Osteonecrosis literally means "death of bone" (osteo = bone, necrosis = death). This condition is often called avascular necrosis. It leads to tiny breaks, and often eventual collapse from within the bone. Osteonecrosis frequently appears in relation to another disease or conditions such as rheumatoid arthritis or alcoholism. The underlying problem of osteonecrosis is a decrease in the blood supply to the affected area. The most common areas affected are the hips, knees, and shoulders, but the elbows, hands and feet also may become involved.
The following groups of people are most at risk for developing this condition:
- People who have a rheumatic disease such as rheumatoid arthritis or systemic lupus erythematosis
- People who are taking high doses of steroids (cortisone-like drugs)
- Professional scuba divers who have the bends (a condition brought on by the rapid reduction of air pressure)
- People who have connective tissue disorders, such as Gaucher's disease.
Osteonecrosis of the hip occurs most often between the ages of 30 and 50, and is slightly more frequent in men than in women. Osteonecrosis of the knee occurs most often between the ages of 50 and 60, or much earlier if other risk factors are present. Osteonecrosis of the knee occurs three to four times more often in women than in men. Osteonecrosis often involves more than one joint at a time.
The primary symptom of osteonecrosis is pain. Other symptoms of osteonecrosis include limitation of motion, joint stiffness and muscle spasms.
Symptoms usually begin slowly. In fact, in the earliest stage, there are usually no symptoms at all. Other people may notice that you are limping before you feel any pain. Once symptoms begin, they come and go. If the condition is left untreated, progressive bone damage will often occur. Surgery is usually required to correct the bone damage.
Early diagnosis of osteonecrosis is important in order to lessen the damage to bone. As the condition progresses, the death of bone often leads to changes within the bone and nearby joints so that a routine x-ray shows these changes. All too often, permanent damage has already developed by this point.
Aspirin and the newer nonsteroidal anti-inflammatory medications can help relieve the pain of osteonecrosis. Heating pads, warm baths, and an electric blanket can relieve muscle spasms and pain. Activity modifications and the use of crutches or canes can unload painful joints, and physical therapy can help maintain flexibility. These measures may provide some relief, but do not change the underlying process.
Keep in mind that it is up to you to keep your doctor informed of any increase in pain or decrease in mobility. This way, he or she can work with you to keep you as comfortable and functional as possible.
In later stages, if the area of bone has been severely damaged, joint replacement surgery called arthroplasty is needed to replace the damaged bone.