Obesity Significantly Impacts Patient Reported Outcomes after Total Ankle Arthroplasty: Results from 615 Controls and 478 Patients with Obesity

Abstract

Category: Ankle Arthritis Introduction/Purpose: There is limited data evaluating the effect of obesity on outcomes following total ankle arthroplasty (TAA), especially in adequate sample sizes to detect impacts on patient reported outcomes (PROs). The purpose of this study was to assess the effect of obesity on complication rates and PROs. Methods: This was a single-institution, retrospective study of 1,093 primary TAA performed between 2001 and 2020. Minimum follow-up was 2 years. Patients were stratified by body mass index (BMI) into Control (BMI=18.5-29.9; n=615), Obesity Class I (BMI=30.0-34.9; n=285), and Obesity Class II (BMI>35.0; n=193) groups. Patient information, intraoperative variables, postoperative complications, PRO measures were compared between groups using univariable statistics. Multivariable Cox regression was performed to assess risk for implant failure. Mean follow-up was 5.6 years (sd:3.1). Results: Compared to Control and Class I, Class II patients had the lowest mean age (p=0.001), highest mean ASA score (p < 0.001), and greatest proportion of female sex (p < 0.001) and Black/African American race (p=0.005). There were no statistically significant differences in postoperative complications (infection, implant failure, or impingement) across the BMI classes (p>0.05). Preoperatively, Class II had lower (worse) mean scores for FAOS Pain and ADL subscales than Controls (posthoc pairwise p< 0.001 for both). At final follow-up, both Class II and Class I had lower (worse) mean SMFA (posthoc pairwise p< 0.001 and p=0.030, respectively) and SF36 scores (posthoc pairwise p< 0.001 and p=0.005, respectively) than Controls. Conclusion: At midterm follow-up, obesity was not associated with increased rates of complications after TAA. Patients with obesity reported worse musculoskeletal function and overall quality of life after TAA but there was no differential improvement in PROs across BMI classes. To our knowledge, this is the largest single institution study to date examining the effect of obesity on outcomes after primary TAA.