Dead Bone Disease

Dead bone disease involves a temporary or permanent lack of blood supply to a certain area of the bones. The affected bones die and eventually collapse, resulting in pain, arthritis and limited mobility. Medically known as osteonecrosis, the condition can be caused by trauma, such as a fracture, but sometimes the cause is indefinable. Several risk factors are associated with nontraumatic cases of osteonecrosis.

Identification

• Normal bone continuously breaks down and is replaced with new bone. This keeps the bone structure strong and helps maintain a proper balance of minerals. During dead bone disease, or osteonecrosis, bone tissue breaks down more rapidly than the body can replace it. The disorder can affect one or several bones, but most often occurs in the ends of the femur, the bone extending from the hip joint to the knee joint. Osteonecrosis also is likely to affect upper arms, shoulders, knees and ankles. Less commonly, it affects the jaw, causing exposure of the jaw bone.

Symptoms

• Early in the disease, people may have no symptoms. Joint pain begins as the disorder progresses. Pain may only occur when the person puts weight on the affected area, but later it occurs even when resting. The pain may become severe, particularly if the bone and surrounding joint surface collapse. This leads to a limited range of motion.

Prevalence

• According to the U.S. National Institutes of Health (NIH), the American Academy of Orthopaedic Surgeons has determined that between 10,000 and 20,000 people develop dead bone disease every year. The most common occurrence is between 20 and 50 years of age. The time frame between the first symptoms and loss of joint function usually ranges from several months to over a year. The NIH notes that about 10 percent of hip replacements are due to osteonecrosis.

Causes and Risk Factors

• A joint fracture or dislocation can damage blood vessels, interfering with circulation to the bone. Outside of traumatic injury, however, no other specific cause for dead bone disease has been identified. Some risk factors include radiation therapy and chemotherapy, and long-term use of corticosteroids. Certain diseases are linked to osteonecrosis, including arthritis, gout, osteoporosis, blood disorders, cancer and human immunodeficiency virus (HIV). People who drink large amounts of alcohol and those who smoke are also more at risk for dead bone disease. Osteonecrosis of the jaw bone may occur after tooth extraction, injury to the head or neck, or radiation treatment to the head and neck. It also is linked to high doses of intravenous bisphosphonates.

Treatment

• Treatment for dead bone disease includes non-steroidal anti-inflammatory drugs (NSAIDs) for pain relief, and anticoagulants if a clotting disorder appears to be causing blood supply blockage. Physical therapy can teach the patient exercises to keep joints mobile and increase range of motion. The patient may need to remove weight from the affected joint by walking with crutches or by limiting certain types of activity. Electrical stimulation therapy is sometimes successful in stimulating new bone growth. Surgery is an option if other treatments are not effective.