Supraspinatus and Infraspinatus Rotator Cuff Repair Prevents Mechanical Damage to the Intact Subscapularis Tendon in a Rat Model

Introduction Rotator cuff tendon tears are a common cause of pain and disability. An intact rotator cuff stabilizes the glenohumeral joint, allowing for concentric rotation of the humeral head on the glenoid. However, large tears involving the supraspinatus and infraspinatus tendons may disrupt the normal balance of forces, resulting in abnormal joint loading which can cause secondary damage to surrounding joint tissues such as cartilage and other tendons. As a result, surgical repair is often recommended to reduce pain and restore function. Our lab has previously shown that the properties of adjacent intact tendons (subscapularis and long head of the biceps) are significantly diminished following combined tears of both the supraspinatus and infraspinatus tendons. However, it is unclear whether early rotator cuff repair can prevent the progression of these secondary degenerative changes. Therefore, the objective of this study was to determine if rotator cuff repair prevents mechanical damage to adjacent tissues (subscapularis and biceps). We hypothesized that rotator cuff repair will provide for superior adjacent tissue mechanical properties compared to no repair.