Osseous Bankart and Hill-Sachs Lesions: Definitions
An osseous Bankart lesion is a fracture of the anterior-inferior glenoid rim that occurs with anterior shoulder dislocation, while a Hill-Sachs lesion is a compression fracture (osseous defect) of the posterosuperior humeral head that results from impaction against the glenoid rim during the same dislocation event. 1, 2
Osseous Bankart Lesion
Represents a bony injury to the glenoid rim (as opposed to a soft-tissue Bankart lesion which involves only the labrum and ligaments without bone) that occurs when the humeral head dislocates anteriorly and shears off a fragment of the anterior-inferior glenoid 1
Glenoid bone loss is a critical factor in recurrent shoulder instability and must be quantified, as defects exceeding certain thresholds may require bone grafting procedures rather than simple soft-tissue repair 1
CT imaging is historically used to assess bony Bankart lesions and quantify glenoid bone loss, though MR arthrography has been shown to be equivalent to CT for assessing glenoid bone loss while being superior for evaluating associated soft-tissue injuries 1
Hill-Sachs Lesion
Occurs in nearly 100% of patients with recurrent anterior shoulder instability, making it an extremely common finding that increases in size with each subsequent dislocation 2
The critical distinction is whether the lesion is "engaging" or "non-engaging": an engaging Hill-Sachs lesion catches on the anterior glenoid rim when the arm is abducted and externally rotated, creating a mechanical block that causes recurrent instability 2, 3, 4
Represents a bipolar injury when combined with glenoid bone loss, and identification of concomitant glenoid defects is essential for optimal treatment planning 2
Some Hill-Sachs lesions affect only cartilage without underlying bone involvement, which is why MR arthrography is superior to CT for complete assessment 1
Clinical Significance
Both lesions commonly coexist in patients with anterior shoulder instability, and up to 10% of patients with recurrent instability have coexisting humeral avulsion of the glenohumeral ligament with significant glenoid bone loss 1
Treatment decisions depend on lesion size and engagement: small, non-engaging Hill-Sachs lesions with minimal glenoid bone loss can be managed with arthroscopic Bankart repair alone, while large engaging lesions may require additional procedures such as remplissage (filling the humeral defect with posterior capsule and infraspinatus tendon) 2, 3, 4
Glenoid bone defects of 10-30% combined with Hill-Sachs lesions can be successfully treated with open Bankart surgery, though larger glenoid defects and Hill-Sachs lesions are associated with higher recurrence rates 5
Imaging Approach
MR arthrography is the gold standard for evaluating both osseous and soft-tissue components of Bankart and Hill-Sachs lesions, as it provides equivalent assessment of bone loss compared to CT while being superior for labroligamentous injuries 1, 6
Standard radiographs should include at least three views (AP in internal and external rotation, plus axillary or scapula Y-view) as the initial imaging study, though these may only provide hints of the lesions 1, 6
CT arthrography is a reasonable alternative in patients with MRI contraindications and shows fair agreement with MR arthrography for diagnosing both Bankart and Hill-Sachs lesions 1