Results after primary reverse shoulder arthroplasty with and without subscapularis repair: a prospective-randomized trial

Introduction Indications for reverse shoulder arthroplasties (rTSA) have increased since their development by Paul Grammont in 1985. Prosthesis design was enhanced over time, but the management of the tendon of the M. subscapularis (SSC-tendon) in primary rTSA is still a controversial subject with regard to perform a refixation or not. Methods 50 patients were randomized in a refixation group (A) and a non-refixation-group (B) of the SSC-tendon in a double-blinded fashion. SSC-function was assessed at baseline before surgery, such as 3 and 12 months after surgery. Constant–Murley-Shoulder Score (CS), American Shoulder and Elbow Surgeons Score (ASES), strength, range of motion (ROM), and pain on numeric rating scale (NRS) were measured in all examinations. An ultrasound examination of the shoulder was performed for evaluation of subscapularis tendon integrity at 3 and 12 month follow-up visits. Pain was evaluated on NRS via phone 5 days after surgery. Surgery was performed by a single experienced senior surgeon in all patients. Results Patients with a refixation of the SSC-tendon and primary rTSA had improved internal rotation [40° (20°–60°) vs. 32° (20°–45°); p = 0.03] at 12 months of follow-up. Additionally, the A-group had increased CS [74 (13–90) vs. 69.5 (40–79); p = 0.029] 1 year after surgery. Results were strengthened by subgroup analysis of successful refixation in ultrasound examination vs. no refixation. No differences were seen in ASES and NRS 1 year after rTSA. Conclusion SSC-tendon repair in rTSA improves CS and internal rotation 12 months after surgery.