Long-term Risk of Subtalar Joint Arthritis After Stemmed Total Ankle Replacement.

Abstract

Ankle arthrodesis has historically been the standard treatment for end-stage ankle arthritis but may accelerate subtalar joint (STJ) degeneration. Stemmed total ankle replacement (TAR) preserves ankle motion but raises concern for iatrogenic STJ injury from intramedullary instrumentation. To evaluate the long-term incidence of subtalar osteoarthritis following stemmed TAR at a minimum 10-year follow-up. Retrospective cohort study. A retrospective review identified 70 patients who underwent primary stemmed TAR between January 2012 and December 2013. Sixteen patients met inclusion criteria of ≥10 years follow-up with complete radiographic data. STJ osteoarthritis was graded preoperatively and at final follow-up using the Kellgren-Lawrence Scale (KLS) on weightbearing radiographs. Statistical analysis included Mann-Whitney U and chi-square testing with significance set at p < 0.05. Mean follow-up was 11.49 ± 0.9 years. Two patients (13%) demonstrated radiographic progression in KLS grade, and no patient required subtalar arthrodesis. Postoperative STJ pain occurred in 6 patients (38%), although 4 demonstrated no radiographic progression. STJ pain was significantly associated with moderate-to-severe implant-related complications requiring reoperation (p = 0.0357) but not with KLS progression (p = 0.0510). Radiographic progression was associated with talar collapse rather than isolated STJ degeneration. At long-term follow-up, stemmed TAR demonstrated minimal progression of subtalar osteoarthritis and no cases requiring STJ fusion.