Description: Thinking about getting a new knee or a new hip next year? You're not alone. For baby boomers, it seems that joint replacements are as prevalent as iPods are for teenagers.

About 500,000 knee replacements and more than 175,000 hip replacements are performed annually, and those numbers are on the rise. In fact, hip replacements are expected to increase 174% in the next 20 years, and knee replacements will rise even more -- 673%, according to a study presented at the American Academy of Orthopaedic Surgeons' 2006 annual meeting.
What's behind the growing demand for new joints?

Blame it on the lifestyle of the baby boom generation, says Mathias Bostrom, MD, an orthopedic surgeon at New York's Hospital for Special Surgery, where total knee replacements were pioneered.

"They're not willing to be sedentary or change their lifestyle," Bostrom tells WebMD. "Their joints are beat up and they're living longer, and they want joints that let them do the things they're used to doing."

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