Humeral avulsion of the glenohumeral ligament (HAGL) is, as the name suggests, avulsion of the inferior glenohumeral ligament (IGHL) from its humeral insertion. It can be associated with a bony avulsion fracture in which case it is referred to as bony humeral avulsion of the glenohumeral ligament (BHAGL lesion).
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Epidemiology
Humeral avulsion of the glenohumeral ligament is much more frequent in young men engaged in contact sports. Prevalence of ~1.5% on MRIs performed for shoulder pain 6.
Clinical presentation
Clinical presentation is usually with a history of shoulder dislocation. Anterior shoulder pain, apprehension in abduction and external rotation, subjective instability, and crepitus are noted on examination.
Pathology
Humeral avulsion of the glenohumeral ligament most often results from anterior shoulder dislocation due to forced hyperabduction and external rotation of the arm 6.
Associations
bony avulsion from the medial cortex of the humeral neck, and when combined with a Bankart lesion are often termed a “floating” inferior glenohumeral ligament: may be seen in ~ 20% of cases ref
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other findings associated with anterior shoulder dislocation are found in ~80% (range 65-95%) of cases 2,6, including:
Classification
Radiographic features
MRI
MRI is the modality of choice for the assessment of HAGL, especially as the finding may be difficult to diagnose on arthroscopy. It should be noted that HAGL can be difficult to diagnose on MRI 6. Typical findings include:
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avulsion of the IGHL from the proximal humerus
it is important to note that failure of the IGHL is more frequent at its glenoid insertion (40%) or midsubstance (35%), with only 25% tearing at the humerus
retraction of the IGHL (so-called J sign): the normal U-shaped inferior glenohumeral recess is disrupted 2
Treatment and prognosis
Shoulder instability as a result of HAGL lesions is reported to occur in ~5% (range 2-10%) 2. The degree of instability and the presence of other associated injuries determines whether surgical repair is required.
Differential diagnosis
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IGHL tears other than at the humeral insertion 2
History and etymology
Humeral avulsion of glenohumeral ligaments (HAGL), was coined by Wolf et al. in 1995 7.