Glenoid avulsion of the glenohumeral ligament (GAGL): a case report and review of the anatomy

Abstract

Shoulder dislocations are frequently seen in the general population and can be a cause of instability. Instability can lead to debilitating symptoms and morbidity as a result of progressive damage to the shoulder. Anterior shoulder dislocations are the most frequent type of dislocations and have been studied extensively with MRI. The soft tissue Bankart lesion is the most well-known entity associated with anterior instability; however, additional structural lesions arising from traumatic events have been described in recent literature which also predispose to anterior shoulder instability. One of these lesions, the glenoid avulsion of the glenohumeral ligament (GAGL), involves avulsion of the inferior glenohumeral ligament from the glenoid and involves separation from an intact labrum. In contrast to the Bankart lesion, there has been limited discussion of the GAGL lesion in the literature and very few imaging examples. We report a case of a GAGL diagnosed on MRI and confirmed with arthroscopy. It is discussed in the context of the anatomy of the inferior glenohumeral ligament and the imaging findings.

Understanding the Glenoid Avulsion of the Glenohumeral Ligaments as a Cause of Shoulder Instability: Surgical and Postsurgical Management

“…Surgical repair of the glenohumeral ligaments is critical to restoring stability in the shoulder. As previously described in the literature, the glenohumeral ligaments stabilize the shoulder throughout motion, with the inferior glenohumeral ligament responsible for preventing anterior and inferior shoulder translation 1, 4, 5, 6, 7, 9, 10, 11. This function is compromised in anterior shoulder dislocations.…”

“…The glenohumeral ligaments and the glenoid labrum are key static stabilizers of the shoulder joint 1, 4, 5, 6, 7, 9, 10. Of the ligaments, the inferior glenohumeral ligament is the most important for providing stability to the joint 4, 6.…”

“…Shoulder instability is a common shoulder pathology in adolescents and young adults, with traumatic anterior dislocations accounting for the majority of cases 1, 2, 3, 4, 5, 6. The full separation of the capsular ligaments and labrum from the anterior glenoid rim, known as the Bankart lesion, is classically described as soft tissue copathology with anterior dislocation 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11.…”

“…Shoulder instability is a common shoulder pathology in adolescents and young adults, with traumatic anterior dislocations accounting for the majority of cases 1, 2, 3, 4, 5, 6. The full separation of the capsular ligaments and labrum from the anterior glenoid rim, known as the Bankart lesion, is classically described as soft tissue copathology with anterior dislocation 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11. Whereas Bankart lesions are common, multiple pathologies frequently present as a result of anterior dislocation, including Hill-Sachs lesions, anterior labroligamentous periosteal sleeve avulsion (ALPSA), humeral avulsion of the glenohumeral ligaments (HAGL, or BHAGL if bony involvement), rotator cuff injury, labral tears, biceps tendon pathology, and bony injury 1, 2, 4, 5, 6, 7, 8, 9.…”

“…The full separation of the capsular ligaments and labrum from the anterior glenoid rim, known as the Bankart lesion, is classically described as soft tissue copathology with anterior dislocation 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11. Whereas Bankart lesions are common, multiple pathologies frequently present as a result of anterior dislocation, including Hill-Sachs lesions, anterior labroligamentous periosteal sleeve avulsion (ALPSA), humeral avulsion of the glenohumeral ligaments (HAGL, or BHAGL if bony involvement), rotator cuff injury, labral tears, biceps tendon pathology, and bony injury 1, 2, 4, 5, 6, 7, 8, 9. Even more rare is the glenoid avulsion of the glenohumeral ligaments (GAGL), in which the labrum remains attached to the glenoid while the inferior glenohumeral ligament complex detaches from the labrum and glenoid 1, 3, 7, 12…”