Radiographic and Clinical Analysis of the Salto Talaris Total Ankle Arthroplasty

Abstract

Category: Ankle Arthritis; Ankle Introduction/Purpose: Total ankle arthroplasty (TAA) has garnered significant interest and increased use over the past decade, with advancements made in both design and surgical technique. The main advantage of TAA for the surgical treatment of ankle arthritis is to preserve range of motion compared to ankle arthrodesis. Among the criteria guiding the choice between arthroplasty and arthrodesis, the long-term survival and postoperative outcomes are of crucial importance. The Salto Talaris is a fixed-bearing implant first approved in the US in 2006, and long-term survivorship data is limited. The purpose of this study is to determine minimum 5-year survivorship of the Salto Talaris prosthesis and causes of failure. In addition, we evaluate long-term radiographic and patient-reported outcomes. Methods: We retrospectively identified 86 prospectively followed patients from 2007 to 2014 who underwent TAA with the Salto Talaris prosthesis at our institution. Of these, 81 patients (84 feet) had a minimum follow-up of 5 years (mean, 7.1; range, 5 to 12). Mean age was 63.5 years (range, 42 to 82) and mean BMI was 28.1 (range, 17.9 to 41.2). Survivorship was determined by incidence of revision, defined as removal/exchange of a metal component. Chart review was performed to record incidences of revision and reoperation. Preoperative, immediate and minimum 5-year postoperative x-rays were reviewed; coronal tibiotalar alignment (TTA) was measured on standing AP radiographs to assess alignment of the prosthesis. A TTA of +-5° from 90° indicated neutral alignment, while 95° was considered varus and valgus alignment, respectively. Radiographic subsidence as well as presence and location of periprosthetic cysts were documented. Pre- and minimum 5-year FAOS domains were compared. Results: Survivorship was 97.6% with two revisions. One patient underwent tibial and talar component revision for varus malalignment of the ankle, another underwent talar component revision for aseptic loosening and subsidence. The rate of other reoperations was 19.5% (18) with the main reoperation being exostectomy with debridement for ankle impingement (12). Average preoperative TTA was 88.8° with 48 neutral (average TTA of 90.1°), 18 varus (82.3°) and 8 valgus (99.6°) ankles. Average postoperative TTA was 89.0° with 69 neutral (89.7°), 6 varus (83°), and 1 valgus ankle (99.3°). Radiographic subsidence was observed in one patient who underwent revision, and periprosthetic cysts were observed in 18 patients. There was significant improvement in all FAOS domains at final follow-up. Conclusion: This is the largest study to date dedicated to evaluating survivorship of the Salto Talaris prosthesis. Our data reflects a high survival rate and moderate reoperation rate with long-term follow-up of the Salto Talaris implant. We observed significant improvement in radiographic alignment as well as patient-reported clinical outcomes at minimum 5-year follow-up.