Patient-Reported Outcomes and Revision Risk Following Total Ankle Replacement With and Without Ipsilateral Hindfoot Fusion

Background: Hindfoot (subtalar, talonavicular, and/or calcaneocuboid) fusion is commonly used to treat arthritis and/or deformity. Some patients undergoing total ankle replacement (TAR) have a history of hindfoot fusion or undergo it concomitantly. This study aims to evaluate Patient-Reported Outcomes Measurement Information System (PROMIS)-based clinical outcomes, revision rates, and radiographic findings of primary TAR with ipsilateral hindfoot fusion at a minimum 2-year follow-up from primary TAR. We hypothesized that TAR patients with ipsilateral hindfoot fusion would have worse patient-reported outcomes and clinical outcomes than TAR-only patients. Methods: A retrospective review of 400 primary TAR patients with or without prior/concomitant ipsilateral hindfoot fusion was conducted. PROMIS domains, radiographs, complications, and revisions were analyzed. Multivariate linear regression models were used to evaluate the associations between hindfoot fusion and 2-year postoperative PROMIS scores. We compared proportions meeting minimal clinically important difference (MCID) and patient-acceptable symptom state (PASS) thresholds. Results: Of 400 ankles, 49 (12.3%) had ipsilateral hindfoot fusion. On multivariate analysis, hindfoot fusion was associated with worse 2-year PROMIS scores in most domains, including Physical Function, Pain Interference, and Global Mental Health. However, rates of achieving MCID and PASS were largely similar between groups. At 2 years, hindfoot fusion patients were equally likely to achieve MCID in Physical Function, Pain Interference, and Depression, and to meet PASS thresholds for Pain Interference, Pain Intensity, and Physical Function. They were significantly less likely to achieve MCID for Pain Intensity ( P = .012) and PASS for Global Mental Health ( P = .015) and Depression ( P = .024). Revision rate was higher in the hindfoot fusion group (10.2% vs. 2.6%, P = .038). Conclusion: Although patients undergoing TAR with ipsilateral hindfoot fusion report lower absolute PROMIS scores in several domains, they appear equally likely to perceive meaningful clinical improvement and reach acceptable postoperative states in pain and function. These patients may still experience more persistent mental health burden and slightly less improvement in pain intensity.