The shoulder joint provides the greatest range of motion of any joint in the body, and as a result is also prone to the highest rate of dislocations. Because of a shallow bony socket, stability is dependent to a great extent on static and dynamic soft tissue structures. Dynamic constraints such as the rotator cuff, long head of the biceps and scapular musculature provide stability in the middle ranges of motion. At the end ranges of motion however, static constraints such as the glenoid cartilage, labrum and capsule provide the majority of stability. The glenoid cartilage and labrum provide stability primarily by deepening the socket. The glenohumeral ligaments are thickenings of the joint capsule and serve as checkreins to excessive humeral movement. The most important of these is the inferior glenohumeral ligament, in particular the anterior band, which is the primary restraint to anterior glenohumeral translation while the arm is in abduction and external rotation, the position in which anterior dislocations usually occur.

Traumatic anterior dislocators represent the most common group of instability patients and also are the group most likely to benefit from surgery. In patients younger than 20 years at initial dislocation, the reported rates of recurrence are as high as 90%. The decision to acutely repair first-time dislocators should be made on an individual basis but there is substantial evidence supporting this approach. First, tissue is well vascularized and in good condition which makes repair easier and healing more predictable. Second, with each dislocation further trauma occurs to the anterior glenoid, with the potential for significant alteration of the anterior bony morphology with recurrent dislocations.   In patients greater than forty years of age at dislocation, the incidence of rotator cuff tear is high.  Treatment options and recommendation for surgery vary for this problem based on age and activity level.

• Dislocated Shoulder