Acromial morphotype in the young asymptomatic athletic shoulder

Several studies have documented an association between the type III acromio n and rotator cuff tears. However, controversy exists as to whether the sha pe of the acromion is an innate anatomic characteristic. The purpose of thi s study was to evaluate the prevalence of the type III acromion in young as ymptomatic athletes. Bilateral supraspinatus outlet radiographs were obtain ed in 100 Division 1 collegiate athletes (average age, 19.9 years). Only 4 (2%) of 200 shoulders were found to have a type III acromion by use of the standard subjective Bigliani classification. Eight (4%) acromion were found to be type III by the use of previously published objective criteria for a cromial measurement. Our results show the type III acromion to be relativel y rare in asymptomatic, young athletes, but the incidence of type III acrom ion in a general population of both young and older individuals is still no t completely understood. However, our results accentuate the possibility th at the higher incidence of type III acromion seen in older populations may in fact be related to secondary acromial changes.