Osteonecrosis of the Knee

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Osteonecrosis

of the Knee

Knee pain has many causes. A relatively common cause

of knee pain in older women occurs when a segment of bone loses its blood

supply and begins to die. This condition is called osteonecrosis,

which literally means " bone death. "

In the

knee, the knobby portion of the thighbone on the inside of the knee (the

medial femoral condyle) is most often affected.

However, osteonecrosis of the knee may also occur

on the outside of the knee (the lateral femoral condyle)

or on the flat top of the lower leg bone (tibial

plateau).

Causes

The

exact cause of the disease is not yet known. One theory is that a stress

fracture, combined with a specific activity or trauma, results in an altered

blood supply to the bone. Another theory supposes that a build-up of fluid

within the bone puts pressure on blood vessels and diminishes circulation.

More than 3 times as many women as men are affected; most are over 60 years

of age.

Osteonecrosis of the knee is

also associated with certain conditions and treatments, such as obesity,

sickle cell anemia, lupus, kidney transplants, and steroid therapy.

Steroid-induced osteonecrosis frequently affects

multiple joints and is usually seen in young patients. Regardless of the

cause, if the disease is not identified and treated early, it can develop

into severe osteoarthritis.

Signs and symptoms

Sudden pain on the

inside of the knee, perhaps triggered by a specific activity or minor

injury

Increased pain at

night and with activity

Swelling over the

front and inside of the knee

Heightened

sensitivity to touch in the area

Limited motion due

to pain

Development

Osteonecrosis of the knee

develops through four stages, which can be identified by symptoms and X-rays.

Stage

I: Symptoms are most intense in the earliest stage. Symptoms may continue for

6 to 8 weeks and then subside. Because X-rays are normal, a positive bone

scan is needed to make the diagnosis. Treatment at this point is nonoperative and conservative, focusing on pain relief

and protected weight-bearing.

Stage

II: It may take several months for the disease to progress to Stage II. At

this point, X-rays will show that the rounded edge of the thighbone is

starting to flatten out. An MRI or bone scan can be used to diagnose the

disease. A CT

scan may also be used to measure the affected area of bone area.

Stage

III: By the time the disease reaches stage III (3 to 6 months after onset),

it is clearly visible on X-rays and no other diagnostic tests are needed. The

articular cartilage covering the bone begins to

loosen as the bone itself begins to die. Operative treatments may be

considered at this point.

Stage

IV: At this point, the bone begins to collapse. The articular

cartilage is destroyed, the joint space narrows, and bone spurs may form.

Severe osteoarthritis results and joint replacement surgery may be necessary.

Treatment options

In the

early stages of the disease, treatment is nonoperative.

If the affected area is small, this treatment may be all that is needed.

Options include:

Medications to

reduce the pain

A brace to relieve

pressure on the joint surface

A conditioning

program with exercises to increase the strengthen of the muscles in your

thighs

Activity

modifications to reduce knee pain

If more

than half of the bone surface is affected, you may need surgical treatment.

Several different procedures may be used to treat osteonecrosis

of the knee. Among the surgical options are:

Arthroscopic

cleansing (debridement) of the joint

Drilling to reduce

pressure on the bone surface

Procedures to

shift weight-bearing away from the affected area

Replacement of one

or both joint surfaces

Your orthopaedic surgeon will discuss the options with you and

make a recommendation based on your individual situation.

Much

Love,

Deanna

LUPUS

Serenity Prayer...

Lord, grant me the

serenity to accept the things I cannot change, the courage to change the things

I can, and the wisdom to hide the bodies of doctors I shot when they said,

You're perfectly healthy, it's all in your head "