What is a total knee replacement?

A total knee replacement is a procedure in which the doctor removes an arthritic knee joint and replaces it with an artificial one.

When is it used?

This procedure is done when your knee joint is painful or is not working well and other treatments have not worked.

Alternatives to this procedure include:

• to use acetaminophen, aspirin, or other drugs for pain and inflammation

• to limit activity (avoid squatting, stairs, and heavy lifting) and use a walking aid, such as a cane or walker

• to use ice to reduce pain and swelling; some people find heat helpful so you may want to try both

• to choose not to have treatment, recognizing your current condition and limitations.

You should ask your doctor whether any of these choices would be of benefit to you.

How do I prepare for a total knee replacement?

You could donate some of your own blood in case you need a transfusion during or after the operation. This requires some planning because the blood should be donated within 4 weeks of the procedure.

Plan for your care and recovery after the operation, especially if you are to have general anesthesia. Allow for time to rest and find people to help you with your day- to-day duties and care for at least the first week at home.

Follow any instructions your doctor may give you. Eat a light meal, such as soup or salad, the night before the procedure. Do not eat or drink anything after midnight on the day of the procedure. Do not even drink coffee, tea, or water.

What happens during the procedure?

A general or spinal anesthetic is given. A general anesthetic will relax your muscles and make you feel as if you're in a deep sleep. It will prevent you from feeling pain during the operation. A spinal anesthetic is a drug that should keep you from feeling pain during the operation.

The doctor will put a tourniquet above your knee and make a cut from above the kneecap to below it. The doctor will expose the knee joint, loosen the muscles connected to it, and turn the kneecap out of its place. The doctor will remove the ends of the thigh and shin bones. The doctor will cement the artificial replacement parts to the remaining ends of the bones. The doctor may cement an artificial surface to the back of the kneecap. He or she will try to remove any excess cement and place a tube in the knee to drain any extra fluid from the cut. The doctor will close the cut and put a bandage and a splint around your knee.

You may require a blood transfusion. The hospital will either use your donated blood or it will use matched blood.

What happens after the procedure?

You may be in the hospital for 3 to 6 days, depending on how fast you heal. At first, you may be confined to bed. You may have a catheter (tube) in your bladder if you are unable to urinate. You will start walking with a walker, crutches, or cane as soon as possible. You may use a continuous passive motion machine (CPM) to keep your knee moving and prevent stiffness.

The replacement knee is designed only for usual day-to-day activity. You will be restricted in your movements initially and will need some physical therapy for weeks to months after your surgery. You will not be able to participate in all sports or heavy activities. Ask your doctor to suggest sports you can safely play.

Ask your doctor what other steps you should take and when you should come back for a checkup.

What are the benefits of this procedure?

You may be able to resume a more normal life. The problems of a painful knee and being able to walk only limited distances should be relieved.

What are the risks associated with this procedure?

• There are some risks when you have general anesthesia. Discuss these risks with your doctor.

• A blood clot may form in the veins and escape into the bloodstream and block an artery in the lungs. You may receive a blood thinner to prevent this.

• If you did not donate your own blood, the hospital will try to match your blood with donated blood. It is not always possible to avoid reactions with donated blood, and you may acquire a disease from donated blood.

• Your legs may not be the same length after the operation.

• Nerves may be injured from swelling or pressure, but this is rare.

• Infection or bleeding may occur.

• Long-term loosening of the new joint may occur (over 10 to 15 years). This occurs only a small percentage of the time.

You should ask your doctor how these risks apply to you.

When should I call the doctor?

Call the doctor immediately if:

• You develop a fever.

• You notice excessive drainage from the wound.

• You are in uncontrollable pain.

• You are short of breath or cough up blood.

• You develop chest pain.

• You have unusual swelling, warmth, or redness in your knee.

Call the doctor during office hours if:

• You have questions about the procedure or its result.

• You want to make another appointment.