Surgical release of the shoulder capsule is one treatment option used for frozen shoulder. The capsule is formed by ligaments that surround the shoulder. The procedure is done arthroscopically. This allows the surgeon to see inside the joint. Capsular release under these conditions reduces the danger of further damage to the joint.
In this study, surgeons perform a capsular release including part of the subscapularis muscle. The subscapularis is one of the four muscles that form the rotator cuff. It helps the shoulder rotate internally. The subscapularis muscle inserts into the front of the shoulder capsule. It helps stabilize the shoulder and prevents anterior (forward) dislocation.
There is some concern that release of the intra-articular part of the subscapularis would affect shoulder rotation. The surgeons only released the subscapularis if they could not externally (outwardly) rotate the frozen shoulder to 50 degrees.
Range of motion, strength, and function were measured comparing the nonoperated shoulder to the operated side. Motion was improved in all directions. Pain was reduced and function improved. Strength testing showed no difference for internal or external rotation strength between the operated and the nonoperated shoulders.
The authors conclude that release of the subscapularis tendon for severe frozen shoulder is safe and effective. Motion is restored without compromising strength. Patients were satisfied with the results.
This study does not answer the question whether capsular release with subscapularis release is more effective than without the tendon release. Further studies are needed to compare these two approaches.