Does morbid obesity negatively impact perioperative outcomes following elective reverse shoulder arthroplasty? a propensity-matched comparative study

Background: The incidence of primary reverse total shoulder arthroplasty (rTSA) and the prevalence of obesity have increased in the United States. Despite this, the literature assessing the effect of morbid obesity (body mass index≥40 kg/m²) on perioperative surgical outcomes remains inconsistent. Methods: A retrospective review of consecutive elective primary rTSA cases from January 2016 through September 2023 at a single tertiary referral center was performed. All cases involved a short-stem humeral component and screw-in glenoid baseplate from the same implant manufacturer. Surgical and patient demographic data were collected. Morbidly obese patients were propensity matched at least 1:1 with non-morbidly obese patients based on age, gender, modified 5-item frailty index score, adjusted Charlson comorbidity index score, and 12-month preoperative emergency department (ED) visit. Regression analysis was utilized to assess the relationship between morbid obesity and operative time, length of stay, intraoperative total blood volume loss, surgical postoperative complications, in-hospital medical complications, disposition, and 90-day ED return and readmission. Results: There were a total of 175 short-stem rTSA cases performed with a median age of 71 years (interquartile range: 66, 76), of which 19 (10.9%) had a body mass index ≥40 kg/m². These 19 patients were propensity score matched to 41 non-morbidly obese patients (9 at 1:3, 4 at 1:2, and 6 at 1:1). There were no significant differences between the groups with regard to intraoperative total blood volume loss, operative time, need for transfusion, hospital length of stay, discharge disposition, prevalence for 90-day return to ED, or unplanned 90-day readmission. Conclusion: Morbid obesity should not be considered an absolute contraindication for elective rTSA, particularly in patients who have undergone appropriate preoperative medical clearance.