Symptomatic thrower's exostosis. Arthroscopic evaluation and treatment.

A long-term follow-up was performed on 22 patients treated for a posterior glenoid osteophyte and symptomatic posterior shoulder pain during either the late cocking, acceleration, or follow-through phases of throwing. Arthroscopic evaluation of these patients revealed undersurface tearing of the rotator cuff in all but one. Fifteen patients also had tearing of the posterior labrum. Anterior labral fraying was noted in four patients. Treatment consisted of debridement of the rotator cuff and labral tears. The posterior glenoid osteophyte was removed arthroscopically in 11 patients. Eighteen of 22 throwers treated were available for long-term follow-up at a mean of 6.3 years (range, 1 to 12). Only 10 of 18 (55%) throwers evaluated had returned to their premorbid level of throwing. All 10 were asymptomatic and had maintained a high level of performance for a mean of 3.6 years (range, 1 to 8). At the time of latest follow-up, five players were still participating at the major league level and five had retired. One patient had recurrence of the exostosis 8 years after surgery. Among our patients a trend existed toward a poorer result and failure of return to activity with a posterior osteophyte greater than 100 mm2. A posterior glenoid exostosis, when identified in the symptomatic shoulder of the throwing athlete, can be considered a definite marker of internal impingement.