Analysis on the acromial curvature and its relationships with the subacromial space and types of acromion☆☆☆

OBJECTIVE To correlate the acromial curvature, using the angles proposed, with the subacromial space and types of acromion. METHODS Ninety scapulas were studied. The acromia were classified as types I, II or III. The acromial curvature was analyzed by means of the alpha, beta and theta angles. We also measured the distance between the anteroinferior extremity of the acromion and the supraglenoid tubercle (DA). The scapulas were grouped in relation to sex and age. The angles proposed were analyzed in relation to each type of acromion and also in relation to the measurements of the distance DA. RESULTS Out of the total number of acromia, 39 (43.3%) were type I, 43 (47.7%) type II and eight (9%) type III. The mean ages for each type of acromion (I-III) were 45.6, 55.2 and 51.1 years, respectively. The proportions of the different types of acromion varied in relation to sex and age. The evaluations on the mean beta angle (p = 0.008) and theta angle (p = 0.028), with comparisons in relation to each type of acromion and measurements of the distance DA (p = 0.037), were shown to be statistically significant. CONCLUSION The angles proposed in our study can be used for morphometric analysis on the acromion, especially regarding its curvature, and can contribute towards studies on diseases of the shoulder and aid in surgical planning and analysis of the acromial slope, by means of radiography or magnetic resonance.