What is a Hill-Sachs lesion?
The shoulder is made up of a ball-and-socket type joint, with the “ball” being the humeral head and the “socket” being the glenoid. A Hill-Sachs lesion is an impaction fracture or indention that occurs in the back of the humeral head during anterior shoulder dislocations as the humeral head impacts against the front of the glenoid. Hill-Sachs defects occur in about half of first-time shoulder dislocations and is almost always seen in people who have recurrent shoulder instability from multiple recurrent dislocations.
What causes a Hill-Sachs lesion?
Your shoulder joint is very flexible. It can move in many directions and is therefore very vulnerable to injury. Shoulders are the most commonly dislocated major joint and can dislocate downward, backward, or forward. A Hill-Sachs lesion only occurs when there is forward dislocation of the shoulder. A dislocated shoulder has a greater risk of recurrence after the first injury. Common causes for a shoulder dislocation include:
- Falls, such as from a ladder or down stairs
- Sports activities, especially contact sports
- Trauma, such as a car accident
What are the symptoms?
- Chronic shoulder pain
- Difficulty moving the joint and loss of mobility
- Arm and shoulder weakness
- Recurrent dislocations
How is a Hill-Sachs lesion diagnosed?
Dr. Potts will obtain a detailed medical history, and will want to know how your shoulder injury occurred, whether it’s happened before, and what your symptoms are. He will also perform a thorough physical examination and order an x-ray to evaluate your bone.
Although larger Hill-Sachs injuries may be visible on x-ray, MRI imaging is typically the most helpful method in diagnosing a Hill-Sachs lesion and determining its size. MRI may also be used to rule out a labral tear (patients < 40 years old) or rotator cuff tear (patient > 40 years old) with shoulder dislocation or instability. CT scans may be helpful in evaluating the glenoid for bone loss in patients with more severe injuries in order to determine the need for a concomitant bony procedure.
What is the treatment for a Hill-Sachs defect?
Treatment is typically based on the size of the lesion, location of the lesion, arm mobility, and the extent of damage to the glenoid socket. Injuries associated with a dislocation such as a labral tear or loss of glenoid bone are usually managed first.
Non-surgical – If a Hill-Sachs lesion affects only a small area of the humeral head (less than 20%), treatment typically centers around physical therapy to strengthen the muscles that support your shoulder joint. In situations where the defect involves between 20% to 40% of the humeral head, Dr. Potts will determine if the defect is contributing to instability in order to plan a course of treatment.
Surgical – If your Hill-Sachs lesions involves more than 40% of the humeral head, it can cause instability of the joint and may require surgery. Surgical interventions include:
- Capsular shift – Tightening of the capsule of the glenohumeral joint to limit movement
- Bone augmentation – can be done on the humeral head or glenoid bone
- Remplissage (filling) – adds tissue in the defect
- Disimpaction – elevating the lesion and supporting it with bone graft
- Resurfacing – accomplished with metal implant or complete replacement of humeral head