Reverse total shoulder arthroplasty in patients of varying body mass index

Background: Body mass index (BMI) is an independent predictor of complications after hip and knee arthroplasty. Whether similar trends apply to patients undergoing reverse total shoulder arthroplasty (RTSA) is unknown. Methods: A retrospective review of primary RTSAs with a minimum 90-day follow-up were included. Complications were classified as major or minor and medical or surgical. Patients were classified into 3groups: normal BMI (BMI <25 kg/m²), overweight or mildly obese (BMI 25-35 kg/m²), and moderately or severely obese (BMI >35 kg/m²). Results: Of the 119 patients met our inclusion criteria, 30 (25%) had a BMI of less than 25 kg/m²; 65(55%) had a BMI of 25 to 35 kg/m², and 24 (20%) had BMI exceeding 35 kg/m². Complications occurred in 30 patients (25%), comprising major in 11 (9%), minor in 19 (16%), surgical in 21 (18%), and medical in 14 (12%). The most common surgical complications were acute blood loss anemia requiring transfusion (8.4%) and dislocation (4.2%). The most common medical complications were atelectasis (2.5%) and acute renal insufficiency (2.5%). Patients with a BMI exceeding 35 kg/m² had a significantly higher overall complication rate (P < .05) and intraoperative blood loss (P = .05) than the other groups. Patients with BMI of less than 25 kg/m² had a greater overall complication rate than those with a BMI of 25 to 35 kg/m² (P < .05). Multivariate regression analysis demonstrated BMI was the only significant determinant of overall complication rates and medical complication rates (P < .05). Conclusion: Patients with a BMI exceeding 35 kg/m² (severely obese) or a BMI of less than 25 kg/m² have higher rates of complication after RTSA.