Massive rotator cuff tear was defined as a complete tear of at least two tendons or a tear size of over 5 cm. Massive irreparable rotator cuff tears often lead to shoulder dysfunction that can significantly affect daily activities. In chronic cases, rotator cuff tears are accompanied by retraction and atrophy of muscles and tendons, followed by muscle fat infiltration, making the rotator cuff irreparable. Rotator cuff tears are considered non-repairable and usually result in structural healing. Various surgical approaches have been used to treat massive irreparable rotator cuff tears, including arthroscopic combined biceps long head tendon fixation, rotator cuff partial repair, tendon transposition, and patch enhancement. However, none of these methods is the best treatment for massive irreparable rotator cuff tears. Their clinical results are not very reliable, and the incidence of postoperative complications increases over time. In patients with glenohumeral arthritis, arthroscopic repair or tendon transposition may be associated with residual pain and dysfunction. RTSA is an option for patients with or without \irreparable rotator cuff tear when the deltoid muscle is functioning well. RTSA was initially designed to improve upper limb elevation and relieve pain in patients with rotator cuff defects combined with glenohumeral arthritis. Since the development of RTSA, many clinical studies have demonstrated that RTSA is an effective treatment for rotator cuff arthropathy. Indications for RTSA have gradually expanded to other shoulder disorders, including irreparable rotator cuff tears that were previously treated differently. Currently, RTSA is the preferred treatment for elderly patients with massive irreparable rotator cuff tears. RTSA can relieve pain and improve shoulder function, thereby improving quality of life, but the prostheses' high complication rate and longevity are of concern. The implementation of RTSA in China is late, and the RTSA for irreparable massive rotator cuff tears is less experienced.

To investigate the clinical efficacy of reverse total shoulder arthroplasty in treating irreparable massive rotator cuff tear.

From May 2018 to January 2020, 13 irreparable massive rotator cuff tear cases were treated in the Affiliated Hospital of Nanjing University of Chinese. The angles of anteflexion, abduction, external rotation, and the scores of ASES (American shoulder and elbow surgeons) and UCLA (University of California at Los Angeles) were recorded before surgery and at the final follow-ups to evaluate the shoulder joint function, and the complications and imaging results were documented as well. Preoperative MR was conducted to assess the degree of rotator cuff fat infiltration, CT was undertaken to evaluate the condition and defect of scapular glenoid bone, and postoperative radiographs were used to assess the status of the prosthesis.

All patients were followed up for at least 12 months. The angles of anteflexion, abduction, and external rotation and the scores of ASES and UCLA after operation were remarkably improved compared to those before the procedure. There was a significant statistical difference (P<0.01) . During the follow-up period, 1 of the 13 patients underwent hematoma removal and drainage one week after surgery due to local hematoma, and all patients had good functional recovery.

RTSA has an excellent clinical effect on irreparable massive rotator cuff tears.