Twelve male competitive athletes (fourteen shoulders) presented with persistent shoulder pain that interfered with athletic participation. Patient ages ranged from 18 to 25 years. Symptoms included impingement-like pain with overhead activity and weightlifting. Local tenderness was present over the acromion near the same coronal plane as the posterior border of the clavicle. In each case, plain radiographs revealed the presence of an unfused anterior meso-acromial fragment. Magnetic resonance images were obtained in 5 shoulders and revealed edema at the junction of the anterior acromial fragment and the body of the acromion. Nine patients (eleven shoulders) were treated with arthroscopic excision of the anterior acromial fragment. They were followed up for a minimum of 2 years after the procedure. All surgically treated patients were able to return to full athletic participation by 14 weeks after surgery. Isokinetic testing at the latest follow-up revealed no significant deficits in abduction, internal rotation, or external rotation strength compared with the opposite side.