Fusion after a failed primary total ankle arthroplasty

When a total ankle arthroplasty (TAA) fails, it can be converted to a fusion or a revision arthroplasty. Despite the increasing numbers of TAAs being undertaken, there is little information in the literature about the management of patients undergoing fusion following a failed TAA. The primary aim of this study was to analyze the survival of fusions following a failed TAA using a large dataset from the National Joint Registry (NJR).

A data linkage study combined NJR and NHS Digital data. Failure of a TAA was defined as a fusion, revision to a further TAA, or amputation. Life tables and Kaplan-Meier graphs were used to record survival. Cox proportional hazards regression models were fitted to compare the rates of failure.

A total of 131 patients underwent fusion as a salvage procedure following TAA. Their mean age was 65.7 years (SD 10.6) and 73 (55.7%) were male. The mean follow-up was 47.5 months (SD 27.2). The mean time between TAA and fusion was 5.3 years (SD 2.7). Overall, 32 (24.4%) underwent reoperations other than revision and 29 (22.1%) failed. Of these 24 (18.3%) underwent revision of the fusion and five (3.8%) had a below-knee amputation. No patients underwent conversion to a further TAA. Failure usually occurred in the first three postoperative years with one-year survival of fusion being 96.0% (95% confidence interval (CI) 90.7 to 98.3) and three-year survival in 69 patients being 77.5% (95% CI 68.3 to 84.4).

Salvage fusion after a failed TAA shows moderate rates of failure and reoperations. Nearly 25% of patients required revision within three years. This study is an extension of studies using the same methodology reporting the failure rates and risk factors for failure, which have recently been published, and also one reporting the outcome of revision TAA for a failed primary TAA, using the same methodology, which will shortly be published.