Supramalleolar Osteotomy for ankle arthritis; single Tertiary Referral Centre - 12 year overview comparing standard and custom implant

SA Ali, I Mubark, K Weerasinghe

The aim was to demonstrate that Supramalleolar osteotomy is a valuable treatment method in eccentric ankle arthritis in young and middle aged since it is an under-utilised procedure. We retrospectively analysed the outcome of it performed over 12 year period. We also compared the results of recently introduced computer-assisted PSI Integrated custom-made implants with standard implants.

Data was analysed from 48 patients over a period of 12 years of which 40 were by standard implant and 8 by computer assisted custom implant. 31 varus, 18 valgus deformity. The mean age was 57 (26-79 y/o), male:female ratio was 27:19. Mean follow-up was 15.25 months for standard implants; For the computer-assisted procedures the follow up range is 24 to 2 months. TAS, TTS and TT angels were measured pre and post-operatively. Fixation using a plate with/without bone graft or custom-made implant was performed by a single surgeon. MOXFQ and AOFAS questionnaires were
completed pre and post-operatively. All followed similar rehabilitation programme.

Average radiological healing time was 24.3 weeks. MOXFQ score improved from 55.17 to 25.11 and AOFAS from 20.16 to 56.21. Complications were 2 non-unions, 1 delayed union, 1 stress fracture. 8 patients require fusion/replacement between 3-5 years. The PSI Integrated computer-assisted technique gave improved accuracy than standard freehand method with better scores and a smoother approach for the surgeon. Early results with this technique are encouraging as we were able achieve 3 dimentional correction compared to the 2 dimentional correction achieved by the freehand method.

Our results are comparable to similar studies. Being a joint preserving technique, Supra Malleolar Osteotomy should be considered either as an interim or definitive procedure especially with the development of computer assisted technologies which makes the technique easier to reproduce.