Transfibular Total Ankle Arthroplasty: Clinical, Functional, and Radiographic Outcomes and Complications at a Minimum of 5-Year Follow-up

Background: The Trabecular Metal Total Ankle Implant differs from other newer-generation implants in the transfibular approach, multiplanar external frame for alignment, tantalum trabecular metal interfaces, curved geometry, and shallow resection depths. The primary aim of this study was to report midterm clinical and radiographic results, as well as survivorship and adverse events at a minimum of 5-year follow-up.Methods: A total of 83 ankles (81 patients, average age 60.6 years old, 50.6% females) with average 6.3 years' (range, 5.0-10.1) follow-up were included. Postoperative patient-reported outcome measures (PROMs) included SF-12 physical (PCS) and mental component summary (MCS) scores, Ankle Osteoarthritis Scale (AOS), pain visual analog scale (VAS). Radiographic outcomes included postoperative range of motion (ROM) and coronal/sagittal alignment. Adverse events were reported using the Canadian Orthopaedic Foot and Ankle Society Reoperation Coding System (CROCS).Results: Preoperative tibiotalar coronal deformity included 27 valgus (10 degrees, range 2-20 degrees) and 25 varus ankles (-9 degrees, range -2 to -25 degrees), corrected to neutral postoperatively. Postoperative tibiopedal ROM was 17.8 degrees dorsiflexion and 21.8 degrees plantarflexion. Adverse events occurred at average 28.7 months, most commonly gutter debridement (n = 17, 16.7%) and subsequent operative treatment unrelated to metal components (n = 10, 12.0%). There were 2 cases (2.4%) of acute deep infection treated with irrigation and debridement, polyethylene exchange, and retention of metal components without recurrence of infection. There were no cases of fibular nonunion, septic or aseptic loosening, or implant subsidence. Postoperative PROMS included SF-12 PCS: 40.4; SF-12 MCS: 56.0; VAS: 2.3; AOS Pain: 17.0; and AOS Disability: 24.9. Overall implant survival, defined by retention of the metal components, was 100% at final follow-up.Conclusion: At a minimum of 5 years, patients who underwent TM TAA reported minimal ankle pain and regained neutral ankle alignment and mobility, without septic or aseptic implant loosening. Although having certain limitations, this study suggests that TM TAA is a viable option for the treatment of end-stage ankle arthritis.