Posterior shoulder instability. Surgical versus conservative results with evaluation of glenoid version.

We conducted a retrospective study on 50 patients with recurrent posterior shoulder instability. Twenty-five patients were treated conservatively with a specific rehabilitation program strengthening the rotator cuff. The other 25 patients, who did not improve with rehabilitation, underwent surgical reconstruction, the majority of these being soft tissue repairs. Recurrence in the surgically treated group averaged 72% while that in the conservatively treated group was 96%. However, 50% of those patients treated surgically and 68% of those treated conservatively felt their symptoms were improved. In view of the high recurrence rate with soft tissue reconstruction, computed tomography scans were obtained to evaluate glenoid version. Those patients with posterior shoulder instability were found to have increased glenoid retroversion when compared to an uninjured population (P less than 0.05). Our conclusions based on this study were that 1) specific therapy in the form of rotator cuff strengthening should be the initial form of treatment in patients with posterior shoulder instability, 2) soft tissue surgery has a high rate of recurrence, 3) the return to sports is variable, 4) there appears to be an increased incidence of glenoid retroversion in this patient population, and 5) the incidence of posttraumatic arthritis is low.