KNEECAP (PATELLA) DISLOCATION
DEFINITION--A displacement of the patella (kneecap) so it no longer touches adjoining bones. Adolescents and young adults are most prone to this injury.
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.
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.
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).
RISK INCREASES WITH
Person with a wide pelvis and "knock-knees."
Contact sports such as football or soccer.
Jumping sports such as gymnastics and basketball.
Previous knee sprains.
Repeated knee injury of any sort.
Arthritis of any type (rheumatoid, gout).
Poor muscle conditioning.
Congenital abnormalities of the knee joint.
HOW TO PREVENT
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.
WHAT TO EXPECT
APPROPRIATE HEALTH CARE
Doctor's treatment. This will include manipulation of the joint to reposition the bones.
Surgery (usually) to restore normal knee-joint function.
Your own observation of symptoms.
Medical history and exam by a doctor.
X-rays of the knee joint and adjacent bones.
AT THE TIME OF INJURY:
Pressure on or injury to nearby nerves, ligaments, tendons, muscles, blood vessels or connective tissue causing numbness, coldness and paleness in the leg or foot.
Excessive internal bleeding around the kneecap.
Impaired blood supply to the dislocated area.
Infection introduced during surgical treatment.
Recurrent dislocations, particularly if the previous dislocation has not healed completely.
Unstable or arthritic knee joint following repeated injury.
PROBABLE OUTCOMEAfter treatment or surgery to correct the dislocation, the joint may be immobilized with a cast for 6 to 8 weeks. Complete healing of injured ligaments requires a minimum of 6 weeks.
HOW TO TREAT
NOTE -- Follow your doctor's instructions. These instructions are supplemental.
Keep the person warm with blankets to decrease the possibility of shock.
Cut away clothing if possible. Don't move the injured area to remove clothing.
Immobilize the knee, hip and ankle joints with padded splints.
Follow instructions for R.I.C.E., the first letters of REST,
ICE, COMPRESSION and ELEVATION. See Appendix 1 for details.
The doctor will realign the dislocated bones with surgery or, if possible, without. This should be done as soon as possible after injury. Within 6 hours after the dislocation, bleeding and displacement of body fluids may lead to shock. Also, many tissues lose their elasticity and become difficult to return to a normal position.
CONTINUING CAREAfter 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.
MEDICATIONYour 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.
Walk on crutches while the cast is in place.
Resume usual activities gradually after surgery.
Begin weight-bearing and reconditioning of the knee after clearance from your doctor.
Don't drive until healing is complete.
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.
Begin daily rehabilitation exercises when supportive wrapping is no longer needed.
Use ice massage for 10 minutes before and after workouts. Fill a large Styrofoam cup with water and freeze. Tear a small amount of foam from the top so ice protrudes. Massage firmly in a circle over the injured area.
See section on rehabilitation exercises.
CALL YOUR DOCTOR IF
You have symptoms of a dislocated kneecap. Call immediately if the leg becomes numb, pale, or cold. This is an emergency!
Any of the following occur after treatment or surgery:
Swelling above or below the cast.
Blue or gray skin color below the cast, particularly under the toenails.
Numbness or complete loss of feeling below the knee.
Increasing pain, swelling or drainage in the surgical area.
Signs of infection (headache, muscle aches, dizziness, or a general ill feeling and fever).
Nausea or vomiting.
New, unexplained symptoms develop. Drugs used in treatment may produce side effects.
Kneecap dislocations that you can "pop" back into normal position occur repeatedly.