BackgroundThis study aimed to evaluate the efficacy of preemptive middle glenohumeral ligament (MGHL) release in arthroscopic rotator cuff repair (ARCR) to reduce postoperative stiffness.MethodsPatients who underwent ARCR were enrolled and allocated into two groups retrospectively: the preemptive MGHL release group (n = 44) and the preemptive MGHL non-release group (n = 42). Clinical outcomes were assessed and compared between the two groups, including the range of motion, Japanese Orthopedic Association Shoulder Score, Constant Shoulder Score, and the University of California, Los Angeles Score preoperatively and 3 months, 6 months, and 12 months postoperatively and complications. The integrity of the repaired tendon was assessed at the 12-month follow-up using magnetic resonance imaging.ResultsThere were no significant differences between the groups in all range of motion and all functional scores at any of the assessed time points. There was also no significant difference in the healing failure rate 2.3% in the preemptive MGHL group and 2.4% in the preemptive MGHL non-release group (p = .97), and postoperative stiffness was 2.3% in the preemptive MGHL group and 7.1% in the preemptive MGHL non-release group (p = .28). There was no postoperative instability in both group.ConclusionARCR effectively facilitates the recovery of range of motion and function in patients with a rotator cuff tear. However, preemptive MGHL release could not be an effective method to reduce postoperative stiffness.