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Kneecap Dislocation (Subluxing Patella)

BODY PARTS INVOLVED

• Knee joint and patella.
• Femur and tibia, the bones of the lower leg.
• Soft tissue surrounding the dislocation, including nerves, periosteum (covering of bone), tendons, ligaments, muscles and blood vessels.

Causes

• Direct blow to the knee.
• End result of a severe knee sprain.
• Powerful muscle contraction.
• "Cutting" moves (movements in which an athlete changes direction suddenly, causing bones in the knee joint to rotate and dislocate the patella).

Signs & Symptoms

• A feeling of the knee "giving way."
• Excruciating pain in the knee at the time of injury.
• Loss of function of the knee, and severe pain when attempting to move it.
• Visible deformity if the dislocated bones have locked in the dislocated position. Bones may spontaneously reposition themselves and leave no deformity, but damage is the same.
• Tenderness over the dislocation.
• Swelling and bruising around the knee.
• Numbness or paralysis below the dislocation from pressure, pinching or cutting of blood vessels or nerves

How is it diagnosed?

Your health care provider will ask about your symptoms and examine your knee. He or she may be able to feel the kneecap slipping to the outside as you bend and straighten your leg. An x-ray may show underdevelopment of the lateral femoral condyle.

Treatment

Follow your doctor's instructions. Instructions are supplemental.

After cast removal:

• Use an ice pack 3 or 4 times a day. Wrap ice chips or cubes in a plastic bag, and wrap the bag in a moist towel. Place it over the injured area for 20 minutes at a time.
• You may try heat instead of ice if it feels better. Use heat lamps, hot soaks, hot showers, heating pads,or heat liniments and ointments.
• Take whirlpool treatments, if available.
• Massage gently and often to provide comfort and decrease swelling.

MEDICATION

Your doctor may prescribe:

• General anesthesia or muscle relaxants to make joint manipulation possible.
• Acetaminophen to relieve moderate pain.
• Narcotic pain relievers for severe pain.
• Stool softeners to prevent constipation due to decreased activity.
• Antibiotics to fight infection

Home Diet

• Drink only water before manipulation or surgery to correct the dislocation. Solid food in your stomach makes vomiting while under general anesthesia more hazardous.
• During recovery, eat a well-balanced diet that includes extra protein, such as meat, fish, poultry, cheese, milk and eggs. Increase fiber and fluid intake to prevent constipation that may result from decreased activity.

Prevention Tips

• Build your overall strength and muscle tone with a long-term conditioning program appropriate for your sport. Include special exercises for strengthening the knee.
• Warm up adequately before physical activity .
• After injury, protect the knee from reinjury by wearing wrapped elastic bandages, tape wraps knee pads or special support sleeves.
• Some cases of knee dislocation may not be preventable, especially if anatomic factors predispose you to dislocation.