Battle of wounded knees: baby boomers aching to stay active are fueling a bonanza for the sports medicine business--and a strain on health-care costs.

• Author: Marshall, Lisa

At age 44, cyclist Scott England has endured no less than 10 surgeries on his knee, shoulder and toes. He goes to physical therapy twice a week, has weekly pain-numbing injections in his joints, and even own his own ultrasound machine.

Runner Kathy Gebhardt, 51, is on "volume 3" of her medical file, with five knee operations behind her and a total joint replacement looking inevitable.

Competitive rower Dr. Richard Flanigan, 70, is already sporting the scars where doctors replaced his worn-out hip and knee with brand new ones.

But ask any one of these active Colorado baby boomers to give up their sport, and they'll you straight up not a chance.

"We're seeing sports injuries in people in their latte 40s and 50s that we used to see only in high school, college or professional athletes," says Dr. Ted Parks, chief of staff at the Colorado Orthopaedic and Surgical Hospital, a new Denver facility specializing exclusively in orthopedics. "Forty-five-, 55-, and even 65-year-olds are out there playing and competing, and when they get hurt they want to get fixed and back to the game ASAP."

In fact, the nation's baby boomers suffered more than 567,000 sports injuries in 2007, according to the Centers for Disease Control, flooding hospital emergency rooms, orthopedic surgeons' offices, and sports medicine clinics in unprecedented numbers. Raised on Jane Fonda aerobics and a "No Pain No Gain" mentality, many of the 78 million American born between 1946 and 1964 are greeting middle-age with a vigor far exceeding what their parents exhibited at their age. Consequently, they've spawned a multibillion dollar industry of braces, orthotics, and shots, new surgical techniques and devices, and specialty hospitals and clinics aimed at keeping them in the game and fixing them when they break.

But the phenomenon, playfully dubbed "Boomeritis," also has its down sides. As more svelte fiftysomething runners file in for ACL repairs and joint replacements, will there be enough doctors to perform them? And as athletic boomers sign up for another MRI, physical therapy session, or exotic pain-killing injection, who will pay for it all?

"They don't take no for an answer, and they have really high expectations of what we can do for them," says Dr. Nicholas DiNubile, a Philadelphia-area orthopedic surgeon who coined the term "Boomeritis" and the accompanying "fix-me-itis" in the mid 1990s. "I see a lot of these boomers with an almost unlimited ability to consume health-care...