Rotator cuff tear infraspinatus, teres minor, and subscapularis, may also be injured. The amount of stress needed to tear a rotator cuff tendon acutely will depend on the underlying condition of the tendon prior to the stress. In the case of a healthy tendon, the stress needed will be high, such as a fall on the outstretched arm. This stress may occur coincidentally with other injuries such as a dislocation of the shoulder, or separation of the acromioclavicular joint. In the case of a tendon with pre-existing degeneration, the force may be surprisingly modest, such as a sudden lift, particularly with the arm
Rotator cuff tear extension, or vertical abduction, it is less likely to suffer from a tear of the tendon. Those suspected of having a rotator cuff tear may have operative or non-operative treatment. No evidence of benefit is seen from early rather than delayed surgery, and many with partial tears and some with complete tears will respond to nonoperative management. Consequently, many recommend initial, nonsurgical management. However, early surgical treatment may be considered in significant (>1 cm-1.5 cm) acute tears or in young patients with full-thickness tears who have a significant risk for the development of irreparable rotator cuff changes. A review in