Body Mass Index ≥45 Is Associated With an Increased Risk of Health Care Utilization and Long-term Complications After Total Ankle Arthroplasty

Background: The impact of obesity on outcomes following total ankle arthroplasty (TAA) remains unclear, with existing literature reporting mixed results. Although some studies have identified obesity as a risk factor for perioperative complications and poor clinical outcomes, others have found no significant association. Thus, the purpose of this study was to evaluate the association between obesity, across a range of body mass index (BMI) classifications, and postoperative complications after TAA. Methods: Patients undergoing primary TAA were identified from a large national insurance database. Individuals with a BMI ≥30 were identified and matched 1:1 to nonobese controls using propensity score matching based on demographics and comorbidities. Obese patients were further stratified into BMI categories: 30-34.9, 35-39.9, 40-44.9, and ≥45. Ninety-day complications and 2-, 5-, and 10-year surgery-specific outcomes were assessed. Odds ratios (ORs) with 95% CIs and Kaplan-Meier survival analyses were used to evaluate complication risks. Results: After matching, 3364 patients were included in each cohort. No significant differences in 90-day complication rates were observed for patients with BMI 30-44.9 compared with controls. Patients with BMI ≥45 had increased risk of surgical site infection (OR 2.21, 95% CI 1.29-3.79, P = .003), emergency department visits (OR 1.43, 95% CI 1.04-1.96, P = .025), and readmissions (OR 2.31, 95% CI 1.47-3.63, P < .001). The pooled 90-day complication rate was significantly higher in this group as well (12.9% vs 7.6%, OR 1.77, 95% CI 1.26-2.48, P < .001). At 10-year follow-up, Kaplan-Meier analysis demonstrated that patients with a BMI ≥45 had a higher risk of periprosthetic joint infection (PJI compared with controls (hazard ratio 1.75, 95% CI 1.07-2.85, P = .03). Patients with BMI 30-34.9 had a significantly lower risk of aseptic loosening at both 5 years (OR 0.68, 95% CI 0.49-0.94, P = .019) and 10 years (OR 0.65, 95% CI 0.48-0.88, P = .005). Conclusion: BMI ≥45 was associated with higher all-cause health care utilization, including emergency department visits and hospital readmissions, as well as higher long-term risk of PJI following TAA. Level of Evidence: Level III, retrospective cohort study.