Long term follow up, re-operations and patient reported outcomes following revision surgery for failed total ankle replacements

A. Somanathan, B. Sharp, F. Saedi, C. Loizou, R. Brown, A. Kendal

¹University of Oxford, Oxford, United Kingdom

²Nuffield Orthopaedic Centre, Oxford, United Kingdom

Winner of the BOFAS 2022 Fifth Prize (Podium)

Introduction: Primary ankle arthroplasty (TAR) is increasingly used to treat end-stage ankle arthritis. Reported revision rates of TAR vary from 8.5% to 11.1% at 9 years. Revision surgery remains technically challenging with options ranging from simple joint debridement to tibio-talar-calcaneal fusion. The efficacy of these procedures remains unclear and there is no consensus on optimal revision options.

Methods: A retrospective cohort study was performed of all patients undergoing surgery for a failed primary TAR at the Nuffield Orthopaedic Centre (2004-2021). TAR failure was determined by clinical assessment, serial radiographs and CT scans. Primary outcome measures included type and time of index surgery post TAR. Secondary outcomes included frequency of re-operations, post-operative complications, patient reported outcomes and union rate (for revision arthrodesis procedures).

Results: 70 failed TARs in 69 patients (35M:34F, mean 65.7 years, s.d.=11.6) underwent re-operation a mean of 6.24 years (range 1-30) post primary. In total, 107 operations were performed including revision fusion (n=50), revision arthroplasty (n=14), bearing exchange (n=9) and joint clearance (n=9). The overall revision fusion union rate was 73.5% over a mean of 12.5 months (s.d.=7.6). 16/23 (69.6%) Tibio-Talo-Calcaneal and 9/12 (75%) ankle fusions (previous subtalar/triple fusion) using a hindfoot nail united over a mean 11.4 months (s.d.=6.0) and 15 months (s.d.=9.48) respectively. Only 64% of ankle fusions using screws alone united (mean=10.6 months, s.d.=8.14). The average postoperative MOXFQ score was 28.3 (s.d.=19.3). 73% said the operation improved their function and would recommend it to a friend/family member.

Conclusion: Despite low post-operative MOXFQ scores, over 70% of patients were satisfied with re-operation for a failed TAR. Over 26% of all TAR revision fusions fail to unite with the highest non-union rates observed post ankle arthrodesis with screws alone (36.4%).

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