Risk factors for failure of total ankle replacements: a data linkage study using the National Joint Registry and NHS Digital

T. Jennison, I. Sharpe, A. Goldberg

Introduction: Despite the increasing numbers of ankle replacements there remains debate about which patients should undergo an ankle replacement and there are limited studies analysing risk factors for failure of an ankle replacement. The primary aim of this study is to analyse the risk factors for failure of total ankle replacements.

Methods: A data linkage study combined National Joint Registry (NJR) Data and NHS Digital data. The primary outcome of failure is defined as the removal or exchange of any components of the implanted device. Kaplan Meier survival charts were used to illustrate survivorship. Multivaraible Cox proportional hazards regression models were fitted to analyse potential risk factors for failures or ankle replacements.

Results: The overall 5-year survival was 90.2% (95% CI 89.2%-91.1%). In multivariable (adjusted) Cox regression models only age (HR 0.96, 95% CI 0.94 to 0.97), BMI (HR 1.03, 95% CI 1.01 to 1.06) and indication (HR 0.88, 95% CI 0.80 to 0.97) were associated with an increased risk of failure.

Conclusion: This study has demonstrated an overall 5 year survivorship of 90.2% and that younger patients, and those with an increased BMI have an increased risk of failure. We also showed that rheumatoid patients appeared to do better than those with osteoarthritis.