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Shoulder Capsule Tears on First Dislocation

Finding the cause of a shoulder that dislocated more than once can be a challenge for the orthopedic surgeon. In this study, doctors from Japan found that a complete tear of the joint capsule is one injury that can cause anterior (forward) shoulder dislocation.

They reviewed over 300 cases of shoulder instability treated with surgery. Twelve of those patients had a complete capsular tear. Twelve out of 300 is a four percent prevalence. Each patient had two or more dislocations of the same shoulder. Major trauma such as a fall or sports injury was the cause of the first dislocation.

The shoulder is kept in its socket by many soft tissue and structural features of the shoulder. There are several ligaments that hold the shoulder in place and make up the entire capsule. For this study a capsular tear was defined as a tear of the inferior glenohumeral ligament. The ligament may tear and pull away from the bone.

All 12 patients had arthroscopic surgery to find and repair the problem. With a complete capsular tear the surgeon can see the subscapularis muscle underneath the ligament. During the repair the surgeon stitches the ligament back together until the muscle can no longer be seen. Results were good. Nine of the 12 patients were able to go back to sports. Only one patient had another dislocation.

The authors conclude that a capsular tear can occur at the time of the first shoulder dislocation. The ligament doesn't just stretch and bleed. It actually tears enough to leave a hole open in the capsule or even pull away from the bone. Sewing the tear back together seems to be enough to repair the problem.

References: Naoko Mizuno, MD, et al. Recurrent Anterior Shoulder Dislocation Caused by a Midsubstance Complete Capsular Tear. In The Journal of Bone and Joint Surgery. December 2005. Vol. 87-A. No. 12. Pp. 2717-2723.

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