Abstract
Research Type:
Level 4 – Case series
Introduction/Purpose:
Previous studies have suggested that modern total ankle arthroplasty (TAA) implants may be used in the setting of severe tibiotalar malalignment, however midterm results are limited. The Zimmer Trabecular Metal TAA is unique in that it utilizes a lateral transfibular approach and an external fixator, which may aid in deformity correction. The aim of this study is to compare midterm clinical and radiographic outcomes in patients with severe varus or valgus tibiotalar deformity treated with primary transfibular TAA at a minimum of 5-years follow-up.
Methods:
Retrospective review was performed on prospectively followed patients who underwent primary transfibular TAA by a single surgeon from October 2012 to January 2020. Inclusion criteria included: minimum 5-years of follow-up, patient-reported outcomes measures (PROM), and radiographs. A total of 210 cases were grouped into Neutral (n=141), Varus (n=36), and Valgus (n=33) based on preoperative coronal talar tilt angle (0±5°, ≤-10°, ≥10°, respectively). ANOVA tests were utilized to compare minimum 5-year PROMs between the 3 groups: 12-item Short Form Health Survey (SF-12) physical (PCS) and mental (MCS) component scores, Ankle Osteoarthritis Scale (OAS), and Visual Analog Scale (VAS). Final postoperative radiographs were assessed for recurrence of deformity. Adverse events and reoperations were reported using the Canadian Orthopedic Foot and Ankle Society (COFAS) Reoperation Coding System (CROCS).
Results:
There were no significant differences between groups in baseline demographics, length of follow-up, or postoperative PROMs. Average preoperative talar tilt was -15.8° (range, -23.7 to -10.0°) in the Varus group, and 16.2° (10.0 to 25.3°) in the Valgus group. In the Varus group, 1 case had recurrent varus deformity, and 2 cases progressed to valgus deformity. One case in the Valgus group had recurrent valgus deformity. A total of 9 ankles had periprosthetic cysts with equal distribution between the three groups. Overall reoperation rates were similar (Neutral, 34.0%; Varus, 33.3%; Valgus, 36.4%), however there were fewer incidences of medial gutter debridement (CROCS code 4) in the Varus and Valgus groups compared to the Neutral group.
Conclusion:
Preoperative coronal tibiotalar malalignment may not be a contraindication to transfibular TAA in the primary treatment of end-stage ankle arthritis. Patients with severe varus or valgus ankle deformity of 10 degrees or more demonstrated similar postoperative clinical and radiographic outcomes at midterm follow-up, without an increased risk for reoperations. Nevertheless, TAA in severe deformity should be performed by experienced surgeons.
Patient baseline demographics, postoperative patient-reported outcomes measures, and adverse events stratified by preoperative tibiotalar deformity.