What is a Hill-Sachs lesion?

A Hill-Sachs lesion, or Hill-Sachs impaction fracture, is an injury to the back portion of the rounded top of your upper arm bone (humerus). This injury occurs when you dislocate your shoulder. It’s named for the two American radiologists who first described the injury in 1940: Harold Hill and Maurice Sachs.

Your shoulder is a ball-and-socket joint held in place with muscles, ligaments, cartilage, and tendons. The humerus bone sits in the socket, the cup-shaped labrum in your shoulder. An injury can pop the ball part of the joint out of the socket, causing pain and damaging parts of the joint.

Your shoulder can dislocate downward, backward, or forward. A Hill-Sachs lesion only occurs when there is forward dislocation of the shoulder. View a detailed BodyMap of the shoulder.

A dislocation injury can happen in sports, in a fall, or in reaching or pulling with your arm extended. Shoulders are the most commonly dislocated major joint. There is an incidence rate in the United States of about 23.9 cases per 100,000 persons per year. Out of these cases, 46.8 percent are people between 15 and 29 years of age. In one study of people with dislocated shoulders, 71.9 percent also had a Hill-Sachs lesion.

Symptoms

A Hill-Sachs lesion or fracture occurs when the humerus bone pops out of the socket, scraping the head of the bone against the edge of the socket. You won’t be able to tell right away if you have a Hill-Sachs lesion. But you’ll feel the pain of your shoulder dislocation.

Also, more than one part of your shoulder may be damaged in an injury. A dislocated shoulder requires emergency care.

The symptoms of a dislocated shoulder are:

  • intense pain
  • difficulty moving the joint
  • visible deformation of the shoulder, often with a bulge in the front of the joint
  • swelling or bruising
  • weakness
  • muscle spasms

Causes and risk factors

Your shoulder joint is very flexible. It can move in many directions and has many parts that can be injured.

The top of the humerus bone is called the humeral head. It’s larger than the socket that holds it. To keep it stable, tendons, muscle, and ligaments hold it in place.

Common causes for a dislocated shoulder include:

  • falls, such as from a ladder or down stairs
  • sports activities, especially contact sports
  • trauma, such as a car accident

A 2010 study of 8,940 people with shoulder dislocations found that 58.8 percent of dislocations resulted from a fall. Of these cases, 47.7 percent occurred at home. And 34.5 percent occurred while playing sports or participating in some other type of recreation. Overall, 48.3 percent of all the dislocations occurred in sports or recreations.

Specific activity risks include:

  • contact sports such as football, hockey, and soccer
  • sports where falls are possible, such as skiing, volleyball, and gymnastics
  • sports with throwing activity, such as tennis and baseball
  • sports involving overhead motion, such as swimming and weight-lifting
  • occupations where you do heavy lifting or pushing or pulling above your shoulder height, or do repetitive work

A dislocated shoulder has a greater risk of recurrence after the first injury. However, data are limited for recurrence of dislocations for people with Hill-Sachs lesions. One meta-analysis cited two studies that showed if you have a Hill-Sachs lesion, you’re 1.55 times more likely to have a recurrence.

Diagnosis

If you suspect a dislocated shoulder, see your doctor as soon as possible. Until then:

A doctor can diagnose a dislocated shoulder during a physical examination, but determining whether you have a Hill-Sachs lesion or other damage will require further testing.

The doctor will ask how your shoulder injury occurred, whether it’s happened before, and what your symptoms are. The doctor will likely order an X-ray to check for other possible damage to the bone, nerves, and muscle. If your range of motion indicates possible damage to the humerus, the doctor may order:

  • a series of shoulder X-rays from different angles
  • an ultrasound
  • a CT scan
  • an MRI

According to one study, MRI is the most helpful method in diagnosing a Hill-Sachs lesion and determining its size.

Treatment

There are many approaches to treating a dislocated shoulder. Some may be done in the doctor’s office with a local anesthetic. Others may require either open surgery or arthroscopic surgery. If the dislocation also involves damage to the humerus bone or surrounding area, your doctor will consider additional treatment.

Treatment for a Hill-Sachs lesion depends on the size of the lesion, its placement, the involvement of glenoid socket bone, and how it affects your arm mobility. If the lesion is small, involving less than 20 percent of the head of the humerus, it’s likely your doctor will leave it alone and suggest physical therapy to strengthen the shoulder.

If the lesion is midsize, involving 20 to 40 percent of the head of the humerus, the treatment option will depend on whether the doctor determines your shoulder will be unstable if not treated.

According to the journal Arthroscopy and Orthopedic Sports Medicine, treatment options include:

  • Bone augmentation: This can be directly done on the humerus head, or onto the glenoid bone in order to prevent its contact with the humerus when you move your shoulder.
  • Remplissage (filling): This technique surgically adds tissue to the lesion. The procedure is usually done on Hill-Sachs lesions that are moderate in size and also have some amount of glenoid defect.
  • Disimpaction: This involves a bone graft under the lesion to lift the humerus up to the pre-injury position. It’s a relatively new procedure best suited for lesions that are less than three weeks old and have under 40 percent of humerus bone involvement.
  • Resurfacing: This can be done with a metal implant or a complete replacement of the humeral head. The complete replacement is called a hemiarthroplasty. It’s done on people who have recurrent problems that involve more than 40 percent of the humerus bone. It’s not recommended for younger people.

Recovery

Recovery time varies depending on the extent of your injury and the type of surgery. Arthroscopic surgery often has a shorter recovery time than open surgery.

If you have surgery for a dislocated shoulder and Hill-Sachs lesion repair, you may have pain and discomfort for a week or more. Your shoulder will be immobilized in a sling for three to six weeks. To guard against stiffness, that length of time may be shorter if you’re older. However, the length of time for immobilization is controversial.

Your doctor will assess when you should begin physical therapy. This usually starts with passive movement that doesn’t involve muscle contraction. The next phase is limited motion exercise, in which you avoid heavy lifting, pushing, and pulling. In about three months, you’ll begin moderate exercise to strengthen your muscles. Talk to your doctor or physical therapist about shoulder rehabilitation exercises you can safely do at home.

Until you’ve completed the first stages of rehabilitation, you’ll have to restrict your activities to protect your injured joint. Activities to avoid include:

  • throwing
  • swimming
  • running
  • racquet sports

Your doctor and physical therapist will advise you when you can resume sports and other activities.

Recovery from surgery for a Hill-Sachs lesion can take several months. Regaining full use of your shoulder depends on your age, level of activity, and general health.

Outlook

The outlook for recovery from a dislocated shoulder and a Hill-Sachs lesion is generally good. But a recurrence of a dislocation is common, especially in younger people.

In the long-term, about one-third of people who have surgery for a dislocated shoulder will develop shoulder arthritis. Talk to your doctor about a treatment and rehabilitation plan that will limit your risk of further complications.