The treatment of symptomatic os acromiale.

Os acromiale is an uncommon condition of the shoulder. When symptomatic, os acromiale may cause impingement pain, rotator cuff tears, or pain through abnormal motion at the unfused apophysis. Treatment of symptomatic os acromiale is controversial. This article reports on four patients with symptomatic meso-acromions who were treated with open reduction and internal fixation. All four patients recovered full function postoperatively with UCLA shoulder rating scores improving from 19 preoperatively to 35 postoperatively. Open reduction and internal fixation of a symptomatic meso-acromion is a reliable and reproducible technique in which the deltoid attachment and lever arm are minimally affected.