Total Ankle Replacement Outcomes in Obese Patients with > 10 Year Follow Up

Submission Type: Total Ankle Arthroplasty Research Type: Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies Introduction/Purpose: Obesity prevalence continues to increase. Clinical studies investigating the effects of obesity on outcomes following total ankle replacement (TAR) have demonstrated variable and contradictory results. The follow-up in these studies is less than 5 years and they have shown opposite values on the percentage of poor outcomes and revision rates, when compared to non-obese cohorts. Longitudinal long-term studies with an average follow-up past 10 years are lacking. Methods: This was a single-institution, retrospective study of primary TARs performed between 2001 and 2014 in patients with a Body Mass Index (BMI) ≥30 kg/m2. Ankle Osteoarthritis Scale (AOS) and Short Form-36 (SF-36) Physical Component Summary (PCS) and Mental Component Summary (MCS) scores were collected pre-operatively(pre-op) and post operatively (post-op). Any secondary operations were recorded. Univariate statistical analysis was undertaken for descriptive statistics including standard deviation (SD) and paired t-test and Wilcoxon signed-ranks test were completed to compare pre-operative and postoperative outcome scores. Statistical analyses were performed using SPSS, Version 29 (IBM Corp., 2023), and significance was determined at a p-value threshold of < 0.05. Results: 168 patients were included with a mean age of 62.3 years (SD±8.5 years) and a mean BMI of 34.9 kg/m2 (SD±5.9 kg/m2). At mean follow up of 14.4 years (SD±3.0 years) AOS pain (51.7±18 to 24.3±22.2), AOS disability (64.0±17.9 to 35.8±27.0) and SF-36 PCS scores (31.2±8.6 to 36.8±10.5) remained significantly improved from pre-operative baseline status (p < 0.001). SF-36 MCS deteriorated from 52.8±11.3 pre-operatively to 50.4±10.9 post operatively (p=0.02). 109 patients (64.9%) required no further procedures following TAR. 20 patients (11.9%) required ankle gutter/heterotopic ossification or osteolytic cyst debridement, 14 patients (8.3%) underwent further ligament repair or osteotomy, 11 patients (6.5%) experienced polyethylene liner failure with subsequent exchange and 3 patients (1.8%) experienced implant failure with revision. 4 patients (2.4%) had a deep infection requiring further intervention. Conclusion: At long term follow up, obese patients continue to experience a significant improvement in ankle pain, ankle disability, and overall physical health scores with TAR. 35% of patients required further procedures. Implant/ P.E failure and infection rate is comparable to non-obese patient rates published in the literature. There is a significant decrease in overall mental health (p=0.02) after 10 years, the SF- 36 MCS is a measure of general health status and may reflect the detrimental long-term mental impact of obesity. To our knowledge, this study is first to present outcomes of TAR in obesity with follow up >10 years.