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 is usually required to reattach the tendon to the bone. If a significant bone spur is present, any of the approaches may include an acromioplasty, a subacromial decompression, as part of the procedure. Subacromial decompression, removal of a small portion of the acromion that overlies the rotator cuff, aims to relieve pressure on the rotator cuff in certain conditions and promote healing and recovery. Although subacromial decompression may be beneficial in the management of partial and full-thickness tear repair, it does not repair the tear itself and arthroscopic decompression has more recently been combined with "mini-open" repair of the rotator