Outcomes Following Conversion of Ankle Fusion to Transfibular Total Ankle Arthroplasty

Background: Surgical management of failed ankle fusion is challenging. The objective of this study is to present the clinical and radiographic results of tibiotalar fusion takedown via a lateral approach with conversion to transfibular, trabecular metal (TM) total ankle arthroplasty (TAA). Methods: Sixteen patients underwent an ankle fusion takedown with conversion to transfibular TAA: 9 patients had prior tibiotalar fusions, and 7 had tibiotalocalcaneal fusion. Patient demographics, complication profiles, and radiographic parameters were collected. Pre- and postoperative patient-reported outcome measures (PROMs) were analyzed with 12-Item Short Form Health Survey (SF-12), visual analog scale (VAS), and the Ankle Osteoarthritis Scale (AOS). Radiographic outcomes included coronal and sagittal alignment, tibiotalar plantarflexion (PF) and dorsiflexion (DF) range of motion, and incidence of periprosthetic radiolucency and/or implant subsidence. Results: < .05). There was 1 (6.3%) case of implant revision for periprosthetic fracture about the tibial component. There were 8 (50%) reoperations at an average of 20.9 ± 10.8 months following fusion takedown, 4 (25%) cases of fibular hardware removal, and 4 (25%) cases of medial gutter debridement. Average radiographic DF and PF postoperatively was 12.5 ± 5.6 degrees and 13.5 ± 9.1 degrees. There was no presence of periprosthetic cysts at final follow-up. Conclusion: Ankle fusion takedown with conversion to a TM ankle through a transfibular approach yielded significant improvement in PROMs and radiographic ROM, with a modest complication rate at average 4.7 years' follow-up. Although technically challenging, transfibular TAA following ankle fusion takedown is a reasonable treatment option for symptomatic tibiotalar or pantalar fusion. Level of Evidence: Level IV, case series.