Outpatient Hip and Knee Arthroplasty in Obese Patients With Body Mass Index Above 40 kg/m2 is Not Associated With Increased Early Complication Rates

Over 35% of the US population is obese, leading to earlier arthroplasty needs, increased comorbidities, surgical challenges, and higher complication and revision rates. Concurrently, outpatient hip and knee arthroplasty procedures are increasing. This study aimed to evaluate early complication rates of same-day discharge (SDD) arthroplasty in severely obese patients (body mass index [BMI] ≥40). We retrospectively reviewed 15,133 primary hip or knee arthroplasty patients from 2015 to 2022, divided into four groups: obese SDD (n = 247), obese overnight (n = 1123), nonobese SDD (n = 5184), and nonobese overnight (n = 8579). Obese SDD patients were significantly younger than obese overnight patients (mean age 58.8 vs. 62.9 years, P < .0001), and obese females were more likely to stay overnight. The average BMI of obese SDD patients was slightly lower (43.3 vs. 44.8). Crucially, the obese SDD group did not show higher rates of intraoperative or 90-day complications compared to nonobese SDD patients and had impressive improvements in patient-reported outcomes. Obese patients in both groups (regardless of discharge status) exhibited slightly higher early revision rates than nonobese patients, as expected. Our findings suggest that SDD for hip and knee arthroplasty can be safely performed in severely obese patients (BMI > 40) without significantly increasing early surgical complications. However, the inherently higher revision rate for high BMI patients undergoing joint replacement remains, irrespective of discharge timing.