Most of us know someone who has had knee replacement surgery. In the past 20 years, the number has gone up more than 100 percent.
Behind those numbers is some good and bad news.
First, the average hospital stay for a knee replacement has dropped from about seven days to about three.
In fact, many hospitals in our area allow some patients to go home the same day.
The surgeries are safe and effective, however, they are also expensive.
The average cost is 15-thousand dollars, and that is a growing burden to the healthcare system.
Dr. Peter Cram, of the University of Iowa medical college, says, "When you multiply 15-thousand dollars by that volume of procedures, you're talking about major money, even by federal Medicare standards. And this is a real challenge for the federal government."
It is expected that by the year 2030, there could be 4 million knee operations a year.
The study in the Journal of the American Medical Association also shows that almost 10% of the operations were re-dos - replacing worn-out artificial joints.
There was an increase in the infection rate for the revision procedures, and re-admissions for complications after the initial surgery went up, too. Doctors say this is something they will be studying further.
Among Medicare patients, the rate for knee replacements rose from 3 per 100,000 to 5 in 100,000.
"There's a huge percentage of older adults who are living longer and want to be active," and knee replacement surgery is very effective, said Dr. Cram.
Doctors believe the rise is also driven by the toll obesity is taking on America's bodies.