This is a Longitudinal Study. Patients were evaluated by orthopedic surgeons as having a rotator cuff tear, confirmed by magnetic resonance imaging (MRI) or ultrasound. If the patients required surgery and were willing to participate in the trial, the research assistant provided informed consent. The exclusion criteria were as follows.

1. Acromioclavicular arthritis requiring distal clavicular resection.
2. Severe glenohumeral arthritis (Hamada classification grade 3 or higher)15.
3. History of shoulder fracture.
4. Absolute contraindications to MRI, such as claustrophobia, pacemakers, neurostimulators, drug infusion pumps, artificial inner ear implants, and metallic implants.

All patients were placed in a semi-sitting position. Initially, a posterior portal was established to explore the inside of the joint, a lateral portal was created for the removal of subacromial bursa, and an additional anterior portal was created for repairing the tendons. Measurements were taken to determine the extent of rotator cuff damage, including its anterior-posterior and medial-lateral dimensions. In cases where complete repair was possible, a single-row or double-row repair technique was used depending on the degree of tendon damage. For situations where complete repair was not feasible, partial repair was performed. If the tendon could be stretched after relaxation, it was repaired to an anatomical position near the bone bed with the assistance of acellular dermal reinforcement. However, if the tendon lacked elasticity and was fully retracted upon relaxation, acellular dermis was used to bridge the tendon back to the anatomical position.

1. Patients were seated comfortably, and a goniometer was used to measure the active range of motion (ROM) of shoulder joint angles, including internal rotation, external rotation, abduction, extension, and flexion.
2. Patients were seated comfortably and a manual hydraulic push-pull dynamometer was used to measure the strength of internal rotation, external rotation, abduction, extension, and flexion.

The following scales were administered to the patients before surgery and at 2 weeks, as well as at 3, 6, 9, and 12 months postoperatively. Owing to notable swelling and discomfort at the surgical site and joint at the 2-week postoperative mark, measurements of shoulder joint angles and strength were not advisable.

At 6 months postoperatively, a musculoskeletal radiologist specializing in soft tissue assessment will perform MRI to determine whether there is a re-tear of the rotator cuff, assess tendon retraction20, evaluate fat infiltration using the Goutallier classification21-23, and measure muscle atrophy24. Among these, the most crucial imaging indicator is the presence of a re-tear, which relates to the extent of postoperative functional recovery and subsequently influences changes in the psychological state. According to previous research, the optimal time for evaluating the degree of rotator cuff healing is 6 months postoperatively