The roentgenographic evaluation of anterior shoulder instability.

Retrospective evaluations of roentgenograms of 83 patients with unilateral shoulder instability were surveyed to evaluate the usefulness of various radiographic projections and to correlate the information with the osseous pathology associated with prior glenohumeral dislocation. The Hill-Sachs and the osseous Bankart defects were considered pathognomonic radiographic signs of glenohumeral joint instability. Based on history, physical examination, and examination under general anesthesia, patients were divided into three categories--(1) dislocation group, (2) subluxation group, and (3) combination group. Roentgen projections evaluated included the anteroposterior view with the humerus in internal and external rotation, axillary view, West Point view, Stryker notch, and Didiee view. The Hill-Sachs defect on the posterolateral aspect of the humeral head was best demonstrated on the combination of an internal rotation and a Stryker notch view. The osseous Bankart defect on the anteroinferior glenoid rim was best documented on the Didiee and West Point views. The external rotation and axillary view did not add significantly to the preoperative radiographic findings. In a patient with an unstable shoulder, a radiographic series that includes an internal rotation, a Stryker notch view, and either a West Point or a Didiee view would maximize the diagnostic yield per radiographic cost, time, and exposure.