End-Stage Ankle Osteoarthritis: Exploring the Precedent Causes and Time Course of Joint Degeneration.

INTRODUCTION

End-stage ankle osteoarthritis (OA) is primarily post-traumatic, following injuries such as fractures, dislocations, and sprains. However, the timeline between initial injury and end-stage OA requiring surgical intervention remains poorly understood. This retrospective study aimed to identify injury patterns leading to post-traumatic osteoarthritis (PTOA) and determine the time from injury to definitive surgical treatment with ankle fusion (AF) or total ankle replacement (TAR).

METHODS

A retrospective cohort study was conducted using medical records of patients who underwent AF or TAR for end-stage OA at a tertiary institution over a 20-year period (2000-2020). Patients were classified into post-traumatic, primary, or secondary OA categories. In PTOA cases, initial injury radiographs were reviewed and classified. The time from injury to surgical intervention was analyzed, and a multivariate regression analysis assessed factors influencing the progression to end-stage OA.

RESULTS

A total of 491 ankles from 479 patients were included, with 81.3% categorized as PTOA. The most common injury was rotational ankle fractures (47.1%), followed by ankle sprains (27.6%) and pilon fractures (15.3%). The average time from injury to AF/TAR was 16.9 years, with pilon fractures progressing the fastest (8.1 years) and tibial shaft fractures the slowest (32.7 years). Factors significantly influencing time to surgery included injury type (p < 0.00001), age (p < 0.00001), smoking status (p = 0.016), and peripheral neuropathy (p = 0.04).

CONCLUSION

PTOA is the leading cause of end-stage ankle OA, with rotational ankle fractures and ankle sprains being the most common etiologies. High-energy injuries progress more rapidly, while lower-energy injuries contribute significantly due to their high prevalence. These findings may contribute to a better understanding of the epidemiology and risk factors of end-stage ankle OA.

LEVEL OF EVIDENCE: Observational comparative study; Level III. See Instructions for Authors for a complete description of levels of evidence.