Total knee replacement surgery, or total knee arthroplasty, is one of the most common major surgeries performed in the U.S.1 It is done to alleviate pain caused by moderate to severe knee arthritis.

During surgery, damaged cartilage and a portion of underlying bone are replaced with a prosthetic knee joint.

Total Knee Replacement
Illustration of total knee replacement surgery. Click to enlarge image

An estimated 676,000 people in the United States undergo total knee replacement surgery each year, and more than 90 % of those surgeries are considered successful, meaning that after recovery patients have both:

  • Significantly less knee pain
  • Greatly improved knee function2,3

However, total knee replacement is still a major surgery. Recovery requires several months of physical therapy. For these reasons, patients are advised to commit to a concerted effort at non-surgical treatment before considering knee replacement.

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How Long Does A Knee Replacement Prosthesis Last?

About 90% of first-time knee replacements last at least 15 years and many last as long as 20 years.4,5 Patients can extend the life of their knee replacements by complying with their physical therapy routines and avoiding high-impact activities, such as jumping or jogging.

When the initial prostheses needs to be replaced, a second surgery called a revision total knee replacement may be needed. Sometimes a person with knee osteoarthritis will postpone an initial knee replacement surgery for many years in hopes of avoiding an eventual revision surgery. However, while people of all ages can benefit from knee replacement surgery, there is evidence that people who are younger tend to fare better and have fewer complications.6

Patients should talk to their doctors about when is the best time to schedule knee replacement surgery.

Indications and Eligibility for Total Knee Replacement Surgery

Not everyone with knee arthritis is a candidate for total knee replacement surgery. Below are lists of indications and contraindications for this surgery.

Who is eligible for total knee replacement surgery?

Patients eligible for this surgery have moderate to severe arthritis in the knee, including osteoarthritis, rheumatoid arthritis or post-traumatic arthritis, that causes pain and interferes with daily living. Typical candidates for knee replacement will have some combination of the following:

  • Walking, going up stairs, and getting in and out of chairs is difficult
  • Pain is moderate to severe even while resting, and may affect sleep
  • Joint degeneration has caused knee deformity, such as bow-legs or knock-knees
  • Swelling and inflammation is chronic and not controlled with medication or rest
  • Symptoms are not alleviated by non-surgical treatments, such as non-steroidal anti-inflammatory drugs (NSAIDs), physical therapy, steroid injections, or non-major surgeries.

Contraindications for total knee replacement surgery
Knee replacement surgery is not recommended for some people, including the following:

  • Smoking. Smokers and other tobacco users face a higher rate of medical complications and a higher risk of needing follow-up surgery, or revision surgery. For example, a survey of more than 131 smokers and 490 non-smokers found that approximately four years after their initial knee replacement surgeries only 1 % of non-smokers had to have revision surgery, while 10 % of smokers had revision surgery.7 To lower post-surgical risks, candidates for total knee replacement are encouraged to quit or cut back on tobacco use.
  • Infection. Infection is considered a serious post-surgical risk; therefore, patients who have systemic infections or are prone to infection may not be eligible for this surgery. Infection affects less than 1% of knee replacement patients and in many cases can be treated with antibiotics.8 However, in other cases infection can result in the removal of the replacement joint and can even be life-threatening if it spreads throughout the body.

Age and weight requirements
There are no age or weight limits regarding who can have knee replacement surgery; however, obesity and advanced age do carry extra risks of complications such as infection. When possible, overweight patients are encouraged to lose weight prior to surgery.

Osteoporosis and knee replacement surgery
Osteoporosis is not a contraindication for knee replacement surgery, however, it may affect how a surgeon plans for surgery. A surgeon may be required to use a stemmed prosthesis in addition to bone cement to attach the new prostheses to the existing bone. If a person has severe osteoporosis or has had stress fractures, a surgeon may want to take steps to improve bone density before knee replacement surgery. This treatment may continue after surgery to enhance the lifespan of the knee replacement.

Patients should talk to their doctors about individual risk.

References:

  1. Finks JF, Osborne NH, Birkmeyer JD. Trends in hospital volume and operative mortality for high-risk surgery. N Engl J Med. 2011;364(22):2128-2137.
  2. See Full References
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