BIOMECHANICS OF HALLUX RIGIDUS: Myths and Misconceptions

BIOMECHANICS OF HALLUX RIGIDUS: Myths and Misconceptions Douglas H. Richie, Jr., D.P.M. Clinical Associate Professor, Department of Applied Biomechanics, California School of Podiatric Medicine Seal Beach Podiatry Group Inc drichiejr@aol.com

Hallux Limitus and Hallux Rigidus: Exploring the Myths and Misconceptions Douglas H. Richie, Jr. D.P.M. Seal Beach, California DRichieJr@aol.com Associate Professor of Podiatric Medicine, Western University of Health Sciences Adjunct Associate Professor of Clinical Biomechanics, California School of Podiatric Medicine, Oakland CA

Doug Richie D.P.M. gratefully acknowledges the support and friendship of Paris Orthotics Douglas H. Richie, Jr. D.P.M. Seal Beach, California DRichieJr@aol.com Associate Professor of Podiatric Medicine, Western University of Health Sciences Adjunct Associate Professor of Clinical Biomechanics, California School of Podiatric Medicine, Oakland CA

For lecture notes: www.richiebrace.com www.richiebrace.com

LIMITATION OF RANGE OF MOTION OF THE 1ST MTPJ Hallux Flexus : Davies-Colley (1887) Hallux Rigidus: Cotterill (1887) Hallux limitus: Hiss (1931) Functional Hallux Limitus: Laird (1972)

MYTHS AND MISCONCEPTIONS ABOUT HALLUX RIGIDUS Normal range of motion of the 1st MTPJ

Question #1 1. A minimum of 60 degrees of dorsiflexion of the hallux on the 1st Met is required for normal gait (True or False?) Reports of clinical measurements of ROM of 1st MTP: 65-110 Degrees Dorsiflexion (Buell, Hopson, Joseph, Mann, Shereff) Reports of ROM during gait: 50-90 degrees Dorsiflexion (Buell, Hopson, Johnson, Milne, Sammarco)

MYTHS AND MISCONCEPTIONS ABOUT HALLUX RIGIDUS Normal range of motion of the 1st MTPJ Clinical assessment of ROM of the 1st MTPJ

Relationship Between Clinical Measurements and Motion of the First Metatarsophalangeal Joint During Gait Nawoczenski et al. JBJS 81-A, pp 370-376, March, 1999. Electromagnetic tracking to determine 3-D motion of the hallux relative to the 1st Metatarsal 33 subjects Four Clinical Tests for ROM of 1st MPJ compared to actual ROM of 1st MPJ during gait

Clinical Tests Active ROM-weight bearing Passive ROM- weight bearing Passive ROM-non weight bearing Heel Rise test

Results Walking ROM dorsiflexion: 42 degrees Heel Rise ROM dorsiflexion: Passive ROM non-wt bear: Passive ROM dorsiflexion: Active ROM dorsiflexion wt.bear: 58 degrees 57 degrees 37 degrees * 44 degrees

Measurement of the active range of motion with the subject weight bearing may be a more appropriate choice for a clinical test because the mean value for dorsiflexion more closely matched that during gait. Relationship Between Clinical Measurements and Motion of the First Metatarsophalangeal Joint During Gait Nawoczenski et al. JBJS 81-A, pp 370-376, March, 1999.

Biomechanics of Hallux Rigidus Key Point #1: Patients do not use all of the range of motion available in their pedal joints during gait. Measuring total range of motion of the 1st MTP does not predict how much motion the patient actually needs or uses during gait.

Research Method Subject criteria: o 6 people o 2 males o 4 females o 12 feet o No foot pain or any limited motion at the first mtpj o Treadmill running and walking

Preliminary Results - Walking SUBJECT MAX MIN DIFFERENCE EP-R 176.54 153.11 23.43 EP-L 166.78 140.03 26.75 MA-R 174.18 147.45 26.73 MA-L 176.67 138.46 38.21 JJ-R 175.99 140.73 35.26 JJ-L 179.44 134.35 45.09 JL-R 176.72 149.19 27.53 JL-L 162.42 132.46 29.96 TS-R 169.89 137.69 32.2 TS-L 167.56 121.11 46.45 ZY-R 175.3 134.11 41.19 ZY-L 176.72 136.69 40.03 AVERAGE 34.4025

Preliminary Results - Running SUBJECT MAX MIN DIFFERENCE EP-R 170.45 156.87 13.58 EP-L 174.15 143.28 30.87 MA-R 174.86 147.6 27.26 MA-L 175.75 149.07 26.68 JJ-R 172.52 152.94 19.58 JJ-L 175.38 144.83 30.55 JL-R 177.22 155.48 21.74 JL-L 174.85 151.16 23.69 TS-R 172.86 140.83 32.03 TS-L 168.02 138.5 29.52 ZY-R 171.75 136.63 35.12 ZY-L 173.08 141.49 31.59 AVERAGE 26.8508

Statistical Significance o Standard Deviation o Walking = 7.7575 o Running = 6.1785 o Ttest p-value = 0.002358

Walking Running

When running, compared to walking: - the ankle flexors (Triceps, FDL, FHL) fire earlier -ground reaction forces in FF peak earlier -Early, greater contraction of FHL limits dorsiflexion of the 1 st MTP

When running the Flexor Digitorum Longus and the Flexor hallucis longus fire earlier and resist DORSIFLXION of the digits to a greater degree than during walking.

The flexor hallucis longus can be a natural splint to resist dorsiflexion of the 1 st MTP.

Hallux Rigidus: Role of Soft Tissue Constraints -plantar aponeurosis -flexor hallucis longus

Sectioning of the plantar fascia results in an increased dorsiflexion of the 1st MTP by 9.8 degrees. Harton FM, Weiskopf SA, Goecker RM. Sectioning the plantar fascia. Effect on first metatarsophalangeal joint motion. J Am Podiatr Med Assoc 2002;92:532-6.

Biomechanics of Hallux Rigidus Key Point #4: Dorsiflexion of the 1st MTP is restricted by tension in the soft tissues around the joint: Plantar aponeurosis, FHL tendon, FHB and other sesamoid anchors. Procedures which improve hallux rigidus do so by decompressing the joint, which relaxes tension on these structures.

MYTHS AND MISCONCEPTIONS ABOUT HALLUX RIGIDUS Normal range of motion of the 1st MTPJ Clinical assessment of ROM of the 1st MTPJ Classification of Grades of Disease of Hallux Rigidus Role of Metatarsus Primus Elevatus

First Ray Hypermobility The term hypermobility was first used to describe the mechanical function of the first ray in 1935 by Dudley J. Morton, Professor of Anatomy, Columbia University, in his classic treatise, The Human Foot, on the evolution, physiology, and functional disorders of the foot

Root et al Extensively Discussed First Ray Hypermobility in 1977 Hypermobility is any motion occurring at a joint in response to forces which are interacting at a joint at a time when the joint should be stable under such forces Hypermobility of the first ray is a state of abnormal 1 st ray instability that occurs while the forefoot is bearing weight

How do we measure hypermobility of the First Ray?

Measuring First Ray Mobility Examiner may use an estimated amount of manual force on first metatarsal head to measure first ray mobility Root ML, Orien WP, Weed JH, RJ Hughes: Biomechanical Examination of the Foot, Volume 1. Clinical Biomechanics Corporation, Los Angeles, 1971. Plane of left thumbnail 2 mm Plane of right thumbnail

Position of Ankle Can Affect First Ray Mobility Plantarflex: Increase mobility Dorsiflex: Decrease mobility Grebing, BR; Coughlin, MJ: The effect of ankle position on the exam for first ray mobility. Foot Ankle Int. 25:467 475.

Devices which measure First Ray ROM Glasoe, WM; Grebing, BR; Beck, S; Coughlin, MJ; Saltzman, CL: A comparison of device measures of dorsal first ray mobility. Foot Ankle Int. 26:957 961. Kim, JY; Keun Hwang, S; Tai Lee, K;Won Young, K; Seon Jung, J: A simpler device for measuring the mobility of the first ray of the foot. Foot Ankle Int. 29:213 218. Klaue, K; Hansen, ST; Masquelet, AC: Clinical, quantitative assessment of first tarsometatarsal mobility in the sagittal plane and its relation to hallux valgus deformity. Foot Ankle Int. 15:9 13.

Glasoe and coworkers have done considerable research on developing a special apparatus that applies a precise amount of loading force on the first metatarsal head to determine the amount of first ray mobility Glasoe WM, Yack HJ, Saltzman CL: The reliability and validity of a first ray measurement device. Foot Ankle Int. 21:240-246, 2000. Glasoe WM, Allen MK, Saltzman CL, et al: Comparison of two methods used to assess first ray mobility. Foot Ankle Int. 23:248-252, 2002. Glasoe WM, Allen MK, Ludewig PM, Saltzman CL: Dorsal mobility and first ray stiffness in patients with diabetes mellitus. Foot Ankle Int. 25:550-555, 2004.

Pronation of the subtalar joint does not appear to be linked to hypermobility of the 1 st ray, or to reduced range of motion of the 1 st MTP.

Hypermobile First Ray? 82 Asyx Adults Dorsiflexion ROM of 1st Ray measured with mobility device as described By Glassoe et al. 3 subgroups defined: hypomobile, normal and hypermobile Plantar pressures and hindfoot kinematics measured during walking Cornwall MW, McPoil TG, Fishco WD, et al: The influence of first ray mobility on forefoot plantar pressure and hindfoot kinematics during walking. Foot and Ankle Int27:539-547, 2006.

RESULTS Based on the findings of this study, it appears that a person with a hypomobile first ray does not demonstrate increased plantar pressure or force under the first metatarsal head or diminished hindfoot eversion during walking. Conversely, the foot with a hypermobile first ray does not show increased pressure and force under the second metatarsal head along with increased hindfoot eversion during walking. Hypomobile First Ray had significantly more hindfoot eversion compared to the normals and hypermobile first rays Cornwall MW, McPoil TG, Fishco WD, et al: The influence of first ray mobility on forefoot plantar pressure and hindfoot kinematics during walking. Foot and Ankle Int27:539-547, 2006.

Is Metatarsus Primus Elevatus equivalent to Hypermobility of the First Ray?

Coughlin MJ, Shurnas PS: Hallux Rigidus: Demographics, Etiology, and Radiographic Assessment. Foot & Ankle International/Vol. 24, No. 10/October 2003, pp 731-743. Hallux rigidus was NOT associated with: MPE First ray hypermobility Increased first metatarsal length Achilles or gastrocnemius tendon tightness Abnormal foot posture

Coughlin MJ, Shurnas PS: Hallux Rigidus: Demographics, Etiology, and Radiographic Assessment. Foot & Ankle International/Vol. 24, No. 10/October 2003, pp 731-743. Hallux rigidus WAS associated with: hallux valgus interphalangeus female gender and a positive family history in bilateral cases. In most cases the problem was bilateral, the exceptions being when there was trauma involved. If trauma had occurred, then the problem was unilateral.

MYTHS AND MISCONCEPTIONS ABOUT HALLUX RIGIDUS Normal range of motion of the 1st MTPJ Clinical assessment of ROM of the 1st MTPJ Classification of Grades of Disease of Hallux Rigidus Role of Metatarsus Primus Elevatus

Mechanical Restriction of ROM of the 1st MTPJ Elevate First Metatarsal 4mm dorsal: Decrease ROM 19% Elevate First Metatarsal 8mm dorsal: Decrease ROM 35% Roukis TS, Scherer PR, Anderson CF: Position of the first ray and motion of the first metatarsophalangeal joint. JAPMA 86: 538, 1996

The present study determined that a statistical difference exists for each of the radiographic measurements performed n the halux valgus, plantar fasciitis, and Morton s neuroma patient populations compared with the hallux rigidus populations. Despite these findings, the role that distal first metatarsal plantar-displacement osteotomy plays in the surgical management of hallux rigidus is questioned based on several studies that have failed to show any reduction in the metatarsus primus elevatus or hallux equinus angles postoperatively and the positive subjective and objective findings obtained after other simpler procedures. Roukis TS: Metatarsus primus elevatus in hallux rigidus: Fact or fiction? JAPMA 95: 221, 2005

Horton, G; Park, Y; Myerson, M: Role of metatarsus primus elevatus in the pathogenesis of hallux rigidus. Foot Ankle Int. 20:777 780, 1999. There did not seem to be any direct or linear relation between the amount of elevation of the first ray and the grade of hallux rigidus. It seems more likely that elevation of the first metatarsal in patients with advanced hallux rigidus is a secondary phenomenon rather than a primary cause. This is evidenced by the fact that patients with grade I or grade I1 hallux rigidus had a mean elevation of 7.3 and 7.4 mm, respectively, whereas those with advanced hallux rigidus had a mean elevation of 9.2 mm.

Coughlin MJ, Shurnas PS: Hallux Rigidus: Demographics, Etiology, and Radiographic Assessment. Foot & Ankle International/Vol. 24, No. 10/October 2003, pp 731-743. Based on the results of this study, there were 10 cases of up to 10 mm of MPE identified. However, it appeared that MPE was a secondary change as there was a correlation with advancing grade of hallux rigidus. We believe that elevatus is a secondary change resulting from an arthritic MTP joint and that the first ray elevation associated with radiographically advanced hallux rigidus is analogous to metatarsus primus varus in hallux valgus; as the bunion deformity progresses so does the 1 2 intermetatarsal angle, and similarly as hallux rigidus progresses so does the first ray elevation.

Coughlin MJ, Shurnas PS: Hallux Rigidus: Demographics, Etiology, and Radiographic Assessment. Foot & Ankle International/Vol. 24, No. 10/October 2003, pp 731-743. However, treating elevatus with osteotomies appears to treat a secondary rather than a primary problem, and these osteotomies have been associated with difficult salvage procedures when they fail.

STUDIES SHOW NO IMPROVEMENT OF METATARSUS PRIMUS ELEVATUS OR HALLUX EQUINUS MEASUREMENTS AFTER DISTAL FIRST METATARSAL HEAD OSTEOTOMIES Laakmann G, Green RM, Green DR: The modified Waterman procedure: A preliminary Retrospective Study in Reconstructive Surgery of the Foot and Leg: Update 95, ed by CA Camasta, p 128, The Podiatry Institute, Tucker, BA, 1995. Dickerson JB, Green R, Gren DR: Long-term follow-up of the Green- Waterman osteotomy for hallux limitus. JAPMA 92: 543, 2002. Roukis TS, Jacobs PM, Dawson DM, ET AL: A prospective comparison of clinical, radiographic, and intraoperative features of hallux rigidus: short-term follow-up and analysis. J Foot Ankle Surg 41: 158, 2002.

Biomechanics of Hallux Rigidus Key Point #2: Metatarsus Primus Elevatus is the RESULT of, not the CAUSE of Hallux Rigidus

Biomechanics of Hallux Rigidus Key Point #3: Osteotomies, intended to plantarflex the first metatarsal will not achieve that end result as long as motion is still available in the joints of the First Ray

What does the science reveal? Attempts to plantarflex the First Ray via Osteotomy will not lead to overall plantarflexion Explanation: Other joints will compensate and increase motion to balance the foot

Question #5 5. A standard lateral weight bearing x-ray depicts the alignment of the osseous structures of the foot during the midstance period of gait (True or False?) Standard Lateral X-Ray Positioning Angle and Base of Gait? Static Stance Intrinsics and Extrinsics Inactive Midstance in Gait: Single Support

RELAXED STANCE 1. Extrinsic foot muscles inactive 2. Arch integrity maintained solely by plantar fascia Basmajian, 1963 Huang, 1993 Reeser, 1983

Static Stance No windlass No plantar intrinsics No peroneus longus

FIGURE 1-96 This figure shows the foot in final propulsion. The hallux is dorsiflexed 75 from the 1 st metatarsal as heel lift elevated the base of the 1 st ray 48 and the 1 st ray plantarflexed in relation to the rest of the foot by 10. The transverse axis of motion of the 1 st metatarsophalangeal joint (T.A.) has shifted to allow the proximal phalanx of the hallux to gllide to the dorsum of the 1 st metatarsal head.

Dynamic Gait In terminal stance: Foot inverts 1 st ray plantar flexes below 2-5 Due to: Peroneus longus Plantar intrinsics Windlass

Dynamic Gait 1 st Ray plantarflexes below 2-5 Inverting Foot

Removing First Ray Elevatus On lateral wt. Bearing radiograph: Hallux Dorsiflexion Stress Coughlin Chinese Finger Trap Bouche

What happens when you surgically Re- Align the First Ray via osteotomy?

6 cadaver specimens Plantar flexion motion of 1st Ray in closed chain measured: Hallux plantar grade & windlass activated Comparison of MPV condition vs corrected In MPV: no signif. PF of 1st Ray with DF of hallux In rectus alignment, PF of 1st Ray increased 4 with DF of Hallux Rush SM. Christensen JC, Johnson CH: Biomechanics of the First Ray. Part II: Metatarsus Primus Varus as a Case of Hypermobility. Jour Foot & Ankle Surg 39: 68, 2000.

The ability of the foot to engage the windlass mechanism is dependant on a fully corrected first ray which realigns the metatarsal with the sesamoid apparatus and hallux. We were able to show in a cadaver model that functional stability can be increased by 26% with deformity correction without an arthrodesis procedure. Rush SM. Christensen JC, Johnson CH: Biomechanics of the First Ray. Part II: Metatarsus Primus Varus as a Case of Hypermobility. Jour Foot & Ankle Surg 39: 68, 2000.

What does the science reveal? Restoration of alignment of the First Ray in the transverse plane will significantly improve stiffness and reduce hypermobility.

What happens when you surgically Re-Align the First Ray via fusion?

MYTHS AND MISCONCEPTIONS ABOUT HALLUX RIGIDUS Normal range of motion of the 1st MTPJ Clinical assessment of ROM of the 1st MTPJ Classification of Grades of Disease of Hallux Rigidus Role of Metatarsus Primus Elevatus Outcomes of Surgical Procedures

Level of Evidence Level I: high quality prospective randomized clinical trial Level II: prospective comparative study Level III: retrospective case control study Level IV: case series Level V: expert opinion

Grades of Recommendation Grade A treatment options are supported by strong evidence (consistent with Level I or II studies) Grade B treatment options are supported by fair evidence (consistent with Level III or IV studies) Grade C treatment options are supported by either conflicting or poor quality evidence (consistent with Level IV studies) Grade I when insufficient evidence exists to make a recommendation

Yee G. Lau J. Current concepts Review: Hallux Rigidus. Foot Ankle Int. 29(6); 637-646, 2008. PROCEDURE Non-Operative (Foot orthoses, footwear Modification, corticosteroid, Sodium hyaluronate) Cheilectomy Grade I and II Grade III Prox. Phal. Osteotomy 1 st Met Osteotomy C GRADE of RECOMMENDATION Keller Arthroplasty B (with reservations) B B I I Interpositional Arthroplasty Arthrodesis Silastic Implant Two Piece Metal Hemi Arthroplasty I B C Not recommended C

Deborah A. Nawoczenski, P.T., Ph.D.1; John Ketz, M.D.2; Judith F. Baumhauer, M.D. Dynamic Kinematic and Plantar Pressure Changes Following Cheilectomy for Hallux Rigidus: A Mid-Term Followup. Foot & Ankle International/Vol. 29, No. 3/March 2008 During gait, however, the amount of dorsiflexion relative to abduction changed between pre-op and postoperative testing. Expressing this kinematic coupling relationship as a ratio, the preoperative ratio of dorsiflexion to abduction was 1.17:1, suggesting that for every 1.17 degree of hallux dorsiflexion, approximately 1 degree of abduction occurred during gait. Following surgery, this ratio increased to 1.7:1, indicating a greater amount of hallux dorsiflexion, relative to abduction during gait. This change in kinematic coupling may be considered a favorable outcome, as first MTP dorsiflexion, rather than off-axis abduction, is the desired motion during terminal stance/push off of gait. These findings may help to explain the satisfactory outcomes following cheilectomy surgery, in spite of motion restrictions.

J Foot Ankle Surg. 2010 Nov-Dec;49(6):553-60. Clinical outcomes after isolated periarticular osteotomies of the first metatarsal for hallux rigidus: a systematic review. Roukis TS. Abstract The author undertook a systematic review of electronic databases and other relevant sources to identify material relating to the clinical outcomes and need for surgical revision after isolated periarticular osteotomy of the first metatarsal for hallux rigidus. Information from peer-reviewed journals, as well as from non-peer-reviewed publications, abstracts and posters, and unpublished works, was also considered. In an effort to procure the highest quality studies available, studies were eligible for inclusion only if they involved consecutively enrolled patients undergoing isolated periarticular osteotomy of the first metatarsal for hallux rigidus, involved a prospective study design, included some form of objective and subjective data analysis, evaluated patients at a mean follow-up 12 months' duration, and included details of complications requiring surgical intervention. Four studies involving 93 isolated periarticular osteotomies of the first metatarsal followed up for a weighted mean of 18.6 months were identified that met the inclusion criteria.

J Foot Ankle Surg. 2010 Nov-Dec;49(6):553-60. Clinical outcomes after isolated periarticular osteotomies of the first metatarsal for hallux rigidus: a systematic review. Roukis TS. Peak dorsiflexion range of motion of the first metatarsophalangeal joint for the entire cohort of 93 patients increased 10.4. The American Orthopaedic Foot and Ankle Society Hallux Metatarsophalangeal-Interphalangeal Scoring Scale for the entire cohort of 93 patients increased 39 points from a weighted mean of 47.2 preoperatively to 86.2 postoperatively. For the two studies that included it, complete satisfaction or satisfaction with reservations was reported in only 55/75 (73.3%) patients, with the remainder being dissatisfied. A total of 21 (22.6%) procedures underwent surgical revision in the form of hardware removal (n = 8), lesser metatarsal surgery for intractable postoperative metatarsalgia (n = 7), no mention of revision procedure (n = 3), Keller resection arthroplasty (n = 2), and treatment of infection with revision of non-union (n = 1). Two studies specified the grade of hallux rigidus that underwent revision surgery after isolated periarticular osteotomy of the first metatarsal as follows: grade I, 16.7% (n = 3/18) and grade II, 30.5% (n = 18/59).

J Foot Ankle Surg. 2010 Nov-Dec;49(6):553-60. Clinical outcomes after isolated periarticular osteotomies of the first metatarsal for hallux rigidus: a systematic review. Roukis TS. Finally, a total of 30.5% (n = 18/59) of patients developed postoperative metatarsalgia or stress fracture. Additional prospective studies involving validated subjective and objective outcome measurement tools with computerized gait analysis and long-term follow-up after isolated periarticular osteotomy of the first metatarsal for the various grades of hallux rigidus, as well as with comparison with isolated cheilectomy and Valenti arthroplasty, would be beneficial. Based on the high incidence of complications until these studies can be completed, routine use of isolated periarticular osteotomy of the first metatarsal for hallux rigidus should be performed with caution or not at all.

J Foot Ankle Surg. 2010 Nov-Dec;49(6):546-52. Epub 2010 Sep 15. Does total joint replacement or arthrodesis of the first metatarsophalangeal joint yield better functional results? A systematic review of the literature. Brewster M. Abstract As first metatarsophalangeal joint arthrodesis is generally considered to be a successful procedure for the treatment of hallux rigidus, many surgeons question the usefulness of total joint replacement. In an effort to elucidate the clinical evidence, we undertook a systematic review of the literature comparing the functional outcomes of arthrodesis and joint replacement in first metatarsophalangeal surgery. Using multiple search engines and medical subject headings, 10 articles were eligible for inclusion: 5 featured arthrodesis and 5 featured total joint replacement. The American Orthopaedic Foot and Ankle Society-Hallux metatarsophalangeal-interphalangeal score was used in all articles. The mean age at operation was 53 years for joint replacement patients and 55 for those undergoing joint arthrodesis. Most patients in all studies were female. There was a significant increase from pre- to postoperative scores in both procedures. The median postoperative score for joint replacement was 83/100 (range 74-95) and 82/100 (range 78-89) for arthrodesis. The median revision rate in joint replacements was 7% (range 0%-10%) and 0% (range 0%-12%) for arthrodesis. This systematic review reveals that arthrodesis achieves better functional outcomes than total joint replacement. The operative techniques and prostheses for joint replacements are however still in an early stage of development and advances still need to be achieved to produce a more successful and anatomical prosthesis that could be functionally superior to an arthrodesis.

COMPENSATION FOR A PAINFUL 1ST MTP Alteration in gait by weight shifting laterally and toeing off over the lesser metatarsal (fourth and fifth) heads externally rotating at the hip during swing phase of gait to allow for complete toe clearance. Ankle push-off power is reduced VanGheluwe, B; Dananberg, HJ; Hagman, F; Vanstaen, K: Effects of hallux limitus on plantar foot pressure and kinematics during walking. J. Am. Podiatr. Med. Assoc. 96:428 436, 2006. Brodsky, JW; Baum, BS; Pollo, FE; Mehta, H: Prospective Gait Analysis in Patients with First Metatarophalangeal Joint Arthrodesis for Hallux Rigidus. Foot Ankle Int. 28:162 165, 2007. Mulier, T; Steenwerckx, A; Thienpont, E; et al.: Results after cheilectomy in athletes with hallux rigidus. Foot Ankle. 20:232 237, 1999. Nawoczenski, DA: Nonoperative and operative intervention for hallux rigidus. J Orthop. Sports Phys. Ther. 29:727 735, 1999

Hallux Rigidus Maher AJ, Metcalfe SA. First MTP joint arthrodesis for the treatment of hallux rigidus : Results of 29 consecutive cases using the foot health status questionnaire validated measurement tool. The Foot 18: 123-130, 2008. Concerns exist within the literature that fusion of the first MTP joint may be detrimental to foot function and normal gait. However, in this series foot function as judged by the FHSQ scores improved significantly supporting the argument that fusion actually stabilizes the first MTP joint restoring weight bearing under the joint and in doing so allows the restoration of hallux propulsion.

Studies of gait after fusion of 1st MTPJ Brodsky JW, Baum BS, Pollo FE, Hehta H, et al. Prospective gait analysis in patients with first metatarsophalangeal joint arthrodesis for hellux rigidus. Foot Ankle Int 2007: 28(2): 162-5. DeFrino PF, Brodsky JW, Pollo FE, Crenshaw SJ, Beischer AD, et al. First metatarsophalangeal arthrodesis: a clinical, pedobarographic and gait analysis study. Foot Ankle Int 2002: 23(6): 496-502.

Vol. 23(3): 496-502, 2002 Summary: -Normal peak pressures across hallux over shorter duration. -Weight-bearing role of 1 st ray reestablished. -Force & pressure in lesser toes increased. -Shorter step-length when pushing-off involved side. -Reduction of ankle PF angle at toe-off. -Decreased ankle PF moment & ankle power at toe-off. -No change in hip or knee angle at toe-off.

Altered gait patterns in hallux rigidus -Are the changes due to restricted ROM of the 1 st MTP? -Or, are the changes due to pain?

Therefore, should the goal of surgery be restoration of ROM of the 1 st MTP? Or Elimination of pain at the 1 st MTP?

The best surgical outcomes for hallux rigidus do not increase ROM of the 1 st MTP.they eliminate pain

What are the best surgical options for the Active Patient? Grade 1 and 2: Cheilectomy Grade 3 and 4: Arthrodesis

Hallux Rigidus in the Running Athlete Rationale for Cheilectomy - Literature supports the favorable outcomes in all patient populations - Relative low risk, and minimal disability - Will reduce pain and may improve ROM - Downside: Probably not a lifetime correction for the runner

Deborah A. Nawoczenski, P.T., Ph.D.1; John Ketz, M.D.2; Judith F. Baumhauer, M.D. Dynamic Kinematic and Plantar Pressure Changes Following Cheilectomy for Hallux Rigidus: A Mid-Term Followup. Foot & Ankle International/Vol. 29, No. 3/March 2008 Conclusion: Cheilectomy was effective in maintaining balanced plantar loading. First MTP motion increased but dorsiflexion was still less than normative values. The magnitude of dorsiflexion relative to abduction favorably improved during gait. These findings suggest that kinematics continue to be altered and may lead to further degenerative joint changes. Exploration of alternative surgical techniques is warranted.

Hallux Rigidus in the Running Athlete: Downside of Distal 1st Metatarsal Osteotomies - Success is based upon decompression of the 1st MTP, not plantarflexion - The more decompression, the more shortening - The more shortening, the greater the risk of transfer metatarsalgia - Greater peak forefoot pressures in running will accentuate metatarsalgia

Hallux Rigidus in the Running Athlete Downside of Implant Arthroplasty - Current understanding of the mechanics of the 1st MTP in walking is limited - Current understanding of the mechanics of the 1st MTP in running is non-existent - Speculate that compressive forces and shear forces are magnified in running - Little good options available when implant fails

Do prosthetic implants for the 1 st MTP function allow the coupled motion of the 1 st MTP? - dorsiflexion-abduction -plantarflexion-inversion

First Ray First Ray dorsiflexion preceeds MTJ supination about longt. axis. First Ray dorsiflexes and inverts. Kelso SF, Richie DH, Cohen IR, Weed JH and Root M: Direction and range of motion of the first ray. JAPMA 72: 600, 1982

First Ray Average total ROM = 12.38 mm Total frontal plane motion = 8.23º Sagittal Ratio = 0.77º Frontal Kelso SF, Richie DH, Cohen IR, Weed JH and Root M: Direction and range of motion of the first ray. JAPMA 72: 600, 1982

8º

Hallux Rigidus in the Running Athlete Rationale for Arthrodesis - In Grade 3 and 4 the ROM of the 1st MTP has already been lost - The athlete has been running with little ROM for years - The disability of hallux rigidus is the PAIN, not loss of ROM - Goal of surgery is to eliminate PAIN, not restore ROM

Current Understanding of Hypermobility of the First Ray Why is the science so contradictory? We do not know how to measure this condition We do not understand the role of this condition in common pathologies: Hallux valgus, hallux rigidus, adult acquired flatfoot

Metatarsus Primus Elevatus What are the final recommendations? To reduce hypermobility: Restore transverse plane alignment of the 1 st metatarsal over the sesamoids To improve alignment of the medial arch: Fuse the 1 st TMT (Lapidus)

Biomechanics of Hallux Rigidus Key Point #5: Foot orthotic interventions which decrease tension on the plantar aponeurosis can be expected to improve range of motion and decompress the 1st MTP.

What are the essential and nonessential joints of the First Ray?

Question #8 8. The majority of sagittal plane motion of the 1st Ray takes place at the 1st Met Medial Cuneiform joint (rather than Med.Cun.-Navicular Joint) (True or False) Which joint in the First Ray Segment provides the most motion? 1st Met-Medial Cuneiform Navicular-Cuneiform

Medial view of first ray dissected free of skin and muscle attachments. Method of sagittal plane measurement is demonstrated showing calipers on pin in medial cuneiform and Devil s Level on platform on 1 st metatarsal.

First Ray First Ray dorsiflexion preceeds MTJ supination about longt. axis. First Ray dorsiflexes and inverts. Kelso SF, Richie DH, Cohen IR, Weed JH and Root M: Direction and range of motion of the first ray. JAPMA 72: 600, 1982

First Ray Average total ROM = 12.38 mm Total frontal plane motion = 8.23º Sagittal Ratio = 0.77º Frontal Kelso SF, Richie DH, Cohen IR, Weed JH and Root M: Direction and range of motion of the first ray. JAPMA 72: 600, 1982

What happens when you fuse one of the joints of the First Ray?

Results of Fusion of Joints of the First Ray

Fusion of the First Ray Summary Out of 17 specimens, only 5 demonstrated significant reduction of motion by fusing either the 1st TMT or the Nav Cun joints. The 1st TMT fusion had the largest restriction of motion.

Fusion of the First Ray Summary Three specimens demonstrated mild reduction of motion, with either fusion showing similar results.

Fusion of the First Ray Summary The nine remaining specimens showed no significant reduction of motion of the First Ray, either by fusing the 1st TMT or the Nav Cun joints.

Fusion of the First Ray Summary When there was a significant reduction of overall motion of the First Ray, it was the 1st TMT fusion which appeared to have the largest influence. However, this only occurred in 1/3 of the cases.

Fusion of the First Ray Summary Out of 17 specimens, only 5 demonstrated significant reduction of motion by fusing either the 1st Met-Cun or the Nav Cun joints. The 1st Met-Cun fusion had the largest restriction of motion. Three specimens demonstrated mild reduction of motion, with either fusion showing similar results. The nine remaining specimens showed no significant reduction of motion of the First Ray, either by fusing the 1st Met-Cun or the Nav Cun joints. When there was a significant reduction of overall motion of the First Ray, it was the 1st Met- Cun fusion which appeared to have the largest influence. However, this only occurred in 1/3 of the cases.

Current Understanding of Hypermobility of the First Ray Why is the science so contradictory? We do not know how to measure this condition We do not understand the role of this condition in common pathologies: Hallux valgus, hallux rigidus, adult acquired flatfoot

Metatarsus Primus Elevatus What are the final recommendations? To reduce hypermobility: Restore transverse plane alignment of the 1 st metatarsal over the sesamoids To improve alignment of the medial arch: Fuse the 1 st TMT (Lapidus)

Biomechanics of Hallux Rigidus Key Point #1: Patients do not use all of the range of motion available in their pedal joints during gait. Measuring total range of motion of the 1st MTP does not predict how much motion the patient actually needs or uses during gait.

Biomechanics of Hallux Rigidus Key Point #2: Metatarsus Primus Elevatus is the RESULT of, not the CAUSE of Hallux Rigidus

Biomechanics of Hallux Rigidus Key Point #3: Osteotomies, intended to plantarflex the first metatarsal will not achieve that end result as long as motion is still available in the joints of the First Ray

Biomechanics of Hallux Rigidus Key Point #4: Dorsiflexion of the 1st MTP is restricted by tension in the soft tissues around the joint: Plantar aponeurosis, FHL tendon, FHB and other sesamoid anchors. Procedures which improve hallux rigidus do so by decompressing the joint, which relaxes tension on these structures.

Biomechanics of Hallux Rigidus Key Point #5: Foot orthotic interventions which decrease tension on the plantar aponeurosis can be expected to improve range of motion and decompress the 1st MTP.

The Twisted Plate Theory of Foot Stability Key Point: With the foot resting on the ground, everting the hindfoot will increase ground reaction forces (plantar pressure) against the First metatarsal head. Applying a 6 degree medial (varus) wedge across the forefoot will increase ground reaction forces (plantar pressure) against the First metatarsal head. A Cotton osteotomy or plantar flexion osteotomy anywhere along the First Ray will increase ground reaction forces (plantar pressure) against the First metatarsal head.

The Twisted Plate Theory of Foot Stability Essential Key Point! Any measure which increases plantar pressure at the 1st metatarsal will deliver dorsiflexion moment, resulting in dorsiflexion motion across the key joints of the First Ray. As long as there is motion available in the N-C and Med Cun-1st Met joints, any surgical procedure which increases pressure against the plantar surface of the first metatarsal will cause an immediate dorsiflexion of the first ray back to its original state of equilibrium. In the lateral column, increased plantar pressure under 4th and 5th metatarsals does not cause dorsiflexion motion of the Calc-Cuboid or Cuboid-4th and 5th mets because these joints are inherently stable.

COMPENSATION FOR A PAINFUL 1ST MTP Alteration in gait by weight shifting laterally and toeing off over the lesser metatarsal (fourth and fifth) heads externally rotating at the hip during swing phase of gait to allow for complete toe clearance. Ankle push-off power is reduced VanGheluwe, B; Dananberg, HJ; Hagman, F; Vanstaen, K: Effects of hallux limitus on plantar foot pressure and kinematics during walking. J. Am. Podiatr. Med. Assoc. 96:428 436, 2006. Brodsky, JW; Baum, BS; Pollo, FE; Mehta, H: Prospective Gait Analysis in Patients with First Metatarophalangeal Joint Arthrodesis for Hallux Rigidus. Foot Ankle Int. 28:162 165, 2007. Mulier, T; Steenwerckx, A; Thienpont, E; et al.: Results after cheilectomy in athletes with hallux rigidus. Foot Ankle. 20:232 237, 1999. Nawoczenski, DA: Nonoperative and operative intervention for hallux rigidus. J Orthop. Sports Phys. Ther. 29:727 735, 1999

Vol. 23(3): 496-502, 2002 Summary: -Normal peak pressures across hallux over shorter duration. -Weight-bearing role of 1 st ray reestablished. -Force & pressure in lesser toes increased. -Shorter step-length when pushing-off involved side. -Reduction of ankle PF angle at toe-off. -Decreased ankle PF moment & ankle power at toe-off. -No change in hip or knee angle at toe-off.

Altered gait patterns in hallux rigidus -Are the changes due to restricted ROM of the 1 st MTP? -Or, are the changes due to pain?

Therefore, should the goal of surgery be restoration of ROM of the 1 st MTP? Or Elimination of pain at the 1 st MTP?

The best surgical outcomes for hallux rigidus do not increase ROM of the 1 st MTP.they eliminate pain

BEFORE AFTER

Functional Hallux Limitus Enhance 1 st MPJ Motion: Kinetic Wedge 1 st Met Cutout Cluffy Wedge

KINETIC WEDGE 1 ST MET CUT OUT CLUFFY WEDGE

Hallux Rigitus / Sesamoid Injuries Block 1st MPJ Motion: Plate Insole Plate Midsole Orthotic Foot Plate Extension

MYTHS AND MISCONCEPTIONS ABOUT HALLUX RIGIDUS Normal range of motion of the 1st MTPJ Clinical assessment of ROM of the 1st MTPJ Classification of Grades of Disease of Hallux Rigidus Role of Metatarsus Primus Elevatus Outcomes of Surgical Procedures

Level of Evidence Level I: high quality prospective randomized clinical trial Level II: prospective comparative study Level III: retrospective case control study Level IV: case series Level V: expert opinion

Grades of Recommendation Grade A treatment options are supported by strong evidence (consistent with Level I or II studies) Grade B treatment options are supported by fair evidence (consistent with Level III or IV studies) Grade C treatment options are supported by either conflicting or poor quality evidence (consistent with Level IV studies) Grade I when insufficient evidence exists to make a recommendation

Yee G. Lau J. Current concepts Review: Hallux Rigidus. Foot Ankle Int. 29(6); 637-646, 2008. PROCEDURE Non-Operative (Foot orthoses, footwear Modification, corticosteroid, Sodium hyaluronate) Cheilectomy Grade I and II Grade III Prox. Phal. Osteotomy 1 st Met Osteotomy C GRADE of RECOMMENDATION Keller Arthroplasty B (with reservations) B B I I Interpositional Arthroplasty Arthrodesis Silastic Implant Two Piece Metal Hemi Arthroplasty I B C Not recommended C

Deborah A. Nawoczenski, P.T., Ph.D.1; John Ketz, M.D.2; Judith F. Baumhauer, M.D. Dynamic Kinematic and Plantar Pressure Changes Following Cheilectomy for Hallux Rigidus: A Mid-Term Followup. Foot & Ankle International/Vol. 29, No. 3/March 2008 During gait, however, the amount of dorsiflexion relative to abduction changed between pre-op and postoperative testing. Expressing this kinematic coupling relationship as a ratio, the preoperative ratio of dorsiflexion to abduction was 1.17:1, suggesting that for every 1.17 degree of hallux dorsiflexion, approximately 1 degree of abduction occurred during gait. Following surgery, this ratio increased to 1.7:1, indicating a greater amount of hallux dorsiflexion, relative to abduction during gait. This change in kinematic coupling may be considered a favorable outcome, as first MTP dorsiflexion, rather than off-axis abduction, is the desired motion during terminal stance/push off of gait. These findings may help to explain the satisfactory outcomes following cheilectomy surgery, in spite of motion restrictions.

J Foot Ankle Surg. 2010 Nov-Dec;49(6):553-60. Clinical outcomes after isolated periarticular osteotomies of the first metatarsal for hallux rigidus: a systematic review. Roukis TS. Abstract The author undertook a systematic review of electronic databases and other relevant sources to identify material relating to the clinical outcomes and need for surgical revision after isolated periarticular osteotomy of the first metatarsal for hallux rigidus. Information from peer-reviewed journals, as well as from non-peer-reviewed publications, abstracts and posters, and unpublished works, was also considered. In an effort to procure the highest quality studies available, studies were eligible for inclusion only if they involved consecutively enrolled patients undergoing isolated periarticular osteotomy of the first metatarsal for hallux rigidus, involved a prospective study design, included some form of objective and subjective data analysis, evaluated patients at a mean follow-up 12 months' duration, and included details of complications requiring surgical intervention. Four studies involving 93 isolated periarticular osteotomies of the first metatarsal followed up for a weighted mean of 18.6 months were identified that met the inclusion criteria.

J Foot Ankle Surg. 2010 Nov-Dec;49(6):553-60. Clinical outcomes after isolated periarticular osteotomies of the first metatarsal for hallux rigidus: a systematic review. Roukis TS. Peak dorsiflexion range of motion of the first metatarsophalangeal joint for the entire cohort of 93 patients increased 10.4. The American Orthopaedic Foot and Ankle Society Hallux Metatarsophalangeal-Interphalangeal Scoring Scale for the entire cohort of 93 patients increased 39 points from a weighted mean of 47.2 preoperatively to 86.2 postoperatively. For the two studies that included it, complete satisfaction or satisfaction with reservations was reported in only 55/75 (73.3%) patients, with the remainder being dissatisfied. A total of 21 (22.6%) procedures underwent surgical revision in the form of hardware removal (n = 8), lesser metatarsal surgery for intractable postoperative metatarsalgia (n = 7), no mention of revision procedure (n = 3), Keller resection arthroplasty (n = 2), and treatment of infection with revision of non-union (n = 1). Two studies specified the grade of hallux rigidus that underwent revision surgery after isolated periarticular osteotomy of the first metatarsal as follows: grade I, 16.7% (n = 3/18) and grade II, 30.5% (n = 18/59).

J Foot Ankle Surg. 2010 Nov-Dec;49(6):553-60. Clinical outcomes after isolated periarticular osteotomies of the first metatarsal for hallux rigidus: a systematic review. Roukis TS. Finally, a total of 30.5% (n = 18/59) of patients developed postoperative metatarsalgia or stress fracture. Additional prospective studies involving validated subjective and objective outcome measurement tools with computerized gait analysis and long-term follow-up after isolated periarticular osteotomy of the first metatarsal for the various grades of hallux rigidus, as well as with comparison with isolated cheilectomy and Valenti arthroplasty, would be beneficial. Based on the high incidence of complications until these studies can be completed, routine use of isolated periarticular osteotomy of the first metatarsal for hallux rigidus should be performed with caution or not at all.

J Foot Ankle Surg. 2010 Nov-Dec;49(6):546-52. Epub 2010 Sep 15. Does total joint replacement or arthrodesis of the first metatarsophalangeal joint yield better functional results? A systematic review of the literature. Brewster M. Abstract As first metatarsophalangeal joint arthrodesis is generally considered to be a successful procedure for the treatment of hallux rigidus, many surgeons question the usefulness of total joint replacement. In an effort to elucidate the clinical evidence, we undertook a systematic review of the literature comparing the functional outcomes of arthrodesis and joint replacement in first metatarsophalangeal surgery. Using multiple search engines and medical subject headings, 10 articles were eligible for inclusion: 5 featured arthrodesis and 5 featured total joint replacement. The American Orthopaedic Foot and Ankle Society-Hallux metatarsophalangeal-interphalangeal score was used in all articles. The mean age at operation was 53 years for joint replacement patients and 55 for those undergoing joint arthrodesis. Most patients in all studies were female. There was a significant increase from pre- to postoperative scores in both procedures. The median postoperative score for joint replacement was 83/100 (range 74-95) and 82/100 (range 78-89) for arthrodesis. The median revision rate in joint replacements was 7% (range 0%-10%) and 0% (range 0%-12%) for arthrodesis. This systematic review reveals that arthrodesis achieves better functional outcomes than total joint replacement. The operative techniques and prostheses for joint replacements are however still in an early stage of development and advances still need to be achieved to produce a more successful and anatomical prosthesis that could be functionally superior to an arthrodesis.

COMPENSATION FOR A PAINFUL 1ST MTP Alteration in gait by weight shifting laterally and toeing off over the lesser metatarsal (fourth and fifth) heads externally rotating at the hip during swing phase of gait to allow for complete toe clearance. Ankle push-off power is reduced VanGheluwe, B; Dananberg, HJ; Hagman, F; Vanstaen, K: Effects of hallux limitus on plantar foot pressure and kinematics during walking. J. Am. Podiatr. Med. Assoc. 96:428 436, 2006. Brodsky, JW; Baum, BS; Pollo, FE; Mehta, H: Prospective Gait Analysis in Patients with First Metatarophalangeal Joint Arthrodesis for Hallux Rigidus. Foot Ankle Int. 28:162 165, 2007. Mulier, T; Steenwerckx, A; Thienpont, E; et al.: Results after cheilectomy in athletes with hallux rigidus. Foot Ankle. 20:232 237, 1999. Nawoczenski, DA: Nonoperative and operative intervention for hallux rigidus. J Orthop. Sports Phys. Ther. 29:727 735, 1999

Vol. 23(3): 496-502, 2002 Summary: -Normal peak pressures across hallux over shorter duration. -Weight-bearing role of 1 st ray reestablished. -Force & pressure in lesser toes increased. -Shorter step-length when pushing-off involved side. -Reduction of ankle PF angle at toe-off. -Decreased ankle PF moment & ankle power at toe-off. -No change in hip or knee angle at toe-off.

Altered gait patterns in hallux rigidus -Are the changes due to restricted ROM of the 1 st MTP? -Or, are the changes due to pain?

Therefore, should the goal of surgery be restoration of ROM of the 1 st MTP? Or Elimination of pain at the 1 st MTP?

The best surgical outcomes for hallux rigidus do not increase ROM of the 1 st MTP.they eliminate pain

1 ST MTPJ ARTHRODESIS

PRE-OP

POST-OP

POST-OP FUNCTION

6 Yrs S/P 1 st MTPJ Fusion Right

Hallux Rigidus Maher AJ, Metcalfe SA. First MTP joint arthrodesis for the treatment of hallux rigidus : Results of 29 consecutive cases using the foot health status questionnaire validated measurement tool. The Foot 18: 123-130, 2008. Concerns exist within the literature that fusion of the first MTP joint may be detrimental to foot function and normal gait. However, in this series foot function as judged by the FHSQ scores improved significantly supporting the argument that fusion actually stabilizes the first MTP joint restoring weight bearing under the joint and in doing so allows the restoration of hallux propulsion.

Studies of gait after fusion of 1st MTPJ Brodsky JW, Baum BS, Pollo FE, Hehta H, et al. Prospective gait analysis in patients with first metatarsophalangeal joint arthrodesis for hellux rigidus. Foot Ankle Int 2007: 28(2): 162-5. DeFrino PF, Brodsky JW, Pollo FE, Crenshaw SJ, Beischer AD, et al. First metatarsophalangeal arthrodesis: a clinical, pedobarographic and gait analysis study. Foot Ankle Int 2002: 23(6): 496-502.

What are the best surgical options for the Active Patient? Grade 1 and 2: Cheilectomy Grade 3 and 4: Arthrodesis

Hallux Rigidus in the Running Athlete Rationale for Cheilectomy - Literature supports the favorable outcomes in all patient populations - Relative low risk, and minimal disability - Will reduce pain and may improve ROM - Downside: Probably not a lifetime correction for the runner

Deborah A. Nawoczenski, P.T., Ph.D.1; John Ketz, M.D.2; Judith F. Baumhauer, M.D. Dynamic Kinematic and Plantar Pressure Changes Following Cheilectomy for Hallux Rigidus: A Mid-Term Followup. Foot & Ankle International/Vol. 29, No. 3/March 2008 Conclusion: Cheilectomy was effective in maintaining balanced plantar loading. First MTP motion increased but dorsiflexion was still less than normative values. The magnitude of dorsiflexion relative to abduction favorably improved during gait. These findings suggest that kinematics continue to be altered and may lead to further degenerative joint changes. Exploration of alternative surgical techniques is warranted.

Hallux Rigidus in the Running Athlete: Downside of Distal 1st Metatarsal Osteotomies - Success is based upon decompression of the 1st MTP, not plantarflexion - The more decompression, the more shortening - The more shortening, the greater the risk of transfer metatarsalgia - Greater peak forefoot pressures in running will accentuate metatarsalgia

Hallux Rigidus in the Running Athlete Downside of Implant Arthroplasty - Current understanding of the mechanics of the 1st MTP in walking is limited - Current understanding of the mechanics of the 1st MTP in running is non-existent - Speculate that compressive forces and shear forces are magnified in running - Little good options available when implant fails

Do prosthetic implants for the 1 st MTP function allow the coupled motion of the 1 st MTP? - dorsiflexion-abduction -plantarflexion-inversion

Hallux Rigidus in the Running Athlete Rationale for Arthrodesis - In Grade 3 and 4 the ROM of the 1st MTP has already been lost - The athlete has been running with little ROM for years - The disability of hallux rigidus is the PAIN, not loss of ROM - Goal of surgery is to eliminate PAIN, not restore ROM

Advantages of Locking Plate for 1st MTP Arthrodesis Locking plates are more stable than non-locking plates DeTora M, Kraus K. Mechanical testing of 3.5 mm locking and nonlocking bone plates. Vet Comp Orthop Traumatol. 2008; 21(4):318-22

Locking Plates: Advantages - Locking plates do not rely on plate/bone compression and precise plate contouring is not critical. - Therefore, in contrast to the use of conventional plating, one can implant locked plating without compressing the periosteum. - Unicortical fixation helps preserve the blood supply and reduces screw-induced stress in bone. - With conventional plating, the bone is pre-stressed. - With locked plating, the plate and not the bone is pre-stressed.

Advantages of Screw Fixation for 1st MTP Arthrodesis - Less expensive - Less likely to require removal of hardware - Easier to customize the alignment of fusion

Disadvantages of Screw Fixation for 1st MTP Arthrodesis - Technically more difficult - Less contact across the arthrodesis interface - Theoretically less stable than plate compression

Conical Reamers: Improved technique for 1st MTP Arthrodesis - The reamers remove the articular cartilage and subchondral bone, which is critical to healing. - The reamers also create a machined fit with the hallux in variable positions. - The favorable joint debridement and congruent machined fit of the arthrodesis interface improves arthrodesis rates as much as the type of fixation one employs. Goucher NR, Coughlin MJ. Hallux metatarsophalangeal joint arthrodesis using dome-shaped reamers and dorsal plate fixation: a prospective study. Foot Ankle Int. 2006; 27(11):869-76.

CONCLUSION 40 degrees of dorsiflexion (extension) of the 1 st MTP is adequate for normal walking gait and 30 degrees dorsiflexion may be adequate for running

Locking Plates: Description - Locking plates and screws consist of threaded screw heads and plate holes that allow one to insert the screw into the plate itself, thereby facilitating a form of cortical purchase. - The penetration of the screw through the near cortex to the plate serves as the second cortex. - One can achieve further stability via bicortical screw purchase but this is not a requirement.

Locking Plates: Principles - Each screw forms a fixed right angle and this eliminates the potential for toggle. - Multiple fixed, right angle anchors provide excellent fixation. - Therefore, locking plates function similarly to external fixation by not requiring friction between the plate and bone to provide stabilization. - Locking plates have a shorter distance between the plate and bone construct than an external fixator does, thus making locking plates more stable.

Negative Aspects of Conventional Plating: - Bicortical screw fixation required - Potential for irritation of sesamoid apparatus - Bicortical fixation along the plantar surface of the proximal phalanx could cause pressure pain and/or flexor hallucis brevis and longus tendonitis

Locking Plates for 1st MTP Arthrodesis: Advantages - New first MPJ specific plates are prepositioned to ensure accurate alignment (the single most crucial component other than stabilization) - Furthermore, the new plates allow polyaxial locking, providing multi-axial, fixed angle constructs. - This is especially important for first MPJ arthrodesis due to architecture of the first MPJ and the irregular surface shapes. - Not only is the surgeon able to place the screws at an angle of 15 degrees to the plate with each hole but the plate itself also allows for polyaxial loading

Disadvantages of Locking Plate for 1st MTP Arthrodesis - Theoretically, locking plates use the same principles as external fixators and do not require compression against the bone for stability - However, for 1st MTP arthrodesis, a hybrid technique is often employed where the plate is compressed into the dorsal surface of the bone. - Once one applies a locking plate to a bone and compresses the plate in a traditional fashion, the favorable aspect of preserving the periosteal blood supply is lost.

Disadvantages of Plate Fixation for 1st MTP Arthrodesis In addition, the rigid stability afforded by locking plates and the compromise of the periosteal blood supply beneath the plate is a detriment to bone healing based on current understanding of bone and fracture healing with plate fixation. Ganesh VK, Ramakrishna K, Ghista DN. Biomechanics of bonefracture fixation by stiffness-graded plates in comparison with stainlesssteel plates. Biomed Eng Online. 2005; 4:46.

Disadvantages of Locking Plates Alternatively, application of a locking plate that is not directly compressed to the bone results in a dorsally prominent implant that is likely to irritate the soft tissues clinically. This type of application is less problematic in subcutaneous plating of the distal tibia or femur, but often results in hardware irritation over the first MPJ

Conventional Plating of 1st MTP Arthrodesis Furthermore, there is abundant evidence to suggest dorsal plate fixation using conventional implants affords predictable arthrodesis rates and high patient satisfaction Kumar S, Pradhan R, Rosenfeld PF. First metatarsophalangeal arthrodesis using a dorsal plate and a compression screw. Foot Ankle Int. 2010; 31(9):797-801. Berlet GC, Hyer CF, Glover JP. A retrospective review of immediate weightbearing after first metatarsophalangeal joint arthrodesis. Foot Ankle Spec. 2008; 1(1):24-8

LOCKING PLATES vs CONVENTIONAL PLATES: PROVEN ADVANTAGE? - There is little evidence to suggest locking plates are any better or even comparable to traditional plates with respect to MPJ arthrodesis. - A study presented at the American Academy of Orthopaedic Surgeons showed that there was a higher nonunion rate with locking plates for MPJ arthrodesis Hunt KJ, Ellington K, Anderson RB, et al. Locked versus non-locked plate fixation for hallux MTP arthrodesis. Presented at the 25th Annual Summer Meeting of the American Orthopaedic Foot and Ankle Society, July 15-18, 2009. Vancouver, British Columbia.

POSITIVE OUTCOMES OF 1st MTP ARTHRODESIS WITH SCREW FIXATION The forces acting across the MPJ during healing are primarily bending and, to a lesser magnitude, shear. Historically, transarticular screw fixation has shown very favorable arthrodesis rates dating back 30 years Wassink, S, VAn Den Oever M. Arthrodesis of the first metatarsophalangeal joint using a single screw: retrospective analysis of 109 feet. J Foot Ankle Surg. 2009; 48(6):653-61. Brodsky JW, Passmore RN, Pollo FE, Shabat S. Functional outcome of arthrodesis of the first metatarsophalangeal joint using parallel screw fixation. Foot Ankle Int. 2005; 26(2):140-6.

J Am Podiatr Med Assoc. 2005 May-Jun;95(3):221-8. Metatarsus primus elevatus in hallux rigidus: fact or fiction? Roukis TS. Abstract Two hundred seventy-five lateral weightbearing radiographs of isolated pathology were reviewed and stratified into hallux rigidus (n = 100), hallux valgus (n = 75), plantar fasciitis (n = 50), and Morton's neuroma (n = 50) groups. The patient population consisted of healthy individuals with no history of foot trauma or surgery. The first to second metatarsal head elevation, Seiberg index, first to second sagittal intermetatarsal angle, first to fifth metatarsal head distance, and hallux equinus angle were measured in each population. Statistically significant differences were found between the hallux valgus, plantar fasciitis, and Morton's neuroma populations and the hallux rigidus population, which showed greater elevation of the first metatarsal relative to the second for each radiographic measurement technique. In the hallux rigidus population, there was a statistically significant difference between grade II and grades I and III regarding the first to fifth metatarsal head distance (greater in grade II) and the hallux equinus angle (lower in grade II). A review of the literature and comparison with historical controls reveals that metatarsus primus elevatus exists in hallux rigidus and is greater than that found in hallux valgus, plantar fasciitis, and Morton's neuroma groups.

First Ray Elevatus: Cause or Effect of Hallux Rigidus? Meyer, J.O., Nishon, L.R., Weiss, L., and Docks, G.: Metatarsus primus elevatus and the etiology of hallux rigidus. J. Foot Surg., 26:237-241, 1987. The authors concluded that approximately 7.0 mm of first ray elevation is a consistent radiographic finding in patients with and without hallux rigidus. In addition, they discouraged basing surgical correction of the presumed deformity on radiographic elevatus. It should be noted, however, that they believed that metatarsus primus elevatus was paramount in the pathogenesis of hallux rigidus.

Do lateral weight bearing radiographs accurately depict the functional position of the first ray during gait?

Question #5 5. A standard lateral weight bearing x-ray depicts the alignment of the osseous structures of the foot during the midstance period of gait (True or False?) Standard Lateral X-Ray Positioning Angle and Base of Gait? Static Stance Intrinsics and Extrinsics Inactive Midstance in Gait: Single Support

Static Stance No windlass No plantar intrinsics No peroneus longus

FIGURE 1-96 This figure shows the foot in final propulsion. The hallux is dorsiflexed 75 from the 1 st metatarsal as heel lift elevated the base of the 1 st ray 48 and the 1 st ray plantarflexed in relation to the rest of the foot by 10. The transverse axis of motion of the 1 st metatarsophalangeal joint (T.A.) has shifted to allow the proximal phalanx of the hallux to gllide to the dorsum of the 1 st metatarsal head.

What are these procedures? Cheilectomy Arthrodesis

Hallux Rigidus in the Running Athlete Rationale for Cheilectomy - Literature supports the favorable outcomes in all patient populations - Relative low risk, and minimal disability - Will reduce pain and may improve ROM - Downside: Probably not a lifetime correction for the runner

CONCLUSION Active range of motion of the 1 st MTP while standing is the best indicator of true range of motion used by the patient during gait

The FDL can also become a pathologic force across the 1 st MTP.

Screw vs Plate Fixation for 1st MTP Arthrodesis: Cost Comparison There is evidence showing dorsal plate fixation to be significantly more expensive. Further buttressing this argument is that there was no significant difference in fusion rates between screw fixation and more expensive plate fixation. Hyer, CF, Glover JP, Berlet GC, Lee TH. Cost comparison of crossed screws versus dorsal plate construct for first metatarsophalangeal joint arthrodesis. J Foot Ankle Surg. 2008; 47(1):13-8.