An anatomical study of the correlations between degeneration of the coracoacromial arch and rotator cuff tears

This paper examines the age-related changes in the shape of the coracoacromial arch and their correlation with rotator cuff tears. Bilateral anatomical dissection of the shoulder was performed on 40 cadavers aged 26-82 yr (mean 58.4±15.6), followed by histological examination of the coracoacromial ligament and gross assessment of the cuff. Statistics were obtained with Student's t test, using 0.05 as the significance cut-off. Ten incomplete and four full-thickness cuff tears were found. Age-related alterations in the shape of the coracoacromial ligament were noted in general and in all subjects with cuff tears. There were no alterations of the coracoid process, whereas the anteroinferior third of the acromion displayed marked age-related degeneration. This was classed in three degrees of increasing gravity. There was a significant con-elation beween age and gravity. In addition, all full-thickness or incomplete bursal-side cuff tears were accompanied by second or third-degree degeneration of the inferior surface of the acromion. Anterior osteophytosis of the acromion was present in 35 cases (mean age 70.5±10). Its association with cuff tears was only significant when the acromion was curved or uncinate (type II or III). These findings suggest that coracoacromial arch degeneration is ahvays age-related, but only results in a higher incidence of cuff tears if the acromion is curved or uncinate