Impact of morbid obesity on postoperative outcomes in reverse total shoulder arthroplasty: A national inpatient sample analysis.

Introduction: Reverse total shoulder arthroplasty (rTSA) is a widely used procedure for rotator cuff arthropathy, with indications expanding to include fractures, osteoarthritis, and revision arthroplasty. Obesity poses significant challenges in arthroplasty, yet the impact of morbid obesity (BMI ≥40 kg/m Methods: We conducted a retrospective cohort study using the National Inpatient Sample (NIS) database from 2016 to 2019. Patients aged ≥18 years who underwent rTSA were stratified into morbidly obese (Morbid-Obesity (+)) and non-morbidly obese (Control) cohorts. Outcomes analyzed included demographic factors, length of stay (LOS), discharge disposition, and postoperative complications. Statistical analyses were performed using chi-squared tests, independent t-tests, and multivariate logistic regression to assess associations. Results: The study included 4850 Morbid-Obesity (+) patients and 55,075 Control patients. The Morbid-Obesity (+) cohort was younger (mean age: 67.74 vs. 71.67 years; p < 0.001) and more likely to be from minority groups, particularly Black patients (7.71 % vs. 3.94 %; p < 0.001). They had significantly longer LOS (mean: 2.23 vs. 1.87 days; p < 0.001) and higher rates of discharge to non-routine facilities. Major complications were more common in the Morbid-Obesity (+) cohort, including periprosthetic dislocation (2.60 % vs. 1.59 %; OR 1.65, p < 0.001), deep vein thrombosis (0.17 % vs. 0.07 %; OR 2.27, p = 0.03), blood loss anemia (11.61 % vs. 10.12 %; OR 1.17, p < 0.001), and acute renal failure (3.53 % vs. 2.11 %; OR 1.69, p < 0.001). Conclusions: Morbid obesity is associated with higher complication rates, prolonged hospital stays, and increased non-routine discharge rates in rTSA patients. These findings underscore the need for tailored preoperative planning and postoperative management in this high-risk population.