Hill-Sachs lesions are a posterolateral humeral head compression fracture, typically secondary to recurrent anterior shoulder dislocations, as the humeral head comes to rest against the anteroinferior part of the glenoid. It is often associated with a Bankart lesion of the glenoid.
In addition to being acutely painful at the time of dislocation, Hill-Sachs lesions may promote future dislocation/subluxation due to the lever-like effect of the defect during external rotation 4.
Bankart lesions are up to 11 times more common in patients with a Hill-Sachs lesion, with increasing incidence with increasing size 8.
Hill-Sachs lesions may be difficult to appreciate on x-rays, frequently requiring CT or MRI for full characterisation. When a Hill-Sachs lesion is identified careful assessment of the anterior glenoid rim and labrum should be performed to identify a potential Bankart lesion.
These lesions are best seen following relocation of the joint, and better appreciated on internal rotation views. It appears as a sclerotic vertical line running from the top of the humeral head towards the shaft. If large, a wedge defect may be evident.
CT and MRI
Both MRI and CT are very sensitive to this lesion, which appears as a region of flattening or a wedge-shaped defect (with bone marrow oedema on MRI acutely) seen involving the posterolateral humeral head above the level of the coracoid. This is usually seen in the most superior few slices, were the humeral head should be rounded. It is important to note that below the level of the coracoid the humeral head normally flattens out posterolaterally (sometimes termed pseudo-Hill-Sachs lesion), and this should not be misinterpreted as a Hill-Sachs lesion 2,4.
Treatment and prognosis
The bony defect can also be treated with bone grafting or placement of soft tissue within the defect, but this is generally reserved for large defects 6-7.
The Connolly procedure is performed by an open posterior approach and involves transferring the infraspinatus with a portion of greater tuberosity into the defect, and rendering the defect extra-articular; although this procedure restore the stability but it reduces the shoulder range of movement 6-7. The arthroscopic approach of the same procedure is known as remplissage (French for fill in) 6.
History and etymology
It was first described in 1940 by H A Hill and M D Sachs 3.
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- 8. Horst K, Von Harten R, Weber C et-al. Assessment of coincidence and defect sizes in Bankart and Hill-Sachs lesions after anterior shoulder dislocation: a radiological study. Br J Radiol. 2004;87 (915): 20130673. doi:10.1259/bjr.20130673 - Pubmed citation