About total knee replacement

What is total knee replacement?

Total knee replacement facts

  • Patients with severe destruction of the knee joint associated with progressive pain and impaired function may be candidates for total knee replacement.
  • Osteoarthritis is the most common reason for knee replacement operation in the U.S.
  • Risks of total knee replacement surgery have been identified.
  • Physical therapy is an essential part of rehabilitation after total knee replacement.
  • Patients with artificial joints are recommended to take antibiotics before, during, and after any elective invasive procedures (including dental work).

What is a total knee replacement?

A total knee replacement is a surgical procedure whereby the diseased knee joint is replaced with artificial material. The knee is a hinge joint which provides motion at the point where the thigh meets the lower leg. The thighbone (or femur) abuts the large bone of the lower leg (tibia) at the knee joint. During a total knee replacement, the end of the femur bone is removed and replaced with a metal shell. The end of the lower leg bone (tibia) is also removed and replaced with a channeled plastic piece with a metal stem. Depending on the condition of the kneecap portion of the knee joint, a plastic "button" may also be added under the kneecap surface. The artificial components of a total knee replacement are referred to as the prosthesis.

The posterior cruciate ligament is a tissue that normally stabilizes each side of the knee joint so that the lower leg cannot slide backward in relation to the thighbone. In total knee replacement surgery, this ligament is either retained, sacrificed, or substituted by a polyethylene post. Each of these various designs of total knee replacement has its own particular benefits and risks.

What are the causes for total knee replacement?

The most common reason for knee replacement surgery is to relieve severe pain caused by osteoarthritis. People who need knee replacement surgery usually have problems walking, climbing stairs, and getting in and out of chairs. Some also have knee pain at rest.

What are the risk factors for total knee replacement?

Knee replacement surgery, like any surgery, carries risks. They include:

  • Infection
  • Blood clots in the leg vein or lungs
  • Heart attack
  • Stroke
  • Nerve damage

Signs of infection

Notify your doctor immediately if you notice:

  • Fever greater than 100 F (37.8 C)
  • Shaking chills
  • Drainage from the surgical site
  • Increasing redness, tenderness, swelling and pain in the knee

An infected knee replacement usually requires surgery to remove the artificial parts and antibiotics to kill the bacteria. After the infection is cleared, another surgery is performed to install a new knee.

Artificial knees can wear out

Another risk of knee replacement surgery is failure of the artificial joint. Daily use wears on even the strongest metal and plastic parts. Joint failure risk is higher if you stress the joint with high-impact activities or excessive weight.

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