Anteroinferior Glenoid Research Articles

The Bankart repair illustrated in cross-section. Some anatomical considerations.

The Bankart repair for chronic anterior shoulder instability effectively addresses the pathologic components responsible for repeated dislocation or subluxation. However, contrary to popular belief, the Bankart repair does not precisely restore the premorbid anatomy. The capsule is reattached to the boney rim of the anterioinferior glenoid deep to and lateral to the torn cartilagenous labrum, thus excluding the labrum from the joint anteriorly. This was demonstrated by cross-sectional cadaver dissections performed to illustrate this complex surgical anatomy to orthopaedic residents in training. In addition, when correlated with double-contrast computerized axial tomography, we noted five predominant patterns of anatomical lesions which by common use have been collectively termed the "Bankart lesion." These are: 1) the rare "classic" Bankart lesion in which the cartilagenous labrum and capsular origin are torn from the glenoid rim; 2) the capsule stripped from the scapular neck and the labrum detached from the glenoid rim remaining fixed to the overlying capsule; 3) the capsule stripped from the scapular neck and the labrum separated from the glenoid rim, but separately; 4) the labrum abraded away and no longer radiographically detectable; and 5) glenoid rim fracture.

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.

Arthroscopic Findings in the Subluxating Shoulder

The arthroscopic findings in 19 shoulders (18 patients) with subluxation are described. The clinical diagnosis of subluxation of the shoulder is primarily based on clinical history with inconsistent physical findings and radiographic studies. Arthroscopic findings in these patients were consistent. Increased translation of the humeral head in the anteroposterior plane was noted secondary to attenuation of the anteroinferior glenohumeral ligament. Incompetence of this ligamentous structure obviated its function as an anterior buttress and allowed the humeral head to translate anteriorly on the glenoid. Fraying, tearing, or detachment of the anteroinferior glenoid labrum and articular defects in the posterolateral humeral head were also consistent findings, thought to be secondary to repeated injury as the humeral head translates forward and backward in the glenoid fossa. In several cases the classic "click" that occurs with subluxation of the shoulder could be reproduced under arthroscopic visualization and corresponded to the defect in the posterolateral humeral head riding over the torn labrum and/or anterior glenoid rim. Shoulder arthroscopy is an accurate method for confirming the clinical impression of subluxation of the shoulder, especially in subtle glenohumeral instability, and should be helpful in selecting specific surgical reconstruction procedures.