The role of body mass index on survivorship and clinical outcomes in total shoulder arthroplasty.

BACKGROUND: Increased body mass index (BMI) is a potential risk factor for poorer outcomes and complications. However, the influence of BMI on the long-term outcomes of anatomic and reverse total shoulder arthroplasty (aTSA and rTSA) remains to be fully elucidated. METHODS: Institutional records were queried to identify patients who underwent primary TSA between 2009-2020 with a minimum of 2 years of clinical follow-up. Retrospective review was performed to collect demographics, comorbidity status, and range of motion and strength measurements in forward elevation, external rotation, and internal rotation. Patients were called to obtain patient reported outcomes. Patients were stratified into 3 cohorts, by BMI: underweight or normal weight (U/NW, BMI≤25), overweight (OW, 2530). RESULTS: Among 466 TSA patients, 245 underwent aTSA while 221 underwent rTSA. In the aTSA cohort, 40 were classified as U/NW, 72 as OW, and 133 as obese. Comparatively, the rTSA cohort was composed of 33 U/NW, 79 OW, and 209 obese patients. aTSA and rTSA patients had an average follow-up of 5.8±3.2 years and 4.5±2.3 years, respectively. No differences were found in age at surgery for the aTSA group (U/NW: 65.2±7.9 vs obese: 61.9±8.9 years; p=0.133), however, in the rTSA cohort, BMI was found to be inversely related to age at surgery (U/NW: 72.4±8.8 vs obese: 65.7±8.3 years; p<0.001). Across all BMI cohorts, patients saw great improvement in range of motion and strength. Postoperative patient reported outcomes for TSA did not vary by BMI in SANE, SST, VAS pain, and ASES scores. There was no significant difference in survival rates at 10-year follow-up in aTSA (U/NW: 95.8% vs obese: 93.2%; p=0.753) or rTSA (U/NW: 94.7% vs obese: 94.5%; p=0.791). CONCLUSION: With dramatic improvements in range of motion, minimal differences in patient reported outcomes, and high rates of implant survival, TSA is a safe and effective treatment option for all patients, including for overweight and obese patients.