Glenohumeral osteometry by computed tomography in normal and unstable shoulders.

Past radiologic and anthropometric studies report a high incidence of glenoid anteversion and increased humeral retrotorsion in patients with recurrent anterior dislocation (RAD) of the shoulder. However, recent radiologic studies do not demonstrate significant developmental variations between normal and unstable shoulders. To investigate these conditions, the authors used computed tomography (CT), which offered the advantage of permitting a transverse view at different levels of the glenohumeral joint. CT also avoided the typical distortion inherent in plain radiographs performed in the axial projection. No significant developmental differences in glenohumeral index, glenoid anteroposterior orientation, and humeral retrotorsion were found between 50 normal subjects and 40 patients with RAD. Only erosions and fractures of the glenoid may affect orientation and anteroposterior diameter of the glenoid. Mainly, traumatic lesions rather than developmental abnormalities seem to affect these parameters in RAD patients.