An Overview of Osteonecrosis of the Knee

A condition cryptically referred to as 'bone death' is osteonecrosis. This condition is a relatively common cause of knee pain in middle aged and older individuals and occurs when a segment or portion of bone loses its blood supply and starts to die off. According to statistics, nearly three times as many women are affected by the condition as men; most of which are over the age of sixty.

Symptoms of Osteonecrosis

Symptoms of osteonecrosis include the following:

繚 Increased pain at night and with activity

繚 Abrupt pain along the inside of the knee that is triggered by activity or a minor injury

繚 Swelling along the front and inside of the knee

繚 Limited range of motion and flexibility due to increased pain

繚 The area becomes highly sensitive to touch and very tender, with increased pain when mobile

Cause of Osteonecrosis

The exact cause of osteonecrosis is unknown. One theory suggests that a stress fracture combined with activity and trauma may result in an altered blood supply to the bone. Other theories suggest that the build up of fluid within the bone adds pressure on the blood vessels and begins to diminish circulation.

No matter what the cause, if left untreated, severe problems may arise. It is important for the condition to be identified early and treated appropriately.

Various Stages of Osteonecrosis of the Knee

Osteonecrosis of the knee develops in four stages, which can all be identified via x-rays and through the symptoms reported. The following stages include:

Stage I - The symptoms are the most severe during this early stage of the condition. The x-rays are typically normal and reveal few problems, but the symptoms generally continue for six to eight weeks. Treatment for this stage does not require surgery.

Stage II - It takes several months for the disease to progress to this stage and at this point the symptoms begin to show up on the x-rays. An MRI or bone scan can be used to diagnose the stage and condition.

Stage III - This stage develops after about three to six months and is clearly visible on the x-rays at this point. The articular cartilage that covers the bone begins to loosen as the bone dies. Surgical treatments may be necessary at this stage.

Stave IV - During this stage the bone begins to collapse and completely die. The articular cartilage is completely destroyed and the joint space narrows. Bone spurs typically develop and joint replacement surgery is almost inevitable.

If you are experiencing unexplained knee pain that is not improving, seek the advice of an orthopedic surgeon.