Total Knee Replacement

When knee replacement is indicated, you can trust the joint surgeons at Sinai and Northwest hospitals. As evidenced by our high number of referrals from other regional physicians, our surgeons are the most experienced in Maryland at performing these complicated surgeries. We will reconstruct your knee joint so that you have the last pain and the fastest return to function.

Overview

Total knee replacement is a surgical procedure in which injured or damaged parts of the knee joint are replaced with artificial parts.

Components used for knee replacement
Components used for
knee replacement

The procedure is performed by separating the muscles and ligaments around the knee to expose the knee capsule (the tough, gristlelike tissue surrounding the knee joint). The capsule is opened, exposing the inside of the joint. The ends of the thigh bone (femur) and the shin bone (tibia) are removed and often the underside of the kneecap (patella) is removed. The artificial parts are cemented into place.

Your new knee will consist of a metal shell on the end of the femur, a metal and plastic trough on the tibia, and if needed, a plastic button in the kneecap.

Total knee replacements are usually performed on people suffering from severe arthritic conditions. Most patients with artificial knees are over age 55, but the procedure is performed in younger people. The circumstances vary somewhat, but generally you are considered for a total knee replacement if:

  • You have daily pain.
  • Your pain is severe enough to restrict work, recreation and the ordinary activities of daily living.
  • You have significant stiffness of your knee.
  • You have significant instability (constant giving way) of your knee.
  • You have significant deformity (lock-knees or bowlegs).

An artificial knee is not a normal knee, nor is it as good as a normal knee.

Before Surgery

Preparing for a total knee replacement begins several weeks ahead of the actual surgery date. Maintaining good physical health before your operation is important. Activities that increase upper body strength will improve your ability to use a walker or crutches after the operation.

Repaired knee joint

Repaired knee joint

A blood transfusion is sometimes necessary after knee surgery. You may wish to donate several pints of blood prior to your surgery so that you receive your own blood if you require a transfusion. This is called autologous blood donation. The first donation must be given within 42 days of the surgery and the last, no less than seven days before your surgery.

The physician may order blood tests and urinalysis two weeks before surgery to make sure that a urinary tract infection is not present. Urinary tract infections are common, especially in older women, and often go undetected. Teeth must also be in good condition. An infected tooth or gum may be a possible source of infection for the new knee. The orthopaedic physician may ask you to see a medical doctor, especially if medical problems have been present in the past.

When making preparations for surgery, you should begin thinking about the recovery period following surgery. A patient with a new knee will need help at home for the first several weeks. Assistance with dressing, getting meals, etc., may be necessary. Discharge from the hospital is usually anticipated in about 3-4 days. Your energy level will not have returned by then. If assistance from someone at home is not possible, it may be necessary to make arrangements to stay a few weeks in an extended care facility. A social worker is available at the hospital to plan an extended period of recovery if necessary.

Outcomes

The operation will provide pain relief for at least ten years. If knee replacement provides you with pain relief and if you do not have other health problems, you should be able to carry out many normal activities of daily living. The artificial knee may allow you to return to active sports or heavy labor under your physician's instructions. Activities that overload the artificial knee must be avoided. About 90 percent of patients with stiff knees before surgery will have better motion after a total knee replacement.

Complications

Total knee replacement is a major operation. About one patient in four develops one or more complications. The effect of most complications is that you must stay in the hospital longer. The most common complications are not directly related to the knee and usually do not affect the result of the operation. These complications include urinary tract infection, blood clots in a leg or blood clots in a lung.

Complications affecting the knee are less common, but in these cases the operation may not be as successful. These complications include:

  • some knee pain
  • loosening of the prosthesis
  • stiffness
  • infection in the knee

A few complications such as infection, loosening of prosthesis and stiffness may require reoperation. Infected artificial knees sometimes have to be removed. This would leave a stiff leg about one to three inches shorter than normal. However, your leg would usually be reasonably comfortable, and you would be able to walk with the aid of a shoe lift and cane or crutches. After a course of antibiotics the surgery can often be repeated.

About 85 to 90 percent of total knee replacements are successful up to ten years. The major long-term problem is loosening. This occurs because either the cement crumbles (as old mortar in a brick building) or the bone melts away (resorbs) from the cement. By ten years, 25 percent of total knee replacements may look loose on X-ray, and about 10 percent will be painful and require reoperation. By ten years, possibly 20 percent may require reoperation.

Loosening is in part related to your weight and activity. For that reason, total knee replacement usually is not performed on very obese or young patients. A loose, painful artificial knee can usually, but not always, be replaced. The results of a second operation are not as good as the first, and the risks of complication are higher.