Severe Ankle Deformity Correction Following Transfibular Total Ankle Arthroplasty: A Comparative Cohort Analysis With Minimum 5-Year Follow-Up.

BACKGROUND: There are limited results about total ankle arthroplasty (TAA) in the setting of severe malalignment. The aim of this study was to compare midterm patient-reported and radiographic outcomes in patients with severe varus or valgus tibiotalar deformity treated with primary transfibular TAA at a minimum of 5-year follow-up. METHODS: Retrospective review was performed of all primary transfibular TAA by a single surgeon from October 2012 to January 2020 and grouped based on preoperative coronal talar tilt angle. Severe preoperative deformity included cases with ≥10° of varus (n = 36) or valgus (n = 33), while cases within 5° of neutral coronal alignment (n = 140) served as a control group. PROMs included 12-item Short-Form Health Survey physical and mental component scores, Ankle Osteoarthritis Scale, and Visual Analog Scale. Alignment and periprosthetic cysts (>2 mm) were assessed on postoperative radiographs. Adverse events and reoperations were reported using the Canadian Orthopaedic Foot and Ankle Society Reoperation Coding System. RESULTS: Aside from age (Neutral vs. Valgus, 58.1 vs. 64.2 years; p = 0.01), there were no significant differences in demographics, preoperative, or postoperative PROMs among the 3 groups. The median preoperative talar tilt was -15.1° (interquartile range [IQR], -17.8° to -13.1°) in the Varus and 16.0° (IQR, 12.0° to 19.5°) in the Valgus groups; there were no significant differences in median tibiotalar alignment between the 3 groups postoperatively. In the Neutral group, 1 patient had postoperative varus, and 2 patients had postoperative valgus deformity. In the Varus group, 1 patient had recurrent varus, and 1 patient progressed to valgus. Seven ankles had periprosthetic cysts. Overall reoperation rates were similar (Neutral, 34%; Varus, 33%; Valgus, 36%) with no implant revisions. CONCLUSION: Transfibular TAA is capable of correcting severe coronal tibiotalar malalignment in the primary treatment of end-stage ankle arthritis. Patients with ≥10° varus or valgus deformity demonstrated postoperative patient-reported and radiographic outcomes similar to those with neutral ankle alignment at midterm follow-up, without an increased risk of reoperations. LEVEL OF EVIDENCE: Level III. See Instructions for Authors for a complete description of levels of evidence.