MRI Assessment of Biologic Incorporation of the Graft after ACL Reconstruction with Hamstring Tendons

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1 MRI Assessment of Biologic Incorporation of the Graft after ACL Reconstruction with Hamstring Tendons Poster No.: P-0030 Congress: ESSR 2012 Type: Scientific Exhibit Authors: I. Staikidou 1, G. Giannikouris 1, I. Apostolopoulos 2, K. Pikoulas 1, A. Keywords: DOI: Andreakos 2, G. Mantzikopoulos 1 ; 1 Athens/GR, 2 Melissia, Athens/ GR Musculoskeletal joint, MR, Comparative studies, Grafts /essr2012/P-0030 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 9

2 Purpose For anterior cruciate ligament ( ACL ) reconstruction as an alternative to the bone-patellarbone reconstruction technique the hamstring autograft technique can be used to avoid interfering with the extensor mechanism. In hamstring ACL reconstruction the fixation of the autograft is achieved with different techniques. The purpose of this study is to compare three graft fixation techniques for graft incorporation at the femoral and tibial tunnels with post operative follow-up MRI. Methods and Materials 26 patients were included in the study (16-50 years, mean 30y, 25 male and 1 female). The patients underwent ACL reconstruction with hamstring autograft. Methods of femoral fixation were: Femoral extracortical (Retrobutton)14 patients (group A), femoral transfixation pin fixation device (CrossPin) 5 patients (group B) and aperture fixation (AperFix) 7 patients (group C). Hybrid tibial fixation with interference screw and staple was performed on all patients. All procedures were performed by the same Orthopeadic team. The mean time interval from injury to reconstruction was 10 months. The patients were post operatively followed from 03/2009 to 12/2011. Evaluation was done with clinical examination, knee scores and laxity measurements at 3,6,12 and 24 months. MRI evaluation was done at 6,12 and 24 months on the same MR machine ( Philips Gyroscan 1.5 Tesla, knee coil, axial PDW/TSE/SPIR TR 3300ms TE 17ms 4mm, sagittal T2W/ SE and PDW/SE TR 2360 ms TE 20/80 ms 4mm, coronal T1W/SE TR 569 ms TE 17 ms 3mm and coronal PDW/TSE/SPIR TR 2560 ms TE 17 ms 3mm sequences ). The signal at bone/graft interface, the dimensions and shape of femoral and tibial tunnels and presence of fluid were recorded. Results Clinical evaluation by Lachman and pivot shift tests was normal or nearly normal in 25 patients. 1 patient had a KT-1000 difference of 4mm without any evidence of graft failure. All other patients had a KT-1000 #3mm. No significant differences between the groups were observed with the KT-1000 evaluation. Mean post operative IKDC evaluation was 87/ 85/ 86 and Lysholm score was 89/ 86 /85 respectively for group A,B &C. We considered a >2mm tunnel widening as tunnel emlargement. There was a 10% - 44% increase of diameter of femoral tunnels and 12% - 43% of tibial tunnels at 6 months. Furthermore no enlargement >1mm was observed, except for 1 patient (group A) who Page 2 of 9

3 showed an advancement from 30% at 6 months to 44% at 12 months with no change at 24 months. 2 patients in group A showed a reduction of femoral tunnel diameter by 4%-5% at 24 months (fig. 1 and 2) and 1 patient in group B showed a reduction of femoral tunnel diameter by 11% at 24 months. 3 patients in group A (21,4%), 4 patients in group B (57%) and 2 patients in group C (40%) did not exhibit femoral tunnel enlargement of more than 2mm. 5 patients did not exhibit tibial tunnel enlargement of more than 2mm. Based on the absence or the presence of high signal at the bone/ graft interface, graft incorporation was characterized as complete or incomplete. 64,3% / 80% /85,7% of the grafts (groups A,B,C respectively) were completely incorporated in the femoral tunnel at 6 months and 78,5% / 80% /100% at 12 months, compared to 34,6% at 6 months and 55,6% at 12 months in the tibial tunnel (fig 3 and 4). At 24 months 89% / 100% /100% of the grafts were completely incorporated in the femoral tunnel and 87% in the tibial tunnel(fig 5,6 and 7). Images for this section: Fig. 1: Group A patient. Coronal images (A)PDW/TSE/SPIR, (B)TIW/SE, at 6 months, show high signal at graft/ bone interface on (A)and femoral tunnel widening, best appreciated on (B) [arrows]. Page 3 of 9

4 Fig. 2: Group A patient, the same with fig.1. Coronal images (A)PDW/TSE/SPIR, (B)TIW/ SE, at 24 months. Note the absence of high signal at graft/ bone interface on (A),indicating graft incorporation as well as reduction of femoral tunnel width compared with the image at 6 months in fig. 1, best appreciated on (B) [arrows]. Page 4 of 9

5 Fig. 3: Group B patient. (A) axial image PDW/TSE/SPIR, (B) sagittal image T2W/SE, at 6 months. There is clearly high signal at graft/ bone interface in the tibial tunnel [arrows]. Fig. 4: Group B patient, the same with fig.3. (A) axial image T2W/TSE/SPIR, (B) sagittal image T2W/SE, at 12 months. The high signal at graft/ bone interface in the tibial tunnel that was seen at 6 months (see fig. 3) has been replaced by low and isointense signal, indicating graft incorporation in the tunnel. Page 5 of 9

6 Conclusion Tunnel enlargement after ACL reconstruction with hamstring autografts does not seem to have a negative effect on clinical scores or patient satisfaction. This enlargement has been reported in several publications and its cause is thought to be multifactorial. Variables include both mechanical and biological factors. In our study although the small number of the patients enrolled at this point does not allow for a thorough statistical analysis, there are indications that femoral tunnel enlargement of more than 30% is more common in group A and group B. Similarly, it seems that tibial tunnel enlargement was greater at the intra articular side (funnel shaped) and this may be related to screw position. Although tunnel enlargement does not appear to adversely affect clinical outcome in the short term, it must be noted that it may complicate revision surgery. The presence of high signal at the graft/bone interface on long TR sequences, bone edema around the graft and the presence of fluid in the tunnel have been reported as indications of incomplete graft incorporation in the femoral and tibial tunnels. Using MRI to look for these findings we observed an earlier graft incorporation in the femoral than in the tibial tunnel. We also noted that all these findings decrease continuously with time (fig 5,6 and 7). Factors reported to affect the lack of graft incorporation in the tunnel include graft movement in the tunnel, mismatch of the graft to the tunnel size and shape and early movement of the knee. All these may explain why tunnel widening presents early after ACL reconstruction and stabilizes over time. We believe that in combination with clinical examination and measurements, post operative MR Imaging signal changes at bone/graft interface may be a useful index of biologic ACL graft incorporation. Images for this section: Fig. 5: Group A patient. (A) axial image PDW/TSE/SPIR, (B) and (C)Coronal images PDW/TSE/SPIR, at 6 months. High signal at graft/ bone interface as well as tibial and femoral bone tunnel widening, can be appreciated on all three images [arrows]. Page 6 of 9

7 Fig. 6: Group A patient, the same with fig.5. (A) axial image PDW/TSE/SPIR, (B) and (C)Coronal images PDW/TSE/SPIR, at 12 months. High signal at graft/ bone interface is still apparent at both tibial and femoral tunnels. Note that no further tunnel widening is evident ( compare with fig. 5). Fig. 7: Group A patient, the same with fig.5 and fig.6. (A) axial image PDW/TSE/SPIR, (B) and (C)Coronal images PDW/TSE/SPIR, at 24 months. High signal at graft/ bone interface is still apparent at the tibial tunnel but not at the femoral tunnel. Graft/ bone interface at the femoral tunnel has changed to low/iso-intense. These findings indicate complete graft incorporation in the femoral tunnel and incomplete incorporation (delayed) in the tibial tunnel ( compare with fig. 5 and fig. 6). Page 7 of 9

8 References 1. Murakami Y, Sumen Y, Ochi M, et al. Appearance of anterior cruciate ligament autografts in their tibial bone tunnels on oblique axial MRI.Magn Reson Imaging 1999;17(5): Lajtai G, Humer K, Aitzetmüller G, et al. Serial magnetic resonance imaging evaluation of operative site after fixation of patellar tendon graft with bioabsorbable interference screws in anterior cruciate ligament reconstruction. Arthroscopy 1999;15(7): Uchio Y, Ochi M, Adachi N, et al. Determination of time of biologic fixation after anterior cruciate ligament reconstruction with hamstring tendons.am J Sports Med 2003;31(3): Ma CB, Francis K, Towers J, et al. Hamstring anterior cruciate ligament reconstruction: a comparison of bioabsorbable interference screw and endobutton-post fixation. Arthroscopy 2004;20(2): Weninger P, Zifko B, Liska M, et al. Anterior cruciate ligament reconstruction using autografts and double biodegradable femoral cross-pin fixation: functional, radiographic and MRI outcome after 2-year minimum followup.knee Surg Sports Traumatol Arthrosc 2008;16(11): Silva A, Sampaio R, Pinto E. Femoral tunnel enlargement after anatomic ACL reconstruction: a biological problem? Knee Surg Sports Traumatol Arthrosc 2010;18(9): Jansson KA, Harilainen A, Sandelin J, et al. Bone tunnel enlargement after anterior cruciate ligament reconstruction with the hamstring autograft and endobutton fixation technique. A clinical, radiographic and magnetic resonance imaging study with 2 years follow-up. Knee Surg Sports Traumatol Arthrosc 1999;7(5): Simonian PT, Monson JT, Larson RV. Biodegradable interference screw augmentation reduces tunnel expansion after ACL reconstruction. Am J Knee Surg 2001;14(2): Buelow JU, Siebold R, Ellermann A. A prospective evaluation of tunnel enlargement in anterior cruciate ligament reconstruction with hamstrings: extracortical versus anatomical fixation. Knee Surg Sports Traumatol Arthrosc 2002;10(2): Fules PJ, Madhav RT, Goddard RK, et al. Evaluation of tibial bone tunnel enlargement using MRI scan cross-sectional area measurement after autologous hamstring tendon ACL replacement. Knee 2003;10(1): Wilson TC, Kantaras A, Atay A, et al. Tunnel enlargement after anterior cruciate ligament surgery. Am J Sports Med 2004;32(2): Fauno P, Kaalund S. Tunnel widening after hamstring anterior cruciate ligament reconstruction is influenced by the type of graft fixation used: a prospective randomized study. Arthroscopy 2005;21(11): Kobayashi M, Nakagawa Y, Suzuki T, et al. A retrospective review of bone tunnel enlargement after anterior cruciate ligament reconstruction with Page 8 of 9

9 hamstring tendons fixed with a metal round cannulated interference screw in the femur. Arthroscopy 2006;22(10): Sabat D, Kundu K, Arora S, et al. Tunnel widening after anterior cruciate ligament reconstruction: a prospective randomized computed tomography-- based study comparing 2 different femoral fixation methods for hamstring graft.arthroscopy 2011;27(6): Personal Information Page 9 of 9