The Influence of Sex on Outcomes at Various Time Points after Total Ankle Arthroplasty

Abstract

Category: Ankle Arthritis; Ankle Introduction/Purpose: Total ankle arthroplasty (TAA) is regarded as an increasingly accepted alternative to ankle arthrodesis in patients with ankle arthritis that have failed conservative management. While significant focus within orthopedic literature has been placed on determining various risk factors for particular outcomes, the stratification of outcomes based on sex has been insufficiently investigated. Moreover, as the number of TAAs performed continues to increase, there is a growing need to examine the effects of sex on outcomes after TAA. We sought to compare patient reported outcome measures (PROMs), ankle range of motion (ROM), and complications at multiple time points in the post-operative period after TAA as stratified by sex. Methods: undergoing TAA during the years 2013 to 2018 at a single academic institution who had minimum follow-up of two years. A total of 133 patients met inclusion criteria, comprising 55.6% males and 44.4% females. Patients were evaluated pre- operatively and at 6 months, 1-year, and 2-years post-operatively. PROMs, including the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot Score, Visual Analog Scale (VAS) score, and the Short Form - 12 (SF-12) were administered, and ROM was assessed at all time points. Post-operative complications were also recorded. Student t-test were used to determine differences between the outcome measures. Eighty-nine patients received the Zimmer total ankle (39 females), whereas 44 patients (20 females) received the mobile bearing Hintegra. Results: The average age was 53.6 in the male cohort as compared to 53.8 in the female cohort (p=0.93). Both pre-operatively and at 6-months post-operative, the cohorts did not differ statistically in any of the measured outcomes. At 1-year post-operative, females had a lower SF-12 PCS score (44.1 versus 47.1, p=0.019) and less plantarflexion (20.5 versus 23.5, p=0.029) as compared to males. While both cohorts saw a significant step-wise increase in AOFAS scores between pre-operative, 6-months, and 1-year post-operative (p<0.001), the AOFAS score of the female cohort plateaued at 1-year while the male cohort continued to improve significantly (<0.015). Ultimately by 2-years post-operative, females had a statistically significant lower AOFAS score as compared to males (80.3 versus 85.4, p=0.04). Conclusion: Our results show that while both cohorts experienced significant improvement in all measured outcomes, women have lower SF-12 PCS scores and AOFAS score at 1- and 2-years post-operative, respectively, as well as less plantarflexion at 1- year post-operative with a trend towards increased complication rate after TAA. While our results add to the growing body of literature supporting TAA as a reliable means of treating ankle arthritis, our results are novel in that they were stratified and analyzed based on sex. Understanding these differences in outcomes is critically important for effectively managing expectations and treating both male and female populations.