Definition of Knee joint replacement:

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

See also: Unicompartmental knee arthroplasty

Description:

Knee joint replacement surgery involves removing damaged cartilage and bone in the knee joint. Man-made (artificial) pieces, called prostheses, are then placed in the knee.

You will not feel any pain during the surgery because you will receive anesthesia. You will have one of these two types of anesthesia:

• General anesthesia. This means you will be unconscious and unable to feel pain.
• Regional (spinal or epidural) anesthesia. Medicine is put into your back to make you numb below your waist. You will also get medicine to make you sleepy.

After you receive anesthesia, your surgeon will make a cut over your knee to open it up. Then your surgeon will:

• Move your kneecap (patella) out of the way, then cut the ends of your thigh bone and shin (lower leg) bone to fit the prosthesis.
• 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.
• Attach both parts to the underside of your kneecap. A special bone cement is used to attach these parts.
• Repair your muscles and tendons around the new joint and close the surgical cut.

The surgery usually takes around 2 hours.

Usually, artificial knees have both metal and plastic parts. Some surgeons now use different materials, including metal on metal, ceramic on ceramic, or ceramic on plastic.

MINIMALLY INVASIVE KNEE REPLACEMENT

Some surgeons are using a newer surgery technique called "minimally invasive" knee joint replacement. This type of surgery uses a smaller surgical cut.

The surgeon will use special instruments to work through the small cuts. In minimally invasive surgery, your surgeon will:

• Cut and remove bone and cartilage
• Move some muscles and other tissues, but less than in open (traditional) surgery. Fewer muscles around the knee may need to be cut or detached.
• Use the same implants as in open surgery, or use newer implants