Study Reports Good Long-Term Results for Total Knee Replacement

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If you had a knee replacement 20 years ago, chances are you’re getting around just fine, according to the results of a new study released at the American Academy of Orthopaedic Surgeons’ annual meeting.

Most patients who undergo total knee replacment (TKR) are age 60 to 80. More than 90 percent of these individuals experience a dramatic reduction in knee pain and a significant improvement in the ability to perform common activities. However, questions have been raised about the decline in physical function over the long term despite the absence of implant-related problems.

About 581,000 knee replacements are done annually in the U.S., according to the AAOS, often after the knee is severely damaged by arthritis or injury.

New research unveiled at AAOS evaluated patient functionality 20 years after knee replacement.

“It is a common concern for older adults to wonder how they will function several years after the knee replacement and if revision will be necessary,” said John B. Meding, M.D., study author and Attending Orthopaedic Surgeon, The Center for Hip and Knee Surgery, Mooresville, Ind.

Although aging may cause a gradual decline in physical activity, a remarkable functional capacity and activity level continues 20 years of more after TKR, study authors concluded.

Between 1975 and 1989, 1,757 primary cruciate (the ligament behind the knee)-retaining TKRs were preformed at the Center for Hip and Knee Surgery. The study examined 128 patients who were living at the 20-year follow-up. The average age at operation in the group of 171 TKRs was 63.8 years. Eighty-two percent of these patients had osteoarthritis and 73 percent were female. The average follow-up was 21.1 years and the average age at follow-up was 82.3 years.

The study found:

• Ninety-five patients could walk at least five blocks;
• Nearly half, 48 percent, of patients reported unlimited walking;
• All but two patients could negotiate up and down stairs without a banister;
• Only three patients were considered housebound; and
• There were no implant failures after 20 years.

“These findings definitely add to the conversation with patients considering surgery. If a patient actually lives that long, a well-functioning TKR may help allow them to maintain a remarkable functional capacity and activity level not just for five or 10 years but for 20 years and beyond,” said Meding. “This research refutes any perception that the importance of a well-functioning TKR diminishes over time because of an overall declining functional status. Elderly people are using their surgically replaced knees for fairly active lifestyles many years after surgery.”

Patients considering knee replacement should talk to their orthopaedic surgeons about the implant’s life expectancy, researchers urged.

Dr. Meding and his co-authors received no compensation for their study.