopedic surgery, Copenhagen University Hospital of Hvidovre, Denmark Background: Low knee awareness and high knee function during activities of daily living has become the main goal after primary TKA. Evidence based information regarding the influence of patient derived factors on knee awareness and functional outcome after TKA, however, is sparse. Purpose / Aim of Study: To investigate the influence of age, gender, KL-grade, prosthetic design, year of surgery and pre- and postoperative knee alignment on postoperative Forgotten Joint Score (FJS) and Oxford knee score (OKS). Materials and Methods: Through database search we randomly selected 360 patients receiving a previous generation standard CR TKA, a newer generation CR TKA or mobile bearing TKA at our institution between 2010 and 2012 (1 to 4 years follow-up). Age at surgery, gender, KL-grade, prosthetic design, year of surgery and pre- and postoperative knee alignment was documented. Patients were asked to complete the FJS and OKS questionnaires. 316 patients completed the survey and were eligible for analysis. A predictive linear regression model evaluating the impact of patient derived factors on FJS and OKS scores was created. Findings / Results: We found that female gender (p=0.002), low preoperative KL-grade (p=0.03) or a previous generation CR TKA prosthetic design (p=0.04) led to statistically significant lower postoperative FJS scores. Regarding the OKS scores, we found that female gender (p=0.001), preoperative valgus mal- alignment (p=0.04) or a previous generation CR TKA prosthetic design (p=0.005) led to statistically significant lower postoperative scores. Conclusions: A good result after TKA is influenced by gender, kl-grade, preoperative knee alignment and prosthetic design. Knee awareness and function during activities of daily living, however, was not influenced by postoperative knee alignment, time since surgery or age at surgery at 1 to 4 years follow-up. 154 DOS Abstracts

Does knee awareness and functional outcome differ between knees of bilateral simultaneous total knee arthroplasty (BSTKA) and unilateral total knee arthroplasty (UTKA)? A cross-sectional, matched, case control study. 102. Roshan Latifi, Morten G. Thomsen, Thomas Kallemose, Henrik Husted, Anders Troelsen Orthopaedic Surgery, Copenhagen University Hospital Hvidovre Background: Considerable controversy exists regarding the practice of BSTKA compared with UTKA. Published studies have primarily focused on perioperative complications, short-term outcome and mortality, whereas publications comparing longer term functional outcome and knee awareness between BSTKA and UTKA are lacking. Purpose / Aim of Study: To compare the knee awareness (Forgotten Joint Score FJS) and functional scores (Oxford Knee Score OKS) of patients treated with BSTKA compared with UTKA, thereby to assess if BSTKA knees obtain a result different from that of UTKA knees. Materials and Methods: Through database search we identified 69 patients receiving BSTKA and 240 randomly selected patients receiving UTKA at our institution between 2010 and 2012.The mean follow up time was 3.2 years. All patients were asked to complete the FJS and OKS questionnaires. 210 of UTKA patients and 65 of BSTKA patients completed the survey.patients were matched regarding age, gender, year of surgery, KL-score, pre- and postoperative knee alignment leaving a study cohort of 94 knees in 47 patients in the BSTKA and 94 knees in 94 patients in the UTKA group.the FJS and OKS scores of the two groups were then compared.all TKAs were cemented and cruciate retaining (AGC, Biomet). Findings / Results: The mean value of the OKS score in BSTKA and UTKA were 37.6(SD: 9.0) and 36.1(SD: 9.9) respectively. The mean value of FJS score in BSTKA and UTKA were 59.9(SD: 27.5) and 57.5(SD: 28.8) respectively. Mixedeffect models were used to evaluate the difference between BSTKA and UTKA, giving a mean difference of 2.3(p- value=0.59) and 1.5(p-value=0.22) in FJS and OKS scores respectively. Conclusions: Patients undergoing BSTKA have similar knee function and knee awareness compared with patients undergoing UTKA. Our results support the use of BSTKA in patients suffering from bilateral osteoarthritis. DOS Kongressen 2014 155

Hip fractures: Can Thrombelastography (TEG) on admission predict overall blood loss Peter Toft Tengberg, Henrik Palm, Nicolai Foss, Jakob Stensballe, Thomas Kallemose, Anders Troelsen 103. CORH, Hvidovre Hospital; Anesthesiologic dept, Hvidovre Hospital; the blood bank, Rigshospitalet Background: Blood loss increases mortality and morbidity following major orthopedic surgery, particularly among the frail hip fracture patients. The ability to predict patients at risk of a large blood loss could be a valuable tool to optimize care pathways. Thrombelastography (TEG) is used routinely to monitor hemostasis in patients with massive bleeding, in order to guide and reduce transfusion requirements. The advantage of TEG over conventional coagulation tests is that is measures real time clot formation reflecting the multifactorial causes for hemostasis deficits. Purpose / Aim of Study: To test the viability of TEG as a routine blood sample, taken on admission, in hip fracture patients, with the purpose of identifying patients at risk of large blood losses. Materials and Methods: The study was a prospective observational study. TEG results were blinded. From December 2013 to April 2014 all patients admitted with a hip fracture were subjected to TEG analysis on admission. Of the 227 consecutively admitted and operated patients, 180 completed a full data collection and were included into the study. Findings / Results: Mean overall blood loss, calculated as decrease in hemoglobin from admission to the fourth-postoperative day, was 1679 ml (1114). A linear regression model for prediction of blood loss was constructed. The model included several interactions between the four TEG variables (R, K, angle and MA), with a significant effect (both p < 0.03). The effect of the inclusion of the individual TEG variables in the model was tested and found no significant effect for any one of them (all p > 0.09). Conclusions: There are several factors that determine the overall blood loss. Coagulation status on admission, as measured by TEG, is only one of them. TEG may very well have a role in guiding transfusion therapy for hip fracture patients 156 DOS Abstracts

Validation of the Danish version of the Quick-DASH questionnaire. Jesper Ougaard Schønnemann 104. Orthopedic Department, Sygehus Sønderjylland, Åbenrå Background: The Quick Disabilities of Arm, Shoulder and Hand(Quick-DASH) questionnaire is a 11-item region specific questionnaire used to measure the effect of clinical treatment to disorders and injuries to the upper extremity. The Quick-DASH has under its original development been shown as a valid and reliable outcome measure. Such a study has never been published regarding the Danish version of the Quick-DASH. Purpose / Aim of Study: The purpose of this study is to validate the Danish version of the Quick-DASH in patients with wrist fractures, using the Nottingham Health Profile(NHP) as an evaluation tool Materials and Methods: We included patients with wrist fractures. Patients either received conservative or operative treatment They all answered the Quick-DASH and NHP during their ambulatory follow-up. We investigated time to complete questionnaire. Internal consistency expressed by Cronbach s alpha and test-retest reliability as intraclass correlation coefficient, Bland- Altmans 95% Limits of agreement and difference of mean. Convergent validity calculated as correlation to the domains pain and physical mobility in the NHP, and content validity to demonstrate floor and ceiling effect. Findings / Results: Study population consisted of 61 patients. Time burden, Cronbach s alpha and intraclass correlation coefficient were excellent and comparable to other studies. Spearman s correlation for convergent validity was high for both pain and physical mobility, and we found divergent validity for the other domains of the NHP(sleep, energy, emotional reation and social isolation). We found good distribution of items showing no floor or ceiling effect. Conclusions: The Danish version of the Quick-DASH is a valid and practical questionnaire for use with Danish patients with wrist fractures. DOS Kongressen 2014 157

Primary brachial plexus reconstructon outcomes in 12 consecutive patients with traumatic brachial plexus injury, treated at the National Center for Brachial Plexus Injuries in Odense between 2010 and 2013. Jerzy Stiasny, Anders Lorentsen, Peter Birkeland 105. Division of Hand Surgery, Orthopaedic Department, Odense University Hospital, Denmark; Håndsektor, Ortopædkirurgisk Afd. O, OUH; Neurokirurgisk Afd., OUH Background: The brachial plexus (BP) lesions result in severe functional impairment of the affected exstremity. For that reason improvement in restoration of the brachial plexus function is strongly desirable. Purpose / Aim of Study: - to analyse the results of primary BP reconstruction at our institution during the first 3 years of activity. - to draw conclusions considering improvement of the results in the future. Materials and Methods: We analysed the data of 12 patients operated on between 2010 and 2013 with 7 partial and 5 total BP injuries. We performed a total of 14 operations where a primary BP restructure was done. Average postoperative follow-up was 27 months, patients were operated on average, 4 months after the injury. In the cases of rupture of the BP structures where the stumps were available we performed a total of 15 different types of nerve grafting. In the cases of root avulsion or non graftable roots, a total of 13 different neurotisation types were utilised. Findings / Results: In the group of patients with partial BP lesions we achieved, in all cases, shoulder stabilisation and some shoulder movement. All patients in this group recovered useful elbow flexion of, at least, grade M3 strength according to Medical Research Council scale. In the group of 5 patients with complete BP injuries we achieved in 2 cases a stable shoulder joint with some abduction and in 4 cases some of elbow flexion, albeit weak ( grade M1 or M2). Conclusions: In our material, satisfactory results were achieved in all cases of partial BP lesions. In the group of total BP lesions only 1 patient recovered a useful function of the limb. Improvement of the results can be achieved by means of more frequent use of neurotisation options and long nerve grafts directly into the target muscles, instead of short grafts within the nerve root and trunks. 158 DOS Abstracts

Osseointegrated prosthesis for the trans-femoral amputees. 106. Peter Holmberg Jørgensen, Klaus Kjær Petersen, Jens Ulrik Petersen, Rene Lessmann Hansen Orthopedic Surgery, University Hospital of Aarhus; Videncenter for Sårheling, Bispebjerg Hospital Background: Osseointegrated (OI) prosthesis for trans-femoral amputees is as a new treatment option in Denmark. The OI- prostheses can often be used when socket prosthesis is not an option e.g. in very short residual bone length. Purpose / Aim of Study: To evaluate the results of the first 20 patients operated with an OI-prosthesis. Materials and Methods: 20 trans-femoral amputees, mean age 48 (range 30-66), were operated through a two stage procedure (S1,S2). At S1, a titanium implant (fixture) was inserted into the distal part of femur. At S2, 6 months later, a rod (abutment) was inserted into the fixture exiting through the skin at the other end to be connected to an external prosthesis. The patients were rehabilitated for six months with increasing load on the OI implant until full weight bearing. Evaluation: Walking ability, Q-TFA questionnaire, complications. Findings / Results: 15 patients report increased walking ability, osseoperception, increased sitting comfort and easier change of external prosthesis. 13 patients are using the external prosthesis all day, 2 use it regularly. 5 patients don t use the prosthesis: one developed severe pain and sensory disturbances of the operated femur after a fall accident, one developed reflex dystrophia which disappeared after removing the abutment, one implant was removed due to loosening and two were removed due to deep infection. One patient developed a soft tissue infection after two years which responded to antibiotic treatment. 3 patients had a soft tissue correction made due to overhang at the prosthetic knee. Conclusions: Osseointegrated prosthesis for trans- femoral amputees is an alternative to a socket prosthesis, and for some patients it is the only option to be ambulatory. Deep infection is a severe complication which aims for further studies on prophylactic procedures. DOS Kongressen 2014 159

Preoperative in-cast intermittent pneumatic compression of malleolar fractures Jesper Schønnemann, Rasmus Buck Bendtson 107. Orthopedic, sygehus sønderjylland, Aabenraa Background: Malleolar fractures are often complicated by tissue swelling due to soft tissue injury, haemorrhage and secondary inflammation. In these situations the patients operation is typically delayed until it is safe to operate again. In order to prevent delay for surgery, studies has shown that the use of intermittent pneumatic compression (IPC) has the potential benefit of reducing oedema and tissue swelling. Purpose / Aim of Study: In a prospective patient cohort measure diagnosisto-surgery time when using IPC, and comparing it to a similar retrospective patient cohort. Materials and Methods: For a 3 month period all patients admitted at Sygehus Sønderjylland, Åbenrå orthopedic department requiring surgery because of malleolar fractures will be fitted with IPC (Flowtron footcompression bandage) in the Emergency Department after, if necessary, reposition, and then a cast. The time for diagnosis-to-surgery will be registered as primary outcome. The data collected in the three month period will be compared to the similar data from the department s treatment of malleolar fractures one year prior to the start of this study. Findings / Results: In the prospective cohort we included 17 patients, mean age 55(24-93) with an average diagnosis-to surgery time of 12 (3-26) hours. No patients were delayed due to swelling. In the retrospective cohort we identified 15 patients, mean age 63(20-89) ) with an average diagnosis-to surgery time of 42(4-138) hours. Three patients were delayed due to swelling. Conclusions: The use of in-cast intermittent pneumatic compression (IPC), may have an influence on swelling after a malleolar fracture, and has the potential benefit of reducing the diagnosis-to-surgery time. Further research should include a randomized study. 160 DOS Abstracts

Retrospective study of fifth metatarsal fractures. Jesper Høeg Vinther, Fanny Olsen 108. Deparment of Orthopaedic Surgery, Kolding Background: Fractures of the fifth metatarsal are common in active people, and are one of the most common fractures of the foot, with the majority being managed conservatively. It is our experience that fifth metatarsal fractures are conservatively treated in many different regimes, and without distinguising to different fracture subtypes. Most types of fifth metatarsal fractures have a favourable prognosis and can be treated conservatively. Purpose / Aim of Study: The aim of our study was to describe the distribution of different treatments in relation to different fracture subtypes and describe treatment types used in different age- groups. Materials and Methods: In this study we included a consecutive series of 165 patients with fifth metatarsal fractures who presented to our department over a period from 2005 2013. Clinical notes and radiographs of included patients were analysed retrospectively, and fractures were classified according to location (zone 1-5, 1e). Serial radiographs were studied to identify displacement. All radiographs were reviewed by first and second authors and any dispute was settled by mutual agreement. Findings / Results: Patients in our population were on average 38 (sd=22) years old, and 54% were males. The zone 1 fracture was the most common fracture (49%). Overall, most fractures were managed conservatively (86%). The zone 1e and 5 fractures were most frequently treated with elastic bandage or spica, and patients in these groups were in general younger with mean age 28 (sd=20) and 28 (sd= 24), respectively. Generally, treatment lasting > 6 weeks were seldom used. Conclusions: In our study we found that patients with fifth metatarsal fractures have most common a fracture in zone 1. Age and fracture type may influence on the decision of treatment, although a general pattern cannot be found. DOS Kongressen 2014 161

A modification of the Tokuhashi Revised score improves prognostic precision in patients with metastatic spinal cord compression. 109. Søren Schmidt Morgen, Martin Gehrchen, Sebastian Bjørck, Claus Falck Larsen, Svend Aage Engelholm, Benny Dahl Spine Section, Department of Orthopedic Surgery, Copenhagen University Hospital, Rigshospitalet ; Trauma Center, Copenhagen University Hospital, Rigshospitalet ; Department of Radiation and Oncology, Copenhagen University Hospital, Rigshospitalet Background: Patients suffering from metastatic spinal cord compression (MSCC) are routinely evaluated with pre-operative prognostic scoring systems. The most well known scoring system is the Tokuhashi Revised score (TR), but recent studies have proposed a modification of the TR due to lack of precision. Purpose / Aim of Study: To modify the TR in order to improve the prognostic precision. Materials and Methods: In 2011 and 2012 a total of 1143 consecutive patients admitted with MSCC were prospectively included and variables for the TR score were collected. In the 2011 cohort each component of the TR including primary cancer diagnosis was analyzed regarding prognostic ability by Cox regression analysis. Based on these findings a modified TR score (MTR) was defined. New prognostic groups were determined using Receiver Operating Characteristics (ROC) analysis for survival < 6 months, >= 6 months, and >= 12 months. These prognostic groups were used to compare the TR and the MTR in the 2012 cohort based on Kaplan-Meier (KM) survival curves and ROC analysis. Findings / Results: There were no significant differences between the 2011 and the 2012 cohort regarding age and gender distribution. The mean age was 66 years (range 20-97) and the most common primary tumor sites were prostate (21%) and lung (20%). In the 2012 cohort the KM curves showed that the actual survival for each prognostic group was separated more accurate with the MTR compared to the TR. The areas under the ROC curves were significant larger for the MTR compared with the TR. The ROC area were for < 6 months survival, MTR = 0.71 and TR = 0.65; p = 0.003, for >= 6 months survival, MTR = 0.71 and TR = 0.65; p = 0.003, for >= 12 months survival MTR = 0.72 and TR= 0.67; p = 0.0015. Conclusions: A modification of the TR can improve the precision in the estimation of survival among patients with MSCC. 162 DOS Abstracts

Reliability and validity of the Danish version of SRS 22r Ane Simony, Karen Højmark Hansen, Leah Carreon, Mikkel Østerheden Andersen 110. Rygkirurgisk Afdeling, Middelfart Sygehus; Research Department for Spine Surgery, Norton Spine Center Background: Adolescent idiopathic scoliosis (AIS) is a three dimensional disease of the spine, with a Cobb angel greater than 10º. AIS affects children in the age of 12-16, and develops during the growth spurt. Treatment of AIS is correction of the spine by either brace treatment or surgery. Haher et al created the SRS 22 questionnaire as a tool to monitor health related quality of life in scoliosis patients, but no previous Danish version has been validated. Purpose / Aim of Study: To evaluate the validity and reliability, of the Danish adapted version of SRS 22. Materials and Methods: The SRS 22 were translated and cross cultural adapted, according to the guidelines from WHO. The SRS22 Danish version was distributed to 262 patients with scoliosis and 50 age matched controls, together with SF12. All data where analyzed by a independent statistician. Findings / Results: A total of 207 questionnaires (79.2% response rate) were retrieved.165 questionnaires from scoliosis patients and 42 from healthy controls. No floor effects was noted. In the scoliosis patients, moderate ceiling effects were observed on the Satisfaction with Management domain. Reliability of the SRS-22 seemed good with a Cronbach á of 0.93 in scoliosis patients, 0.90 in healthy controls. In patients, good reliability was found for all domains: Pain, 0.88; Self-image, 0.87; Function, 0.89; Mental Health, 0.90; Satisfaction with Management, 0.68. The concurrent validity showed good reliability with an overall á of 0.88. The results were statistically significant at P <0.05. The discriminant validity was tested with a t-test. All domains differed significantly and reveal scoliosis patients have lower scores compared with the controls. Conclusions: The Danish translated version of SRS 22 is valid, and can detect difference between patient with scoliosis and a age matched healthy control group. DOS Kongressen 2014 163

Self-reported scoliosis is not a valid method for estimating concordance rates of Adolescent Idiopathic Scoliosis in a Danish twin population 111. Mikkel Andersen, Kirsten O. Kyvik, Karsten Thomsen, Ane Simony Sector of Spine Surgery and Research, Region of Southern Denmark, Sygehus Lillebælt; Institute of Public Health, University of Southern Denmark; Sector of Spine Surgery,, Aleris Background: The aetiology of adolescent idiopathic scoliosis is still unclear and the true mode of inheritance has yet to be established. From the Danish twin cohort concordance rates in monozygotic twins have previously been reported to be 0.13 and in dizygotic twins 0. Studies on concordance in twin pairs provide a basis for analysing the influence of genetic versus environmental factors. Purpose / Aim of Study: To validate if self-reported scoliosis is a valid method to establish incidence and concordance rates in a twin population Materials and Methods: All 46,418 twins registered in the Danish Twin Registry born from 1931 to 1982 were sent a questionnaire, which included questions about scoliosis. A sub group of 344 individuals with self- reported scoliosis were invited to a clinical and a radiologic examination together with their twin, in total 644 individuals/ 322 twin pairs. Zygosity was established by genetic testing. Findings / Results: 203 individuals (31.5% of the cohort) participated. The total number of participants consisted of 95 twin pairs, where one or both twins had scoliosis and 13 individuals. 35 individuals (32.4%) of the 108 participants with self-reported scoliosis presented a clinical and radiological confirmed curve. Of these were 5 twin pairs (4 monozygotic pairs and 1 dizygotic pair) with scoliosis in both twins and 11 twin pairs with scoliosis in only one twin and 3 individuals where only one twin participated. Calculating concordance in twins with curves greater than 15 degrees, we found that the pairwise concordance rate was 0.4 (0.12-0.74) for monozygotic and 0.05 (0.01-0.25) for dizygotic twin pairs, probandwise concordance was 0.45 for monozygotic and 0.1 for dizygotic pairs. Conclusions: Self-reported scoliosis in a Danish twin population is not a valid method to establish the true concordance rates. 164 DOS Abstracts

Investigating human VANGL1, as a candidate gene for adolescent idiopathic scoliosis Malene Rask Andersen, Ane Simony, Lars Allan Larsen 112. Wilhelm Johannesen Centre for Functional Genome Research, Department of Cellular and Molecular Medic, Københavns Universitet; Rygkirurgisk afdeling, Middelfart Sygehus Background: The human VANGL1 genes has been predicted to be associated with idiopathic scoliosis, as a mutation (c.676c>t, L226F) was identified in a family with dominant inheritance of the disease. Previous investigation of the gene revealed the candidate to segregate, with all but one family member. Adolescent idiopathic scoliosis (AIS) is generally considered multi-genic, but the determining genes remain yet to be characterised. Purpose / Aim of Study: In this study we have examined VANGL1 as a contributor to the phenotype of AIS. Materials and Methods: We have conducted automated Sanger sequencing of the seven coding exons of VANGL1 gene in a disease cohort of 170 AIS patients (n=340) and 177 controls (n=354). Localization of mutated VANGL1 proteins were investigeted in cell systems. Findings / Results: Two novel mutations, each in separate individuals within the considered disease cohort, were identified. One mutation is situated in the third coding exon, which encodes the transmembrane parts of the VANGL protein. This mutation is a c.407t>a (L136N) conversion, for which the patient is heterozygotes. This mutation was also identified in the dizygotic unaffected twin of the patient. The second mutation was found in the seventh coding exon, which encode the C-terminal of the VANGL1 protein. This mutation is a c.1318t>g (F440V) conversion, for which the patient is also heterozygotes. Neither of the identified mutations was present in the sequenced controls or in 2000 Danish exomes. Currently, the cellular localization of wt and mutant VANGL1 protein are being investigated using immunofluorescence microscopy. Conclusions: On behalf of the current results of this study we conclude that mutations in the VANGL1 gene may be a rare cause of AIS. Examination of the expression of VANGL1 in teenage-adult stages of life is wanted as well as examinations of effects. DOS Kongressen 2014 165

Does obesity delay time of surgery for Lumbar Disc Herniation, and does it influence surgical outcome in 832 patients treated with discectomy. 113. Rikke Rousing, Ane Simony, Henrik Grønvall, Karen Højmark, Stefan Hummel, Mikkel Østerheden Andersen Rygkirurgisk afdeling, Middelfart sygehus, Vejle sygehus Background: Lumbar disc herniation (LDH) is associated with great morbidity and significant socioeconomics impact. Studies have shown that most LDH can be treated effective conservatively. However for the group of patients where pain and disability is unacceptable, surgical intervention provides effective clinical relief in many cases. Several factors may influence the outcome of surgery for LDH, including obesity and prolonged time of symptoms. Data from the Danish National Healthprofile 2010 state that 47% of the danish population is overweight (BMI 25) and about 13% is classified as obese (BMI 30). Purpose / Aim of Study: To investigate if obesity is correlated with surgical outcome and whether overweight patients has a delayed time of surgery compared with non-obese patients. Materials and Methods: 832 patients with first-time LDH were included in a Single-Center Study. Data were prospectively collected in DaneSpine, the Danish National Spine Register. The patient reported outcome measures (PROMs) EQ5D, SF36, ODI, VAS-leg and -back were correlated with duration of symptoms. A comparison between subgroups of BMI and 1-year follow-up PROMs were performed. Data was analysed with STATA. Findings / Results: Overweight and obese patients have symptoms-relieve following LDH surgery, but the outcome is inferior to patients of normal weight. Patients with BMI 35 are treated conservatively for a longer time and have an inferior outcome. Conclusions: Severe obesity delays time of surgery and influences the surgical outcome. 166 DOS Abstracts

Moderate Precision of the Tokuhashi Revised Score and the Bauer Modified Score in Patients with Metastatic Spinal Cord Compression. 114. Søren Schmidt Morgen, Martin Gehrchen, Dennis Hallager Nielsen, Claus Falck Larsen, Svend Aage Engelholm, Benny Dahl Spine Section, Department of Orthopedic Surgery, Copenhagen University Hospital, Rigshospitalet ; Trauma Center, Copenhagen University Hospital, Rigshospitalet ; Department of Radiation and Oncology, Copenhagen University Hospital, Rigshospitalet Background: Estimated survival is an important element in the evaluation of patients with metastatic spinal cord compression (MSCC). The Tokuhashi Revised score (TR) has been recommended as a prognostic score in many studies, but two recent studies have showed that the Bauer Modified Score (BM) was the more accurate. Purpose / Aim of Study: To compare the TR and the BM in the prediction of survival among patients surgically treated for MSCC. Materials and Methods: From January 1st 2009 to December 31st 2011, a total of 246 MSCC patients were treated surgically for MSCC in one center. These patients were included in a cohort with a minimum of two years followup. The patients were scored with the TR and the BM scoring systems. Findings / Results: The mean age on admission was 63 years (range 27-94) and 54% of the patients were men. The most common primary tumor-sites were lungs (24%) and breast (15%). The logrank test showed that each prognostic group in both scoring system were significantly different (p < 0.001). The Kaplan Meyer survival curves showed good prognostic value in each prognostic group for both of the scoring systems, but the specificity and sensitivity was moderate. In both scoring systems the prognostic groups with a short predicted survival had longtime survivors who lived longer than one-year (20% in the TR-group and 19% in the BM- group). For the prognostic groups with long estimated survival, a considerable proportion of the patients were dead within 6 months (27% in the BM and 31% in the TR). Conclusions: This study showed that the TR and the BM ability to predict survival were almost equal. Both scoring systems performed well in categorizing patients in prognostic groups, but the moderate precision in predicting survival emphasizes that a modification may be necessary. DOS Kongressen 2014 167

Morbidity and mortality of complex spine surgery: a prospective cohort study in 679 patients validating the SAVES system in a European population 115. Sven Karstensen, Tanvir Bari, Martin Gehrchen, John Street, Benny Dahl SpineUnit, Department of Orthopaedic Surgery, Rigshospitalet and University of Copenhagen ; ICORD, University of British Columbia Background: The Spine AdVerse Events Severity system (SAVES) has been found reliable and valid in two North American spine centers, providing precise information regarding all adverse events after complex spine surgery. Purpose / Aim of Study: The purpose of the present study was to assess the generalizability of the SAVES system in a European population of patients, including pediatric patients, undergoing complex spine surgery. Materials and Methods: All patients undergoing spinal surgery in the period January 1, 2013 through December 31, 2013 were prospectively included. A modified SAVES form was used, and a research coordinator collected all data prospectively. Once a week all patients were reviewed for additional events, validation of the data and clarification of any questions. The survival status was registered on January 31, 2014 to obtain 30-day survival. Findings / Results: A total of 679 consecutive patients were included with 100% SAVES data completed. The in-hospital mortality was 1.3% and the 30- day mortality was 2.7 %; all occurring after emergency procedures. There was no significant difference between lengths of stay after elective or emergency surgery. The number of intraoperative AE s was 162 and the number of postoperative AE s was 1415; the most frequent event being postoperative electrolyte imbalance. 2.2% of the patients had postoperative infections requiring surgical revision. The frequency of postoperative AE s was significantly higher in patients 65 years or older compared to young individuals (P=0.002). Conclusions: The results confirm that a rigorous prospective system improves adverse event recognition, confirming the generalizability of the SAVES system to a non-canadian populations including pediatric patients. 168 DOS Abstracts

Clinical correlation of the SRS-Schwab Classification with HRQOL measures in a prospective non-us cohort of ASD patients 116. Dennis Hallager Nielsen, Lars Valentin Hansen, Casper Rokkjær Dragsted, Martin Gehrchen, Benny Dahl Dept. of Orthopaedic Surgery, Rigshospitalet Background: The SRS-Schwab adult spinal deformity (ASD) classification system is considered an important communication tool for spine surgeons as it summarizes the complex pathology of ASD in four coronal curve types with three sagittal modifiers (PI-LL, PT and SVA). The cut-off values separating level 0 from + have been proposed to predict severe disability defined by an Oswestry Disability Index (ODI) of more than 40. The clinical correlations of the classification system have only been evaluated using US ASD patients. Purpose / Aim of Study: The aim of the present study was to assess the clinical correlations of the sagittal modifiers with various HRQOL measures in a prospective, consecutive non-us cohort of ASD patients. Materials and Methods: Between March and August 2013 a total of 112 ASD patients aged >18 years having sufficient long standing X-rays taken at our out-patient clinic completed VAS scores for back pain, ODI, SRS22r, EQ5D and SF36 questionnaires. 14 patients were excluded due to predefined criteria. For each sagittal modifier the variation of score means/ranks across levels 0, + and ++ was assessed with one-way ANOVA/Kruskal-Wallis test. Findings / Results: 98 patients were included with a median age of 64 years (range 18-85). 64% were female, and 49% had a history of previous deformity surgery. We found a significant variation for SF36 physical component summary (PCS) scores across the levels of all modifiers. Significant variation was also found for SRS22r total score across PI-LL and PT levels, EQ5D and VAS for back pain across PI-LL and SVA levels and ODI across SVA levels. Conclusions: We showed that the SRS-Schwab classification modifiers are able to classify patients according to the SF36 PCS and various other HRQOL measures in a non-us cohort of ASD patients. DOS Kongressen 2014 169

Providence Nighttime Bracing in adolescent idiopathic scoliosis Ane Simony, Inge Beuschau, Lena Quisth, Mikkel Østerheden Andersen, Stig Mindedahl Jespersen 117. Rygkirurgisk Afdeling, Middelfart Sygehus;, Ortos, Odense; Rygkirurgisk sektor, Odense Universitets Hospital Background: 6 years ago the primary conservative treatment of adolescent idiopathic scoliosis (AIS) in the southern part of Denmark, went from full time bracing to nighttime bracing. Purpose / Aim of Study: To evaluate the effectiveness of nighttime bracing in AIS. Materials and Methods: Patients diagnosed with AIS and skeletal immature. With an apex of the primary curve from TH7 and below and with a cobb angel between 20-45 degrees. The patients were asked to wear the brace at least 7-8 hours pr. night. No other previous treatments were accepted and a follow up at least 6 months out of brace. The brace treatment was continued until two years post menarche or for male at the expected adult height. Cross-measured x-rays was used to compare the primary cobb angel, the in- brace correction and the outcome cobb angel. A decreased outcome cobb angle as well as the overcorrection of the curve measured in brace was recorded as zero. The brace treatment was considered failed if progression more than 5 degrees occurred and if surgery were performed. Findings / Results: A total of 55 patients, 8 male and 47 female, with the mean age at 14 years (11-16.5) and the mean primary cobb at 31 degrees (20-41) were included in this study. The mean time of treatment was 18 month (5-59). After ended treatment the mean cob angle was 28 degrees (7-50), an average of no progression. The end results were 11 failures (6-15 degrees); equal 20 % and out of these 11 patients, 3 had surgery performed (5%). Conclusions: The results show a good curve control and an acceptable 20 % failure rate, which is equal to other studies. The providens brace is an excellent alternative to standard conservative treatment. Larger studies are needed to establish the relationship between inbrace correction and curve progression. 170 DOS Abstracts

Is the surgical outcome for lumbar disc herniations related to the duration of symptoms? Christian Støttrup, Carsten Ernst, Dorte Clemmensen, Alexander Isenberg-Jørgensen, Randi Holm, Mikkel Østerheden Andersen Rygkirurgisk sektor, Middelfart Sygehus, Vejle Sygehus 118. Background: Lumbar disc herniation (LDH) is associated with great morbidity and significant socio-economic impact in many parts of the world. Studies have shown that most LDH can be treated effectively with conservative management and the passage of time. However for the group of patients where pain and disability is unacceptable, surgical intervention provides effective clinical relief in many cases. Currently there is little consensus in the medical community on the timing of surgery for patients suffering from radicular pain due to LDH. Reports based on the SPORT database indicate that prolonged symptomduration correlates with inferior outcome. Purpose / Aim of Study: The aim of this study is to evaluate if prolonged symptom-duration is correlated with less favorable outcome following surgery for LDH in a Single- Center Study. Materials and Methods: 832 patients with first-time LDH were included in a Single-Center Study. Data were prospectively collected in DaneSpine, the Danish National Spine Register. The patient reported outcome measures (PROM) EQ5D, SF36, ODI, VAS-leg and -back were correlated with duration of symptoms. Findings / Results: 832 patients were included in the study, with complete one-year follow-up on 664 patients (80%) and a reoperation rate of 6%. The duration of symptoms have a negative correlation on all patient related outcome measures. Conclusions: Delayed surgical intervention results in inferior patient related outcome. Our results indicate that patients operated within the first 3 months of leg-pain achieve best outcome. DOS Kongressen 2014 171

Does loss of follow-up bias patient-related outcome measures of spine surgery performed at the Sector for Spine Surgery and Research, Region of Southern Denmark. 119. Karen Højmark, Christian Støttrup, Mikkel Østerheden Andersen Rygkirugisk sektor, Ortopædkirurgisk afdeling Vejle, Sygehus Lillebælt Background: DaneSpine, the Danish National Spine Register, collects patientbased pre- and postoperative questionnaires, completed before surgery and at 1, 2, 5 and 10 years postoperatively. The preoperative data entered into DaneSpine are entirely patient-based, and include age, sex, height, weight, duration of back and leg pain on the VAS-scale, SF-36, ODI and EQ-5D. The database was implemented at the Sector for Spine Surgery and Research on June 1st 2010. So far preoperative data has been collected on 99.3% of surgical patients, with a subsequent 1- year follow-up of more than 80%. Loss of follow-up may bias the outcome assessment of clinical registries. Purpose / Aim of Study: To determine whether patient related outcome measures (PROMs) differed between responders and none-responders. Materials and Methods: In order to validate DaneSpine data, we have performed 1-year follow-up on non-responding patients for a 3 months consecutive period between 1st of August 2013 until 31st of October 2013. Of the 262 patients operated in the same period 1-year prior, 217 (82,8%) had responded, 3 had died and 10 had received other primary spine surgery and therefore restarted in their registration period. During spring 2014 a structured interview was performed by telephone on the remaining 32 patients, 2 of which could not be reached and 2 did not want to participate. Findings / Results: We found no difference in PROMs between responders and non-responders at the Sector for Spine Surgery and Research. Conclusions: A 17% loss of 1-year follow-up does not bias conclusions drawn from PROMs at the Sector for Spine Surgery and Research. 172 DOS Abstracts

Micro dose acquisition in Leg length Discrepancy using the EOS imaging system Janni Jensen, Bo Mussmann, Niels Wisbech, Zaid Al-Aubaidi, Trine Torfing Department of Radiology, Odense University Hospital; Department of Orthopedic Surgery, Odense University Hospital 120. Background: Leg Length Discrepancy (LLD) is often diagnosed in young patients who undergo repeated x-ray examinations quantifying the length discrepancy and monitoring progression. In our department LLD images are currently acquired using a low dose bi-plane system named EOS. Prior to the acquisition of diagnostic images a scout image is acquired at extremely low dose for planning purposes, i.e. approximately 1% of the dose required for diagnostic images. Dose reduction is important because children and adolescents are more sensitive to radiation than adults and they may undergo several LLD examinations. Purpose / Aim of Study: The purpose of the study was to investigate the accuracy and reliability of LLD measurements performed on scout images compared to diagnostic images. Materials and Methods: A retrospective pilot study including 30 consecutive patients (age 6-15 years) was performed. Two senior musculoskeletal radiologists measured the length of the femur, tibia and the total leg length on both legs on scout and diagnostic images. The measurements on scout and diagnostic images were performed in two separate sessions and the radiologists were blinded to the identity of the patients. Findings / Results: No significant differences between scouts and diagnostic images were found. The mean femoral length difference for the observers was 0.11 cm (p=0.09) and 0.07 cm (p=0.24) respectively, mean tibial length difference was 0.02 cm (p=0.77) and 0.01 cm (p=0.84). The mean total leg length difference was 0.01 cm (p= 0.92) and 0.03 cm (p=0.73). ICC was >0.99 indicating excellent inter rater reliability. Conclusions: The results suggest that there is no significant difference in LLD measurements performed on scouts and diagnostic images. Thus, scout based LLD measurements can be accurately and reliably performed in EOS. DOS Kongressen 2014 173

Reliability of Instrumented gait analysis in children with spastic cerebral palsy 121. Helle Mätzke Rasmussen, Dennis Brandborg Nielsen, Niels Wisbech Pedersen, Søren Overgaard, Anders Holsgaard-Larsen The Orthopaedic Research Unit, 1) Department of Orthopaedic Surgery and Traumatology Odense University Hospital 2) Institute of Cli Background: Instrumented gait analysis (IGA) is used to describe gait pattern and impairments in children with cerebral palsy (CP). Gait Deviation Index (GDI) is based upon kinematic data from the IGA and is a quantitative index that summarizes the overall gait function into a single score. Satisfactory concurrent and construct validity of the GDI have been shown in children with CP. But testretest intra- assessor reliability of GDI has not previously been investigated. Purpose / Aim of Study: The aim of this study is to investigate intra- assessor reliability of GDI in children with CP across two repeated sessions. Materials and Methods: For intra-assessor reliability the assessor teams completed the IGA on two different days, separated by 0-9 days. A total of 18 children (mean age 8.0 years, SD 2.1) with spastic CP (10 uni- and 8 bilateral) participated. For each IGA the GDI score of 5 trials were obtained and the median GDI score for each child on the left and right side were used for further analysis. Intra-assessor reliability was investigated with calculation of a paired Intraclass correlation coefficient (ICC), Standard error of measure (SEM), and smallest detectable change (SDC) based on 95% confidence intervals. Findings / Results: The reliability for GDI with ICC was found to be 0.74-0.84 that is considered as moderate to good. SEM was found to be 4.6-6.3 point and finally SDC was found to be 12.7-17.4 points. No significant learning effect and/or systematic bias were observed between test and retest. Conclusions: The present observed moderate to good reliability holds promise for the use of GDI as an outcome in clinical research investigating difference between groups. The SDC was found to be larger than what can be expected for most interventions on an individual level. Thus, GDI is not applicable to evaluate intervention for an individual child. 174 DOS Abstracts

Reliability and validation of the Oxford Ankle Foot Questionnaire (OxAFQ) in 82 Danish patients aged 5 to 16 years 122. Polina Martinkevich, Bjarne Møller-Madsen, Martin Gottliebsen, Line Kjeldgaard Pedersen, Ole Rahbek Children s Orthopaedics, Aarhus University Hospital Background: The OxAFQ was developed to assess disability associated with foot and ankle problems in children aged five to 16 years, as experienced by the child and parents. It has been throughly validated in English. There is currently no Danish validated foot/ankle score for children. Purpose / Aim of Study: To validate the Danish version of the OxAFQ in terms of agreement and reliability (internal consistency, test-retest, child- parent reliability), feasibility and construct validity. Materials and Methods: A prospective observational cohort study. Inclusion criteria were children aged between 5 to 16 years with parents attending the outpatient clinic at children s orthopedics. Patients with a significant proximal musculoskeletal component, cognitive impairment or inability to understand Danish were excluded. Both OxAFQ and Child Health Questionnaire (CHQ) were obtained. Re-test of OxAFQ was done after 2 days. Reliability and agreement was assessed by the intraclass correlation coefficient and as limits of agreement. Construct validity assessed as Spearman rho against CHQ. Findings / Results: Eighty-two children, mean age 11.7 years (range 5.5 to 16.0) and their parents participated. We found good internal consistency for the Physical and the School & Play domain, but lower for the Emotional domain. Construct validity was good for convergent validity. Good agreement was found within and between children and parents. The OxAFQ was fast and easy to complete. A tendency towards ceiling effects was observed in the School & Play and Emotional domains. Conclusions: To our knowledge this is the first independent validation of the OxAFQ. We found it valid and feasible for use in the outpatient clinic to assess the degree to which children are affected by their foot and ankle conditions. OxAFQ is now available in a Danish validated version. DOS Kongressen 2014 175

The revised FLACC behavioural pain scale: Translation, reliability and validation for pain assessment in children with cerebral palsy 123. Line Kjeldgaard Pedersen, Ole Rahbek, Lone Nikolajsen, Bjarne Møller-Madsen Department of Childrens Orthopedics, www.dpor.dk, Aarhus University Hospital; Department of Anaestesiology, Aarhus University Hospital Background: Assessment of pain in children with cerebral palsy (CP) is a challenge since they might not be capable of using a self-rating assessment tool; hence an observational or behavioral pain score is needed. The r-flacc behavioral pain scale has only been assessed for reliability and validity in the original language version. Purpose / Aim of Study: To translate the r-flacc pain scale and evaluate the parameters of reliability and validity in order to use the r-flacc for pain assessment in children with (CP). Materials and Methods: Forward and back-translations were performed according to guidelines. Twenty children with CP undergoing orthopedic surgery were included. The parents assessed the pain intensity with the Observational Visual Analog Scale and a 2 min standardized video recording was made for r- FLACC scoring. Two nurses r-flacc scored the recordings independently. Ten of the recordings were reviewed again 1 year later. Findings / Results: Reliability was supported by three measurement properties. Internal consistency was excellent with a Cronbachs alpha of 0.9278 and 0.9758. A test retest showed excellent intra-rater reliability with a Spearman Correlation of 0.0040 and an intra- class correlation (ICC) of 0.97530. Interrater reliability was acceptable with a Spearman Correlation of 0.000 and an ICC of 0.74576. Validity was supported by three measurement properties. Construct validity was supported by a significant increase in r- FLACC scores following surgery (p=0.0427). Criterion validity was acceptable with Pearson s Correlation Coefficients of 0.75 and 0.59 when comparing the r-flacc scores and the VAS-OBS scores. Conclusions: The translated version of the r-flacc behavioral pain scale has high reliability and validity and may be considered as gold standard for pain assessment in children with CP. 176 DOS Abstracts

Danish Translation and adaptation of Gait Outcomes Assessment List, GOAL Questionnaire, a patient reported priority based outcome measure 124. Kirsten Nordbye-Nielsen, Unni Narayanan, Ole Rahbek, Bjarne Møller-Madsen Department of Children s Orthopedics, Aarhus University Hospital, Denmark; Divisions of Orthopaedic Surgery, The Hospital for Sick Children, & Holland Bloorview Kids Rehabilitation Hospital, Toronto, Canada; Department of Children s Orthopedics, Aarhus University Hospital, Denmark Background: 2/3 of children with cerebral palsy (CP) are ambulant, and undergo interventions to improve their gait, increase physical function and participation in daily activities. The GOAL questionnaire was recently developed in Canada, to serve as a meaningful outcome measurement for these interventions. It identifies children s and parents expectations of interventions, with 48 items across 6 domains, covering all ICF domains, as a priority-based outcome instrument for children with CP. Purpose / Aim of Study: Danish translation and adaptation of GOAL, a patient reported priority based outcome measure for ambulatory children with cerebral palsy GMFCS I, II and III. Materials and Methods: Danish forward and backward translation of the GOAL questionnaire was carried out in accordance with the international guideline set up by the Translation and Cultural Adaptation Group (TCA) Principles of Good Practice (PGP). This guideline consists of 10 items defined as the framework in the translation process. Preparation, Forward Translation, Reconciliation, Back Translation, Back Translation Review, Harmonization, Cognitive debriefing, Review of Cognitive Debriefing and Results and Finalization, Proofreading and Final Report. Findings / Results: The Danish translation process, done by the ten steps, according to the TCA group guidelines, have been carried out to Child and Parent version of GOAL questionnaire. 12 literal and 21 conceptual changes were made. Ex.: Gymnastics was added in item 32, Gait appearance was translated to: Gangmønster. Questionnaires have been accepted for further validation and reliability studies in a Danish context in 2014. Conclusions: The GOAL questionnaire has the potential to become a much needed priority based outcome measure for children with ambulatory CP undergoing various gait interventions, in Denmark. DOS Kongressen 2014 177

Skeletal Healing after Periacetabular Osteotomy Measured by RSA - Preliminary Results Peter Buxbom, Stig Sonne-Holm, Christian Wong 125. Orthopedic Department, Hvidovre Hospital Background: Approximately 25-28% of children with cerebral palsy (CP) develop subluxation or dislocation of the hip that needs surgical intervention. When this problem is discovered in early childhood the preferred treatment is a combination of periacetabular and varizating femoral osteotomy. However, 16-22 % of these children require another similar surgery due to re-luxation during adolescence. Purpose / Aim of Study: To descriptively assess migration and rotation around periacetabular osteotomies in children with CP measured by radiostereometric analysis (RSA). Materials and Methods: A protocol of perioperative insertion of 4-8 tantalum markers on each side of the femoral and periacetabular osteotomy was performed and RSA radiographs were recorded and subsequently analysed longitudinally postoperatively (in cast) and at time 5, 12 weeks, 6 and 12 months after surgery. Findings / Results: The cohort consisted of 6 girls and 9 boys, 8 left and 7 right hips. The median age was 7.3 years. 12 underwent Dega, 2 Salter and 1 Chiari osteotomy. All had 3 months follow- up period, and 9 had been followed 1 year. The average Maximum Total Point Motion (MTPM) is 1.57, 1.52, 1.88 and 2.17 at respectively 5, 12 weeks, 6 and 12 months. Conclusions: Results show initial movement across the osteotomy in spite of being casted for 5 weeks. However, this pattern ceases from 5 weeks to 3 months, where the ΔMTPM decrease the remaining follow-up period. Salter and Chiari osteotomies demonstrate largest MTPM values, though there is not enough data to perform statistical analysis. 178 DOS Abstracts

Measuring the effect of treatment on gait quality in children with cerebral palsy a retrospective study 126. Anders Holsgaard-Larsen, Rasmus Skov Sørensen, Carsten Jensen, Dennis Brandborg Nielsen, Annie Gam-Pedersen, Niels Wisbech Pedersen The Orthopaedic Research Unit, Department of Orthopaedic Surgery and Traumatology Odense University Hospital 2) Institute of Clinic Background: Gait Deviation Index (GDI) describes the overall gait quality and summarizes it into a single score based upon three- dimensional gait analysis (3DGA). In the Region of Southern Denmark, children with cerebral palsy (CP) are referred to 3DGA if surgical intervention is considered and subsequently, as a follow-up. Thus, the effect of treatment on gait quality in children with CP may be quantified. Purpose / Aim of Study: In a retrospective study we investigated the effect of treatment on gait quality (measured by GDI) in children with CP. Materials and Methods: Data from children (<16 years) diagnosed with CP and referred to 3DGA (either as a diagnostic instrument or for the purpose of follow- up) was extracted from a local database for the year 2012. The GDI score was calculated for each child and limb and used for further analysis. Findings / Results: 29 children with follow-up analysis were referred to 3DGA in 2012. Children were diagnosed with unilateral (n = 6) or bilateral spastic CP (n = 23). Age and GDI score at first 3DGA were 8.2 ± 2.8 years and 69 ± 11 (mean ± sd), respectively. Time between follow-ups was 710 ± 367 days. A weak, albeit non-significant association between GDI and age was observed (r = 0.25, 95CI: -0.13 to 0.56), suggesting the effect of age is only weakly reflected in gait quality. However, a significant negative association (r = 0.41, 95CI: -0.93 to -0.24) between GDI at first 3DGA and the improvement in GDI was observed. Proposing, that children with poor gait quality, benefit more from intervention than children with good. Conclusions: Significant improvements in GDI, especially for patients with poor gait quality, were observed. The present study holds promise for future clinical interpretations, involving more patients, and possibly providing a tool for stratification on different treatments. DOS Kongressen 2014 179

Complex regional pain syndrome (CRPS) in children - treatment with peripheral nerve catheter Søren Bødtker, Søren Anker Pedersen, Lene Larsen, Vibeke Rosenkvist, Svandhild Ivarsslaten, Mai Pedersen 127. Orthopaedics, University Hospital Hvidovre; Pediatrics, University Hospital Hvidovre; Anaestecis, University Hospital Hvidovre; physiotherapy, University Hospital Hvidovre Background: Complex regional pain syndrome (CRPS) is a neuropathic condition charterized by circular allodynia and functional loss. Treatment with peripheral nerve blockade in children and adults has yet only been reported as case studies. Purpose / Aim of Study: This study reports our results and complications on treatment combining continous pain relieve combined with physio-occupational therapy in children with CRPS. Materials and Methods: Inclusion criterias were circular sensory disturbances and allodynia, thus loosing ability to self-support on their limb. A catheter was implanted close to either N. ischiaticus, N. saphenous or brachial plexus. Implantation was done in GA and guided by EMG and ultrasound. All patients received a specific and continous pain relieve by Naropin, combined with immidiate physiotherapy and/or occupational therapy with a supplement of 2 hours of walking. The theraphy focused on improving coordination, strength, and sensory motor skills Findings / Results: 16 children were consecutively included (13 girls:3 boys) with foot pain (13), hand pain (2) and combined foot/hand pain (1). At admission the average age was 11 years (9-14); average duration of pain were 9 months (2-33) with a VAS score of 9 (7-10). Initiation of pain was either no (7) or minor trauma (7 distorsions, 1 fracture and 1 surgical induced). After an average observation period of 12 months (6-37) the VAS score was 0 (0-4). No relapses, neurological complications or infection occurred during the observation period. Conclusions: Treatment with pain catheter and training seems safe and effective for children with CRPS, resulting in pain-free or almost pain-free patients. 180 DOS Abstracts

Are pain thresholds in children influenced by orthopedic surgery? - A prospective study Line Kjeldgaard Pedersen, Polina Martinkevich, Ole Rahbek, Lone Nikolajsen, Bjarne Møller-Madsen Department of Childrens Orthopedics, www.dpor.dk, Aarhus University Hospital; Department of Anaestesiology, Aarhus University Hospital 128. Background: The threshold for pain can be measured quantitatively by pressure algometry. To our knowledge pain thresholds in children undergoing orthopedic surgery have never been investigated. Purpose / Aim of Study: To assess pressure pain thresholds (PPT) and level of pain in children before and after orthopedic surgery. Materials and Methods: 24 children aged 6-16 years were included. PPT and Numerical Rating Scale (NRS) were obtained at 3-6 weeks before surgery, on the day of surgery, the first day and 6-12 weeks after surgery. A Somedic pressure algometer was used on the thenar of the dominant hand and the lateral part of the lower leg. PPT is defined as the minimum pressure applied that induces pain. Findings / Results: A decrease in PPT between 3-6 weeks before surgery and the first postoperative day of 20,16 kpa (p=0,20) and 47,6 kpa (p=0,04) was measured by pressure algometry on both the hand and the leg, respectively. An increase in PPT between the first postoperative day and follow-up at 6-12 weeks of 35,7 kpa (p<0,01) and 119,3 kpa (p<0,01) was observed. NRS showed significant changes between these periods (p=0,04; p<0,01; p<0,01). No significant correlations between PPT for both hand and leg measurements and NRS were found. Age and sex of the child influenced pain perception. Conclusions: Children undergoing orthopedic surgery demonstrate significant changes in PPT. The pressure pain threshold decreases in the period between 3-6 weeks preoperatively and increases to a usual level at 6-12 weeks postoperatively, though no correlation between the PPT and NRS could be documented. It is unknown how PPT is influenced by surgery. Modulation of pain threshold could improve future pain management and reduce consumptions of opioids. DOS Kongressen 2014 181

Treatment of clubfoot: Comparing surgical correction and the Ponseti Method A comparative study 129. Mette Tavlo, Lise Karlsmark, Klaus Hindsø Børneortopædkirurgisk Sektion, HovedOrtoCentret, Rigshospitalet; Klinik for Ergo- og Fysioterapi, Rigshospitalet Background: From 2005 2007 two treatments for clubfoot (CF) were offered at Rigshospitalet: the Ponseti and the Copenhagen method (Cph.), which is a surgical procedure. During this period parents chose the treatment. Purpose / Aim of Study: This study aimed to compare mechanical and patient related outcome measures (PROMS) between the treatments. Materials and Methods: A consecutive series of 28 patients met the inclusion criteria. 23 patients with 33 CF participated. The mechanical outcome measures were pedobarographicly collected as heel/foot peak pressure, contactarea-quotient, centre of pressure deviation and heel-foot angle. Mechanical parameters were chosen as they represented CF deformities: cavus, hindfoot and forefoot adduction. PROMS regarding appearance and function were scored by the child and parents using a visual analog scale (0 100). Findings / Results: Relapse rate did not differ between treatment groups (Ponseti 33%, Cph. 36%). Appearance- (VAS-mean Ponseti 5.2, Cph. 12.8, p = 0.01) and functional-limitation (VAS-mean Ponseti 5.5, Cph. 12.6, p = 0.01) differed significantly in favour of Ponseti. Children with bilateral CF were found to be significant more satisfied (VAS-mean unilat. 21.6, bilat. 13.5, p = 0.02) with their feet compared to children with unilateral CF. No pedobarographic parameters differed between treatment groups. Conclusions: Ponseti treatment of idiopatic clubfoot seems to yield better PROMS than surgical correction. The treatments resulted in equal mechanical properties when measured during gait in a pedobarographical analysis. 182 DOS Abstracts

Children and adolescents admitted to the level 1 trauma centre at Odense University Hospital 2002-2011. 130. Rasmus Hviid Larsen, Danny Stefan Ekström, Jens Martin Lauritsen, Christian Færgemann Department of Orthopedics and Traumatology, Odense University Hospital Background: Prevention of mortality and severe injury following trauma requires unbiased epidemiological surveillance. The epidemiology of children or adolescents admitted to a Danish trauma centre is largely unknown in particular in relation to home- and leisure risk areas. Purpose / Aim of Study: To describe the epidemiology and severity of potential severely injured children and adolescents admitted to Odense University Hospital (OUH). Materials and Methods: A descriptive study including all children and adolescents aged 0-17 admitted to the level 1 trauma centre at OUH 2002-2011. Data was extracted from the multiple trauma register and medical records. Findings / Results: 950 children and adolescents were included. The median age was 13 (0-17) years. Boys accounted for 60.6 % of the cases. Accidents accounted for 97.2 %, violence 1.4 %, and self-inflicted injuries 0.4 %. More than ¾ of the injuries occurred either in traffic or at home. The occurrence was greatest in the summer (34.0 %), during weekends (48.9 %), and in the hours between 12.00 and 20.00 (59.2 %). 58.5 % of the injuries were due to traffic. Of these 39.7 % were passengers in motor vehicles, 27.5 % drivers/passengers of a scooter/mc, 21.8 % bicyclists and 10.3 % pedestrians. The median ISS and MAIS was 4 (1-75) and 2 (1-6), respectively. Head/face injuries accounted for 36.5 % and extremities for 30.9 % of all injuries. 153 (16.1 % suffered from severe injuries (ISS>15). Altogether, 49 (5.2 %) died due to their injuries. The mortality among severely injured was 31.4 %. Conclusions: Based on a local trauma register it was possible to describe the epidemiology and severity of potential severely injured children and adolescents admitted to a level trauma centre. DOS Kongressen 2014 183

Outcome after resection of tarsal coalition in children Ahmed Abdul-Hussein Abood, Ole Rahbek, Bjarne Møller-Madsen Dept. of Children s Orthopaedics, Aarhus University Hospital 131. Background: Most common types of coalitions are Calcaneonavicular (CN) and Median Bar (MB). These are classified as a bony coalition and a partial fibrous or cartilaginous type. The condition may cause pain and decreased mobility in the subtalar joints. Purpose / Aim of Study: A retrospective study of the outcome after resection of tarsal coalitions in children. Materials and Methods: Using the Danish medical database, patients with the diagnosis Tarsal Coalition (DQ668A) from 2006 till 2014 treated at Aarhus University Hospital was searched. In addition, 13 operation codes were used to search for patients, with a Tarsal Coalition but who were registered with a different diagnosis. Patients, receiving surgical treatment between the age of 5 and 16 in the year 2006 till 2014 were included in the study. The primary outcome was defined as the number of re-operations performed or planned after initial resection of tarsal bone. Furthermore, the patients were post-operative subjectively classified as better and worse or unchanged, in comparison to prior to the operation. Findings / Results: 24 feet in 18 children were included in study with a mean follow-up of 11 months. Patients were divided into two groups of coalitions, CN in 15 feet, and MB in 9 feet. Three CN feet underwent additional surgery (resection of relapsed bridge n= 3, Arthrodesis n=0) compared to 2 feet in the MB group (resection of relapsed bridge n= 0, Arthrodesis n=2). In the CN group, 11 feet were described as better and 4 as worse or unchanged. In the MB group, 6 feet were described as better and 3 as worse or unchanged. Conclusions: Overall 80 % of the feet improved after surgery, which is in accordance with previous literature. Adiditional surgery was needed in 20 % of the cases. Before surgery, patients should be informed of the relatively high risk of additional surgery. 184 DOS Abstracts

Preparation of the femoral bone cavity for cementless stems: Broaching versus Compaction. A 5 year randomized RSA and DXA study of 40 bilateral 1-stage operations 132. Mette Holm Hjorth, Maiken Stilling, Kjeld Søballe, Poul Torben Nielsen, Poul Hedevang Christensen, Søren Kold Department of Orthopaedics, Aarhus University Hospital Background: Experimental studies have shown superior implant fixation after bone compaction (C) compared to conventional broaching (B). Purpose / Aim of Study: To investigate potential advantages and disadvantages of C compared to B in a randomized clinical trial (RCT) Materials and Methods: 1-stage bilateral cementless THA (Bi-Metric, Biomet) was performed in 20 patients (13 M), mean age 58 (36-70) years. Patients were randomized to bone preparation with C on one side and B on the other side. Patients were followed with RSA and DXA at baseline, 6 and 12 weeks, 1, 2 and 5 years. The subjective part of Harris Hip Score (HHS) and complications/ revisions throughout the observation period were obtained at mean 6.3 (3-9.5) years after surgery. Findings / Results: At 6 weeks, mean absolute mean medio/lateral translations of 0.22 (CI: 0.12 to 0.32) mm in the C group was higher (p=0.04) than 0.11 (CI: 0.07 to 0.16) mm in the B group. At 5 years, the difference was more pronounced (p=0.01) with mean absolute medio/lateral translations in the C group of 0.34 (CI: 0.18 to 0.39) mm versus 0.13 (CI; 0.05 to 0.28) mm in the B group. At 2 years, mean values of percentage change in periprosthetic bone since baseline in Gruen zone 3 was inferior in the C group of 92.6 (CI: 88.1 to 97.1) % versus 100.7 (CI: 93.6 to 107.8) % in the B group (p=0.04). Intraoperative fractures occurred in 2/20 in the C group and in 0/20 in the B group (p=0.02). Clinical outcomes of HHS and dislocations (1 C, 2B) were similar between groups (p>0.59). No stems were revised at 5 years after surgery. Conclusions: Bone compaction as compared to broaching prior to insertion of the cementless Bi-Metric femoral stem results in more absolute medio/lateral translation, starting already 6 weeks and continuing until 5 years follow-up. In this RCT intraoperative femoral fractures only occurred with bone compaction. DOS Kongressen 2014 185

Bone autograft versus recombinant human BMP- 2 (rhbmp-2) at bone docking-site in tibial bone transport. A randomized clinical trial (RCT). 133. Søren Kold, Martin Lind, Susanne Jølck, Knud Christensen Department of Orthopaedics, Aalborg University Hospital Background: Bone autograft is applied at the bone- docking site to increase the union-rate and decrease the time to union after bone transport. However, harvesting of the bone autograft results in donor-site morbidity. rhbmp-2 might replace the need for bone autograft. Purpose / Aim of Study: We investigated the union-rate and the risk of refracture of the bone docking site treated with open debridement and application of either bone autograft or rhbmp-2. Materials and Methods: 41 patients treated for segmental defects of the tibia with bone transport in a circular frame were randomized to either bone autograft (n=21) or rhbmp-2 (n=20) at the docking site. Patients were followed with monthly radiographs. Union was defined as presence of bone callus in 3 out of 4 cortices as well as bony bridge in 3 out of 4 cortices. The minimum followup after frame removal was 12 months. Findings / Results: Radiographic union occurred in 21 out of 21 treated with autograft and in 20 out 20 treated with rhbmp-2. Mean time to union in months was 7 (range: 4 9) with autograft and 7 (range: 4 9) with rhbmp-2. Mean time in hospital stay in days was 6 (range: 2 12) with autograft and 5 (range 1 16) with rhbmp-2. There were no clinical signs of infection at the docking site in either group. Refracture at the docking site after frame removal occurred in one patient in the autograft group compared with 2 patients in the rhbmp-2 group (p=0.5). The risk of refracture was higher when the docking site was located at the mid- diaphyseal tibia (3 out of 15) compared to the metaphyseal tibia (0 out of 26) (p=0.02). Conclusions: No differences in radiographic union rate or time to union were found between autograft and rhbmp-2. Refracture at the docking site occurred in 3 out of 41 cases, and mid- diaphyseal docking might carry a higher risk of refracture compared with metaphyseal docking. 186 DOS Abstracts

Pharmacokinetics of Cefuroxime in Bone, Subcutaneous Tissue and Plasma Comparison of Continuous versus Short-term Infusion 134. Mikkel Tøttrup, Mats Bue, Kurt Fuursted, Tore Forsingdal Hardlei, Kjeld Søballe, Hanne Birke-Sørensen Department of Orthopaedic Surgery and Orthopaedic Research Unit in Aarhus, Hospitalunit Horsens and Aarhus University Hospital; Department of Orthopaedic Surgery Orthopaedic Research Unit in Aarhus, Hospitalunit Horsens and Aarhus University Hospital;, Statens Serum Institute; Department of Clinical Biochemistry, Aarhus University Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital; Orthopaedic Research Unit, Aarhus University Hospital Background: The relatively short half-lives of most beta-lactams suggest that continuous infusion (CI) of these time-dependent antibiotics may be favourable compared to short-term infusion (STI). Nevertheless, only limited pharmacokinetic (PK) data is available to support this theory, particularly in solid tissues like bone. Purpose / Aim of Study: To obtain PK parameters of cefuroxime in plasma, subcutaneous tissue (SCT) and bone in pigs receiving 1500 mg of cefuroxime administered either as STI or as CI, and to compare time above minimal inhibitory concentrations (T > MIC) between the two groups. Materials and Methods: Twelve pigs were included. Each animal was randomly assigned to receive 1500 mg of cefuroxime either as STI or CI. Measurements of cefuroxime were conducted in plasma, SCT, cancellous and cortical bone every 30 min. The measurements in solid tissues were conducted using microdialysis. A two-compartment population model was fitted to the drug concentration data separately for the different tissues using a non-linear mixed effects regression model. Key pharmacokinetic parameters and T > MIC were estimated using Monte Carlo simulations. Findings / Results: Except for SCT in the STI group, tissue penetration was impaired for all tissues. The poorest tissue penetration was found in bone. Both tissue area under the curves and tissue penetration ratios generally appeared to be lower in the CI group. Nevertheless, significantly longer T > MIC was found for CI up until MICs of 4, 2, 2 and 0.5 μg/ml for plasma, SCT, cancellous and cortical bone respectively. Conclusions: CI of beta-lactams with short half-lives may be favourable compared to STI if dosed appropriately. The poorest tissue penetration was found in bone. The high rate of treatment failure for osteomyelitis may therefore partly be attributable to impaired target site penetration of antibiotics. DOS Kongressen 2014 187

Methylprednisolone reduce pain and decrease knee swelling in the first 24 hours after fast-track Oxford unicompartmental knee arthroplasty 135. Søren Rytter, Maiken Stilling, Stig Munk, Torben Bæk Hansen Department of Orthopedics, Holstebro Regional Hospital, Hospital Unit West, Denmark Background: Unicompartmental knee arthroplasty (UKA) operated with minimal invasive surgery (MIS) results in less operative trauma and faster patient recovery than after a conventional total knee arthroplasty. Despite an increased focus on multimodal analgesic strategies there is still a substantial level of patient-reported pain in the early post-surgical period after MIS UKA. Purpose / Aim of Study: The purpose of the study was to evaluate the effect of a single preoperative dose of systemic methylprednisolone (MP) on acute post-surgical pain after fast-track MIS Oxford UKA. Materials and Methods: 72 patients in 2 consecutive series undergoing unilateral UKA were included in a prospective cohort study. Patients (n=35) in the treatment group received a single preoperative dose of systemic MP 125 mg whereas the control group (n=37) did not. Otherwise there was no difference in the operative and postoperative treatment. Outcome measures were postsurgical pain at rest and during walking, consumption of opioids for pain rescue, knee swelling and knee range of motion. Complications were monitored until 4 months after surgery. Findings / Results: In the first 24 hours after surgery the MP group had less pain at rest (p=0.000) and during walking (p=0.000), and less consumption of opioids (p=0.01) in comparison with the control group. Furthermore, the MP group had 2.2 cm less knee swelling (p=0.02) in the 1st postoperative day, and also better (p=0.004) knee extension, whereas flexion was similar (p>0.68) between groups. No serious complications were associated with the treatment. Conclusions: A single preoperative dose of 125 mg systemic MP significantly reduce post- surgical pain and opioid consumption and decrease knee swelling in the first 24 hours after fast-track MIS Oxford UKA. 188 DOS Abstracts

Physical activity and return to work after fasttrack total hip replacement with or without supervised rehabilitation. Results from a randomized controlled trial. 136. Lone Ramer Mikkelsen, Inger Mechlenburg, Kjeld Søballe, Lene Bastrup Jørgensen, Thomas Bandholm, Annemette Krintel Petersen Interdisciplinary Research Unit, Elective Surgery Centre, Silkeborg Regional Hospital ; Department of Orthopaedic Surgery, Aarhus University Hospital; (1)Physical Medicine & Rehabilitation Research Copenhagen (PMR-C), Department of Physiotherapy, (2, Copenhagen University Hospital, Hvidovre; (1)Department of Physiotherapy- and Occupational Therapy, (2)Centre of Research in Rehabilitation (C, (1)Aarhus University Hospital, (2)Aarhus University Background: Total hip replacement (THR) results in pain reduction and functional improvements. However, it is suggested that these improvements are not followed by increases in physical activity level and return to usual activities postoperatively. Furthermore, it is unknown whether supervised rehabilitation affects the activity level as well as return to work after THR. Purpose / Aim of Study: To investigate whether supervised progressive resistance training during the first 10 weeks after THR affects the change in physical activity level from baseline to 6 months after THR and early return to work. Materials and Methods: 73 THR patients were randomly assigned to a control group (CG, home based exercise) or intervention group (IG, supervised resistance training in addition to home based exercise). Preoperative, 6 and 12 months postoperative self-reported physical activity was measured in metabolic equivalents (METS) with the Physical Activity Scale (PAS) and days until return to work. Findings / Results: Follow up was completed by 62 patients (85%). Changes in PAS scores from baseline to 6 months follow up were, mean [95% CI]: IG: 6.32 [3.5;9.1] METS and CG: 0.85 [-2.8;4.5] METS (p=0.02). Sick leave duration in the working population of the sample (n=25) were, median [range]: IG: 46 [6;161] days and CG: 57 [7;146] days (p=0.49). Conclusions: Patients performing supervised resistance training in addition to home-based exercise increased their self-reported physical activity level more than patients performing home-based exercise only, during 6 months after THR however, the difference was eliminated at 1 year follow up. No significant difference was found concerning return to work. DOS Kongressen 2014 189

Preoperative embolization in surgical treatment of spinal metastases: single-blind, randomized controlled clinical trial of efficacy in decreasing intraoperative blood loss 137. Caroline Clausen, Benny Dahl, Susanne C Frevert, Lars Valentin, Michael B Nielsen, Lars Lönn Department of Radiology, Rigshospitalet and University of Copenhagen ; Department of Orthopaedic Surgery, Rigshospitalet and University of Copenhagen Background: An increasing number of patients undergo surgical treatment for symptomatic spinal metastasis. No randomized study has evaluated the effect of preoperative embolization. Purpose / Aim of Study: To assess whether preoperative arterial embolization reduce blood loss, blood transfusion, and duration of surgery in surgical treatment of metastatic spinal cord compression. Materials and Methods: This single-blind, randomized (1:1), controlled, parallel-group, single-center trial was approved by the national committee on biomedical research ethics and preregistered. Informed consent was obtained and the study period was from May 2011 until March 2013. All participants were scheduled for decompression and posterior thoracic/lumbar spinal instrumentation. They were randomly assigned to either 1) preoperative arteriography and embolization the embolization group or 2) preoperative arteriography the control group. Primary outcome: intraoperative blood loss. Secondary outcomes: perioperative blood loss, allogenic RBC transfusion and duration of surgery. Analyses were by intention-to-treat (ITT). Findings / Results: Forty-five randomized patients were available for the ITT. Mean intraoperative blood loss did not differ significantly (P =.270) between the embolization group (618 ml [SD, 282 ml]) and the control group (735 ml [SD, 415 ml]). Neither did perioperative blood loss and allogenic RBC transfusion. The duration of surgery, however, was significantly shorter in the embolization group (P =.031): median 90 minutes (range, 54-252) vs. 124 minutes (range, 80-183). Thirty-four of 45 metastases (76%) were hypervascular. Conclusions: Preoperative embolization does not result in a reduction of intraoperative blood loss, perioperative blood loss and blood transfusion, but reduces the duration of surgery for symptomatic metastatic spinal cord compression. 190 DOS Abstracts

HA-coating may decrease screw migration in the femoral head following hip fracture surgery a double blinded RSA study 138. Henrik Palm, Kim Holck, Steffen Jacobsen, Søren Bøvling, Torben Bæk-Hansen, Maiken Stilling Dept. of Orthopedics, Copenhagen University Hospital Hvidovre Background: Sliding hip screw (SHS) migration in the femoral head after hip fracture surgery may lead to fracture collapse and/or screw cut- out necessitating a reoperation. Purpose / Aim of Study: To investigate if a hydroxyapatite (HA) coated thread could reduce SHS migration. Materials and Methods: 37 patients (31 female) at mean age 79 (range 56-96) years with stable trochanteric fractures were operated in two centers with a 4-hole 135-degrees SHS (HipLoc, Biomet) and randomly allocated to sliding screws with either a non-coated (n=19) or an HA- coated (Bonemaster, Biomet) screw-thread (n=18). Patients and assessors were blinded for choice of screw. Patients were followed after 1.5, 3 and 6 months with marker-based RSA comparing migration between 1) The sliding screw marked with 4 beads and 2) The femoral head marked with 3-5 beads inserted through the drilled SHS canal. Demographic, surgical and radiological parameters (TAD, fracture reduction sum and screw placement in the femoral head) were prospectively collected. Findings / Results: Mean TAD of 2.1 (sd 0.66) mm, fracture reduction sum in AP and LA of mean 0.66 (sd 0.87) mm and screw position in the femoral head were similar between groups (p>0.28). Screws with HA-coated thread had less varus rotation (4.1 vs. 0.3 degrees, p=0.03) after 1.5 months and a reduced lateral translation (0.6 vs. 0.01 mm, p=0.046) after 6 months, with a tendency after 1.5 months (0.4 vs. 0.2 mm, p=0.08). Other translations and rotations were not different and there were no correlation to radiological parameters. No cut-outs or revisions. Conclusions: Coating the SHS thread with HA reduced screw migration in the femoral head at short- term follow-up. Missed late follow-ups might underpower statistics at 3 and 6 months. Migrations were small and larger clinical studies are warranted for evaluation of long- term benefits. DOS Kongressen 2014 191

One-year evaluation: Is there effect of 8 weeks supervised progressive resistance training after unicompartmental knee arthroplasty? 139. Peter Bo Jørgensen, Søren Bie Bogh, Signe Kierkegaard, Henrik Sørensen, Kjeld Søballe, Inger Mechlenburg Orthopaedic Research, Aarhus University Hospital; Center for Quality, Region of Southen Denmark; Sports Science, Aarhus University Background: Muscle atrophy and decreased muscle strength is documented in early stages of knee osteoarthritis and increases with progression. Within the first weeks after Unicompartmental Knee Arthroplasty (UKA) an additional decrease in muscle strength is found. That is the rationale for early initiated resistance training. Purpose / Aim of Study: To evaluate if there is effect of 8 weeks progressive resistance training (PRT) after UKA assessed 1 year postoperative. Materials and Methods: 53 patients (26 males), median age 66 years, scheduled for UKA were randomized to either 8 weeks supervised PRT (n=29) or 8 weeks standard home exercise (HE) program (n=24). PRT was initiated within the first week after UKA and performed 2/week for 8 weeks in training machines. Preoperative assessment, 2-months and 1-year follow-up were performed for leg press power, asymmetry in gait, walking speed and Knee injury and Osteoarthritis Outcome Score (KOOS). Findings / Results: 22 PRT and 18 HE-patients (73%) completed 1-year follow-up and patients in the PRT group participated in mean 11 of 16 training sessions. Leg press power increased from baseline to 1-year follow up (PRT: 29% and HE: 30%, p<0.04 in both groups) and asymmetry was minimally changed (PRT: 0,14% and HE: 0,29%) with no between-group difference (p>0.53 and power >0.89). Walking speed (PRT: 16% and HE: 15%), KOOS symptoms (PRT: 21 point and HE: 15 point), KOOS pain (PRT: 38 point and HE: 32 point), KOOS ADL (PRT: 29 point HE: 28 point) KOOS sport (PRT: 33 point and HE: 42 point), KOOS QoL (PRT: 39 point and HE: 32 point) increased in both groups with no between-group difference (p>0.42). Conclusions: We found no additional effect of an 8-week PRT program compared to HE in this patient group when assessed one year after surgery. 192 DOS Abstracts

Is gait velocity and gait quality associated with hip muscle strength in hip osteoarthritis patients scheduled for total hip arthroplasty? 140. Signe Rosenlund, Dennis Brandborg Nielsen, Søren Overgaard, Carsten Jensen, Anders Holsgaard-Larsen Department of Orthopedic Surgery and Traumatology and Orthopaedic Research Unit, Department of Ortho, Køge Hospital and Odense University Hospital; Orthopaedic Research Unit, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital; Orthopaedic Research Unit, Department of Orthopaedic Surgery and Traumatology and Institute of Clini, Odense University Hospital and University of Southern Denmark Background: Association between lower extremity muscle strength and gait velocity has been documented in healthy elderly individuals but not in patients with end- stage hip osteoarthritis (OA). Three- dimensional (3D) gait analysis help identify gait pathology. But the complexity and amount of data collected during gait analysis lead to challenges when interpreting these. Gait Deviation Index (GDI) summarizes the lower limb kinematic data and describes 98% of the variation in gait. Purpose / Aim of Study: The aim of this study was to investigate associations between hip muscle strength, gait velocity, and GDI in patients with end- stage hip OA. Materials and Methods: A cohort of 20 consecutive patients all with unilateral end-stage hip OA scheduled for THA (5 women and 15 men; age 61± 5.8 years; BMI 28.1 ± 3.4 (mean ± SD)). All completed 3D gait analysis and performed isometric maximal voluntary hip muscle strength (MVC) tests (hip-flexion, -abduction and - extension). A GDI of 100 indicates no gait pathology and a 10 point change represents 1 SD from the reference group. Linear regression analysis were used to determine coefficient of determination using GDI or gait velocity as dependent variables and hip MVC as the independent variables. Findings / Results: A significant association (R2 = 0.43; p=0.03) between gait velocity and hip MVC was observed using multiple linear regression. Furthermore, simple regression analysis revealed a moderate association (R2 = 0.23; p=0.03) between hip abduction and gait velocity. However, no association between GDI and hip MVC was found. Conclusions: The present study confirms an association between hip MVC and gait velocity for OA patients scheduled for THA. However, no association between hip MVC and gait quality was shown. The present data indicate that rehabilitation aimed at improving hip muscle strength would be effective. DOS Kongressen 2014 193

Objectively measured physical activity reference data obtained from a Dutch population with a three-axial accelerometer 141. Signe Kierkegaard, Inger Mechlenburg, Bernd Grimm, Ide Heyligers, Rachel Senden Orthopaedic Research, Aarhus University Hospital, Denmark; Department Orthopaedic Surgery & Traumatology, Atrium Medical Center, Heerlen, The Netherlands Background: Self-reported physical activity (PA) is often under/overestimated and influenced by patient satisfaction and pain. Thus, PA after surgery or rehabilitation should be measured objectively, which is easily done using ambulant accelerometer based activity monitoring (AM). However a reference database of AM parameters is currently lacking. Purpose / Aim of Study: To collect reference data of objectively measured PA. Materials and Methods: 59 Dutch healthy subjects, (37 females) median aged 47.5 (21-66) years with no restrictions in mobility were included. A three-axial accelerometer was attached during waking hours to the participants lateral thigh for four consecutive days. Data was analysed using previously validated algorithms in MatLab 7.10.0. Median values of the four days were calculated and the results were stratified into age groups of decades, 20-29 (30-39) 40-49 (50-59) and 60-69. Findings / Results: Mean measurement time was 13.5 ±1.5 hours per day. Subjects were sitting median 64 (53) 59 (59) 57 %, standing 22 (32) 29 (26) 31 %, walking 9 (14) 13 (11) 12 % and biking 0.5 (0.4) 0.02 (0.4) 0.5 % of the day. Subjects walked on average 5217 (8447) 7666 (8474) 7030 steps per day and performed mean 43 (63) 50 (45) 47 sit to stand transfers a day. There was a tendency towards the youngest group sitting more and standing and walking less than the older groups, but no statistically significant differences were found between the age groups. Conclusions: The present data may serve as initial values for a reference database. However, the results are affected by a large variation in PA and a small age range, which might explain the lack of significant differences between age groups. A larger reference database need to be created where effects of subject characteristics on PA can be investigated and where people above 66 years are included as well. 194 DOS Abstracts

Validation of intraoperative reported angle measurements in periactabular osteotomy 142. Sepp de Raedt, Inger Mechlenburg, Maiken Stilling, Marleen de Bruijne, Lone Rømer, Kjeld Søballe Orthopaedic Research Unit, Aarhus University Hospital; BIGR/DIKU, Erasmus MC Rotterdam/University of Copenhagen; Department of Radiology, Aarhus University Hospital Background: Periactabular osteotomy (PAO) has become the treatment of choice for patients with developmental hip dysplasia. However, it is a technically demanding procedure and achieving an optimal correction can be difficult due to the lack of three-dimensional (3D) feedback. The biomechanical guidance system (BGS) provides the surgeon with live 3D feedback. Purpose / Aim of Study: To validate measurements obtained with the BGS against manual measurements. Materials and Methods: Patients underwent pre- and post-operative CT imaging. Manual center-edge (CE), acetabular index (AI), acetabular anteversion (AcAV), posterior acetabular sector (PASA) and anterior acetabular sector (AASA) angle measurements were performed. The lunate surface was manually delineated and surgical planning was performed. Initial automatic angle measurements were recorded. After the acetabular fragment was repositioned and fixated, the BGS was used to obtain the final angle measurements. The difference between the manual and the BGS reported angle measurements were analyzed by statistical analysis. We report the concordance correlation coefficient (CCC), average difference, and the 95% limits of agreement (LOA). Findings / Results: Initial results for the first five patients included were: CE angle: CCC: 0.93, Avg. Diff.: 0.40, 95% LOA: -4.52;5.31. AI angle: CCC: 0.98, Avg. Diff.: 0.17, 95% LOA: -2.59;2.94. AcAV angle: CCC: 0.96, Avg. Diff.: 0.68, 95% LOA: -2.30;3.66. PASA angle: CCC: 0.92, Avg. Diff.: 0.82, 95% LOA: -4.26;5.90. AASA angle: CCC: 0.98, Avg. Diff.: 0.03, 95% LOA: -4.63;4.69. Conclusions: Initial results show a good agreement between manual and BGS reported angles and are within the variation expected from intra-rater variability. With further development and validation, the system may become a valuable tool to help the surgeon achieve the optimal correction for each patient. DOS Kongressen 2014 195

Safety of Vitamin E infused high wall liners for routine use in primary THA: Single center, short term follow-up of 767 cases 143. Nanna Sillesen Hylleholt, Christopher Barr J., Peter Gebuhr, Henrik Malchau, Henrik Husted, Troelsen Anders Department of Orthopedics Copenhagen University Hospital Hvidovre, Hvidovre Hospital; Harris Orthopaedic Laboratory, department of orthopedics, Massachusetts General Hospital, Harvard Medical School Background: Vitamin E infused highly crosslinked polyethylene liners (VEPE) offer the potential for reduced wear and osteolysis. The extended liners, including the high wall type, leaving parts of the polyethylene uncovered, have been hypothesized to result in increased wear and the potential for liner fracture. Introduction of new implants should be monitored closely to capture any signs of compromising patient safety. Purpose / Aim of Study: The aim of this study was to determine the shortterm safety profile of high wall VEPE for primary total hip replacement (THA), focusing on liner related complications. Materials and Methods: We included 767 consecutive THAs operated from July 2010 to March 2013 with use of a high wall VEPE liner (E1, Biomet). The preferred components used were an uncemented cup (Exceed ABT, Biomet (100 %) and an uncemented stem (Bimetric, Biomet (98 %)). Majority of heads were size 36mm (67 %) and 32mm (32 %).The data collected included demographics, implant data, complications, reoperations, and deaths. Acetabular cup position was measured using Martell Hip Analysis Suite in a subgroup of 407 THAs. Length of follow- up was 1.1-3.8 years. Findings / Results: There were no revisions due to liner failure. Revisions included 5 open reductions, 11 soft-tissue revisions for infection, 28 isolated stem revisions (periprosthetic fractures), 2 isolated cup revisions, and 7 combined cup and stem revisions. The subgroup with cup position measurements showed 77% were in the combined acceptable zone of cup abduction (30-55 ) and version (5-35 ). Conclusions: Early follow-up of routine use of VEPE high wall liners for primary THA have not shown any liner associated complications or revisions. Continued monitoring of new materials are important to capture any signs of compromised patient safety. 196 DOS Abstracts

Acetabular dysplasia increases risk for malpositioning of the acetabular component in Total Hip Arthroplasty (THA) 144. Kirill Gromov, Meridith Greene, Christopher Barr, Peter Gebuhr, Henrik Malchau, Anders Troelsen Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Harris Orthopaedic Laboratory, Massachusetts General Hospital Background: Persistent acetabular dysplasia (AD) following periacetabular osteotomy (PAO) has been hypothesized to increase the risk for malpositioning of the acetabular component that may subsequently lead to higher rates of wear, dislocation and impingement. Purpose / Aim of Study: The purpose of this study was to investigate whether AD is an independent risk factor for cup malpositioning. Materials and Methods: 839 primary THA patients, with pre and postoperative pelvic radiographs, from 16 centers in the USA and Europe are enrolled into a prospective 10year outcome study. All patients were operated using an uncemented Biomet cup and a Biomet stem of surgeons choice. Patient demographics and surgical parameters were recorded. AD was assessed by measuring lateral center edge (LCE) angle and defined as LCE<25. Cup positioning was determined on postoperative AP pelvic images using Martell Hip Analysis Suite. Acceptable ranges were defined as 30-45 abduction and 5-25 version. Multivariate logistic regression analysis was performed to calculate adjusted risk for cup malpositioning. Findings / Results: 504 (60%) acetabular cups were within the abduction range, 608 (73%) were within the anteversion range, and 377 (45%) were within the range of both. Surgical approach, presence of AD, and JSW>0 independently predicted malposition of the acetabular component. Surgical approach (direct lateral vs posterolateral), JSW>0, and AD resulted in a 2.00 (1.24-3.22), 1.51 (1.09-2.01) and 1.49 (1.11-1.99) increase in risk for malposition of the acetabular component, respectively. Conclusions: Presence of AD, defined as an LCE angle <25, is an independent risk factor for malposition of the acetabular component during primary THA. Skin approach and radiological grade of OA were also independently correlated with malpositioned cups. DOS Kongressen 2014 197

High frequency of cystic pseudotumors in largehead metal-on-metal total hip arthroplasty at 5-7 years follow-up. 145. Mette Holm Hjorth, Niels Egund, Inger Mechlenburg, Stig Storgaard Jakobsen, Kjeld Søballe, Maiken Stilling Department of Orthopaedics, Aarhus University Hospital ; Department of Radiology, Aarhus University Hospital Background: Large-head metal-on-metal (MoM) total hip arthroplasty (THA) has been associated with pseudotumor formation and high revision rates. Purpose / Aim of Study: To investigate the frequency of pseudotumors, metal-ion concentrations and radiographic and clinical outcome in patients with MoM THA. Materials and Methods: A consecutively included series of 41 patients/49hips (31 males) with a mean age of 52 (28-68) years, participated in a 5-7- year follow-up study of their large-headmom THA (M2a Magnum, Biomet). Patients were evaluated with magnetic resonance imaging (MRI), serum metal-ion concentrations, conventional radiographs, and clinical outcome measures of Harris Hip Score (HHS) and Oxford Hip Score (OHS). Findings / Results: 18 of 47 hips (38%) had MRI-verified pseudotumors, all cystic, with a mean dimension of 1.1 x 2.6 x 0.4 cm. Acetabular cup anteversion was mean 28+5 in patients with a pseudotumor and mean 24 +7 in patients without a pseudotumor (p=0.009). Serum metal-ion concentrations, acetabular cup inclination and clinical outcome measures of HHS and OHS were similar between patients with and without a pseudotumor. Conclusions: At 5-7 year after surgery, MRI-verified cystic pseudotumors were frequently observed in large-head MoM THA, without relation to clinical symptoms and metal-ion concentrations but with relation to cup- anteversion. The clinical relevance and the natural history of cystic pseudotumors in asymptomatic patients remain unknown; hence, we will continue to monitor these patients regularly. 198 DOS Abstracts

Radiologic and histologic appearance of metalbone interphase in failed tibial component in total knee arthroplasty. A retrieval study. 146. Tue Smith Jørgensen, Thomas Lind, Henrik Schrøder, Eva Balslev Ortopædkirurgisk afdeling, Herlev hospital; ortopædkirurgisk afdeling, Gentofte Hospital; patolgisk afdeling, Herlev hospital Background: Little information is available considering lack of ingrowth of bone into the porous coated knee prosthesis. Ususally described as fibrous tissue in the bone-metal interphase. Our five retrieval cases showed macro- and microscopic signs of hyaline cartilage in the tibia bone-metal interphase. Purpose / Aim of Study: We want to describe the histological findings in the tibia bone-metal interphase, and correlate this to the radiologic and scintigraphic findings in connection with suspected aseptic loosening especially on the tibia side. Materials and Methods: The five patients all underwent primary knee surgery during the period 2004-2006 with uncemented knee prosthesis of porous coated type (PFC). Four with osteoarthritis and one with rheumatoid arthritis. They were chosen for secondary operation because of pain and suspected loose tibia component. At revision the resected bone slice was send for pathological examination. Pre- and post op. x-rays are measured to evaluate the amount of primarily resected bone. Pubmed Keywords: uncemented, TKA, failure, cementless, press fit condylar tibia component, tantalum knee, bone ingrowth. Bone metal interphase Findings / Results: In all the samples, which surface turned against the prosthesis we found hyaline cartilage-like tissue. No articles were found, regarding hyaline cartilage in the bone metal interphase, during our Pubmed search. Only histological confirmed fibrous tissue were described. We discuss some considerations regarding level of resection, possible diagnostic features and the radiological appearance. Conclusions: One of the possible modes of failure of uncemented knee prosthesis could be the interference of cartilage formating cells, occluding the interphase, before the osseointegration can take place. In some of the specimens, small areas of ingrowth around the tibial peg, was observed. DOS Kongressen 2014 199

Hip arthroplasty with the Primoris stem Bone remodelling around a short femoral neck stem 147. Janus Duus Christiansen, Lauersen Mogens Berg, Gordon Blunn, Poul Torben Nielsen Northern Ortopaedic Division, Aalborg University Hospital;, University College London, RNOHT, Stanmore, United Kingdom Background: Total hip arthroplasty gives immediate pain relief and restoration of mobility in patients with end stage osteoarthritis. If the patient returns for revision and after two or three revisions bone stock left for reimplantation will be compromised. The Primoris stem is a development of earlier conceived bone-saving prosthesis in order to preserve bone stock. Purpose / Aim of Study: This study includes postoperative changes in BMD in the proximal femur and evaluation of bone stock preservation at 1 year follow up (FU) in patients with the Primoris stem. Materials and Methods: : A prospective cohort study of 52 patients scheduled for surgery with the femoral neck-preserving Primoris stem was carried out. Patients were studied with DEXA-scans, RSA- analysis, Harris hip score, UCLA activity score, WOMAC, EQ5D health questionnaire and Oxford Hip scores. Results from DEXA-scanner were measured in 3 specific regions of interest (ROI) - the regions of calcar (ROC), trochanter minor (ROT) and a diaphysial reference (ROD). Postoperative BMD results from day one, 6 months and 12 months were analysed. Findings / Results: 3 patients were excluded, leaving 49 patients for BMDanalysis. A slightly significant decrease was found at 6 months FU compared to day one in ROC and ROT. There was no significant difference at 12 months FU compared to day one. A non significant gain of BMD was found at 12 months FU compared to 6 months FU. Conclusions: As to bone preservation the results are encouraging. Later follow up will be performed to evaluate if the bone stock remains. If the proximal femoral bone stock is preserved and diaphysis is not compromised then the potential for successful future revision is maximized. 200 DOS Abstracts

Prevalence of kidney dysfunction at elective total hip arthroplasty operations. Helene Berg-Nielsen, Morten Boye Petersen, Mette Brimnes Damholt, Søren Solgaard 148. Lægevidenskab, Københavns Universitet; Ortopædkirurgisk afdeling, Gentofte Hospital; Nefrologisk afdeling, Rigshospitalet Background: Previous studies in other surgical specialties have shown a clear correlation between even small increases in plasma Creatinine (pcr), development of Acute Kidney Injury (AKI) and increased long-term mortality. Purpose / Aim of Study: To investigate pre-operative kidney function as estimated glomerular filtration rate (egfr) and the occurrence of AKI amongst a population undergoing elective hip arthroplasty. Materials and Methods: The study is a single-center, retrospective, registerbased cohort study including all primary, elective, total hip replacement surgeries (THA) carried out in Hørsholm and Gentofte hospitals from Jan. 2000 to Dec. 2012. Presence of AKI and egfr was evaluated on basis of international KDIGO criteria. Findings / Results: 5687 operations were performed in 4909 patients. Only the first THA for each person was considered. Pre-operative pcr (< 3 months pre operation) could be obtained for 3328 persons (68 %); 2014 females and 1314 males; age 68,6 ± 10,1 years (mean±sd). In this population kidney function was moderately to severely decreased (egfr < 59 ml/min) (CKD 3-5) in 11,9 % of the patients. Both pre- and postoperative pcr (one value within three days after operation) could be obtained in 2388 persons (49% of patients). Development of AKI based on an increase in pcr was seen in 35 persons (1,5 %) in this population. Conclusions: Decreased kidney function seems to be prevalent in an elective orthopedic population. Data is not sufficient to evaluate whether AKI is prevalent in this population, but 1,5 % of the patients, who could be evaluated, meet criteria for development of acute kidney injury. If we are to determine the impact of AKI in orthopedic patients, measuring pcr should be part of the standard postoperative observation. Further studies are ongoing. DOS Kongressen 2014 201

Average cyst volume per cyst-patient decreases over a 10-year period after periacetabular osteotomy 149. Inger Mechlenburg, Jens R. Nyengaard, John Gelineck, Kjeld Søballe Orthopaedic Research, Aarhus University Hospital; Stereology and Electron Microscopy Laboratory and CSGB, Aarhus University; Department of Radiology, Aarhus University Hospital Background: Bone cysts in patients with hip dysplasia are the results of degeneration or defects of the cartilage and local elevated stress in the subchondral bone. Purpose / Aim of Study: To examine how many patients have acetabular or femoral head cysts and investigate whether the volume of cysts change after PAO. Materials and Methods: Magnetic resonance imaging (MRI) was performed in a series of 26 consecutively included patients before periacetabular osteotomy (PAO) and 1, 2½ and 10 years after. 26 patients had MRI preoperatively, 25 returned for MRI at 1 year, 21 at 2½ years and 18 at 10 year follow up. The number of cysts was noted and the total cyst volume in each patient was estimated with a design-unbiased stereology. The Hip disability and Osteoarthritis Outcome Score (HOOS) was collected 4 and 10 years after PAO. Findings / Results: Preoperative, 12 patients had acetabular or femoral head cysts (22 cysts), 1 year postoperative, 15 patients had cysts (23 cysts), 2½ years postoperative, 15 patients had cysts (18 cysts) and 10 years after PAO 9 patients had cyst (9 cysts). Mean total acetabular cyst volume per cyst-patient at the time of MRI was: 3.44 + 6.71 cm3 (1.96 + 3.97 cm3) 0.96 + 1.70 cm3 (0.43 + 0.26 cm3) (p=0.04). All acetabular cysts were located anterolaterally in the acetabulum except for one that was posterolateral. At 4 and 10 years, the mean subscores for HOOS were Pain 75/79, Symptoms 75/73, ADL 83/85, Sport/recreation 63/68 and Quality Of Life 62/61. Conclusions: The mean total cyst volume per cyst- patient decreased significantly over a 10-year period after PAO. We believe this is a result of decreased local stress in the subchondral bone after PAO which also indicates that redirection of the acetabulum reduces the risk of progression of osteoarthritis in the operated hip. 202 DOS Abstracts

Outcome of Two-stage revision of chronic infections in hip joint replacement in Denmark 2003-2008. 150. Jeppe Lange, Alma B. Pedersen, Anders Troelsen, Kjeld Søballe Lundbeckfoundation Centre for Fast-track Hip and Knee Surgery, Tage- Hansens Gade 2, 8000 Aarhus, Den, Department of Orthopaedic Surgery, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus, Den; Department of Clinical Epidemiology, Aarhus University Hospital, Olof Palmes Allé 43-45, 8200 Aarhus, Denmark; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Kettegaard Allé 30, 2650 Hvidovre Denmark Background: Chronic infections in a hip joint replacement (CIHJR) is believed to occur in less than ½% of patients. Currently, the gold-standard treatment for CIHJR is a two-stage revision. Little is known on the overall status of this treatment in Denmark (DK). Purpose / Aim of Study: We aimed to investigate the outcome of two- stage revision in DK. Materials and Methods: We identified patients in the Danish National Patient Registry from 2003-2008 in 11 orthopaedic departments with a primary and secondary ICD10 discharge diagnosis of T84.5 in combination with a hip joint specific procedure code or a hip joint specific infectious surgical procedure code independently of ICD10 code. Patients with a total hip-, hemi hip- or resurfacing hip arthroplasty, a diagnosis of deep infection adapted from the American Musculoskeletal Infection Society and more than 6 weeks since latest surgery to the hip joint were defined as having CIHJR (n=114). Findings / Results: Two-stage revision of the index CIHJR was performed in 80 of 114 (70%) patients. Mean age in the two-stage cohort was 68 years (range 36-92), 35 (44%) were female and 73 (91%) had ASA 1 or 2. 15 (19%) of the index CIHJR were revision prosthesis and 25 (31%) presented with a chronic fistula.49 (61%) had spacer in the interim period. At removal of index CIHJR, Kamme- biopsies were culture negative in 23 (29%). 58 (73%) had cementless stem and 60 (75%) had cementless cup implanted at 2. revision. Median follow up was 7.4 years (range 4-11). 60 (75%) were not revised due to re-infection. However, of these 60, 15 (25%) were revised due to aseptic causes. 28 (35%) died during follow up. Conclusions: Two-stage revision in DK appears to give overall acceptable results. However, hip surgeons must keep in mind that 30% of all chronic infections are not treated with this surgical procedure. DOS Kongressen 2014 203

No dislocations after primary total hip arthroplasty with the AVANTAGE dual mobility cup in Garden Type 3/4 hip fracture patients with dementia: A retrospective study of 26 procedures. 151. Anders Elneff Graversen, Mathias Bjerring Ho, Stig Storgaard Jakobsen, Andrey Kovalev, Pia Kjær Kristensen, Theis Muncholm Thillemann Department of Orthopedic Surgery, Hospitalsenheden Horsens; Department of Clinical Epidemiology, Aarhus University Hospital Background: The dual mobility cup offers intra-joint stability through a large diameter mobile liner and large cup-coverage. The dual mobility cup has therefore been proposed as a treatment option in patients a high risk of luxation e.g. dementia, psychiatric disease, neuromuscular disease, and special revision cases. However, the clinical documentation is still sparse and dislocation rates, reoperation rates and 30 days mortality in patients with Garden type 3/4 femoral neck fracture and dementia is unknown. Purpose / Aim of Study: The aim of this study was to evaluate the dislocation rates, reoperation rates and 30 day mortality following THA with AVANTAGE dual mobility cup in patients with Garden type 3/4 femoral neck fracture and dementia. Materials and Methods: From 2010 to 2014 we retrospectively identified 26 procedures (25 patients) with the AVANTAGE dual mobility cup in patients with Garden type 3/4 femoral neck fractures and dementia. Outcome measures were collected by systematic review of the national medical records The primary outcome was dislocation. Secondary outcomes were revision surgery, 30 days mortality, surgical delay and in hospital stay. Furthermore, the cup inclination was determined. Findings / Results: Median time of follow-up was 7,9 (0,4-40,4) months. None of the patients experienced dislocation or received revision surgery. The 30-days mortality rate was 19,2% (5/26). Mean surgical delay was 30,6 hours (CI 95%: 21,6-39,6) and mean in hospital stay was 7 days (CI 95%: 5,2-8,5). Conclusions: THA with the dual-mobility cup seems favourable in the treatment of patients with a displaced femoral neck fracture and dementia. Correct placement of the cup is pivotal and technically demanding why challenges regarding the logistics can be encountered since time to surgery is known to affect the mortality negatively. 204 DOS Abstracts

DHAR 1-year results of Hip Arthroscopy in Adolescents Bent Lund, Søren Winge, Otto Kraemer, Torsten Grønbech Nielsen, Martin Carøe Lind 152. Dept. of Orthopedics, Horsens Regional Hospital; Copenhagen Private Hospital, ; Dept. of Orthopaedics, Arthroscopic Center of Amager; Orthopedics, Aarhus University Hospital Background: CAM and Pincer FAI leads to early on-set of degenerative arthritis and even in the very young this morphology and symptomatology is seen. Studies have shown that FAI can be seen radiologically from the early teenage years and it seems that it is caused by physeal injury. Treatment of symptomatic FAI is important to prevent the early on-set of osteoarthritis. Purpose / Aim of Study: We present registry data of young FAI patients from DHAR and the early outcomes based on PROM s (Patients Related Outcome Measures). Materials and Methods: Radiology data, indications and operative procedures are registered. These are CE- angle, Alfa angle, labral and cartilage surgery, CAM and Pincer surgery, OR- and traction time. (PROM) preoperatively and 1year follow-up. PROM S used: pain at rest, pain at activity, ihot12, HAGOS. We present a sub-group of < 19 year patients from the registry. Findings / Results: Data from 18 patients < 19 year and 1 year PROM data. 5 males and 13 females. Mean OR-time 75 minutes and mean traction time 57 minutes. Mean CE-angle 32,5 (26-57) and mean Alfa-angle 62 (43-87). Cartilage damage was seen in 13 patients and ICRS classification grade II in 7 patients and III in 6 patients. 14 patients had the labrum reinserted. Mean 3 suture anchors. The depth of resection for CAM was recorded (mean 4 mm s) and extent of rim-trimming was 3 mm. 5 patients had a psoas tenotomy. All patients had antibiotic prophylaxis. No perioperative complications. All patients had significant improvements in ihot12 and HAGOS scores at 1 year. NRS scores also improved significantly. Conclusions: 1 year PROM data show promising early outcomes in these young patients. In the future larger patient numbers and follow-up data will hopefully improve indications and patient selection for hip arthroscopy procedures. DOS Kongressen 2014 205

Cementless Metaphyseal Sleeves without Stem in Revision Total Knee Arthroplasty David Gøttsche, Thomas Lind, Thorbjørn Christiansen, Henrik Morville Schrøder 153. Ortopædkirurgisk, Gentofte Background: Revision knee arthroplasty with cementless metaphyseal sleeve is suggested used without stem in revision total knee arthroplasty (rtka). In order to assess the relevant indications, this study is needed. No papers investigating this have been published. Purpose / Aim of Study: We wanted to review the results of this concept in order to assess clinical outcome and relevant indications. Materials and Methods: In this retrospective study we identified 71 patients operated with revision knee arthroplasty with cementless metaphyseal sleeves without stem in the period 2009-2011. All patients with the prosthesis still in place were invited to a medical examination including x-rays. We used the American Knee Society Score (AKSS) and The Oxford Knee Score (OKS) as the primary clinical outcomes. Findings / Results: We found a significant increase in AKSS; from 62.7 to 109.6; (p-value <0.0000001) and a postoperative OKS of 32.1. We found an overall satisfaction of 2.5 on a four stage scale, going from very satisfied to dissatisfied (range 1-4). The Anderson Orthopaedic Research Institute (AORI) classification showed 63 % of the tibias and 56 % of the femurs to be AORI type 2B, whereas 19 % tibias and 5 % femurs were AORI type 3. The review of the x-rays showed all prostheses fixed. The mean number of revisions was 1.7 (range 1-5). Six patients were not evaluated. One died, one had an above knee amputation, and four were revised (one infection, one aseptic loosening; one instability, and one pain without loosening). Conclusions: We found that the prostheses were overall well fixed and patients AKSS increased significantly. Many patients had comorbid pain conditions, and realistic expectations are crucial in order to get satisfied patients. 206 DOS Abstracts

Pain distribution in primary care patients with hip osteoarthritis a descriptive study Erik Poulsen, Søren Overgaard, Jacob Toft Vestergaard, Henrik Wulff Christensen, Jan Hartvigsen 154. Research, Nordic Institute of Chiropractic and Clinical Biomechanics; Department of Orthopaedic Surgery and Traumatology, Odense University Hospital; Department of Sports Science and Clinical Biomechanics, University of Southern Denmark Background: When adult patients present in primary care with hip pain, the most common diagnosis is hip osteoarthritis (OA). A number of studies have reported pain location and distribution in hip OA patients but findings relate to patients just prior to total hip arthroplasty (THA) and include patients with rheumatoid arthritis, osteonecrosis and severe dysplasia. A single study has examined pain location in primary care patients with hip pain but 2/3 of the patients did not have hip OA. Purpose / Aim of Study: To describe pain location and pain distribution in a cohort of primary care patients with unilateral hip OA. Materials and Methods: Primary care patients with unilateral early to moderate clinical and radiographic hip OA recorded distribution of hip pain on a manikin displaying three separate planes: frontal, back and lateral views. Pain drawings were analysed using a template and drawings were subsequently digitally processed to produce a composite image. Findings / Results: A total of 109 patients completed pain drawings. The mean age was 65 (SD 9), 44% were females, the right/left hip ratio was 66/43 respectively, the mean pain duration was 32 months (SD 36, range 4 300), and mean pain intensity was 5.4 (SD 2.0). A minority of patients reported pain in only one area, most commonly the greater trochanter area (16%). No patients marked pain exclusively in the areas of the knee, posterior thigh or lower leg. Conclusions: The most common pain locations of symptomatic hip OA presenting in primary care are the greater trochanter, groin, thigh and buttock areas. When adult patients in primary care present with pain in the greater trochanter, groin, anterior lateral thigh or buttock areas, the clinician as a minimum should include a physical examination of the hip joint. DOS Kongressen 2014 207

The effect of periacetabular osteotomy (PAO) on the clinical outcome in patients with retroverted acetabulum - a prospective cohort study 155. Victoria Schmiegelow, Bjarke Løvbjerg Viberg, Ole Ovesen, Søren Overgaard Orthopaedic Surgery and Traumatology, Odense University Hospital, Denmark Background: A retroverted acetabulum can cause pincer impingement with deep groin pain, reduced quality of life and activity level. Retroverted acetabulum is over time to be associated with osteoarthritis (OA). Few studies have evaluated the effect of PAO and reorientation of the retroverted acetabulum and this is the first Danish cohort. Purpose / Aim of Study: was to investigate the effect of PAO in patients with retroverted acetabulum and pincer impingement on pain, clinical outcome and quality of life. Materials and Methods: Inclusion criterias were daily pain for at least 6 months, positive impingement test and verified retroverted acetabulum on radiographs and CT- scan. Patients had no OA. Exclusion criterias were previous operation in the hip for any reason. The patients were operated from December 2004 - May 2013 with at least 1 year of follow-up. They were scored with HHS, EQ5D-3L and VRS (pain on verbal rating scale) pre- and postoperatively. In addition, they were evaluated on 3 Anchor questions regarding their hip. Findings / Results: 106 patients (83F) with 120 PAO with a median age of 21.4 years (IQR 18.1-26.8) were included. The median follow-up time was 1.1 year (IQR 1-1.6). The median HHS (IQR) improved from 68 (61-72) to 94 (91-96). Median (IQR) VRS improved from 8 (6-9) to 0 (0-2). Median (IQR) EQ5D- 3L improved from 0.72 (0.66-0.77) to 0.824 (0.72-1). Compared to preoperative HHS, VRS and EQ5D-3L all improved significantly (p< 0.0001, Wilcoxon matched sign rank test). 78-80 % reported good to excellent health and result of PAO and a better hip function than prior to surgery. Conclusions: PAO for a patient with pincer impingement and retroverted acetabulum shows good postoperative results regarding HHS, VRS, EQ5D-3L and specific anchor questions. 208 DOS Abstracts

Evaluation of bone mineral density and bone markers in femoral amputees prior to osseointegrated implant surgery 156. Rehne Lessmann Hansen, Peter Holmberg Jørgensen, Kjeld Søballe, Klaus Kjær Petersen, Maiken Stilling Department of orthopaedic research, University Hospital of Aarhus; Department of orthopaedic surgery, University Hospital of Aarhus Background: Amputees often have radiological halisteretic bone in the residual femur. The status of periimplant bone mineral density (BMD) and general skeletal bone activity may offer important information prior to osseointegration (OI) surgery. Purpose / Aim of Study: Evaluation of preoperative data of the first 20 patients. Materials and Methods: 20 patients (13 male) with mean age 48 (range 30-66) years, and mean 10.5 (range 0-39) years since amputation, were scheduled for surgery with an OI-implant. Preoperative assessment included AP and LA radiographs of the femur, DXA scans with measurement of systemic and femoral/pelvic bone mineral density (BMD) and thigh muscle mass, and biomarkers (BASP bone-type, Ca2+, PTH, D2+D3, creatinine). Findings / Results: Mean length of the residual femur was 20.3cm (range 4.7 41cm). 9 patients had a normal systemic BMD (T>-1), 9 were osteopenic ((T -1), and 2 patients were osteoporotic ((T < -2.5) (male:30 yr, male:45yr). The BMD of the femur, hip and pelvis on the amputated leg was decreased by 40%, 35% and 21%, and the muscle mass in the gluteal region and femur was decreased by 9,5% and 47,5%, compared to the healthy leg (p<0.001). The BMD in the distal 12 cm of the amputated femur correlated positively with the length of the femur (spearman s rho 0.64, p=0.002) and negatively with the years since amputation (spearman s rho -0.71, p=0.0004). 7 patients had vitamin D insufficiency, 5 patients had elevated PTH-levels, 5 patients had elevated BASP and all had normal Ca2+ and BASP bone-type. Conclusions: Femoral amputees have an almost 50% reduced BMD and muscle mass in the affected leg and the degree depends on the years since amputation and the length of the residual femur. Low systemic BMD and vitamin D insufficiency with sec. hyperparathyroidism was seen in 1/3 of patients indicating a general need for screening. DOS Kongressen 2014 209

Amputation after failed knee arthroplasty Tinne B Gottfriedsen Tinne Brandt Gottfriedsen, Anders Odgaard, Henrik M Schrøder 157. Department of Orthopaedics, Copenhagen University Hospital Gentofte Background: Existing data on amputation for failed knee arthroplasty is limited. Data from the Danish Knee Arthroplasty Register (DKR) suggests that only 3 amputations have been performed since 1997. Purpose / Aim of Study: To identify the incidence and causes of above knee amputation after failed knee arthroplasty. Materials and Methods: Nationwide data was extracted from the Danish Hospital Episodes Statistics and DKR. Relevant patient notes were retrospectively reviewed. Findings / Results: We identified 89,545 primary knee arthroplasties performed in Denmark from 1997-2013. 250 arthroplasties were followed by amputation corresponding to an overall crude incidence of 0.28%. Of these, 111 were performed for causes related to the knee arthroplasty corresponding to an incidence of 0.12% (range among regions, 0.07-0.16%, p=0.42). Survival data will be presented. Mean age was 69.1 years (66.9-74.5, p=0.80). Mean time between primary arthroplasty and amputation was 4.1 years (1.8-5.5, p=0.16). The patients underwent an average of 2.7 knee surgeries prior to amputation including arthrodesis in 23 cases (1.7-3.8, p=0.06). 54% of cases were assessed at a highly specialised hospital (18-90%, p=0.001). Indications for amputation included infection in 91 cases (82%), soft tissue deficiencies in 24 cases (22%), bone loss in 20 cases (18%), extensor mechanism disruption in 11 cases (10%), pain in 10 cases (9%), periprosthetic fracture in 10 cases (9%) and vascular complications in 9 cases (8%). In 88 cases (79%) there were at least two or more indications for amputation. Conclusions: We found significantly more amputations than reported to DKR. 56% of these were performed for causes other than failed knee arthroplasty. The majority of amputations related to failed knee arthroplasty were performed for several indications, of which infection was present in most cases. 210 DOS Abstracts

Acceptable agreement between Inertia-based Measurement Unit and Optical Motion Capture System applied in quantitative measurement of physical function in patients 158. Inger Mechlenburg, Peter Bo Jørgensen, Henrik Sørensen, Dennis B Nielsen, Bernd Grimm, Kjeld Søballe Orthopaedic Research, Aarhus University Hospital; Section of Sports, Aarhus University; ATRIUM Medical Center, AHORSE Foundation, The Netherlands Background: There is need for valid objective measures of physical function when outcome after orthopaedic or rehabilitation interventions are evaluated. Purpose / Aim of Study: The aim of this study was to validate an Inertia-based Measurement Units (IMU) against an Optical Motion Capture System (OMCS). Materials and Methods: Ten patients (eight females), mean age 28 (16-43) years with hip dysplasia were tested. The test battery included four lower extremity performance measures: sit-stand-sit (STS), stair climbing (SC), block stepping test (BST) and counter movement jump (CMJ). We applied an IMU (Micro Strain Inertia-Link) and recorded data at 100 Hz. Kinematic data were recorded at 240 Hz with an 8-camera ProReflex MCU 1000 OMCS. Rotations were measured as range between highest and lowest value. Agreement between the two systems was analyzed and presented with Limits of Agreement (LOA) (mean difference ±1.96 x SD). Findings / Results: Overall, the agreement between the results acquired by the IMU and the OMCS was acceptable. LOA for rotations in the frontal plane in degrees for STS were 3.7±15.4 in ascending and 3.3±11.1 in descending. For SC, LOA for rotations in the sagittal plane were 2.2±6.9 deg in ascending and -3±5.8 deg in descending. LOA for rotations in the sagittal plane at the BST were -0.7±5.3 deg in ascending and -1.2±5.9 deg in descending. LOA for vertical translation for CMJ were -0.6±5.5 cm. There were systematic differences between the IMU and OMCS in SC (mean diff 2.2 deg p=0.03 and mean diff -3 deg p<0.01 respectively). Conclusions: The IMU showed acceptable agreement with OMCS when applied in test of physical function in patients. There is a clear perspective for clinicians to apply the IMU in the evaluation of orthopaedic or rehabilitation interventions. DOS Kongressen 2014 211

Intervertebral disc degenerative changes after intradiscal injection of TNF-α in a porcine model 159. Ran Kang, Haisheng Li, Kresten Rickers, Steffen Ringgaard, Lin Xie, Cody Bünger Orthopaedic Research Lab, Aarhus University, Aarhus C 8000, Denmark; The MR Research Centre, Aarhus University Hospital, Skejby, Aarhus C 8000, Denmark; Department of Orthopedic Surgery, Jiangsu Province Hospital on Integration of Chinese and Western Medicine, Nanjing 210028, China Background: While high expression of tumor necrosis factor-α (TNF-α) is commonly found in already degenerated discs, whether or not exogenous TNF-α will initiate a degeneration process in a healthy disc in vivo has not been studied assertively. Purpose / Aim of Study: To investigate whether exogenous TNF-α will initiate intervertebral disc degeneration. Materials and Methods: Exogenous TNF-α in dosages of 50 ng and 100 ng in 50 ÌL Dulbecco s Modified Essential Medum (DMEM) was injected into porcine lumbar discs; a third disc was injected only with 50 ÌL DMEM as a control. Magnetic resonance imaging (MRI) yielding T1- and T2-weighted images, T2 maps, and post-contrast T1 images was performed and histology was studied as well. Findings / Results: After three months, a significant decrease in T2 value was observed in the annulus and nucleus of both groups injected with TNF-α along with a slight decrease in disc height and nucleus volumes in comparison to the control discs. No obvious differences among the groups were observed in the normal T1- and T2-weighted MRI images. Post- contrast T1 MRI showed increased annulus enhancement in both TNF-α- injected groups compared to the control discs, while no enhancement difference was observed in the nucleus. Histological analysis showed degenerative changes with annulus fissure, cell cluster, nucleus matrix loss, and vascularization in the outer annulus of both TNF-α- injected discs, while no degenerative changes were observed in the control discs. Conclusions: Intradiscal injection of exogenous TNF- α caused disc degeneration in a porcine model. Accordingly, such preventive measures as anti- inflammatory treatment might be considered as a means of protecting the disc when there are high TNF-α levels in the serum. 212 DOS Abstracts

A month of heavy resistance exercise increases the amount of Collagen XIV in the endomysium close to the human MTJ 160. Jens Rithamer Jakobsen, Abigail Mackey, Andreas Knudsen, Manuel Koch, Michael Kjaer, Michael Rindom Krogsgaard Department of sportstraumatology M51,, Bispebjerg University Hospital; Institute of Sports Medicine Copenhagen, Department of Orthopaedic Surgery M, and Department of Biom, Bispebjerg University Hospital and University of Copenhagen; Institute for Dental Research and Oral Musculoskeletal Biology, and Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany Background: Strain injuries are a common cause of absence from sports. They occur most often at the myotendinous junction (MTJ). So far the best prevention seems to be heavy resistance exercise (HRE), but it is unknown which adaptions HRE induces in the human MTJ that could explain this lowering in risk of strain injuries. Purpose / Aim of Study: To investigate how the MTJ and endomysium adapts to one month of HRE training. Materials and Methods: Ten patients scheduled for cruciate ligament reconstruction with a hamstrings graft were randomized into either a control group or a training group (1 month of HRE). At the operation, samples were collected from the semitendinosus and gracilis MTJ and fixed in liquid nitrogen-cooled isopentane. Samples were sectioned and stained with immunofluorescent antibodies against seven collagen types. The amounts of collagen were estimated visually using a scale from 0-2 where 2 is the highest amount. Findings / Results: Compared with our control group, a significantly higher collagen XIV content of the muscle endomysium (P = 0,0132) was found in the training group. No significant differences for any of the investigated collagen types where seen at the MTJ. Conclusions: 1 month of HRE does not lead to detectable increases in the amount of collagen I, III, IV, VI, XII and XIV at the MTJ. However, it leads to a significant increase in collagen XIV content in the endomysium of human muscle tissue close to the MTJ. These findings suggest that collagen XIV has a role in the adaptation of the connective tissue sheath to heavy loading. It is possible that longer training periods are required to induce measurable increases for the other collagen types at the MTJ or alternatively that structural changes increasing the muscle-tendon contact area explain the improved resistance to strain injury at the MTJ after HRE. DOS Kongressen 2014 213

Pharmacokinetics of vancomycin in porcine bone obtained by microdialysis 161. Mats Bue, Hanne Birke-Sørensen, Theis Muncholm Thillemann, Kjeld Søballe, Mikkel Tøttrup Department of Orthopaedic Surgery, Hospital Unit Horsens; Orthopaedic Research Unit, Aarhus University Hospital Background: Traditionally, the pharmacokinetics of antimicrobials in bone has been investigated using bone biopsies, which suffers from considerable methodological limitations. Microdialysis (MD) offers an attractive alternative to obtain bone concentrations of antimicrobials. Purpose / Aim of Study: The aims of this study were to investigate the suitability of the MD-method for vancomycin measurement in a laboratory setting and to apply MD for measurement of vancomycin in subcutaneous tissue, cancellous and cortical bone. Materials and Methods: Laboratory studies were conducted to determine in vitro recovery by gain and by loss (1-25 µg/ml), appropriate flow rate, calibration concentrations and the effect of temperature and concentration on recovery. In a porcine study MD-catheters were placed in subcutaneous tissue, cancellous and cortical bone. CMA 63 catheters were used, and were in bone placed in drill holes, made by use of a 2 mm drill. Blood samples were drawn from a central venous catheter. CMA 107 pumps produced flow rates of 0.5 µl/min. All dialysates were analysed with an UHPLC-method, and vancomycin concentrations in plasma were determined with cobas (c501, Roche). Verification of catheter locations was performed by autopsy, and intra cortical placement of drill holes was verified by post-mortem CT. Findings / Results: Laboratory study: Recovery by gain equalled recovery by loss, and was independent of the concentration. Recovery increased slightly with increasing temperature. Porcine study: For all extravascular tissue, a heterogeneous distribution was demonstrated. Significant differences in AUC were found for bone, cancellous as well as cortical, when compared to free plasma. The lowest AUC was found in cortical bone. Conclusions: MD is a reliable method for assessment of the penetration and pharmacokinetics of vancomycin in bone and soft tissue. 214 DOS Abstracts

Collagen types and distribution at the human myotendinous junction (MTJ) 162. Jens Rithamer Jakobsen, Abigail Mackey, Andreas Knudsen, Manuel Koch, Michael Kjaer, Michael Rindom Krogsgaard Department of sportstraumatology M51,, Bispebjerg Hospital, University of Copenhagen, Denmark.; Institute of Sports Medicine Copenhagen, Department of Orthopaedic Surgery M, and Department of Biom, Bispebjerg University Hospital and University of Copenhagen; Institute for Dental Research and Oral Musculoskeletal Biology, and Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany Background: The MTJ is the interface between the muscle and tendon, through which force produced in the muscle is transmitted. Excessive loading of muscles can result in strain injuries, which often occur at the MTJ. However, very little is known about the composition of the human MTJ. In animals, collagen type XXII seems to be located exclusively in the MTJ, and has been shown to contribute to the stabilization of MTJ and strengthening of skeletal muscle attachments during contraction. Similarly, a lack of Collagen XXII results in a higher susceptibility to ruptures of the MTJ. Purpose / Aim of Study: The aim of this study is to investigate the distribution of collagen type XXII in human MTJ and the localisation of other collagen types (I, III, VI, XII, XIV) in relation to collagen XXII. Materials and Methods: Samples of MTJ were collected from the hamstring muscles of 15 patients during ACL-reconstruction and frozen in liquid nitrogen, cut on a cryostat and stained with antibodies against collagen I, III, IV, VI, XII, XIV and XXII. The sections were analysed immunohistochemically with fluorescent wide-field and confocal microscopes and the amounts of stained protein were estimated visually on a score from 0 to 2, where 2 is highest. Findings / Results: Collagen XXII was located only at the MTJ, but not in all regions. It was detected between the dystrophin-labelled myofibre membrane and the endomysium, which was rich in collagen types III and VI. Collagen types XII and XIV were also observed to be closely associated with XXII. Conclusions: The human MTJ has a very complex composition of different collagen types. The possible roles of these collagens in force transmission are discussed. Collagen type XXII was the only type to be solely located at the MTJ, and is therefore a valuable marker for human MTJ even though it is not found in all regions. DOS Kongressen 2014 215

CAN GAIT DEVIATION INDEX BE USED EFECTIVELY FOR THE EVALUATION OF GAIT PATHOLOGY IN TOTAL HIP ARTHROPLASTY? AN EXPLORATIVE RANDOMIZED TRIAL 163. Carsten Jensen, Signe Rosenlund, Dennis B. Nielsen, Søren Overgaard, Anders Holsgaard-Larsen Orthopaedic Research Unit, Department of Orthopaedic Surgery and Traumatology, Odense University Hos, Institute of Clinical Research, University of Southern Denmark; Departments of Orthopedic Surgery and Traumatology, Køge and Odense Hospital; Orthopaedic Research Unit, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital Background: Three-dimensional gait analysis (3DGA) is widely used in the quantitative evaluation of gait. However, 3DGA produces a large volume of data, and simplifying such complex data into a single measure of patients overall gait quality would be valuable in clinical practice. The experience with GDI in osteoarthritis (OA) patients following total hip arthroplasty (THA) is novel. Purpose / Aim of Study: The aim of our study was to use the GDI to evaluate post-operative gait quality changes in patients with hip OA following two types of THA. Materials and Methods: A total of 38 patients (11F:27M, age 56 ± 5.6, BMI 27.8 ± 3.6) with unilateral end-stage primary hip OA were evaluated pre-operatively, two- and six- months after THA, while walking at self- selected speed. From the entire gait cycle, rather than a small number of discrete parameters, the GDI was calculated for each limb (n=76 limbs). The normative mean and standard deviation from age-matched controls (n=20) were used as reference. A fixed-effects multilevel regression model was employed to evaluate the treatment effects. Findings / Results: Patients had a moderate deviation from normative gait (score = 100) before surgical treatment (83.4 ± 10.9). After surgery, the score improved significantly by 4.9 [95CI: 2.1 to 7.9]. There was no difference in GDI scores between the two treatments; 1.8 [95CI: -2.8 to 6.4]. However, the GDI score for the non-operated limb was higher than the GDI score for the operated limb; 2.5 [95CI: 0.1 to 4.8]. Conclusions: GDI increased after THA, which indicates an overall improvement in gait quality. No difference between treatments was observed. Asymmetrical gait pattern do not disappear following THA. Further research is required to establish the clinical relevant difference for the GDI score for THA patients. 216 DOS Abstracts

Validation and inter-tester reliability of a tri-axial accelerometer-based classification of daily activities 164. Marianne Tjur, Kenneth Juul Laugesen, Kamilla Nygaard Jensen, Mads Grosmann Svendsen, Inger Mechlenburg, Signe Kierkegaard Orthopaedic Research, Aarhus University hospital; Bachelor of Applied Science in Physiotherapy, VIA University College Aarhus Background: Daily physical activities (PA) are often used as outcome in the evaluation of orthopaedic or rehabilitation interventions. Self-reported PA suffers from recall bias and imprecision, thus there is a need for objective measures. Purpose / Aim of Study: The aim was to investigate the inter-tester reliability and precision of the classification of PA measured with a tri-axial accelerometer, and a MatLab-based algorithm. Materials and Methods: 27 healthy participants were observed with video recordings while performing 30 min of various time intervals of the activities; resting, standing, walking, cycling and running. A tri-axial accelerometer (GCDataconcepts, US) was mounted on lateral side of right thigh while performing the activities. Two blinded analysers performed the classification of activities using the algorithm. The relative reliability was expressed with Intraclass Correlation Coefficient (2,1)(ICC), the absolute reliability with Limits of Agreement (LOA) and precision with LOA of the proportion of analysed activity compared to observed. Findings / Results: ICC was high for resting 0.99, standing 0.99, walking 0.88 and running 0.99 and acceptable for biking 0.73. LOA were acceptable for resting [-0.34;0.42], standing [-0.98;1.28], walking [-449;368], running [-0.39;0.32] and biking [-368;448]. The precision of classifying PA was acceptable with LOA [0.99:1.02] for resting, [0.94:1.10] for standing and [0.98:1.07] for biking. Walking was underestimated (mean= 0.71 (p=0.03), LOA [0.19:2.60]) while running was overestimated (mean= 1.39 (p=0.001), LOA [0.64:2.98]). Conclusions: Inter-tester reliability was high while precision of classification of resting, standing and cycling was acceptable. More precision is necessary in the classification of walking and running. The perspectives for monitoring daily PA with accelerometer seem promising. DOS Kongressen 2014 217

Does an intensive alcohol cessation intervention at the time of fracture surgery induce spontaneous smoking cessation? - The Scand-Ankle study 165. Erika Wernheden, Marianne Aalykke, Bolette Pedersen, Julie W. M. Egholm, Hanne Tønnesen WHO-CC, Frederiksberg Hospital; Clinical Health Promotion Centre, Lund University; Syddansk Universitet, Sygehus Sønderjylland Background: Patients with high alcohol consumption are at greater risk of developing postoperative complications than patients with low/no alcohol consumption. Other risk factors are smoking, overweight, malnutrition and physical inactivity. Preoperative alcohol and smoking cessation programs have been found effective in reducing postoperative morbidity, but it remains unknown whether these induce a general change of lifestyle. Purpose / Aim of Study: The aim of this study was to find out whether the gold standard alcohol intervention programme (GSP-A) used in the Scand-Ankle study, affected smoking, overweight, malnutrition and physical inactivity. Materials and Methods: 64 patients with high alcohol consumption, who underwent ankle fracture surgery, were randomized to the GSP-A or usual care (control). The two groups were compared at baseline and 6 weeks follow- up regarding changes in lifestyle factors. Data were analyzed on an intention to treat (ITT) basis using non-parametric statistics. A per protocol analysis of whether alcohol cessation, regardless of study group, affected lifestyle risk factors after 6 weeks was also performed. Findings / Results: The ITT-analysis showed no significant differences between the GSP-A and control group regarding lifestyle risk factors other than alcohol. The per protocol analysis showed that alcohol cessation regardless of study group did not influence the other lifestyle risk factors. Conclusions: The GSP-A, which has been proven effective on short-term alcohol cessation, does not affect smoking, overweight, malnutrition and physical inactivity. Thus, a potential effect of the GSP-A on postoperative complications will likely be due to the effect on alcohol intake and not to a general change in lifestyle. The findings suggest that multiple lifestyle interventions are required, e.g. combined alcohol and smoking cessation. 218 DOS Abstracts

Compression in Anklefracture Treatment, the CATstudy Rikke Winge, Stig Sonne-Holm, Camilla Ryge, Hans Gottlieb, Lasse Bayer Orthopedic Surgery, Nordsjællands Hospital 166. Background: Malleolar fractures in Denmark has an incidence of 107/100.000 person, making it one of the most common fracture types in the country. In Denmark 6000 malleolar fractures are operated each year. Studies have shown increased complication rates in the elderly, diabetics, smokers, patients on immunomodulating medication, alcoholics, and patients with osteoporosis and peripheral neuropathy. Nordsjællands Hospital has decided, to implement a standard regime of elevation, Flowtron Hydroven 3 and Coban 2 lite, to prevent oedema formation and blistering. The decision came after clinicians having observed a high incidence of oedema, blistering and wound healing problems in this cohort of patients, often forcing surgeons to postpone surgery and prolonging inpatient stay, resulting in a long and cumbersome rehabilitation for the patient. Purpose / Aim of Study: To perform a randomized, controlled cohort study, to evaluate the effect of Flowtron Hydroven3 and Coban2 lite on the incidence of complications (infection, wound dehiscence, prolonged healing, skin necrosis, exposed hardware, DVT, amputation and death) after operation for mono-, biand trimalleolar fractures at Nordsjællands Hospital. Materials and Methods: 156 Patients with an unstable malleolar fracture, included and randomized in the ED. Intervention: Compression therapy in the form of Flowtron Hydroven3 and Coban2 lite compression bandage. Controle: Elevation of the ankle on a Braun frame. Follow-up: 6 weeks. The project manager will note any wound healing problems (infection, wound dehiscence, skin necrosis, visible osteosynthesis material). Findings / Results: By the time of the DOS-congress, the authors are ready to present the preliminary data, concerning the first 78 patients (50% of expected) Conclusions: Awaiting analysis of preliminary data. DOS Kongressen 2014 219

Characteristics of non-participants in orthopaedic research A study of patients undergoing ankle fracture surgery and declining participation in a randomized clinical trial 167. Marianne Aalykke, Erika Wernheden, Bolette Pedersen, Julie Weber Melchior Egholm, Hanne Tønnesen WHOCC, Clinical Health Promotion Centre, Frederiksberg Hospital; WHOCC, Clinical Health Promotion Centre and Clinical Alcohol Research, Frederiksberg Hospital and Lund University ; WHOCC, Clinical Health Promotion Centre and Orthopedic Surgery, Frederiksberg Hospital and Sygehus Søndejylland ; WHOCC, Clinical Health Promtion Centre and Clinical Alcohol Research, Frederiksberg Hospital and Lund University Background: Clinical experience indicates that patients declining participation in randomized clinical trials (RCTs) are older, less healthy and of lower social status than participants, bringing the non-participants in a higher risk at surgery. Results from studies investigating non-participants of RCTs in surgical settings are conflicting, and to our knowledge none of these studies exist on patients with risky drinking, who are already at high risk at surgery. Purpose / Aim of Study: The aim of this study was to investigate characteristics and outcomes of patients undergoing ankle fracture surgery with risky drinking declining participation in the Scand-Ankle RCT. Materials and Methods: The Scand-Ankle study is an on-going RCT, that investigates the effect of a 6- week gold standard alcohol intervention (GSP-A) on postoperative complications in patients drinking >21 units/week and undergoing ankle fracture surgery. This retrospective study included eligible patients that declined to participate in the Scand-Ankle RCT, but gave informed consent to follow-up in their medical record (N=67). Their perioperative patient characteristics and 6-week complication rate were obtained from their medical record material and the characteristics were compared to the patients enrolled in the study so far (N=61). Findings / Results: The analyses on patient characteristics are on-going. 34% of the non-participants had complications, and the most frequent complication was wound infections. Conclusions: A complication rate at 34% indicates that patients drinking > 21 units/week are at high risk at ankle fracture surgery, and the analyses on patient characteristics will show if the non-participants are at even greater risk. 220 DOS Abstracts

Early Complications of Ankle Fractures Following Treatment with Ilizarov External Fixator or Open Reduction Internal Fixation 168. Josefin Roslund, Matilda Svenning, Michael Brix, Morten Schultz Larsen Orthopaedic Surgery, Odense University Hospital Background: Objective: Open reduction and internal fixation (ORIF) is the standard surgical treatment for ankle fractures in Denmark. In cases of compromised soft tissue, the Ilizarov external fixator (IEF), might be a safer alternative when fixation is needed. Purpose / Aim of Study: The aim of this study is to analyse the short term complications following treatment of ankle fractures using IEF or ORIF. Materials and Methods: Method: The study population consisted of 122 consecutive patients who were surgically treated for ankle fractures at Odense University Hospital (OUH) during the time period 01.05.2012 31.04.2013. Patients were divided into groups based on surgical treatment method (IEF or ORIF). Pre- defined outcomes, predisposing factors and other variables of interest were registered from medical records and x-rays. Findings / Results: Results: 23 patients received IEF treatment and 99 received ORIF. Among the predisposing factors the variable hypertension and/ or hyperlipidemia varied significantly, occurring more often in the IEF group, whereas the rest of the predisposing factors did not. Among the defined postoperative outcomes secondary loss of reduction showed a significant higher rate in the IEF group. Infection and reoperation did not differ significantly between the groups. No case of compartment syndrome or amputation occurred in any of the groups. Conclusions: Conclusion: Even though the patients in the IEF group were generally considered to be in poorer condition prior to operation (higher age and rate of predisposing factors), the only outcome that was significantly different was secondary loss of reduction. This is consistent with the theory that IEF might be a good alternative for patients with less desirable preoperative conditions. DOS Kongressen 2014 221

The epidemiology of acute Achilles tendon ruptures in the south Copenhagen area in the period 2004-2013 169. Ann Ganestam, Anders Troelsen, Kristoffer W. Barfod Orthopedic surgery, Copenhagen University Hospital Hvidovre Background: Acute Achilles tendon rupture (ATR) is a frequent and potentially disabling injury that typically occurs among young active adults. Epidemiological studies have shown an increasing incidence but data are old and might not be accurate. The last epidemiological study from Denmark was published in the year 1998 and showed an increase from 18.2/10 5 inhabitants in 1984 to 37.3/10 5 in 1996. Purpose / Aim of Study: To investigate the incidence of acute Achilles tendon rupture in the south Copenhagen area from 2004 to 2013 with focus on sex, seasonal variation and changes over time. Materials and Methods: By using the ICD-10 code for acute Achilles tendon rupture (DS86.0) the National patient register was searched to find the number of acute Achilles tendon ruptures at Hvidovre Hospital in the time period of 2004-2013. Information concerning sex, date of treatment and month of injury was retrieved. Regional population data for the region of south Copenhagen was retrieved from the Hospital administration. Findings / Results: An increase in incidence from 15.8/10 5 in 2004 to 23.0/10 5 in 2013 was found. 22% were women and 78% were men. The seasonal incidence over the ten year period showed a distribution with peak incidence in May (20.6/10 5 ) and September (18.1/10 5 ). The lowest incidence was found in July and December (8.6/10 5 ). Conclusions: The incidence of ATR increased from 15.8/10 5 to 23.0/10 5 over the ten year period. However, the incidence is markedly lower than the incidence of 37.3/10 5 found in 1996. As such there is no evidence of a continuing rise in incidence of ATR. The seasonal variation is supported by earlier epidemiological studies. It might be explained by the seasonal variation in activity in recreational sports and gymnastics. 222 DOS Abstracts

Regional Differences in Number of Meniscal Procedures in Denmark Kristoffer Borbjerg Hare, Jesper Høeg Vinther, L Stefan Lohmander, Jonas Bloch Thorlund Department of Sports Science and Clinical Biomechanics, University of Southern Denmark; Department of Orthopedic, Kolding Hospital 170. Background: A recent study reported a large increase in the number of arthroscopic meniscal procedures from 2000-2011 in Denmark. This large increase was observed almost exclusively in middle- aged and older patients. Regional differences have previously been reported for the use of surgical interventions. Purpose / Aim of Study: In this study we examined regional differences in number of meniscal procedures performed in Denmark. Materials and Methods: We extracted data from the National Patient Register. Data was retrieved on all patients who underwent arthroscopic meniscus surgery either as primary procedure or part of other surgery in the years 2005 to 2011. Data was extracted on age, sex and hospital identification code for each contact, which enables linkage of performed procedures to hospital and regional location. Yearly incidence rates per 100 000 were calculated (with 95 % confidence intervals) for all procedures performed in each of the five regions in Denmark. Findings / Results: From 2005 to 2011 the overall yearly incidence rate increased from 214 (210-217, 95% CI) to 312 (307-316, 95% CI). In the Capital Region the incidence rate more than doubled from 165 (159-171, 95% CI) to 366 (357-375, 95% CI). In Region Mid the incidence rate increased from 255 (246-264, 95% CI) to 294 (284-303, 95% CI) while the highest incidence rate was observed in the Region of Southern Denmark rising from 298 (288-308, 95% CI) to 438 (426-450, 95% CI). In Region Zealand and Region North there was a slight decrease from 131 (123-139, 95% CI) to 124 (116-131, 95% CI) and 206 (195-218, 95% CI) to 195 (183-206, 95% CI), respectively. Conclusions: Large regional differences were apparent in the use and increase of meniscal procedures in Denmark from 2005-2011. In 2011 the incidence rate in Region of Southern Denmark was 3.5 times greater than in Region Zealand. DOS Kongressen 2014 223

Differences in MACI Patient Characteristics in European Countries Casper Bindzus Foldager, Martin Lind 171. Orthopaedic Research Lab, Aarhus University Hospital; Sports Trauma Clinic, Aarhus University Hospital Background: Matrix-Assisted Chondrocyte Implantation (MACI ) is a commercially available cell- based technique for treatment of articular cartilage defects. Randomized controlled trials has suggests the use of this treatment for younger patients with focal cartilage lesions in the knee larger than 3cm2. Purpose / Aim of Study: To investigate demographics and cartilage defect sizes of patients receiving MACI treatment in the knee in European countries. Materials and Methods: Data was obtained from the Sanofi database on patients receiving autologous chondrocyte cultured in the European Sanofi facility in Copenhagen, Denmark. Countries with more than ten patients treated from 2008-2013 were included. Patient demographics (age, gender) and cartilage defect characteristics (size, number of defects) were evaluated. Data was analyzed using one-way ANOVA analyses. P-values < 0.05 were considered significant. Findings / Results: A total of 1909 patients from 9 European countries, including Denmark, were eligible for evaluation. The average age was 35.5 years (range 11-65) and male:female ratio of 67:33. Mean defect size was 5.70 cm2 (range 0.16-47cm2). Single defects accounted for 78% while 22% were multifocal. There were significant differences in mean cartilage defect size between the countries (p<0.0001),. On average 18.9% were small cartilage defects (<3cm2) of which 63.1% were <2cm2. Eleven percent of the cartilage defects were large (>10cm2), and thus the majority of the defects were 3-10cm2 (70%). Conclusions: This study show differences in sizes of the cartilage defects in patients receiving MACI treatment in 9 European countries. In general the treatments are being assigned to patients matching criteria in age and defect size for which evidence have suggested benefit of chondrocyte transplantation compared with alternative treatments. 224 DOS Abstracts

PROM in the referral of patients to knee arthroscopy Peter Christian Siesing, Claus Hjorth Jensen, Thomas Lind, Anders Odgaard Orthopedic Surgery, Gentofte Hospital, University of Copenhagen 172. Background: Knee arthroscopy for knee pain, effusion and locking is commonly performed. Quality assurance of the operations was introduced in our department by the administration of the Oxford Knee Score (OKS). The measures ability to predict outcome was studied. Purpose / Aim of Study: Can OKS help to determine which patients are candidates for a knee arthroscopy? Materials and Methods: The OKS assessed 232 patients scheduled for knee arthroscopy preoperatively and at three months. The preoperative score was related to improvement by 8 points or deterioration at 3 months. Findings / Results: Of 62 patients having a preoperative score of 35, 11 patients increased their score with 8. Of 170 patients having a preoperative score of <35, 99 increased their score by 8. p<0.001 chi-sq. 16 of the 62 patients with a preoperative score of 35 decreased their score as compared to 20 of the 170 patients with a score of <35. p<0.01 chi-sq. Conclusions: A preoperative OKS of 35 suggests a fairly well functioning knee and leaves a narrow interval for improvement. Worsened knee function at 3 months was seen in one fourth of the patients with a high preoperative OKS. DOS Kongressen 2014 225

Diagnosis and treatment of chronic exertional compartment syndrome - a proposition for an algorithm based on case series of patients treated at Sports Medicine Division, Department of Orthopaedic Surgery, Viborg Regional Hospital, Denmark Peter Birk, Steffen Skov Jensen, Bente Overgaard Hansen, Janni Stroem 173. Ortopæd kirurgisk afd. T, Viborg Regionshospital; Ortopæd kirurgisk afd. T, fysioterapien, Viborg Regionshospital; Ortopæd kirurgisk afd. T, klinisk sygepleje, Viborg Regionshospital Background: Chronic exertional compartment syndrome (CECS) is a well recognized but often under diagnosed cause of chronic exertional lower extremity pain, most often encountered in young physically active individuals. Purpose / Aim of Study: The aim of this preliminary study is to present an algorithm for diagnosis and treatment of CECS. We hypothesize that specific activity induced strain (SAIS) can be used to diagnose the specific affected compartments, and in this way be able to safely and effectively treat this disorder using endoscopic assisted selective fasciotomy (EASF). Materials and Methods: Retrospective follow-up study of 13 consecutive selected patients seen in the period from Nov 2011 to May 2014 (6 women and 7 men, mean age 26 years, range 15-46 years). We used an algorithm of MRI scan or bone scintegraphy to rule out other pathology. Subsequently the patient was examined by a physiotherapist and exposed to SAIS. The objective findings in conjunction with a thorough medical history formed the basis for the diagnosis. Findings / Results: 11 patients were offered surgical treatment consisting of EASF of the affected compartment (10 bilateral and 1 unilateral, 8 affected in specific compartments and 3 affected in all compartments. Only 1 patient required additional EASF of other compartments than primarily diagnosed. At three months follow up 82% of the patients had regained their physical capabilities as prior to the condition. Conclusions: Diagnosing CECS using an algorihm consisting of physiotherapist examination including SAIS allows the surgeon to diagnose the specific affected compartments. In our study we can conclude that this practice represents a reliable diagnostic identifier, and that EASF is a safe and effective surgical treatment. Further studies are needed to confirm the benefits. 226 DOS Abstracts

Knee Joint Loading Indices Before and 3 Months after Arthroscopic Partial Medial Meniscectomy Jonas B. Thorlund, Mark W. Creaby, Martin Englund, Nis Nissen, L. Stefan Lohmander, Anders Holsgaard-Larsen 174. Department of Sports Science and Clinical Biomechanics, University of Southern Denmark;, Australian Catholic University, Brisbane, Australia; Department of Orthopedics, Lillebaelt Hospital, Kolding; Department of Clinical Science and Department of Orthopedics and Traumatology, University of Southern Denmark and Odense University Hospital Background: Increased knee adduction moment (KAM) is considered an important biomechanical marker of medial compartment loading in knee osteoarthritis (OA) research. Patients undergoing arthroscopic partial medial meniscectomy (APMM) are at increased risk of developing medial compartment knee OA. APMM may contribute to altered knee joint loading patterns. However, this is currently unknown. Purpose / Aim of Study: The aim of this study was to determine the shortterm changes in knee joint loading indices from before to after medial APMM. Materials and Methods: We investigated indices of knee joint loading (peak KAM and KAM impulse) using 3D gait analysis in 23 middle-aged patients (17 men, 46.3 yrs (SD 6.4), BMI 25.8 kg/m2 (3.4) before and 3 months after APMM for a degenerative tear. Patients had no radiographic knee OA (i.e. Kellgren & Lawrence grade 0 or 1) in the leg undergoing APMM or in their uninjured control leg prior to surgery. Data were collected during barefoot gait at self-selected walking speed (± 5% at follow-up). Paired t-tests were used to test for differences at baseline and differences in change over time between operated and control legs. Findings / Results: No differences were observed between the operated and uninjured control leg in peak KAM (p=0.42) or KAM impulse (p=0.14) before APMM. No difference in change from before to 3 months after APMM were observed between operated and uninjured control legs in peak KAM (0.17 [95% CI, -0.13-0.49] Nm/BW*HT%), whereas a border line significant increase was observed in the APMM leg in KAM impulse (0.09 [95% CI, -0.01-0.19] Nms/ BW*HT%). Conclusions: Knee joint loading indices - as indicated by the KAM - do not appear to substantially increase in the operated leg compared with the uninjured control leg from before to 3 months after APMM in middle-aged patients with degenerative meniscal tears. DOS Kongressen 2014 227

Inter-tester reliability of four tests measuring muscle strength in the shoulder using a handheld dynamometer 175. Mikkel Bek Clausen, Peter Andreas Rothe, Jens Langermann, Per Hölmich, Kristian Thorborg School of Physiotherapy, Institute of Rehabilitation and Nutrition, Faculty of Health and Technology, Metropolitan University; Arthroscopic Centre Amager, SORC-C, Copenhagen University Hospital, Amager-Hvidovre, Denmark Background: Weakness in isometric shoulder protraction (PT), horizontal extension (HE), abduction (ABD) and external rotation (ER) muscle strength is reported in patients with shoulder pathology, why objective testing is relevant in both research and clinical settings. The inter-tester reliability for tests of ABD and ER using a handheld dynamometer is found to be acceptable to excellent, though most of the described tests are performed with the shoulder in positions not suitable for patients with severe problems. For test of PT and HE the intertester reliability has not previously been investigated and no suitable testing protocols for these tests is found in the literature. Purpose / Aim of Study: The aim of this study was investigate the intertester reliability for the standardized tests of strength in shoulder PT, HE, ABD and ER, performed in positions most suitable for patients with severe shoulder problems. Materials and Methods: Twenty-five asymptomatic adults underwent standardized testing of isometric muscle strength in PT, HE, ABD and ER measured by handheld dynamometer, using the best of two trails as the test result. Order of tests and order of tester were randomized for all participants. Relative reliability were assessed for all tests using ICC2,1 two-way mixed model - absolute agreement, thereby taking any bias between testers into account. Findings / Results: The inter-tester reliability were excellent for tests of PT (ICC 0.92 95%CI:0.80-0.97), ABD (ICC 0.93 95%CI:0.84-0.97) and ER (ICC 0.91 95%CI:0.81-0.96), but only acceptable for test of HE (ICC 0.79 95%CI:0.45-0.91). Conclusions: The tests of strength in shoulder PT, ABD and ER were found sufficiently reliable to be implemented in both scientific and clinical settings, while the test of strength in shoulder HE should mainly be used in scientific settings with large samples. 228 DOS Abstracts

Osseointegrated (OI) Prothesis for Upper Limb Amputees. Klaus Kjær Petersen, Peter Holmberg Jørgensen 176. Department of Orthopedic Surgery, Aarhus University Hospital, Aarhus, Denmark Background: Conventional socket prothesis in upper limb amputees do not always fullfill demands for stability, comfort and function. OI prothesis is an option for upper limb amputees without or with insufficient function of a socket prosthesis. Purpose / Aim of Study: We present the concept and our early experiences. Materials and Methods: Since 2013 four patients have been treated with a two stages operations, where a titanium fixture is surgically inserted into the bone of the amputated limb, and (up to 3 monts later) a skin penetrating abutment to which the prosthesis is attached is inserted. Findings / Results: 1.Woman, 56 years old, who had a MP- joint amputation of the dominant thumb. OI-procedures were completed 18 months ago and the patient is now wearing a finger prothesis. The patient has a stable and firm pinchgrib. She can hold a cake stand, knit, do embroidery cross stitchs and has some sensory feedback (osseoperception). 2. Male truck driver, 41 years old with a 10 cm short proximal humerus stump following a traumatic amputation. Conventional socket prosthesis was not possible. The patient is now using a mechanical prosthesis without elbow joint and is able to shift gears, control joystick on the truck crane and write. 3. Male carpenter, 49 years old with partial amputation on proximale phanlanges of 1., 2. and 3. finger on the dominant hand following frost bites. The second operation has recently been performed and the patient is awaiting three finger prosthesis. 4. Man, 63 years old, with a very short ulna following a traumatic forearm amputation. The second operation has recently been performed and the patient is awaiting a stable myoelectric forearm prosthesis and a free elbow joint. Conclusions: OI prothesis is an option for selected upper limb amputees and which can improve functionality and introduce new prosthetic technology. DOS Kongressen 2014 229

Outcome and risk of revision after shoulder replacement in patients with osteoarthritis: 1,209 cases from the Danish Shoulder Arthroplasty Registry 177. Jeppe Rasmussen, Anne Polk, Anne Kathrine Belling Sørensen, Bo Sanderhoff Olsen, Stig Brorson Orthopaedic Surgery, Herlev Hospital Background: Hemiarthroplasty (HA) including resurfacing hemiarthroplasty (RHA) and stemmed hemiarthroplasty (SHA)are widely used in Denmark but the efficacy in comparison to that of total shoulder replacement (TSA) is poorly documented. Purpose / Aim of Study: In this study we used patient reported outcome and risk of revision to compare HA and TSA in patients diagnosed with osteoarthritis and secondly to compare SHA and RHA. Materials and Methods: We included all patients reported to the Danish Shoulder arthroplasty registry (DSR) between January 2006 and December 2010. 1209 arthroplasties in 1109 patients were eligible. Western Ontario Osteoarthritis of the Shoulder index (WOOS) was used to evaluate patient reported outcome 1 year postoperatively. For simplicity of presentation, the raw scores were converted to a percentage of a maximum score. Revision rates were calculated by checking reported revisions to DSR until December 2011. WOOS and risk of revision were adjusted for age, gender, previous surgery and type of osteoarthritis. Findings / Results: There were 113 TSA and 1096 HA (837 RHA and 259 SHA). Patients treated with TSA had a statistically better WOOS, exceeding the predefined minimal clinically important difference, at one year (mean difference 10, P<0.001). RHA had a statistically significant better WOOS compared to SHA (mean difference 5, P=0.024) but the difference did not exceed the minimal clinically important difference. There were no statistically significant differences in revision rate or adjusted risk of revision between any groups. Conclusions: Our results are in accordance with the results from other national shoulder registries and the results published in systematic reviews favoring TSA in the treatment of osteoarthritis. 230 DOS Abstracts

MRI IMAGING AND PATHOLOGY OF AVASCULAR NECROSIS IN THE PROXIMAL POLE OF THE SCAPHOID BONE AFTER FRACTURE 178. Britt Mejer, Niels Søe, Nina Vendel Jensen, Katalin Kiss, Lone Larsen, Lars B. Dahlin Ortopædkirurgisk O, Hillerød Hospital; Håndkirurgisk klinik, Gentofte Hospital; Anæstesiologisk afdeling, Gentofte Hospital; Patologisk afdeling, Rigshospitalet; Radiologisk afdeling, Herlev Hospital; Håndkirurgisk afdeling, Malmø og Lund sykehus Background: MRI imaging is considered the gold standard in order to diagnose avascular necrosis after a scaphoid fracture prior to surgery Purpose / Aim of Study: A comparative study on ten patients who suffered from scaphoid fracture with avascular proximal pole necrosis was done, where MRI images with contrast were compared against histological findings of the excised proximal pole of the scaphoid bone. We reviewed the accuracy of MRI findings compared to histological findings of the entire proximal pole of the scaphoid. Materials and Methods: A comparative study on ten patients who suffered from scaphoid fracture with avascular proximal pole necrosis was done, where MRI images with contrast were compared against histological findings of the excised proximal pole of the scaphoid bone. The patients were initially treated with screw fixation due to a fracture, but due to avascular necrosis of the proximal pole they were reoperated with APSI prosthesis. Prior to surgery all patients were examined with X-ray and MRI that both showed the signs of necrosis of the proximal pole of the scaphoid. Findings / Results: All ten patients showed different degrees of avascular proximal pole necrosis in ordinary X-ray, and the histological findings showed more extensive necrosis in the bone than the MRI. The histological findings are more precise in the degree of vascularity than the MRI. Conclusions: MRI findings seem to be less specific than the histological findings described with degree of avascular necrosis. The MRI technique with contrast that is used now will probably better correlate to histological findings. DOS Kongressen 2014 231

Early experience with bone scan SPECT CT in assessing adolescents with complex problems in the foot and ankle region 179. Ole Rahbek, Deborah M Eastwood, Marina Easty, Lorenzo Biassoni Department of Orthopaedics, Great Ormond Street Hospital for Children NHS Foundation Trust, London (UK); Department of Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London (UK) Background: Adolescents, particularly those with proven foot pathology, may develop unexpected foot pain during periods of changing growth rates. It can be difficult to differentiate between functional and organic foot pain. Purpose / Aim of Study: The aim of this retrospective study was to review our preliminary experience on bone scan with SPECT CT in the assessment and management of the child with complex foot/ankle pain. Materials and Methods: We reviewed the notes and imaging of 11 patients with complex foot and ankle pain, referred for bone scanning (12 scans performed). All patients had plain films, 7/11 patients had MRI (1 patient had CT). Bone scanning was performed with a dual head Siemens Symbia T2 SPECT/CT gamma camera. Planar blood pool and delayed static images of the feet, with SPECT/CT images of both feet and ankles, were acquired Findings / Results: Mean age was 13yr (range 9-17), 9/11 patients were female. The underlying diagnoses were: tarsal coalition [n=3], non-specific inflammation [n=2], spastic diplegia [n=2], clubfeet [n=2], chronic regional pain syndrome, dystonic foot posturing [n=1]. Four feet had undergone previous surgical treatment. Bone scan SPECT/CT added decisive clinical value versus x-rays and MRI/CT in 9/12 cases. In four cases it prompted surgical management (fusion, screw removal, coalition excision, arthrodesis). In two patients it showed other focal areas of mechanical stress, thus excluding surgery. In 3/12 patients the bone scan confirmed the diagnosis without adding significant clinical information. Conclusions: These preliminary results are encouraging and suggest that a prospective evaluation of bone scan with SPECT/CT in adolescents with foot pain and complex problems of the foot and ankle is justified. 232 DOS Abstracts

Supramelleolar tibial osteotomy without fibular osteotomy, allowing immediate weightbearing, is safe. 180. Ida Marie Rahbek, Gert Rahbek Andersen Ortopaedic dept. U, Rigshospitalet Background: Children with cerebral palsy have a risk of developing external tibial torsion secondary to a persisting fetal femoral anteversion. External tibial torsion can lead to gait disturbances, patello- femoral instability and pain. This can be corrected by surgery, which can be performed with different procedures. These vary in terms of level of the osteotomy, the treatment regimen, the method of fixation, and whether concomitant fibular osteotomy is performed. Purpose / Aim of Study: The purpose of this study is primarily to examine the results of supramalleolar tibial osteotomy with plate fixation and immediate weight bearing, including rate of complications and course of mobilization. Secondarily to compare this study to previous studies in terms of fixation methods and treatment regimens. Materials and Methods: Data is collected retrospectively from medical charts at the Children s Orthopedic Department of Rigshospitalet. The included patients were diagnosed with cerebral palsy, and received surgery in the period 1999-2013. The osteotomies were fixated with a plate, and full weightbearing was allowed. Forty patients were included, with a total of 65 osteotomies. Findings / Results: In the 65 osteotomies, 5 complications was reported (7.7%), including 3 major complications and 2 minor. There were no cases of malunion or non-union. Median age at surgery was 14.8 years. Surgery to remove the plate was performed in 22 of the 65 osteotomies and median followup was 2.6 years. Conclusions: This study shows that supramalleolar tibial osteotomy with primary weight bearing is a safe method, that doesn t result in more frequent or severe complications, than observed with 4 weeks of immobilization without weight bearing. Primary mobilization leads to less loss of muscle mass, which is essential to the target group. DOS Kongressen 2014 233

Biomechanical symmetry of a hip joint altered by Perthes disease Remel Salmingo, Tina Skytte, Marie Sand Traberg, Kaj-Åge Henneberg, Klaus Hindsø, Christian Wong 181. Biomedical Engineering, Department of Electrical Engineering, Technical University of Denmark; Department of Orthopaedics, Hvidovre Hosptial Background: Perthes is a disease characterized by a loss of blood supply of the hip joint resulting to malformation of the femoral head. Until now, the underlying biomechanical changes of Perthes disease need to be further elucidated. Purpose / Aim of Study: The objective of this study was to investigate the changes specifically the biomechanical symmetry of a unilateral Perthes hip. Materials and Methods: Finite Element (FE) modeling was performed to investigate the biomechanics of a healthy and diseased hip of a unilateral Perthes case. The image MRI slices were obtained to segment the bones and cartilages, and to build the 3D models. The elastic modulus for the pelvis, femur, cartilages and necrotic bone (Perthes hip only) were, 5 GPa, 500 MPa, 50 MPa, 20 MPa, respectively. The most distal part of the femur was fixed while the pelvis was displaced to -1.5 mm to simulate load. Findings / Results: The result indicates that the symmetry of the hip joint of the unilateral Perthes case was altered biomechanically. The highest displacement of the healthy hip occurred at the supero-medial side of the femoral head. On the other hand, in Perthes hip, the displacement occurred at the superior part of the femoral head and gradually reduced towards the distal part of the femur. Localized contact pressure and stresses were also found in the Perthes hip. Conclusions: As a mechanical analogy, the healthy hip is experiencing bending load similar to a curved-cantilever beam where the maximum displacement is located at the end. The Perthes hip resembles a stacked column structure where the load is transmitted through compression. This indicates an aggravation of Perthes disease because bone overloading by compression around the proximal part might occur. The FE method developed in this study can be used to estimate the prognosis of the Perthes disease. 234 DOS Abstracts

The postoperative rehabilitation of lumbar disk patients in the Region of Southern Denmark Rune Tendal Paulsen, Erik Bergholdt, Mikkel Østerheden Andersen, Rikke Rousing Sector for Spine Surgery and Research, Middelfart 182. Background: Following the municipal reform in Denmark in January 2007, the municipalities gained responsibility for the postoperative rehabilitation. In the Region of Southern Denmark this task were decentralized to a total of 22 municipalities implying a possible risk for considerable variation within the legal framework. An observational study was needed to clarify the rehabilitation programs across the region. Purpose / Aim of Study: This study elucidates the post-surgical rehabilitation programs of patients with lumbar disk herniation in the 22 municipalities of the Region of Southern Denmark and furthermore performs a statistical analysis of the patient reported outcome measures 1 year after surgery. Materials and Methods: 22 Physiotherapists answered a questionnaire regarding visitation, methods of training and their general rehabilitation offer. 368 operated patients were linked with zip codes and the different municipalities were then compared with parameters as ODI, EQ-5D and sick leave time. Findings / Results: Patient reported outcome measures showed no statistical difference in ODI, EQ-5D or sick leave time at 1 year follow up across the 22 municipalities. Rehabilitation programs across the region were comparable upon several factors. The questionnaire revealed potential for improved cooperation between hospitals and rehabilitation centers. Conclusions: Rehabilitation is broadly similar and patient outcome after 1 year does not differ across the 22 municipalities. Generally all municipalities requests better cooperation between hospital and rehabilitation unit to insure the best patient treatment. Further studies should focus on the effect of rehabilitation and thus generate evidence on this topic. DOS Kongressen 2014 235

Can older patients survive 8 hours spine reconstruction surgery for degenerative scoliosis? Jens Egebjærg Rye Svendsson, Valancius Kestutis 183. Department of Orthopedic surgery, Aarhus University Hospital Background: Adult scoliosis is one of the most challenging spinal disorders defined as a spinal deformity in a skeletally mature patient. Degenerative, or de novo, scoliosis is usually seen in elderly adults over the age of 60. In selected patients surgery is an effective treatment; however, it is associated with significant risks and major complications. Purpose / Aim of Study: To analyze and compare perioperative and in-hospital complications and challenges in to patients groups (older and younger) treated for adult degenerative scoliosis. Materials and Methods: Operations between 01/2003 and 12/2013 were reviewed. Inclusion: degenerative scoliosis; age >40 years; no scoliosis surgery previously; cranial fixation point in the thoracic region, caudal fixation point in the iliac bones; one stage procedure. Patients divided in two groups: age <65 and 65. Groups were compared in terms of demographics, admission, per operative data and in-hospital complications. Findings / Results: 26 patients met inclusion criteria. Group 1, age <65: 12 patients (mean age 57, 43-65). Group 2, age 65: 14 patients (mean age 72, 66-81). Operation time: Group 1-8.7h ±2.2, Group 2-8.2h ±1.9. Perioperative bleeding: 1.7±1.3 and 1.8±0.7 L respectively. No perioperative complications in Group 1, while in Group 2 two patients experienced complications. Average stay in post anesthesia care unit: Group 1-1,7 (range 1-5), Group 2-1,6 (range 1-4) days. Postoperative general complications: Group 1-4 patients, Group 2 7. Hospitalization days: Group 1-11 (range 7-23), Group 2-11 (range 6-18). Two patients from Group 1 needed transfer for further medical treatment, while in Group 2 only one. Conclusions: We were not able to show increased risk for perioperative complications among older people operated for adult degenerative scoliosis compared to younger population. Thou number of postoperative general complications was slightly higher. 236 DOS Abstracts

The EOS imaging system: Workflow and radiation dose in scoliosis examinations Bo Mussmann, Stig Jespersen, Trine Torfing 184. Department of Radiology, Odense University Hospital; Department of Orthopedic Surgery, Odense University Hospital Background: The EOS imaging system is a biplane slot beam scanner capable of full body scans at low radiation dose and without geometrical distortion. It was implemented in our department primo 2012 and all scoliosis examinations are now performed in EOS. The system offers improved possibility to measure rotation of individual vertebrae and vertebral curves can be assessed in 3D. Leg length Discrepancy measurements are performed in one exposure without geometrical distortion and no stitching. Full body scans for sagittal balance are also performed with the equipment after spine surgery. Purpose Purpose / Aim of Study: The purpose of the study was to evaluate workflow defined as scheduled time pr. examination and radiation dose in scoliosis examinations in EOS compared to conventional x-ray evaluation. Materials and Methods: The Dose Area Product (DAP) was measured with a dosimeter and a comparison between conventional X-ray and EOS was made. The Workflow in 2011 was compared to the workflow in 2013 with regards to the total number of examinations and the scheduled examination time for scoliosis examinations. Findings / Results: DAP for a scoliosis examination in conventional X-ray was 185 mgy*cm2 and 60.36 mgy*cm2 for EOS. The scheduled time for scoliosis was 15 minutes in conventional X-ray which remained unchanged after implementation of EOS. The number of scoliosis examinations has increased from 396 to 1.145 since the implementation. Conclusions: The radiation dose for a scoliosis examination in EOS can be reduced to approximately 30 % of the radiation dose in conventional X-ray. The increased number of scoliosis examinations is related to increased referral and not due to optimized workflow. DOS Kongressen 2014 237

Stand-alone XLIF; 22 Consecutive patients with degenerative scoliosis and foraminal stenosis a 2 year follow-up 185. Emil Hansen Sector for Spine surgery and Research, Middelfart Hospital Background: The extreme lateral approach to the intervertebral spaces in the lumbar and thoracic spine is a procedure developed to allow a larger footprint cage to be inserted when performing spondylodesis. In the litterature not many studies have been made to investigate the role of the cage as a stand-alone option for degenerative scoliosis. While the patients often are fragile and with poor bone quality, a single surgical option, preserving the posterior structures, could be beneficial. Purpose / Aim of Study: The purpose of the study is to evaluate the complication rate and clinical/radiological results in DS patients undergoing spondylodesis with a XLIF stand-alone procedure Materials and Methods: 22 consecutive patients with DS, underwent surgery with the XLIF stand-alone procedure, follow-up 24 months. Validated clinical outcome scores were collected preoperatively, at 1 and 2 years. Complications were recorded. Findings / Results: 22 patients with a mean age of 65 (48-81) underwent surgery on 49 levels (1-4) between L1-L5. Visual Analog scores for leg pain improved from 59,4-34,9 (P<0,05) and back pain from 59,1-36,8 (P<0,05). EQ5D scores improved from 0,29-0,62 (P<0,05). 7 patients (31,8 %) underwent revision surgery. Osseous fusion was obtained in 53% of the treated levels at 1 year. Anterior thigh pain was recorded in 12 patients postoperatively but only 2 had consistent sypmtoms at 1 year follow-up. Conclusions: The XLIF stand-alone procedure is a relatively safe procedure compared with other surgical alternatives as ALIF and PLIF. Our results show a significant improvement in clinical outcome scores during 2 year follow-up. Stand alone XLIF should only be advised for single-level and only mild deformity. In most cases we recommend posterior instrumentation. 238 DOS Abstracts

Early surgical stabilization of rib fractures using a minimally invasive procedure: a pilot study Kiran Anderson, Jesper Ravn, Henrik Eckardt 186. Ortopædkir. afd., Rigshosptialet; Thoraxkir. afd., Rigshosptialet; Ortopædkir. afd., Rigshospitalet Background: In spite of considerable development in surgical fracture treatment, most patients with rib fractures are still treated non-operatively, although the respiratory consequences of rib fractures may have severe impact on the prognosis after severe trauma. Recently, a number of studies have suggested that a more active approach may decrease the number of days on ventilation as well as reducing long-term pain in these patients. Purpose / Aim of Study: The purpose of the present study was to report our initial experience with early surgical stabilization using a minimal invasive procedure of open reduction and internal fixation of multiple rib fractures. Materials and Methods: 12 consecutive patients received in our level 1-traumacenter with one of the following inclusion criterias were operated: flail chest with at least two rib fractures on two adjacent ribs or four adjacent dislocated rib fractures. The basic principles were: A. No osteosyntesis of costa # 1, 2 or 3. B. Operative fixation of only dislocated ribs. In ribs with multiple fractures only one fracture was stabilized. C. Small incisions with minimal dissection of muscle tissue. Findings / Results: None of the patients had postoperative infections, seromas or wound problems. Skin incisions were 10-15 cm. The average number of costae fixated was 3. Postoperation time in ICU averaged 2,8 days. Postoperative number of days on assisted ventilation averaged 1,16 days. Total number of admission days postoperatively averaged 9,6 days. Lung function at 3 month was equal to background population. Conclusions: Rib fracture stabilization is a safe procedure that can be performed with small incisions, without transection of muscles and with low morbidity. The intraoperative impression is that operative fixation provide sufficient stabilization for unstable chestwalls and provides a normal lung function. DOS Kongressen 2014 239

Open showering of external ring fixators in combination with occlusive pin care. A prospective study of infection rate. 187. Mykola Horodyskyy, Søren Kold, Pernille Bønneland, Anne Mette Pedersen, Juozas Petruskevicius Department of Orthopedic Surgery, Aalborg University Hospital Background: Pin site infection is a common complication in patients treated with external ring fixation. At our institution prophylactic pin care includes occlusive pin site dressings and bah care with a covered frame. However, patients have a wish for showering without the need for covering the frame. Purpose / Aim of Study: Prospective study of deep pin-site infection rates in patients allowed showering without covering of external frame. Materials and Methods: Open showering was allowed for patients who both had no inflammation at pin-sites and were able of uncovering pin-sites without help. This open care stopped if pin- site inflammation occurred. 32 (20 females, mean age of 54 years) of 143 patients treated with external ring fixation due to tibia fracture from 2011 to 2013 fulfilled inclusion criteria and were prospectively included. We registered overall use of antibiotics, time in frame, number of showers taken during the treatment, rate of complications and re- operations. Findings / Results: All fractures united. Frame was removed after a mean time of 24 weeks (range 13 to 43). Median time from operation to showering was 7 weeks (range 2 to 34). Median number of open showers taken during treatment period was 8 (range 1-32). Pin-site inflammation was observed in 17 patients after they began showering. These patients had to stop showering (for median 4 weeks) and 15 of them needed treatment with antibiotics. Median length of treatment with antibiotics was 15 days (3 to 128). There were 3 patients with deep pin sites infection. Two patients were hospitalized for intravenous antibiotics, and one of them underwent two re-operations because of acute osteomyelitis at the fracture site. Conclusions: Comparative studies with control group are needed to investigate whether showering of uncovered frames is a risk factor for pin site infection. 240 DOS Abstracts

1-year follow up after a 3 months training program mean 3 years after THA following a femoral neck fracture 188. Christina Frölich, Inger Mechlenburg, Sara Birch, Lone Lundager, Torben Baek-Hansen, Maiken Stilling Orthopaedics, Hospital Unit West; Physiotherapy, Hospital Unit West Background: Poor gait function and functional capacity may be a limitation for activities of daily living (ADL) even years after displaced femoral neck fracture (FNF). We have formerly shown a 3-months training program initiated 1-7 years after THA to result in increased mobility, muscle strength and walking speed. Purpose / Aim of Study: To evaluate 1-year results of a 3-months resistance training program Materials and Methods: 27 patients were invited and followed a 3- months resistance training program in 2013, and 24 participated in a 1 year followup (2 dead, 1 denied). Patient reported questionnaires regarding function, training frequency and health problems affecting training over the last year, and OHS were collected. Physical activity for 4 days was monitored by an accelerometer, fitted on the right thigh. Findings / Results: At 1 year 30.5% reported higher level of ADL and 74% had continued the training but at a lower level. 58% were walking outside every day, compared with 71% after 3- months training (p=0.32). 54% walked more than 30 min per walk, compared to 21% after 3-months training (p=0.02). 48% had been sick to degree that had affected their training during the past year. OHS had improved from 32 to 36 since baseline (p=0.02). Activity data showed that patients sat more (p=0.02) and stood less (p=0.02) but walked (p=0.55) the same as after the 3-months training program. Conclusions: 1 year after a 3-months standardized resistance training program 3 out of 4 patients had continued training exercises, and reported similar walking frequency with increased time per walk. Objective activity data did not support sustained activity on whole day observations but supported maintained walking activity. Almost half of the patients had been immobilised due to comorbidity which may have affected their endurance and the measured total activity. DOS Kongressen 2014 241

Coagulant preventing drugs in patients with hip fractures Bjarke Viberg, Lasse Enkebølle Rasmussen 189. Dept. of Orthopaedic Surgery and Traumatology, Odense University Hospital Background: Anticoagulants and antiplatelets are widely used in the elderly population and new drugs have emerged on the market. Hip fracture patients often needs major surgery and the national guidelines recommend surgery within 24 hours. Some of the coagulant preventing drugs may increase perioperative bleeding and surgical delay. Purpose / Aim of Study: To estimate how many elderly hip fracture patients are treated with anticoagulants or antiplatelets. Materials and Methods: Data on all hip fractures in patients above 60 years old undergoing surgery at Funen were retrieved for the period of 2008 to 2013. The first hip fracture for each patient within the study period was eligible for analysis. Patient id was matched in the prescription database for drug use, which was assessed as the proportion of patients having filled a prescription for an anticoagulant or antiplatelet drug within 120 days prior to their surgery. The following drugs were included: (1) vitamin K antagonists (VKA), (2) new oral anticoagulants (NOAC), (3) ADP-receptor blockers, (4) dipyridamole and (5) low-dose acetylsalicylic acid (ASA). Findings / Results: 4,253 patients were included in the study. 70.6% were female and the median age were 83.2 (IQR 60.1-88.4). Over the entire study period, 40.3% (n=1,716) had filled a prescription for one or more anticoagulants or antiplatelets. 11.4% had filled more than one drug class. 31.6% had filled a prescription for ASA, 10.2% for dipyridamole, 6.1% for VKA, 3.7% for ADP-receptor blockers, and 0.4% for NOACs. Over the study period, use of VKA and ADP-receptor blockers increased from 4.7% to 8.2% and 2.4% to 6.9% respectively. NOAC was registered in 2011 and the use of NOAC increased from zero to 1.8% Conclusions: Use of coagulant preventing drugs are common among patients with hip fractures. 242 DOS Abstracts

Impact of timing of soft tissue coverage and antibiotics in outcome of open tibial 2 fractures 190. Ulrik Kähler Olesen, Rasmus Juul, Christian Bonde, Claus Moser, Henrik Eckardt Ortopædkirurgisk Klinik U, Rigshospitalet; Ortopædkirurgisk afdeling, Slagelse Hospital; Plastikkirurgisk klinik, Rigshospitalet; MIkrobiologisk afdeling, Rigshospitalet; Department of Traumatology, University Hospital Basel, Switzerland Background: Treatment of open fractures is complex and somewhat controversial. The purpose of the present study is to add evidence to the management of open injuries to the lower extremity, where tissue loss necessitates using a free flap. Purpose / Aim of Study: We identify factors for a successful outcome: Avoidance of amputation and infection, achievement of union of the fracture and obtaining tissue coverage over the bone. Our study also evaluates the microbiology of open fractures and suggests the choice of antibiotic prophylaxis for this serious condition Materials and Methods: From January 2002 to June 2013 we treated 56 patients with an open tibial fracture requiring coverage with a free flap. We reviewed patient records and databases for information on time to coverage, infection, microbiology, amputations, and union of the fracture. Follow-up was minimum one year Findings / Results: In 45 patients, data was complete. When soft tissue coverage was delayed beyond 7 days, infection rate increased from 27% to 60%. High-energy trauma patients had a higher risk of amputation, infection, flap failure and non-union. Smokers had a higher risk of flap failure and non-union. Most organisms found in the infected wounds of open fractures were resistant to cefuroxime, aminoglycosides and amoxicillin, but sensitive to vancomycin and meropenem. Conclusions: To our knowledge, our study is unique in its combination of data on timing and microbiology. We conclude that flap coverage within one week remains essential for successful outcome. We suggest antibiotic prophylaxis treatment with vancomycin and meropenem until the wound is covered, in these rare injuries DOS Kongressen 2014 243

Intraoperative 3D imaging is useful in the operative treatment of displaced calcaneal fractures Marianne Vestergaard Lind, Henrik Eckardt 191. Ortopædkirurgisk Klinik, Rigshospitalet; Ortopædkirurgisk Klinik, Rigshospitalet Background: One goal in the operative treatment of displaced calcaneal fractures is to restore the anatomy of the posterior facet. Conventional fluoroscopes are unable to viaualise the posterior facet. Purpose / Aim of Study: We used intraoperative CT-scans for 3D- imaging to aid the reduction af fixation of calcaneal fractures and report our results and experiences Materials and Methods: 62 non-consecutive patients received open reduction and internal plate fixation of displaced calcaneal fractures that were aided by intraoperative CT-scans for 3D imaging. Findings / Results: The postoperative articular dislocation was 0 mm in 69% of the Sanders type 2 fractures and 57% of hte Sanders type 3 fractures. In 40% of the operations, the intraoperative scan visualised articular steps, screws penetrating joints or being to long, with the possibility of revision before wound closure. Conclusions: Intraoperative CT-scanning in calcaneal fracture surgery facilitates the reduction and correct placement of plate and screws, leads to good operative results, and obviates the risk for reoperations. Scanning prolongs the operative procedure, but does not increase the infection rate. 244 DOS Abstracts

Ewings sarcoma of the calcaneus treated by limb sparing surgery with calcanectomy and reconstruction with a composite of an allograft and a vascularised osteocutaneous fibula graft. 192. Werner Hettwer, Lisa Toft Jensen, Michael Mørk Petersen Musculoskeletal Tumor Section, Department of Orthopaedic Surgery, Rigshospitalet, University of Copenhagen; Department of Plastic Surgery, Rigshospitalet, University of Copenhagen Background: Primary malignant bone tumours of the calcaneus are very seldom. Due to poor possibilities to do surgery with wide margins in this region and limited options for reconstruction after calcanectomy many orthopaedic oncologists use amputation as the preferred surgical treatment. Purpose / Aim of Study: We present two cases of Ewings sarcoma of the calcaneus treated with limb sparing calcanectomy and reconstruction with a composite of an allograft and a vascularised osteocutaneous fibula graft. Materials and Methods: Case 1: a girl, almost 6 years old at the time of calcanectomy of the left calcaneous August 7th 2012. Case 2: a girl 16 years old at the time of right calcanectomy October 16th 2013. Both patients received pre- and post- operative chemotherapy because of Ewings sarcoma. In both cases removal of the calcaneus was performed using a combined medial and lateral incision. In case 1 a femoral head allograft was fitted to replace the removed calcaneus, and in case 2 a calcaneus allograft was used. In both cases, with the aim of obtaining arthrodesis, the allograft was fixed to the talus and cuboid bone with Acutrak titanium screws. A distally pedicled osteocutaneous flap was used for reconstruction of soft tissue, and a 5-6 cm piece of vascularised fibula bone was fitted into the allograft and fixed using staples. Findings / Results: Case 1 was allowed weight-bearing in an ankle brace after 3½ months and full weight- bearing with-out brace 8 months postoperatively, when the arthrodesis between allograft and talus was considered healed. Case 2 was allowed increasing weight-bearing in a ROM walker 7 months postoperatively, when the arthrodesis between allograft and talus was considered healed. Conclusions: Limb sparing calcanectomy was feasible with reconstruction using a composite of an allograft and a vascularised osteocutaneous fibula graft. DOS Kongressen 2014 245

Pathway Leading To Lower Limb Amputation a Danish national registry study 193. Pia Søe Jensen, Klaus Kirketerp-Møller, Nasrin Faqir, Janne Petersen, Ingrid Poulsen, Ove Andersen Department of Orthopedic Surgery, Clinical Research Centre, University Hospital of Copenhagen, Hvidovre ; Department of Orthopedic Surgery, University Hospital of Copenhagen, Hvidovre ; Clinical Research Centre, University Hospital of Copenhagen, Hvidovre; Department of Neurorehabilitation/TBI Unit, Glostrup Hospital, University Hospital of Copenhagen, Hvidovre Background: Patients with non-traumatic lower limb amputation are characterised by high age, multiple medical co-morbidities including lifestyle diseases, repeated hospital admissions, need of rehabilitation and a high mortality rate. No papers have described the pathway leading to major lower limb amputations in Denmark. Purpose / Aim of Study: The purpose of this study was to describe patients pathway leading to lower limb amputation in Denmark. Materials and Methods: A national registry based study. We defined an index amputation as the first Above Knee amputation (AKA), Below Knee Amputation (BKA), Foot or Toe Amputation procedure performed respectively. Our cohort included patients with an index amputation in 2010 or 2011. We included data on demographic, admissions, diagnoses, surgical procedures and medical treatment 14 years prior to the index operation. Data was provided by Statistics Denmark. Findings / Results: The cohort included 2829 patients with an index amputation. Of these 1010 (36 %) patients had an AKA, 752 (26%) had a BKA, 986 (35 %) had a foot or ankle amputation, and 81 (3 %) patients had a toe amputation. In the cohort 63 % was men with a mean age of 71. At time of index amputation the mean age for women was 74 and for men 68 years. Furthermore, 71 % were retired and the majorities (53 %) were living alone. For patients with AKA and BKA 89 % and 86 % respectively, had no prior lower limb a Conclusions: A large group of patients begins their pathway with a major amputation which indicates that patients were waiting too long to seek medical advice or that they were without symptoms for a long time. Further analysis of data will show the distribution of comorbidities such as diabetes and arteriosclerosis and use of medical services will provide more information about different pathways leading to lower limb amputation. 246 DOS Abstracts

Clinical outcome after CT-guided radiofrequency ablation of osteoid osteoma. Long-term follow up in 52 patients. 194. Morten Knudsen, Andreas Riishede, Arne Lücke, John Gelineck, Johnny Keller, Thomas Baad-Hansen Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Radiology, Aarhus University Hospital Background: Osteoid osteoma (OO) is a benign bone tumor characterized by a small central nidus with a high production of prostaglandins in the nidus resulting in characteristic clinical symptoms of constant local pain, most severe at night. Most commonly OO occurs in children and young adults. Surgical excision of the nidus has previously been the first- choice treatment. CT-guided radiofrequency ablation (RFA) has been introduced as a safe, minimal invasive treatment of OO. Purpose / Aim of Study: The aim of this study was to evaluate the longterm clinical outcome after CT-guided RFA in patients with OO performed from 1998 to February 2014 at Aarhus University Hospital. Materials and Methods: The study population included 52 patients with typical clinical history and radiologically confirmed OO who received CT-guided RFA treatment. Clinical outcome was evaluated based on patient questionnaire and medical record review. Findings / Results: Response rate was (52/60) 87% Clinical success of pain relief after the first RFA treatment was found in (46/52) 88% of the patients and after re-rfa clinical success of pain relief in (51/52) 98% of the patients. One patient had an open resection made after RFA. No major complications occurred and four patients had minor complications in terms of small skin burn, minor skin infection and hypoesthesia at the entry point. (50/52) 96% of the patients reported to be very satisfied with the RFA treatment. Conclusions: CT-guided RFA is a safe and effective treatment, with good clinical results and a high patient satisfaction rate with strong reduction of pain and improvement in quality of life. RFA should be the treatment of choice for most OO. DOS Kongressen 2014 247

Extended Antibiotic Prophylaxis is associated with Low Rate of Infection after Tumor Resection and Endoprosthetic Reconstruction involving the Proximal Femur 195. Werner H. Hettwer, Thea B. Hovgaard, Peter Horstmann, Thomas A. Grum- Schwensen, Michael M. Petersen Department of Orthopedics, Rigshospitalet, University of Copenhagen Background: Endoprosthetic reconstruction after tumor resection involving the proximal femur is associated with a substantially higher risk of periprosthetic joint infection (PJI), with reported rates around 10% in a recent systematic review. The optimal duration of antibiotic prophylaxis for this patient population is unknown. Purpose / Aim of Study: To determine the rate of infection and other complications after tumor resection and endoprosthetic reconstruction at our institution. Materials and Methods: We performed a retrospective review of all adult patients who underwent endoprostetic reconstruction of the proximal femur after tumor resection for primary bone sarcomas (n=11) or metastatic bone disease (n=113) in our department from 2010 to 2013. We found 118 patients (F/M =64/54) with a mean age of 65 years (range 16 92) received a total of 124 implants. Findings / Results: We identified 18 major complications (15%): 12 dislocations (10%), 5 PJI (4%), one mechanical complication (1%) and one local recurrence (1%) resulting in a total of 23 revision procedures. Two- stage revision was performed sucessfully in 3 of the 4 patients with infection. Ten patients with instability underwent successful stabilisation by implantation of a constrainment device and did not experience further episodes of dislocation. Conclusions: Compared to the published average we found a low infection rate (4 %) after tumor related enoprothetic reconstruction. Given the very low infection rate identified in our patients, we see no reason to change our current practice of extended antibiotic prophylaxis for high risk patients until very convincing evidence to the contrary becomes available. 248 DOS Abstracts

DOS Bestyrelse Formand Professor, overlæge, dr. med. Søren Overgaard Ortopædkirurgisk afdeling O Odense Universitetshospital Søndre Boulevard 29 5000 Odense C E-mail: president@ortopaedi.dk Næstformand Overlæge, Ph.D. Klaus Hindsø Børnesektionen Ortopædkirurgisk Klinik 2161 HovedOrtoCentret Rigshospitalet Blegdamsvej 9 2100 København E-mail: vicepresident@ortopaedi.dk Afgående formand Ledende overlæge Benn Rønnow Duus Ortopædkirurgisk afdeling M Bispebjerg Hospital, Bispebjerg Bakke 23 2400 København V E-mail: pastpresident@ortopaedi.dk Kasserer Overlæge Henrik Palm Ortopædkirurgisk afdeling Hvidovre Hospital Kettegårds Allé 30 2650 Hvidovre E-mail: tresurer@ortopaedi.dk Redaktør Specialeansvarlig overlæge, ph.d. Steen Lund Jensen Ortopædkirurgien Nordjylland Klinik Farsø, Højgårdsvej 11 9640 Farsø E-mail: editor@ortopaedi.dk Formand for Videnskabeligt Udvalg Overlæge, forskningslektor, Ph.D. Ole Rahbek Børneortopædi, afd. E. Århus Universitetshospital Nørrebrogade 44 8000 Århus C E-mail: scientific@ortopaedi.dk Formand for Kvalitetsudvalget Ledende overlæge Claus Munk Jensen Ortopædkirurgisk afdeling Gentofte Hospital Niels Andersensvej 65 2900 Hellerup E-mail: quality@ortopaedi.dk Formand for Uddannelsesudvalget Overlæge, Ph.D Søren Kold Ortopædkirurgisk afdeling Aalborg Universitetshospital Hobrovej 9000 Aalborg E-mail: education@ortopaedi.dk DOS Kongressen 2014 249