Risk Factors for Neurological Injury After Reverse Total Shoulder Arthroplasty

Nerve injury after total shoulder arthroplasty (TSA) can be a significant complication. Recent interest has been focused on the rate of nerve injury in reverse TSA (rTSA), given the anatomic changes inherent to the prosthetic design. The purpose of this study is to assess the rate of neurological injury after rTSA and correlate this with risk factors. We hypothesized that low body mass index (BMI) would be associated with an increased rate of neurological injury. A retro-spective chart review of 91 consecutive rTSAs was conducted. All cases were analyzed for clinically relevant postoperative neurological injury. Sex, height, weight, age, smoking status, diabetes, rheumatoid arthritis, operative time, history of shoulder surgery, preoperative diagnosis, thickness of polyethylene insert, and acromiohumeral distance were assessed. The relationship of these factors with neurological injuries was assessed using a Fisher exact test. There were 91 cases (57 female and 34 male), with a mean age of 68 (range, 42 to 87) y. The average BMI of the affected patients was 19.0, compared with a BMI of 30.0 for the remaining patients. Low BMI (<22) was the only risk factor for neurological injury identified, with 29% of patients with a BMI < 22 sustaining a neurological injury.