Posterior addition acromioplasty in the treatment of recurrent posterior instability of the shoulder

The purpose of the present study is to describe a previously unreported extraarticular surgical procedure for the treatment of recurrent posterior instability of the shoulder. Stabilization is achieved by grafting an inverted segment of the scapular spine to the posterior border of the acromion. The osseous segment is removed from the middle third of the spine and is positioned so that it exerts a slight pressure over the infraspinatus muscle. Eight consecutive patients with nontraumatic, recurrent posterior dislocation of the shoulder and 2 who had a history of minor trauma were operated on and reviewed at a mean follow-up of 9.5 years. Seven patients underwent addition acromioplasty alone, but the first 3 patients of the series also underwent posterior capsular plication. There were no operative complications. All of the patients were fully satisfied with the results. None complained of pain or recurrent dislocation. A slight and not incapacitating limitation of internal rotation of the shoulder was noted in 2 of the 3 patients of the group in which capsular plication was associated. This limitation was overcome in all successive patients by intraoperative fixation of the graft to the acromion with the arm positioned in extension and internal rotation. The procedure is a new and safe treatment option for achieving stabilization of this rare juvenile condition.