Avascular necrosis, also known as osteonecrosis, is a disorder in which the bone does not receive enough blood, resulting in small breaks that can eventually cause it to collapse. Insufficient blood flow to a bone may occur as a result of a fracture or dislocation, excessive alcohol use, extended use of corticosteroids, or certain diseases that impede blood flow, such as sickle cell anemia, diabetes, lupus, Gaucher disease and HIV. Medications taken for osteoporosis or bone cancer, called bisphosphonates and radiation therapy also increase the risk of a patient developing avascular necrosis. The condition can occur in numerous joints, but it most commonly affects the hip.
Symptoms of Avascular Necrosis
In the early stages of avascular necrosis, patients may be asymptomatic. As the disease progresses, patients typically experience pain and a diminished range of motion in the affected area. In addition to occurring in the hip, this disorder can affect the knee or shoulder, feet, ankles, spine, jaw or wrists.
The pain from avascular necrosis may begin as mild discomfort, experienced only when joint is weight-bearing. Over time, however, the pain will become more severe and the patient may experience pain even when at rest. The pain associated with avascular necrosis of the hip may radiate into the thigh, buttock or groin. It is not unusual for some patients to experience bilateral pain from the condition, such as in both hips or both knees.
Diagnosing Avascular Necrosis
In order to diagnose avascular necrosis, a thorough review of the patient's medical history and a full physical examination of the patient are necessary. Because joint pain can be caused by a variety of conditions, imaging tests are normally administered as well, such as X-rays, MRI, CT or bone scans.
Treatment for Avascular Necrosis
There are several treatments available for avascular necrosis. Some are designed to reduce inflammation and relieve pain and some are recommended as a means of improving the patient's condition or preventing further bone deterioration. Rest, at times including the use of crutches, is usually the first treatment prescribed, followed by one or more of the others listed below.
Patients with avascular necrosis may be advised to take:
- Over-the-counter anti-inflammatories
- Medications normally prescribed for osteoporosis
- Cholesterol-lowering drugs
- Anti-coagulants (blood thinners)
The last two on this list may be of help in keeping blockages that interfere with blood circulation from occurring and so assist the bones in receiving proper nourishment.
Physical therapy may be useful during the early stages of avascular necrosis. Such rehabilitation efforts may include exercises to maintain range of motion and electrical stimulation of the affected area.
Most patients don't have symptoms of avascular necrosis until the condition is well-advanced, at which point surgery may be necessary. Procedures performed to help patients with avascular necrosis include:
- Core decompression
- Bone transplant
- Joint replacement
Of these three surgical procedures, joint replacement is the most complex operation, usually requiring the lengthiest rehabilitation. It is also the procedure most likely to provide a permanent solution to the problem.
While patients with mild, early stage avascular necrosis may be helped by noninvasive treatments, for most patients the disorder requires surgical intervention.