Survival of revision ankle replacements after a failed primary ankle replacement: a data linkage study using the National Joint Registry and NHS Digital

T. Jennison, I. Sharpe, A. Goldberg

Introduction: The number of revision ankle replacements is increasing. There are limited numbers of publications on survivorship. The primary objective was to analyse the survival of revision ankle replacements using a large dataset from the National Joint Registry. Secondary aims were to summarise patient demographics, indications, further operations and predictors of survival.

Methods: A data linkage study combined National Joint Registry (NJR) Data and NHS Digital data. The primary outcome of failure is defined as a revision fusion procedure, conversion to ankle replacement or amputation. Life tables and Kaplan Meier survival charts were used to illustrate survivorship. Cox proportional hazards regression models were fitted to compare failure rates.

Results: 228 patients underwent revision ankle replacement. The mean follow-up was 2.6 years The mean time from primary to revision was 2.3 years. 77.2% were for aseptic causes. 56.6% of implants were the Inbone ankle replacement. 29 (12.7%) failed. 9 underwent a further revision, 19 conversion to fusion and 1 The 1-year survivorship was 95.4% (95% CI 91.6% to 97.5%), 3-year survivorship in 124 was 87.7% (95% CI 81.9% to 91.7%), and the 5-year survivorship in 57 was 77.5% (95% CI 66.9%-85.0%). Revision specific implants has better survivorship than primary implants used for revisions. In total 50 (21.9%) patients had further surgery of which 19 (8.3%) underwent re-operations in the first 12 months. Cox regression models were undertaken. In crude analysis the only significant risk factors for failure were the use of cement (HR 3.02, 95% CI 0.65-1.25) and time since primary ankle replacement (HR 0.67, 95% CI 0.47-0.97). In multivariable Cox regression modelling no risk factors for failure were identified.

Conclusion: Revision ankle replacements have good medium term survivorship and low rates of further surgery. New modular revision implants appear to have improved survivorship compared to traditional ankle replacement implants.