Knee joint replacement Health Article

Definition

Knee joint replacement is surgery to replace a knee joint with an artificial joint. The artificial joint is called a prosthesis.

Alternative Names

Total knee replacement; Knee arthroplasty; Knee replacement - total; Tricompartmental knee replacement

Description

You may receive general anesthesia before this surgery. This means you will be unconscious and unable to feel pain. Or, you may have a spinal or epidural anesthesia. In this kind of anesthesia, medicine is put into your back to make you numb below your waist.

After you receive anesthesia, your surgeon will make an incision (cut) over your knee to open it up. Then your surgeon will:

• Move your kneecap (patella) out of the way, then shape the ends of your thigh bone and shin bone to fit the prosthesis. Your surgeon will also cut the underside of your kneecap to prepare it for the artificial pieces that will be attached there.
• Fasten the two parts of the prosthesis to your bones. One part will be attached to the end of your thigh bone and the other part will be attached to your shin bone. Both parts will then be attached to the underside of your kneecap. Your surgeon will use a special bone cement to attach these parts.

Usually, artificial knees have metal parts. Now, though, some surgeons are using some different materials, including metal on metal, ceramic on ceramic, or ceramic on plastic.

Why the Procedure Is Performed

Knee joint replacement may be recommended for:

• Severe arthritis (osteoarthritis or rheumatoid arthritis) of the knee that has not gotten better with medicine, injections, and physical therapy after 6 months or more of treatment. Your doctor may recommend knee replacement for these problems:
  • Inability to sleep through the night because of knee pain
  • Knee pain that has not improved with other treatment
  • Knee pain that limits or keeps you from being able to do your normal activities, especially your daily activities such as bathing, preparing meals, household chores, and other things.
• Some tumors that affect the knee

Even when a knee replacement is needed, some medical problems may lead your doctor to recommend that you not have it done. Some of these problems are:

• A knee infection
• Morbid obesity (weighing over 300 pounds)
• Very weak quadriceps, the muscles in the front of your thigh. Weak quadriceps could make it very hard for you to walk and use your knee.
• Unhealthy skin around your knee
• Severe mental dysfunction
• Poor blood flow in the leg from peripheral vascular disease. This could keep the incision from healing.
• A terminal disease, such as cancer, that has spread