The Effect of Obesity on Functional Outcomes and Complications in Total Ankle Arthroplasty

Abstract

The prevalence of obesity in the United States is staggering. Currently, the effect of obesity on third-generation total ankle replacement (TAR) is unknown. We prospectively identified a consecutive series of 455 primary TARs operated between May 2007 and September 2013 who had a minimum follow-up of 2 years. We identified 266 patients with a body mass index (BMI) <30 (control), 116 with a BMI between 30 and 35 (Obese I), and 73 with a BMI >35 (Obese II). Clinical outcomes including wound issues, infection rate, complications, and failure rates were compared. Functional outcomes including American Orthopaedic Foot & Ankle Society hindfoot score, Short Form-36 (SF-36), Short Musculoskeletal Function Assessment (SMFA), Foot and Ankle Disability Index (FADI), and Foot and Ankle Outcome Score (FAOS) were compared. Average patient follow-up in the Obese I group was 44.7 ± 17.3 months, Obese II was 42.7 ± 16.4 months, and 45.2 ± 17.4 months in the control group. Age, race, and smoking history in the obese group were not significantly higher than the control group; however, sex was significantly related to BMI. There was no difference in complication, infection, or failure rates between the groups. Preoperatively, the Obese II group had significantly lower SF-36 scores and higher SMFA function, FADI, and FAOS Symptoms scores. For each of the Obese I, Obese II, and control groups, all functional outcome scores 1 year postoperatively and at most recent follow-up were significantly improved. However, at most recent follow-up, Obese II patients had lower FAOS Pain and SF-36 scores and higher FADI and SMFA Functional scores. Total ankle arthroplasty in obese patients was a relatively safe procedure. Although obese patients after TAR had lower functional outcome scores compared to their nonobese counterpart, they did experience significant functional and pain improvements at most recent follow-up. Level III, comparative series.