The main aim and scope of this study is making observation and comparing the difference in the tear position in the patients suffered form rotator cuff tear with different arthroscopic anatomy of the middle glenohumeral ligament. The results may identify the influence of the middle glenohumeral ligament anatomy type on the rotator cuff tear.

Inclusion Criteria:

• partial or full-thickness but reparable rotator cuff tear;
• small- to large-sized rotator cuff tears being defined by DeOrio and Cofied4;
• no improvements after at least 1 month of conservative treatment such as NSAIDs or corticosteroid injection.

Exclusion Criteria:

• massive rotator cuff tears being defined by DeOrio and Cofied;
• patients with osteoarthritis of the glenohumeral joint;
• trauma or a history of surgery at the shoulder.

Patients with rotator cuff tears received the arthroscopic rotator cuff repair.