Nearly 1 in 20 US adults over 50 have fake knees

CHICAGO (AP) ? New research shows that nearly 1 in 20 Americans older than age 50 are living with artificial knees.

It’s the first such estimate and amounts to about 4.5 million people.

Experts say it’s important to know the number to help doctors assess future needs for health care resources. People with knee replacements sometimes need additional care for infections, scar tissue and other issues,

The estimate is from researcher Elena Losina at Harvard’s Brigham and Women’s Hospital. She prepared a report for presentation at the American Academy of Orthopedics Surgeons’ annual meeting Friday in San Francisco.

The operations have been on the rise, and doctors think reasons include the obesity epidemic and amateur athletes who don’t adjust workouts to spare aging joints.