Long Life for Knee Replacements

Just like the battery bunny that keeps chugging along, replacement knees are still working well 20 years out.

Researchers followed up on nearly 1,800 people who had knees replaced at an Indiana hospital between 1975 and 1989. The average age at the time of the surgery was 64. Of those still living 20 years later, all said they were at least moderately active - even jogging or playing tennis.

"The whole point of having a total joint replacement is to maintain a functional knee that allows patients to maintain a good deal of activity for a long time," says study author John B. Meding, M.D., at St. Francis Hospital in Mooresville, Ind. "This shows it lasts 20 years or more after the [operation]."

Help for arthritic joints

Knee replacement surgery is done to relieve pain and restore normal use of the joint, usually for people afflicted by severe arthritis. During the procedure, a surgeon removes damaged bone and cartilage, and replaces them with an artificial knee. The devices are made from plastic, polymers, and metal alloys, and are available in different designs aimed at different patients' needs.

In the study, 128 of the original 1,757 people were alive 20 years later. All were assessed for knee flexibility, walking distance, ability to climb stairs, and level of pain.

All but two could use stairs, only three were housebound, and 95 could walk at least five blocks. Many (82) were able to walk indefinitely, and 81 were pain-free. Against doctors' advice, 22 participated in hard-impact sports, such as jogging, volleyball, and tennis - some with both knees replaced.

Common procedure

Up to 500,000 knee replacement surgeries are done each year in the U.S. The study findings are important for younger patients in their late 50s who are considering a knee replacement, says Howard Luks, M.D., at Westchester Medical Center in Valhalla, N.Y.

"Until this time, I have been telling my patients the surgery is good for 15 to 20 years, but this is showing good to excellent results that can last 20 years and beyond," Dr. Luks says.

He cautions, however, that the study needs to be backed up by further research.

Always talk with your health care provider to find out more information.