Effect of body mass index on complications following total shoulder arthroplasty: a population-wide analysis

Evidence regarding the effect of body mass index (BMI) on complications following anatomic shoulder arthroplasty (aTSA) and reverse shoulder arthroplasty (rTSA) remains controversial. This high-powered study examines the effect of BMI on surgical and medical complications following aTSA and rTSA.

This retrospective cohort study was conducted using the Premier Healthcare Database to query all adult patients who underwent primary, elective TSA (aTSA, rTSA) from 2016 to 2020. Patients eligible for inclusion were identified using International Classification of Diseases -10 and CPT codes for primary TSA. Patients were stratified into 3 subgroups based on BMI (BMI <30 kg/m², BMI 30-35 kg/m², BMI >35 kg/m²). The primary endpoints assessed were 90-day risks of postoperative complications, revisions, and readmissions among the 3 BMI groups undergoing primary TSA.

A total of 32,645 patients were analyzed; 10,951 patients underwent aTSA and 21,694 patients underwent rTSA. Patient populations for aTSA and rTSA differed significantly across all BMI categories in terms of age, sex, cost of care, and insurance status. After multivariate regression analysis, there was no increased risk of surgical complications in the aTSA and rTSA cohorts with BMI 30-35 kg/m² and BMI >35 kg/m². In the aTSA cohort, rates of acute respiratory failure (adjusted Odds Ratio [aOR] 2.65) was all significantly higher in the BMI >35 kg/m² group. As for rTSA cohort, acute respiratory failure (aOR 1.67) and acute renal failure (aOR 1.53) were significantly higher in the BMI >35 kg/m² group.

While we found no increased risk of immediate postoperative surgical risks, patients with a BMI >35 kg/m² demonstrated greater risk of medical complications after rTSA. Given this trend, providers should exercise caution in patient selection for TSA and counsel obese patients as to these increased risks. Future studies should aim to provide a more comprehensive picture of the effect of BMI on functional outcomes after TSA.