Avascular Necrosis

What is avascular necrosis?

Avascular necrosis is a condition in which interruption of the blood supply causes the bone to die and collapse. This is a painful process that creates deformity in the bone and leads to arthritis, damage to the shiny white cartilage covering the bone. This disease process can affect many bones, but will typically involve the shoulder, hip and knee.

What causes avascular necrosis?

Factors associated with avascular necrosis include oral steroid use, sickle cell anemia, alcohol abuse, lupus, and vasculitis. In many cases, no cause is found.

How is avascular necrosis diagnosed?

Avascular necrosis may be diagnosed on X-ray. MRI may also be used to determine the presence or extent of the disease.

How is avascular necrosis treated?

Treatment for avascular necrosis of the shoulder depends on how advanced the disease is. In younger patients with early disease, core decompression can be performed with shoulder arthroscopy and fluoroscopy (intraoperative x-ray). In older patients or in patients with advanced collapse and deformity of the humeral head, shoulder replacement is most appropriate.

What happens if I need surgery?

In the early stages, avascular necrosis may be treated with decompression, which basically involves drilling the area of damage to stimulate the blood supply and initiate healing of the bone. This is typically an outpatient procedure. In later stages, the bone may become severely deformed and cause arthrtitis, which is damage to the smooth cartilage covering the ends of the bone. This problems is best treated with shoulder replacement. This may be either anatomic shoulder replacement or reverse shoulder replacement, depending on the integrity and function of the rotator cuff.

Avascular necrosis of the humeral head (shoulder)

Fig 1. Xray demonstrating collapse and deformity of the bone.

Fig 2. MRI demonstrating collapse of bone and rotator cuff tear.

Fig 3. Intraoperative picture of the humeral head.

Fig 4. Reverse shoulder replacement replaces deformed bone and treats chronic cuff tear.