Effect of obesity on short- and long-term complications of shoulder arthroplasty

Background: The proportion of patients undergoing total shoulder arthroplasty (TSA) with obesity continues to grow every year in the United States. Although comorbid obesity is common among TSA patients, the relationship of obesity on medical and surgical com-plications remains debated. The goal of this study was to evaluate a national database for postoperative medical and surgical compli-cations in patients undergoing TSA with comorbid obesity. Methods: Patients undergoing anatomic and reverse TSA were studied in the PearlDiver database. Current Procedural Terminology (CPT) and International Classification of Diseases (ICD) codes were used to compare patients with and without preoperative obesity who underwent TSA, and they were stratified based on body mass index (BMI) into nonobese, obese, morbidly obese, and superobese. A matched comparison was performed at a 1:1 ratio based on age, sex, diabetes, smoking, tobacco use, and Charlson Comorbidity Index. Results: From 2010 to 2020, a total of 113,634 patients undergoing anatomic or reverse TSA were identified in a national database. During this time, the percentage of TSA patients with obesity increased every year. Matched cohort analysis demonstrated higher odds of readmission, deep vein thrombosis and pulmonary embolism, superficial infection, and prosthetic joint infection at 90 days post-operatively in the obesity group. There were no increased odds of mechanical complications or revision surgery at 2 years in the obesity group when matched to nonobese patients with similar comorbidities. Conclusion: The number of patients undergoing TSA with obesity is rising. Medical complications and infection after TSA are greater in obese patients even when matching for medical comorbidities, age, and sex, and rates of complication increase as BMI increases. Obesity is not an independent risk factor for mechanical surgical complications and revision surgery, and the relatively higher rates are likely due to an increased burden of other comorbidities. Surgeons should counsel obese patients appropriately regarding their peri-operative risk of medical complication, but they should not expect higher rates of mechanical complication or revision surgery at 2-year follow-up when compared to a matched control group with similar comorbidities. Level of Evidence: Level III; Retrospective Cohort Comparison using Large Database; Prognosis Study (c) 2022 The Author(s). This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).