Avascular Necrosis of the Hip (AVN)

What is Avascular Necrosis?

Avascular necrosis, also called osteonecrosis, is a condition in which bone death occurs because of inadequate blood supply to it. Lack of blood flow may occur when there is a fracture in the bone or a joint dislocation that may damage nearby blood vessels. Hip joint is most commonly affected; however, the knee and shoulder may also be involved.

Factors that can lead to Avascular Necrosis

Chronic use of high doses of steroid medications and heavy alcohol consumption are the two main risk factors of avascular necrosis. Initially, small breaks appear in the bone that may eventually collapse.

Symptoms of Avascular Necrosis

The symptoms appear suddenly if it is the result of an injury. In other situations, the pain and stiffness may gradually appear over a period. Typically, avascular necrosis causes pain and restricted range of motion in the affected joint. Your doctor will diagnose the condition using imaging tests such as X-rays, MRI scan and bone scan that help rule out other causes of joint pain.

Treatments for Avascular Necrosis

The treatment for avascular necrosis aims at preventing further loss of bone and it depends on the bone damage that has occurred already. Conservative treatment would reverse early stages of avascular necrosis, whereas surgical treatment may be required in more advanced stages.

Conservative Approach for Avascular Necrosis

Medications: Non-steroidal anti-inflammatory drugs (NSAIDS) may be prescribed that help control your pain and swelling.
Rest: Restriction of physical activities and use of crutches to decrease weight-bearing on your joints may be beneficial.
Exercises: Regular exercises that improve your range of motion are recommended.
Electrical stimulation: Electric currents promote new bone growth. They can be applied directly to the area of damage or through electrodes fixed on the skin. They help to replace damaged bone.

Surgical Treatments for Avascular Necrosis

Avascular necrosis can be treated by one of the following methods:

Core decompression: During this procedure, a portion of the inner layer of the bone is removed to relieve the pressure inside the bone. This decreases the pain and allows growth of new blood vessels, thereby stimulating new bone growth.
Bone transplant: A healthy bone harvested from another part of your body is grafted into the affected area.
Bone reshaping (osteotomy): This procedure is done in advanced stages and involves reshaping of the bone which is done to decrease the stress placed over the affected bone.
Joint replacement: Joint replacement surgery is performed as a last resort when the bone has collapsed, needing artificial replacement