Chronic unreduced dislocations of the glenohumeral joint: imaging strategy and pathologic correlation.

Although the evaluation of acute or recurrent dislocations of the glenohumeral joint (GHJ) using routine radiography, specialized views, arthrography, and computed tomography (CT) has been extensively studied, methods of evaluation and osseous pathology of chronic unreduced GHJ dislocations are not well documented. In order to define such methods and pathology, we studied nine patients with chronic (greater than 6 months) unreduced anterior, posterior, superior, or central dislocations as well as one patient with a chronic rotator cuff injury; and seven scapular specimens, six with matching humeral specimens, with osseous abnormalities similar to those in the patients. We examined 15 additional scapular specimens with evidence of subluxation secondary to chronic rotator cuff injury. Standard, reformatted, and three-dimensional (3D) CT techniques were used to evaluate both the patients and the specimens. Our results indicate that characteristic alterations occur in the scapula and humeral head that are far more extensive than the classic Hill-Sachs, Bankart, and trough lesions. Such alterations occur at sites of osseous contact between the malpositioned humerus and scapula and are modified owing to prolonged adjustments made by the patients in an attempt to increase GHJ motion. Although routine radiography and specialized views are of some value, standard and 3D CT provide a more accurate analysis of the location and extent of the bone abnormalities and, as such, should be employed, particularly in the evaluation of patients in whom surgery is being considered.