Relationship between calcifying tendinitis and subacromial impingement: a prospective radiography and magnetic resonance imaging study.

In a prospective study radiographs and magnetic resonance images of 75 patients with calcifying tendinitis of the rotator cuff were analyzed. The aim was to evaluate any relation between calcifying tendinitis and subacromial impingement. A total of 83% of the calcifications were located in the supraspinatus or the adjoining part of the subscapularis tendon. On T1-weighted images they could be demonstrated with high accuracy as areas of decreased signal intensity. A magnetic resonance imaging categorization of the calcium deposits was carried out by means of a differentiation of form, outline, and density. A partial rotator cuff tear was found in one shoulder; in 11% variable aspects of degenerative alteration of the affected tendon were seen. By analysis of the radiographic outlet view 16% of the cases had a type III acromion. In conclusion, little correlation exists between calcifying tendinitis and additional findings associated with subacromial impingement.