Shoulder Avascular Necrosis

Avascular necrosis, or osteonecrosis, of the shoulder occurs when the blood supply to the humeral head is disrupted, leading to a lack of nutrients and oxygen delivery to the bone. Without these necessities, the bone dies. Over time, the dead bone weakens and eventually collapses, interfering with the articular cartilage on the surface. This leads to progressive osteoarthritis and destruction of the shoulder which can be painful and disabling.

AVN can occur in anyone, but it is most common in individuals between the ages of 40 and 65. It is also more common in men than women. In some instances, both shoulders may be affected by AVN.

There have been several risk factors that have been identified for shoulder AVN. Most commonly, patients who develop AVN have a history of excessive alcohol use or chronic corticosteroid use. Both substances lead to fatty deposits in the bone marrow which result in decreased blood flow to the bone. Trauma to the shoulder, such as a dislocation or fracture, is another known cause of AVN. Trauma can damage the blood vessels in the humeral head and disrupt its blood supply. Although rarer, a handful of medical conditions have also been associated with the development of AVN. These include Caisson disease (“the bends”), sickle cell disease, myeloproliferative disorders, Gaucher’s disease, systemic lupus erythematosus, Crohn’s disease, arterial embolism, thrombosis, and vasculitis.

AVN usually presents initially with new-onset shoulder pain. This may progress to dull aching or throbbing pain. As shoulder AVN progresses, it is more difficult to move the shoulder, sleep on the shoulder, or carry weighted items.

It may take anywhere from a few months to a year for the disease to progress. Early diagnosis is important because some studies have shown better outcomes when treated earlier in the AVN disease process.

• Pain that worsens with movement.
• Stiffness
• Swelling
• Limited Range of Motion
• Weakness may develop due to lack of use.

The combination of a detailed history, comprehensive physical examination, x-rays, and an MRI (magnetic resonance imaging) is the key to a successful diagnosis of AVN. A detailed history will first be obtained to learn more about your past medical history and evaluate for any possible risk factors of AVN. Dr. Jorge Chahla and his team will then perform a thorough physical exam, assessing your range of motion, strength, and location of pain.

The diagnosis of AVN relies heavily on imaging studies. An x-ray of the shoulder is the initial study to examine the bony structures of the joint. This allows Dr. Chahla to determine if the bone in the humeral head has collapsed and to what degree. A common x-ray finding is a wedge-shaped area of dense, whitish substance in the superior portion of the humeral head.

However, if the x-ray is normal, an MRI of the shoulder is obtained to look for early signs of AVN. An MRI has the added advantage of picking up signs of AVN that would be otherwise missed on x-ray. An MRI is an important diagnostic imaging test to understand the full extent of the injury. The MRI also allows Dr. Chahla to fully assess surrounding shoulder structures, including the proximal biceps tendon, superior labrum, and rotator cuff.