Restricting Access to Care by Using Body Mass Index as Eligibility Criteria for Total Ankle Arthroplasty

Research Type: Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies Introduction/Purpose: Body mass index (BMI) screening has been extensively studied in total hip and knee arthroplasty, where obesity has been correlated to higher rates of complications, infections, and revisions. As a result, many surgeons use BMI as a screening criteria to assess surgical candidacy. However, the impact of obesity and BMI screening on total ankle arthroplasty (TAA) remains underexplored. Current literature on TAA lacks robust evidence regarding its association with complications. This study investigates the compromise between avoiding complications and limiting access to care when using BMI screening for TAA. Methods: This retrospective cohort study utilizes the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database to review 2,629 patients who underwent primary total ankle arthroplasty from January 2007 to December 2022. We determined how many complications would have been avoided and how many complication-free surgeries would have been denied based on specific BMI eligibility criteria. We also determined the positive predictive value (PPV) for complications within each BMI enforced eligibility criteria. For comparison, we also calculated expected outcomes if eligibility was determined by random selection. Results: With a BMI cutoff of ≥40 kg/m 2 , 203 patients would have been denied a surgical procedure free of major or minor complications, 8 patients would have avoided a complication, and the PPV was 3.8% (95% confidence interval [CI], 1.2%-6.4%). For each complication avoided, 25 patients would have been denied a complication-free surgery. Using a BMI cutoff of ≥30 kg/m 2 , 1303 patients would have been denied a complication-free surgery, 77 patients would have avoided a complication, and the PPV for complications was 5.6% (95% CI, 4.4%-6.8%). For each complication avoided, 17 patients would have been denied a complication-free surgery. Comparatively, patients selected randomly for surgery had a PPV of 5.6%. For each complication avoided, 17 patients would have been denied a complication-free surgery. Conclusion: A ≥30 kg/m 2 BMI cutoff for TAA screening is equivalent to random selection and should not be used to determine TAA eligibility. At the ≥40 kg/m 2 BMI cutoff, the number of patients denied a complication-free surgery is about 25 times larger than those spared a complication and is worse at predicting complications compared to a random selection.