Outcomes of Bilateral Scandinavian Total Ankle Replacement: A Detailed Analysis of Implant Survivability and Patient-Reported Outcomes.

Abstract

Background: Total ankle replacement (TAR) is an established treatment for end-stage ankle arthritis, offering pain relief and improved functionality. The Scandinavian Total Ankle Replacement (STAR) was first used in the United States in 1998 and although unilateral STAR has been extensively studied, there is limited documentation on the outcomes of simultaneous bilateral STAR procedures. This study aimed to evaluate the survivability and patient-reported outcomes of simultaneous bilateral STAR, focusing on implant survival rates and improvements in quality of life, function, and pain relief.

Methods: A retrospective cohort study was conducted on all patients managed with primary TAR performed simultaneously with bilateral STAR prostheses at our institution from July 1998 to February 2008. Demographics and perioperative characteristics were collected. Poisson regression was used for analyzing implant survivability, and generalized linear mixed models were applied to assess patient-reported outcomes, including the visual analog scale (VAS), Short Musculoskeletal Function Assessment (SMFA), 36-Item Short Form Health Survey (SF-36), and American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot, at multiple follow-up time points.

Results: Twenty-one patients were included for a total of 42 implants. The average length of follow up was 4.9 ± 2.7 years. The implant failure rate at 5 years was 12.0% (95% CI 4.5%-32.0%). The last recorded failure occurred at 8 years postimplant, with an implant failure rate of 19.2% (95% CI 17.2%-51.1%). Statistically significant improvements were observed in all patient-reported outcome measures from baseline to the 5-year follow-up (P < .05) except SMFA bother because of high variability and small sample size.

Conclusion: At midterm follow-up, patients who underwent bilateral simultaneous TAR with the STAR prosthesis experienced a significant and durable improvement in patient-reported outcome scores across multiple functional indices. Failure rates were within range to those reported in previous studies evaluating unilateral STAR, with an estimated average survivorship of 80.8% at 8 years.

Level of evidence: Level IV, case series.