Knee Replacement Surgery Is 'Durable, Reliable, and Successful'

From the WebMD Archives

Feb. 7, 2000 (New York) -- In recent years, orthopaedic surgeons have made tremendous strides in total knee replacement surgery or total knee arthroplasty for people with severe arthritis of the knee.

And that's good news, because more than 245,000 total knee replacements are performed in the U.S. annually, and this number is expected to increase as the percentage of Americans over 65 years of age rises in the coming years, write study authors Peter J. Thadani, MD, and Andrew I. Spitzer, MD, of the Kerlan-Jobe Orthopaedic Clinic in Los Angeles, in the January issue of the Current Opinion in Orthopedics.

In knee arthritis, the cartilage in the joint gradually wears away, resulting in pain, swelling, and a decrease in motion. First developed in 1974, knee replacement surgery has undergone many technical improvements and is now an "accepted, reliable form of treatment of the end-stage arthritic knee." The procedure basically involves removing or resurfacing parts of the kneecap and putting in an implant made, usually, of metal alloy and plastic. The ends of the bone are capped with a metal substance and a plastic liner is placed between them to create a smooth gliding surface, and presumably less pain.

"The take-home message is that your own God-given knee is the best. However, as the knee wears and the arthritis becomes severe and unresponsive to pain killers and other nonsurgical treatments, knee replacement is a very viable, reliable, and durable option," Spitzer tells WebMD.

"Implants are not made for running, jumping and other high-impact activities, but they can enable you to participate in a whole host of other activities," he says. "While current implants can last from 12 to 25 years, implants may last as long as 20-30 years in the next millennium."

After reviewing published data on available knee replacement implants and surgeries, Spitzer and Thadani conclude that many of the new implants and surgical procedures are "durable, reliable, and successful over the long term." Most procedures evolved from total condylar knee prosthesis, a surgery which involved sacrificing the posterior cruciate ligament (PCL), a ligament found behind the knee, and uses cement to hold the new implant in place. The majority of newer surgical innovations involve salvaging the ligaments surrounding the knees, Spitzer says.


In terms of available implants, "in straightforward cases, the choice of one design over another is largely a matter of surgeon preference," they write.

After reviewing several studies on the outcomes of knee replacements, the authors find "excellent long-term success" with most of the studies showing well over 90% survivorship at periods ranging from 10 to 16 years and annual failure rates significantly under 1%.

Newer implants include "cementless" implants, which show promising results and may become particularly beneficial for younger patients. A lot of research is now being directed at improving these implants for younger, more active patients, the authors report.

The new findings also bring good news for younger people with severe knee arthritis who may need replacement surgery, Spitzer says. "The younger arthritic patient (aged 55 or under) has traditionally represented a frustrating dilemma for the knee surgeon, but recent literature supports the decision to proceed with arthroplasty when end-stage disease is identified," the authors report.

"This new article really tells us where things are at in the world of knee replacement," Ronald P. Grelsamer, MD, chief of hip and knee surgery at Maimonides Medical Center in Brooklyn and an attending orthopaedic surgeon at the Hospital for Joint Diseases in New York, tells WebMD. "There are a number of available knee implants with reasonable track records, and my advice is to go to a surgeon who uses an implant that has been around for a long time as those are the ones with the most evidence supporting their use."

Vital Information:

  • For patients with severe knee arthritis, orthopaedic surgeons have made great advances in total knee replacement surgery, with an annual failure rate significantly less than 1%.
  • The surgery involves resurfacing the kneecap and putting in an implant made of steel and plastic.
  • Researchers report that procedure can even be recommended for younger patients with severe knee arthritis, a group to which physicians are sometimes hesitant to advise surgery.
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