Karen Ferriera is all about being active, but not so long ago she was anything but.
"I was wearing a brace every day, living on painkillers and I could barely walk my dogs around the block," said Ferriera.
Her doctor tried several things, including physical therapy and cortisone shots, but ultimately she was told she needed a new knee.
"I thought he was pretty much crazy," said Ferriera. "I was 46 at the time. It just didn't seem possible."
But it was. Recent studies show the number of knee surgeries has doubled in the last decade and more women than men are ending up in the operating room.
Currently, 4.5 million Americans live with one knee replacement. And the people getting them are younger and younger.
"Historically, knee replacements were meant primarily for older populations," said orthopedic surgeon Dr. Maury Harwood. "What we've seen with this rise in Baby Boomers is that a lot of people worked hard and played hard and now they need to pay hard."
Harwood says the trend is growing due to improved technology.
"The main advancement in knee-replacement technology is that we're moving toward custom implants," said Harwood. "Nowadays what we're doing is we're using technology such as MRIs and CT scans and we're actually building 3-dimensional models of people's knees and making implants that fit them specifically."
The younger and more active you are, the more likely you'll damage your replacement, so talk to your doctor about proper use.
Karen says she's not missing a step.
"I'm back to walking my five, six miles," said Ferriera. "I can ride my bike. I can do all the activities I love."
Experts say avoiding certain pounding exercises could help the replacement last longer.
In 2009 alone, the number of surgeries topped 600,000, twice the number of procedures in the past decade.