Do subscapularis integrity and posterosuperior cuff tear severity affect scapular impingement and joint stability during external rotation in lateralized reverse total shoulder arthroplasty?

Lateralizing RTSA and repairing the subscapularis can significantly reduce scapular notching-related impingement, improve joint stability, and support ER torque generation by increasing posterior deltoid force in patients with posterosuperior cuff tears. These findings provide critical insights for surgical planning, supporting the use of a lateralized implant and subscapularis repair to reduce the risk of scapular notching and joint subluxation while enhancing ER torque generation.