Relationship of Acromial Morphology and Rotator Cuff Integrity

The influence of individual acromial morphology on the pathogenesis of rotator cuff tears remains controversial. Since Neer first described the impingement syndrome, several authors have described the morphology of the acromion. In this study, we try to find a physiopathological correlation between the anatomical morphology of the acromion based on these two recently descripted parameters (Acromial index and Critical Shoulder Angle) and rotator cuff tears. Thirty-six consecutive conventional rotator cuff repair patients were retrospectively reviewed at our institution. Standardized, true anteroposterior radiographs with the arm in the neutral position were used to assess the acromion index, and the critical shoulder angle according. On standardized outlet views, the acromion morphology was classified according to Bigliani and Morrison. The acromion was flat in 2 patients (6%), curve (type 2) in eight patients, and hooked. The mean acromial index was 0.7. The mean critical shoulder angle was 37°. Acromial morphology plays without any doubt an important role in the pathogenesis impingement and its evolution to cuff rotator tears. The results of our study confirm the importance of a more comprehensive evaluation of the morphology of the acromion, which take in consideration not only acromial shape, but especially its lateral extension evaluated by the acromial index and the critical angle of the shoulder.