Other common names include: Avascular Necrosis, AVN, Aseptic Necrosis
Osteonecrosis is a condition where part of the bone dies due to lack of blood flow to the area. This condition most commonly occurs at the hip and shoulder, but can also occur at the knee, elbow, wrist, and ankle. The Adult Lower Extremity Joint Reconstruction Clinic evaluates patients who are affected with osteonecrosis of the hip and/or knee. Osteonecrosis can be caused by trauma, long term prednisone use, sickle cell disease, excessive use of alcohol, or could occur without a known cause.
Early in the disease, before the changes can be seen only on an MRI and not on a plain X-ray, there is an intense inflammatory response which is very painful with sharp stabbing pain in the groin with any motion of the leg. There are very few interventions that have been shown to reverse the condition. A steroid injection may significantly improve the pain during this early phase.
Once the blood supply is cut off and death of bone occurs, the bone can go on to collapse and lead to arthritis in the affected joint.
Can range from no symptoms to significant pain in the affected area.
As damage to the bone progresses or collapse occurs a patient may experience gradual or sudden increases in pain with weight bearing activities. Range of motion of the joint can be affected. A patient may experience pain at rest occasionally, and may begin to limp to accommodate for these progressing symptoms. At this point the symptoms and disease are very similar to hip arthritis (LINK TO HIP OA)
Radiographic examination (x-rays) are used first to help diagnose osteonecrosis and to make sure there is no other condition like a fracture (break) or condition causing the symptoms. However, early stages of osteonecrosis are not always seen on radiographs (x-ray) and an MRI (magnetic resonance imaging) may be needed to further diagnose this condition.
- Stage I: X-rays are normal. An MRI may be needed for diagnosis.
- Stage II: X-rays will show that the rounded edge of the bone is starting to flatten out. An MRI or bone scan can be used to diagnose the disease.
- Stage III: Disease is visible on X-rays and no other diagnostic tests are needed. The rounded surface of the joint and cartilage is collapses. Surgical treatments are limited to replacement.
- Stage IV: There is radiographic evidence of bone collapse in this stage. Arthritic changes may also be noted. Again, surgical treatments may be considered at this point.
- Stage I: Treatment at this point is not surgical. The focus is on pain relief (medications, bracing, injections, strengthening programs) and protected weight bearing techniques (utilization of cane, crutches, trekking poles).
- Stage II: Treatment remains non-surgical at this time. Continued focus on pain relief (medications, bracing, injections, strengthening programs) and protected weight bearing techniques (utilization of cane, crutches, trekking poles).
- Stage III: Continued non-operative measures versus surgical treatments may be considered at this point including replacement or fusion depending on the joint involved.
- Stage IV: Patient has option of continued non-operative measures versus proceeding with surgery.
Consideration of medications such as anti-inflammatories to minimize pain, injections to minimize inflammation and pain, utilization of an assistive device while walking, attempting a strengthening program to work on increased thigh and lower extremity strength, bracing if warranted to unload the affected area, modifying activities to reduce pain, and diet modification and weight loss if warranted.
If there is evidence of collapse or a significant area of the joint is affected you may be a candidate for surgical intervention.
Surgical options in the Adult Lower Extremity Joint Reconstruction Clinic include:
- Microdrilling or forage procedures for areas that have not gone on to collapse- Microdrilling or Forage Procedure (sometimes also called Core Decompression) can sometimes be considered during the early stages of osteonecrosis prior to collapse of bone. Once collapse occurs a patient is no longer considered a candidate for this procedure. The idea behind this treatment method is to decrease pain. It does not cure the disease.
- Total hip replacement
- Total (tricompartmental) knee replacement
- Partial (unicompartmental) knee replacement
Total Hip Replacement, Total Knee Replacement and Partial Knee Replacement is considered once non-operative management has failed and a patient has evidence of collapse of the bone. The goal of these procedures is to replace the involved bone at the joint with artificial parts to decrease pain and allow a patient to potentially return to some of their previous activities of daily living.
Frequently Asked Questions:
- Where can people go to find more information about Osteonecrosis?
- What causes osteonecrosis?
Loss of blood supply to affected bone.
- Who may develop osteonecrosis?
Anyone, but more commonly seen in patients who have history of trauma, have history of long term prednisone (steroid) use, sickle cell disease, excessive use of alcohol, or could occur without a known cause.
- What are symptoms present with osteonecrosis?
Ranges from no symptoms to significant pain with weight bearing activities at involved joint.
- How is osteonecrosis diagnosed?
X-ray and/or MRI typically
- How is the type of treatment decided on?
Dependent on stage of osteonecrosis and symptoms present.