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Osteonecrosis of the Knee
Restoring your active life
What is Osteonecrosis of the knee?
Osteonecrosis of the knee (also known as avascular necrosis) is a painful condition that occurs when the blood supply to a section of bone in the femur (thighbone) or tibia (shinbone) is disrupted.
Because bone cells need a steady supply of blood to stay healthy, Osteonecrosis can ultimately lead to destruction of the knee joint and severe arthritis.
Using the latest technology, advanced treatments and highly qualified team, NSOC provides personalized care for your knee to restore your active life.
Causes of Osteonecrosis of the Knee
Osteonecrosis of the Knee develops when the blood supply to a segment of bone is disrupted. Without adequate nourishment, the affected portion of bone dies and gradually collapses. As a result, the articular cartilage covering the bone also collapses, leading to disabling arthritis.
A stress fracture or trauma results in altered blood supply to the bone, fluid buildup within the bone increases the pressure on the blood vessels resulting in decreased circulation.
Osteonecrosis of the Knee can affect anyone, but is more common in people over the age of 60. Woman are three times more likely than men to develop the condition.
Factors that increase the risk of developing Osteonecrosis of the Knee
It is not always known what causes the lack of blood supply, but doctors have identified a number of risk factors that make someone more likely to develop osteonecrosis.
- Injury. A knee injury—such as a stress fracture or dislocation—combined with some type of trauma to the knee, can damage blood vessels and reduce blood flow to the affected bone.
- Excessive alcohol use. Over time alcohol intake can cause fatty deposits to form in the blood vessels as well as elevated cortisone levels, resulting in a decreased blood supply to the bone.
- Certain conditions and treatments that are associated with osteonecrosis of the knee are obesity, sickle cell anemia, lupus, kidney transplants, and steroid therapy.
Symptoms of Osteonecrosis of the Knee
Osteonecrosis of the Knee develops in stages. The first symptom is typically pain on the inside of the knee. This pain may occur suddenly and be triggered by a specific activity or minor injury. As the disease progresses, it becomes more difficult to stand and put weight on the affected knee, and moving the knee joint is painful.
Other symptoms may include:
- Swelling over the front and inside of the knee
- Sensitivity to touch around the knee
- Limited range of motion in the joint
Osteonecrosis of the knee stages and diagnosis
There are four stages of development of Osteonecrosis of the Knee which can be distinguished by symptoms and X-rays.
- Stage I: The symptoms are most intense in the earliest stage, and may subside in 6 to 8 weeks. In this stage, the X-rays are normal; a positive bone scan may be required to make the diagnosis. Treatment for Stage I disease is non surgical, focusing on pain relief and protected weight-bearing.
- Stage III: At this stage the condition becomes clearly visible on X-rays and no other diagnostic tests are required. At this point the bone, itself, begins to decay away, and cartilage covering the bones loosens from other segments of the leg.
- Stage IV: In this stage, the bone collapses, joint space narrows, bone spurs form, and the articular cartilage is destroyed. The only treatment at this point is joint replacement surgery.
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Treatment of Osteonecrosis of the Knee
The treatment for osteonecrosis of the knee at NSOC aims at preventing further loss of bone and it depends on the bone damage that has occurred already. Conservative treatment would reverse early stages of osteonecrosis whereas surgical treatment may be required in more advanced stages.
In the early stage of the disease, non-surgical treatment options that include anti-inflammatory medications, braces, strengthening exercises for thigh muscles, and activity modification may be needed to reduce the knee pain.
Surgical Treatment
Surgical treatment for Osteonecrosis of the Knee is considered in advanced stages where more than half of the bone surface is affected. Surgical treatment options include:
- Core decompression:During this procedure, a portion of the inner layer of the bone is removed to relieve the pressure inside the bone. This decreases the pain and allows growth of new blood vessels thereby stimulates new bone growth
- Bone transplant:A healthy bone from harvested from other part of your body is grafted into the affected area.
- Bone reshaping (osteotomy):This procedure is done in advanced stages and involves reshaping of the bone which is done to decrease the stress placed over the affected bone.
- Joint replacement:Joint replacement surgery is done as a last resort when the bone has collapsed needing artificial replacement