This is a current-concepts review of imaging for glenohumeral instability. It walks through radiographs, conventional and CT arthrography, routine MRI, and MR arthrography. The focus is on which modality and which views detect each instability lesion and how to avoid misreading normal variants.
When a young patient has recurrent anterior instability, order MR arthrography with an ABER sequence rather than plain MRI. The reason is mechanical: contrast distends the joint and ABER tensions the anterior band of the inferior glenohumeral ligament, which unmasks nondisplaced and partially healed labral tears the arm-neutral study will miss.
Use age as a decision anchor. Under 35, expect a Bankart or its variant. Over 35, look first for a cuff tear, greater tuberosity avulsion, or subscapularis avulsion, because a missed subscapularis injury drives recurrent instability and pain.
Know the mimics before you call a tear. The Buford complex, the anterosuperior sublabral sulcus, and the normal middle glenohumeral ligament all fool the unwary reader and can turn a normal shoulder into a false-positive labral tear.
Finally, hunt for the HAGL lesion in recurrent anterior instability, since a humeral-side ligament avulsion is easy to miss arthroscopically and changes the operative plan.
This is a current-concepts review of imaging for glenohumeral instability. It walks through radiographs, conventional and CT arthrography, routine MRI, and MR arthrography. The focus is on which modality and which views detect each instability lesion and how to avoid misreading normal variants.
When a young patient has recurrent anterior instability, order MR arthrography with an ABER sequence rather than plain MRI. The reason is mechanical: contrast distends the joint and ABER tensions the anterior band of the inferior glenohumeral ligament, which unmasks nondisplaced and partially healed labral tears the arm-neutral study will miss.
Use age as a decision anchor. Under 35, expect a Bankart or its variant. Over 35, look first for a cuff tear, greater tuberosity avulsion, or subscapularis avulsion, because a missed subscapularis injury drives recurrent instability and pain.
Know the mimics before you call a tear. The Buford complex, the anterosuperior sublabral sulcus, and the normal middle glenohumeral ligament all fool the unwary reader and can turn a normal shoulder into a false-positive labral tear.
Finally, hunt for the HAGL lesion in recurrent anterior instability, since a humeral-side ligament avulsion is easy to miss arthroscopically and changes the operative plan.