Rotator cuff tears involving the subscapularis tendon are rare. Usually the supraspinatus and/or infraspinatus tendons are injured instead. The direction of the more common tears is posterior (backwards). But with a subscapularis rupture, damage occurs at the top of the shoulder (superior portion) and moves in the anterior (forward) direction.
In this study, the unique features of anterosuperior subscapularis tears and their response to surgical repair are examined. Trauma to the shoulder is the usual mechanism of injury. A sudden outward rotation of the shoulder with force can tear the subscapularis. The force is often enough to also tear the supraspinatus tendon and the long head of the biceps brachii tendon.
Besides the history of a specific kind of trauma, the physical exam helps the surgeon make an accurate diagnosis. There are several signs present when the subscapularis is torn. These include weak shoulder internal rotation, too much external rotation, a positive lift-off sign, and a positive belly-press sign.
The lift-off test involves placing the affected arm behind the back (a position of shoulder internal rotation). The back of the hand is against the low back area. The patient attempts to lift the hand away from the spine. The examiner provides resistance to this motion and observes for strength while watching the shoulder blade for abnormal motion.
The belly-press test also checks the subscapularis muscle. The examiner places his or her hand on the patient’s abdomen. The patient places his or her hand of the affected arm over the examiner’s hand. The patient presses his or her hand into the belly while at the same time moving the elbow forward. This action requires the subscapularis to rotate the shoulder. An inability to complete the test suggests dysfunction of the subscapularis.
In this study, thirty (30) patients with a torn subscapularis (confirmed by MRI) had surgery to repair the damage. Not everyone with an anterosuperior rotator cuff tear was offered surgery as an option. Patients were selected carefully by the surgeon.
For example, recent injuries (less than three months) were given priority and advised to have surgery. Patients who tore the rotator cuff within the last three to six months were advised to have surgery if they had pain and loss of motion. Patients with older injuries (more than six months) were included if the surgeon could repair the tendon.
The surgical approach and technique used to repair the damage was determined based on the severity and direction of the tear. X-rays and MRIs helped the surgeon plan the procedure but sometimes, the final decision had to be made during the operation.
The authors explained both their rationale and specific surgical methods used for the group. Treatment with open surgical repair of the rotator cuff tear was discussed as well as treatment of any other tendon damage in the shoulder (e.g., biceps tendon disorder).
Patient characteristics were collected and analyzed. There were far more males than females (80 per cent men, 20 per cent women). Left and right arms were affected fairly equally. Only a small portion of the patient population smoked. More than half had some other medical condition. Three-fourths had a biceps tendon disorder (long head of the biceps torn at the same time as the subscapularis).
Everyone was evaluated thoroughly before surgery. Preoperative motion, strength, function, and pain were measured and compared to postoperative values for each area. Insurance status and satisfaction with results were also evaluated.
Results showed that scores on surveys of the various measures were improved in all areas. Motion, strength, and function related to the rotator cuff were restored to near normal. Near normal values for internal rotation strength showed that healing of the subscapularis occurred. All but one patient said they would have the same surgery again if they had to do it all over again. But 30 per cent weren’t happy with their residual (leftover) symptoms.
In general, satisfaction was less when the supraspinatus or infraspinatus tendon was torn along with the subscapularis. The authors say this makes sense because larger tears involving more soft tissue structures don’t recover as well as simple tears. Patients with worker’s compensation were more likely to have a poor result.
Most of the patients in this study had surgery within six months of the injury. The authors think this may account for better results than is reported in other studies where surgery was done later. Scarring and tendon retraction increase with time. When these factors are combined with poor tendon quality, results can be less than optimal.
The final conclusion of this study was that it is possible to restore a traumatically injured anterosuperior rotator cuff tear to near normal. Surgery done early after the injury can restore shoulder function.