Three-dimensional evaluation of scapular morphology in primary glenohumeral arthritis, rotator cuff arthropathy, and asymptomatic shoulders

Recently, the 3-dimensional (3D) morphology of the coracoacromial complex in nonpathologic shoulders has been described. The aim of this study was to evaluate and compare the coracoacromial complex in pathologic shoulders (glenohumeral osteoarthritis [GHOA] and cuff tear arthropathy [CTA]) and nonpathologic shoulders.A 3D computed tomography reconstruction of 205 scapulae was performed (49 with GHOA, 48 with CTA, and 108 in normal shoulders [NL]). Subsequently, the center of the glenoid circle and several points at the coracoid, acromion, and glenoid were determined. The distances between these points and the rotation of the coracoacromial complex were calculated, and the acromion-glenoid angle was measured.The acromial overhang was significantly different between the NL (37 mm) and CTA (35 mm) groups (P = .045), as well as between the CTA and GHOA groups (33 mm) (P = .010). The acromion-glenoid angle showed a significant difference between the NL (mean, 50°) and GHOA (mean, 42°) groups (P.001) and between the CTA (mean, 50°) and GHOA groups (P.001). Furthermore, a significant difference was found in the acromial height, which was larger in the GHOA group (36 mm) than in the CTA group (30 mm) (P.001) or NL group (30 mm) (P.001).This 3D morphologic study showed that the acromial part of the complex was turned more posteriorly in both pathologic groups. Furthermore, we found the coracoacromial complex to be more cranial to the glenoid center in the GHOA group. Finally, a significant difference in the lateral overhang of the coracoacromial complex was observed between the 3 groups. The NL group had a larger overhang than the CTA group, and the CTA group in turn had a larger overhang than the GHOA group.