Bilateral reverse shoulder arthroplasty: functional outcomes and technical considerations.

As the incidence of reverse total shoulder arthroplasty (RSA) continues to increase with its expanding indications, a growing number of patients are being considered for bilateral RSA. This review aims to explore the functional outcomes of patients with bilateral RSA and examine the effect of risk factors and implant positioning on internal rotation. Multiple studies have reported favorable results in bilateral RSA patients, with significantly improved patient-reported and clinical outcomes bilaterally. Although challenges remain in achieving reliable improvements in internal rotation following RSA, several studies to date have demonstrated that bilateral RSA patients are able to retain independence in personal hygiene and activities of daily living, with difficulty experienced primarily only in extreme internal rotation tasks, such as washing the back or securing a bra. Nevertheless, compensatory strategies can enable patients to manage these limitations effectively. Patients who have undergone bilateral RSA demonstrate functional outcomes and perform internal rotation tasks at a level comparable to that of patients who have undergone bilateral anatomic total shoulder arthroplasty or a combination of total shoulder arthroplasty and RSA. Risk factors for internal rotation deficits after RSA include poor preoperative functional internal rotation, increased body mass index, preoperative opioid use, and preoperative diagnosis of a massive irreparable rotator cuff tear. Lateralization and inferior positioning of the glenoid component as well as humeral component retroversion can increase functional internal rotation, while repairing the subscapularis does not appear to offer any clinically significant benefit. Although some patient and surgical factors have been associated with internal rotation deficits after RSA, further investigation is necessary to better characterize the underlying causes of this issue.