THE OS ACROMIALE - ANOTHER CAUSE OF IMPINGEMENT

Impingement of the shoulder is a relatively common clinical entity. Th e os acromiale anomaly is an uncommon one (1-8%) but can be an importa nt cause of the impingement syndrome. The most common place of nonfusi on is between the meso- and meta-acromion. The key to diagnosis is a h istory and physical examination compatible with the impingement syndro me and appropriate radiologic studies (i.e., an axillary view or profi le view or computed tomographic scan if necessary). After diagnosis, t he initial treatment is conservative with rest, ice, nonsteroidal anti -inflammatory drugs (NSAIDs), injections of corticosteroids in the sub acromial space, and most importantly, an appropriate rehabilitation pr ogram. If unsuccessful, treatment should be planned based on the size of the unfused fragments. Small fragments (< 4 cm) may be removed by e ither arthroscopic or open means. Larger fragments may require an atte mpt at bone grafting and fixation since their removal may result in lo ss of strength of the deltoid.