Total knee replacement

Alternative names

Knee joint replacement; Knee arthroplasty

Definition

Knee joint replacement is surgery to replace a painful damaged or diseased knee joint with an artificial joint (prosthesis).

Description

The operation is performed under general anesthesia. The orthopedic surgeon makes an incision over the affected knee. The patella (knee cap) is moved out of the way, and the ends of the femur and tibia are cut to fit the prosthesis and to provide better adhesion of the prosthesis. Similarly, the undersurface of the knee cap is cut to allow for placement of an artificial component.

The two parts of the prosthesis are implanted onto the ends of the thigh bone (femur), the shin bone (tibia), and the undersurface of the knee cap (patella) using a special bone cement. Usually, metal is used on the end of the femur, and plastic is used on the tibia and patella, for the new knee surface. However, newer surfaces including metal on metal, ceramic on ceramic, or ceramic on plastic are now being used.

You will return from surgery with a large dressing to the knee area. A small drainage tube will be placed during surgery to help drain excess fluids from the joint area.

Your leg may be placed in a continuous passive motion (CPM) device after surgery. This is a mechanical device that flexes (bends) and extends (straightens) the knee to keep the knee from getting stiff.

Gradually, the rate and amount of flexion will be increased as tolerated. The leg should always be in this device when in bed. The CPM device helps speed recovery, decreases post-operative pain, bleeding and infection.

You will experience moderate pain after surgery. However, you may receive injections of narcotic medications, patient-controlled analgesia (PCA) or epidural analgesics (spinal) to control your pain for the first 3 days after surgery.

The pain should gradually decrease, and by the third day after surgery, oral medications may be sufficient to control your pain. Try to schedule your pain medications about one half hour before walking or position changes.

You will also return from surgery with several IV lines in place to provide fluid and nutrition. The IV will remain in place until you are taking adequate amounts of fluids by mouth.

Antibiotics may be given to reduce the risk of developing an infection, necessitating removal of the artificial joint.

You will also return from surgery wearing anti-embolism stockings or inflatable pneumatic compression stockings. These devices are used to reduce your risk of developing Blood clots, which are more common after lower extremity surgery.