Avascular necrosis is the death of bone tissue due to a lack of blood supply. Also called osteonecrosis, avascular necrosis can lead to tiny breaks in the bone and the bone's eventual collapse.
The blood flow to a section of bone can be interrupted if the bone is fractured or the joint becomes dislocated. Avascular necrosis is also associated with long-term use of high-dose steroid medications and excessive alcohol intake.
Anyone can be affected by avascular necrosis. However, it's most common in people between the ages of 30 and 60. Because of this relatively young age range, avascular necrosis can have significant long-term consequences.
Many people have no symptoms in the early stages of avascular necrosis. As the condition worsens, your affected joint may hurt only when you put weight on it. Eventually, the joint may hurt even when you're lying down.
Pain can be mild or severe and usually develops gradually. Pain associated with avascular necrosis of the hip may be focused in the groin, thigh or buttock. In addition to the hip, the areas likely to be affected are the shoulder, knee, hand and foot.
Some people develop avascular necrosis bilaterally — for example, in both hips or in both knees.
See your doctor if you have persistent pain in any joint. Seek immediate medical attention if you believe you have a broken bone or a dislocated joint.
Avascular necrosis occurs when blood flow to a bone is interrupted or reduced. Reduced blood supply can be caused by:
For about 25 percent of people with avascular necrosis, the cause of interrupted blood flow is unknown.
During a physical exam your doctor will likely press around your joints, checking for tenderness. Your doctor may also move the joints through a variety of positions to see if your range of motion has been reduced.
Many disorders can cause joint pain. Imaging tests can help pinpoint the source of pain. The options include:
Untreated, avascular necrosis worsens with time. Eventually the bone may become so weakened that it collapses. Avascular necrosis also causes bone to lose its smooth shape, potentially leading to severe arthritis.
To reduce your risk of avascular necrosis and improve your general health:
Risk factors for developing avascular necrosis include:
Medical conditions associated with avascular necrosis include: