Nearly 1 In 20 US Adults Over 50 Have Fake Knees

LINDSEY TANNER

CHICAGO (AP) — Nearly 1 in 20 Americans older than 50 have artificial knees, or more than 4 million people, according to the first national estimate showing how common these replacement joints have become in an aging population.

Doctors know the number of knee replacement operations has surged in the past decade, especially in baby boomers. But until now, there was no good fix on the total number of people living with them.

The estimate is important because it shows that a big segment of the population might need future knee-related care, said Dr. Daniel Berry, president of the American Academy of Orthopedic Surgeons and chairman of orthopedic surgery at the Mayo Clinic in Rochester, Minn. He was not involved in the research.

People with knee replacements sometimes develop knee infections or scar tissue that require additional treatment. But also, even artificial knees wear out, so as the operations are increasingly done on younger people, many will live long enough to almost certainly need a second or even third knee replacement.

The new estimate comes in an analysis being presented Friday at the academy's annual meeting in San Francisco.

"These data are sobering because we didn't know what an army of people we've created over the last decade," said Elena Losina, lead author of the analysis and co-director of the Orthopedics and Arthritis Center for Outcomes Research at Harvard's Brigham and Women's Hospital. "The numbers will only increase, based on current trends."

Replacement joints can greatly improve quality of life for people with worn-out knees, but they're not risk-free and it's a major operation that people should not take lightly, she said.

Modern knee replacements in the United States date back to the 1970s. Since then, advances in materials and techniques, including imaging scans to create better-fitting joints, have made the implants more durable and lifelike, surgeons say.