Comparison of the Outcome of the 3-Component Salto Total Ankle Arthroplasty for Ankle with Preoperative Varus, Valgus and Neutral Alignment in End-Stage Osteoarthritis

Abstract

Category:Ankle; Ankle ArthritisIntroduction/Purpose:As the popularity of total ankle arthroplasty (TAA) increases, indication of TAA also expands. Recently, the ankles more than 20° of varus or valgus deformity in the coronal plane are treated with TAA. However, severe varus or valgus deformity should be corrected in the coronal plane to avoid residual mal-alignment that leads to instability, insert wear, and clinical failure. In this study, we compare the clinical and radiologic outcome of the Salto mobile bearing 3-component total ankle prosthesis for ankles with preoperative varus, neutral, and valgus alignment.Methods:TAA was performed in 101 consecutive ankles (99 patients) by a single surgeon using 3-component Salto total ankle implant from June 2014 to October 2019. A prospectively collected database was used to identify all patients who underwent primary TAA with a minimum 1-year follow-up. We classified the enrolled ankles as neutral, varus, or valgus groups. More than 10° of tibial anterior surface angle, talta tilt angle, tibial axis-talar dome angle, talar dome-ground surface angle (TD-GSA), or tibio- calcaneal angle was defined as varus or valgus groups. All patients were followed up at postoperative three months, six months, at one year and yearly thereafter. Clinical outcome scoring was done pre-operatively and post-operatively. American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot functional score, pain VAS, satisfaction score and clinical range of motion (ROM) were collected along with weight-bearing radiographs of the ankle. Post-operative coronal alignment of the component were evaluated with radiographs.Results:The average follow-up was 21.6 months (range, 12-71). Preoperatively, there were 63 ankles (62%) with varus deformity, 27 ankles (27%) with neutral alignment, and 11 ankles with valgus deformity. In preoperative varus group, 13 ankles (21%) were performed with concomitant lateral sliding calcaneal osteotomy, and 23 ankles (37%) with deltoid release. No additional procedures for the correction of ankle and hindfoot deformity were performed in preoperative neutral and valgus groups. VAS pain score and AOFAS score were significantly improved in all groups (p < 0.05). Overall satisfaction rate was 88%. After TAA, there were no significant radiologic alignment among the groups (3.9° (range, 0.7°~9.7°) in varus group, 4.1° (range, 0.4°~6.8°) in neutral group, and 2.2° (range, -0.4°~4.4°) in valgus group; p > 0.05).Conclusion:There was no significant difference in outcome among the varus, neutral, and valgus groups postoperatively in the TAA series using single Salto 3-componenet implant. Postoperative neutral alignment was achieved in all ankles. For favorable long-term outcomes, coronal alignment should be corrected with proper additional procedures in TAA.