Overview
Shoulder instability simply means the shoulder is loose. The shoulder may pop out of the socket or simply feel like it is about to come out during certain activities. The most common type is traumatic instability, which occurs after an injury. Normally, the major stabilizing ligaments of the shoulder are firmly attached to the bone. During a shoulder dislocation, these ligaments can tear away from the bone. This injury is called a Bankart lesion and is one of the main reasons the shoulder may continue to dislocate after the initial injury.
A second, much less common type is multidirectional instability. Rather than being caused by a single injury, these patients are naturally loose or "double-jointed." Their ligaments are naturally looser, allowing the shoulder to slip out with much less force than a traumatic dislocation.
Presentation
Patients with traumatic instability usually describe a definite injury in which the shoulder popped out of the socket. The shoulder may have gone back in on its own or been put back in by the patient or another person. Young, active patients—especially males—have a very high risk of recurrent instability after a first dislocation. Older patients are less likely to have recurrent instability but are much more likely to have an associated rotator cuff tear. Temporary numbness or weakness may occur because the nerves can be stretched during the dislocation. Patients with multidirectional instability usually describe repeated slipping episodes without a major injury.
Conservative Treatment
After a first-time traumatic dislocation, the shoulder is typically placed in a sling for approximately three weeks. The future risk of recurrence depends largely on the patient's age, sex, and activity level. Physical therapy focuses on restoring motion and strength before returning to sports or higher-demand activities. Patients with multidirectional instability rely much more heavily on therapy, with emphasis on strengthening the muscles that stabilize the shoulder.
Surgical Treatment
After a second dislocation, surgery should be strongly considered. After a third dislocation, I generally recommend surgical stabilization because another episode is highly likely. Surgery is performed arthroscopically through several small portals. The torn ligaments are repaired back to the bone or the stretched ligaments are tightened, depending on the type of instability. The procedure takes approximately 25 minutes and has a success rate that approaches 90% in preventing another dislocation.
Recovery
Most patients return to moderate activities such as tennis at approximately three months. Contact and collision sports, including football and wrestling, generally require four to six months before full return.