Posterior Shoulder Instability in Athletes.

Abstract

Posterior instability represents up to 10% of all cases of shoulder instability1. In athletes, posterior instability can result from a single traumatic injury, repetitive microtrauma, or, rarely, atraumatic instability. The demands on the athlete’s shoulder, especially in contact or overhead throwing sports, can be dramatic, and, as a result, the managing orthopaedic surgeon must understand the complexities of such an injury complex. Participation in contact sports may result in an increased risk for the development of traumatic posterior instability. In overhead athletes, posterior instability can result from repetitive microtrauma sustained from an early age, which can be further exacerbated with the increase in year-round play. ### Static Stabilizers The static stabilizers of the glenohumeral joint include the glenoid and the humeral head, the capsulolabral complex, the articular surface, and the glenohumeral ligaments. Anatomic alterations of the retroversion of the osseous and chondrolabral portions of the glenoid have been shown to be associated with posterior shoulder instability2. Cadaveric studies of …