Osteonecrosis

Osteonecrosis is also known as avascular necrosis, aseptic necrosis and ischemic necrosis. Osteonecrosis occurs when a portion of bone loses its blood supply and begins to die. The American Academy of Orthopaedic Surgeons (AAOS) says doctors see about 10,000-20,000 new cases of osteonecrosis each year. Common locations include the knee and the hip, but other areas can be affected as well. The exact cause is unknown, but AAOS and the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) say factors that increase your risk of developing osteonecrosis include:

• previous fracture or trauma to the bone (Read about "Bone Fractures")
• corticosteroid use e.g., prednisone
• excessive use of alcohol (Read about "Alcoholism")
• obesity (Read about "Obesity")
• certain diseases and conditions including sickle cell anemia, lupus and rheumatoid arthritis (Read about "Sickle Cell Disease" "Lupus" "Rheumatoid Arthritis")

Osteonecrosis causes pain, swelling and limited range of motion. The amount of disability that results from osteonecrosis depends on what part of the bone is affected, how large an area is involved and how effectively the bone rebuilds itself.

X-rays can detect bone changes that may indicate osteonecrosis. A bone scan, magnetic resonance imaging and/or CT scan can be used in diagnosis as well. (Read about "X-rays" "DEXA Scan - Dual Energy X-Ray Absorptiometry/Densitometry" "CT Scan - Computerized Tomography" "MRI - Magnetic Resonance Imaging")

NIAMS says appropriate treatment for osteonecrosis is necessary to keep joints from breaking down. Without treatment, most people with the disease will experience severe pain and limitation in movement within 2 years. Early treatment focuses on pain relief and efforts to prevent injury. Strengthening exercises and braces may be used also. (Read about "Rehabilitation") Nonsteroidal anti-inflammatory drugs (NSAIDs) can be prescribed to reduce pain. People with clotting disorders may be given blood thinners to reduce clots that block the blood supply to the bone. Surgical options include core decompression, which removes the inner cylinder of bone, reduces pressure within the bone and increases blood flow to the bone. Another procedure is osteotomy, which involves reshaping the bone to reduce stress on the affected area. In later stages, joint replacement surgery may be the best option. In fact, NIAMS says osteonecrosis is the underlying diagnosis in approximately 10 percent of hip replacements. (Read about "The Hip" "Joint Replacement")

Related Information:

    Skeletal System