What Is a Hill-Sachs Lesion?

A Hill-Sachs lesion is an impaction fracture — a compression defect — on the posterolateral surface of the humeral head. It forms during anterior shoulder dislocation, when the relatively soft cancellous bone of the humeral head is driven against the harder, denser anterior-inferior glenoid rim as the humerus levers out of the socket. The resulting dent in the bone surface can range from a small groove barely visible on imaging to a substantial defect occupying a significant proportion of the articular surface. First described by Harold Hill and Maurice Sachs in 1940, this lesion is found in approximately 40% of first-time anterior dislocations and in over 90% of recurrent dislocations — making it one of the most common structural consequences of shoulder instability.

How the Lesion Forms and Why It Matters

During anterior glenohumeral dislocation, the humeral head translates forward and inferior, pivoting over the anterior-inferior glenoid. The bony contact creates a localised compression injury to the posterolateral humeral head. In isolation, a small Hill-Sachs lesion may be asymptomatic and clinically inconsequential. The concern arises when the defect is sufficiently large and oriented such that it engages the anterior glenoid rim during normal shoulder movement — a phenomenon called an engaging Hill-Sachs lesion. When the arm is placed in a position of abduction and external rotation (common in throwing, swimming, and overhead activity), the rim of the defect catches on the glenoid edge, creating a sensation of the shoulder slipping, clicking, or giving way. This engagement is the primary biomechanical mechanism driving recurrent instability in many patients.

Clinical Assessment and Imaging

The Hill-Sachs lesion is typically identified on plain radiography (Stryker notch view or AP in internal rotation) or MRI following dislocation. CT with 3D reconstruction provides the most accurate quantification of defect size and is used when surgical planning is being considered. Clinically, the Rowe test and apprehension-relocation test are used to assess anterior instability, while the engaging nature of the lesion is assessed in dynamic shoulder positions. The glenoid track concept — developed by Yamamoto and colleagues — provides a framework for determining whether a Hill-Sachs lesion will engage: if the defect extends medial to the glenoid track (the area of glenoid contact during arm movement), it is classified as off-track and at high risk of engagement.

Glenoid track concept: A Hill-Sachs lesion is considered "on-track" (unlikely to engage) if it remains within the width of the glenoid contact zone during shoulder movement. An "off-track" lesion extends beyond this zone and engages the glenoid rim — significantly increasing recurrent dislocation risk and influencing surgical decision-making.

Conservative vs. Surgical Management

Management depends on lesion size, engagement status, the presence of concurrent glenoid bone loss, and patient age and activity demands. Small, non-engaging lesions in low-demand patients are managed conservatively: structured shoulder rehabilitation addressing posterior capsule flexibility, rotator cuff strength, scapular stability, and proprioception. The goal is to optimise dynamic joint centring such that compensatory muscular control offsets the structural deficit. Large or engaging lesions, or those associated with significant glenoid bone loss (the "bipolar lesion" — combined Hill-Sachs and anterior glenoid defect), typically require surgical intervention. Options include the Latarjet procedure (coracoid transfer to augment the anterior glenoid), remplissage (arthroscopic posterior capsulodesis to fill the Hill-Sachs defect and prevent engagement), or humeral head augmentation in severe cases.

Rehabilitation After Hill-Sachs Injury

Whether managed conservatively or post-operatively, rehabilitation follows progressive phases. Initial management focuses on pain control, restoring range of motion (prioritising external rotation and posterior capsule length), and re-establishing rotator cuff activation — particularly the posterior cuff muscles that dynamically compress and centre the humeral head. Intermediate phases develop scapular stability and progressive rotator cuff loading through range. Final phases address sport-specific demands: overhead loading, throwing mechanics, or contact sport preparation as relevant. Proprioceptive training is essential — the mechanoreceptors disrupted by dislocation require systematic retraining to restore the joint's protective neuromuscular reflexes.

Prognosis and Recurrence Risk

Age at first dislocation is the strongest predictor of recurrence: patients under 20 have recurrence rates approaching 90% without surgery, while those over 40 have significantly lower recurrence risk (partly due to softer tissue injury predominating over bony injury in older presentations). Appropriate management of the Hill-Sachs lesion — whether through optimised rehabilitation or surgical correction of engaging lesions — substantially reduces this risk. Return to overhead and contact sport is achievable for the majority, though the timeline varies considerably with the extent of injury and management pathway chosen.

References & Further Reading

  1. Yamamoto N, et al. Arthroscopic anatomy of the anterior band of the inferior glenohumeral ligament. J Shoulder Elbow Surg. 2007;16(1):35–38.
  2. Di Giacomo G, et al. Evolving concept of bipolar bone loss and the Hill-Sachs lesion. Am J Sports Med. 2014;42(9):2147–2160.
  3. Shaha JS, et al. Redefining "critical" bone loss in shoulder instability. Am J Sports Med. 2015;43(7):1719–1725.