Prospective Study of a Cementless, Mobile-Bearing, Third Generation Total Ankle Prosthesis

Abstract

Background: The SALTO total ankle prosthesis is a nonce-mented mobile bearing anatomic design characterized by dual Ti-HA coating. This study reviews our results with this prosthesis. Materials and Methods: Between 2001 and 2007, 413 consecutive SALTO prostheses were implanted in our institution in 215 women and 198 men, aged 57.1 ± 11.9 years. At the last visit, 401 implants (47% in the left ankle) were available with a mean followup of 29 (range, 1 to 84) months. Results: Based on the results of the 218 patients with at least 2 years of postoperative followup, the 5-year estimated survivorship, with the primary end-point being implant removal, was 86.6% and ranged from 85.1% in patients with post-traumatic osteoarthritis to 95.6% in those with rheumatoid arthritis. The AOFAS score increased from 50.9 ± 16.8 points preoperatively to 82.2 ± 14 points at followup (mean difference, 31. 1 ± 1.4, 95% confidence interval (C.I.) for the difference, 28. 3 to 33.8, p < 0.001). Visual analog scale for pain decreased from 7.4 ± 1.1 preoperatively to 2.0 ± 2.0 postoperatively (mean difference, −5.4 ± 0.7, 95% C.I. for the difference, −5.6 to −5.2, p < 0.001). Flexion/extension ROM increased from 25.2 ± 14.1 degrees to 33.1 ± 13.6 degrees at the last followup visit (mean difference, 7. 9 ± 0.5 degrees, 95% C.I. for the difference, 4. 3 to 7.2, p < 0.001), while pronation/supination ROM increased from 23.8 ± 13.7 degrees to 25.4 ± 14.5 degrees (mean difference, 1. 6 ± 0.7 degrees, 95% C.I. for the difference, 0. 9 to 2.2, p = 0.005). Conclusion: The SALTO prosthesis provided good clinical and functional results and we believe helps validate the concept of anatomic replacement. Level of Evidence: IV, Retrospective Case Series