Avascular necrosis
Avascular necrosis (AVN), also called osteonecrosis or bone infarction, is death of bone tissue due to interruption of the blood supply. Early on, there may be no symptoms. Gradually joint pain may develop, which may limit the person's ability to move. Complications may include collapse of the bone or nearby joint surface.
| Avascular necrosis | |
|---|---|
| Other names | Osteonecrosis, bone infarction, aseptic necrosis, ischemic bone necrosis |
| Femoral head showing a flap of cartilage due to avascular necrosis (osteochondritis dissecans). Specimen removed during total hip replacement surgery. | |
| Specialty | Orthopedics |
| Symptoms | Joint pain, decreased ability to move |
| Complications | Osteoarthritis |
| Usual onset | Gradual |
| Risk factors | Bone fractures, joint dislocations, high dose steroids |
| Diagnostic method | Medical imaging, biopsy |
| Differential diagnosis | Osteopetrosis, rheumatoid arthritis, Legg–Calvé–Perthes syndrome, sickle cell disease |
| Treatment | Medication, not walking on the affected leg, stretching, surgery |
| Frequency | ~15,000 per year (US) |
Risk factors include bone fractures, joint dislocations, alcoholism, and the use of high-dose steroids. The condition may also occur without any clear reason. The most commonly affected bone is the femur (thigh bone). Other relatively common sites include the upper arm bone, knee, shoulder, and ankle. Diagnosis is typically by medical imaging such as X-ray, CT scan, or MRI. Rarely biopsy may be used.
Treatments may include medication, not walking on the affected leg, stretching, and surgery. Most of the time surgery is eventually required and may include core decompression, osteotomy, bone grafts, or joint replacement.
About 15,000 cases occur per year in the United States. People 30 to 50 years old are most commonly affected. Males are more commonly affected than females.