Posterior shoulder instability in the contact athlete: a review of the diagnosis, management and outcomes.

Posterior shoulder instability should be increasingly recognized in patients with acute shoulder dislocations or instability, while also warranting a high index of suspicion in contact athletes with insidious onset of shoulder pain. Athletes often present with vague symptoms, typically including deep-seated joint pain and frequently without a described acute traumatic event. The contact athlete will often complain of pain with push-ups and bench press, particularly provoked during blocking motions relevant to football linemen and linebackers. In addition to a patulous posterior capsule, bony morphology can contribute to increased risk of posterior shoulder instability, such as a reverse Hill-Sachs lesion, glenoid dysplasia, glenoid retroversion and posterior acromial height. Posterior bone defects occur in a predictable pattern within the posteroinferior quadrant of the glenoid face and 15% of posterior glenoid bone loss can lead to a 25 times higher failure rate of arthroscopic posterior shoulder stabilization alone. While arthroscopic posterior shoulder stabilization is the gold standard in the absence of substantial posterior glenoid bone loss, posterior bone block stabilization may be necessitated in patients with significant posterior glenoid bone loss or retroversion, or who have failed a previous arthroscopic soft tissue procedure. Free bone block augmentation for posterior glenoid reconstruction has demonstrated compelling short-term results, yet there are no long-term outcome data or comparative studies reporting on the outcomes of these relatively new techniques. Overall, arthroscopic posterior shoulder stabilization leads to high patient satisfaction and excellent clinical outcomes. Contact athletes generally demonstrate similar patient-reported and functional outcomes when compared to overhead throwing athletes. However, contact athletes generally return to sport and previous level of play at a higher rate compared to overhead throwing athletes, potentially due to the lower dynamic stressor applied across the glenohumeral joint, typically at mid-range of motion, compared to the overhead throwing athlete. Findings suggest that comprehensive evaluation and individualized treatment strategies are necessary for optimizing patient outcomes and return to sport among contact athletes.