Before reports surfaced last week that he flunked a drug test, the biggest medical concern facing Tour de France champion Floyd Landis was joint replacement surgery for his much-publicized bum hip.
And in that problem, at least, the cyclist has plenty of company.
Fueled in part by fitness-crazed baby boomers and aging jocks who refuse to be sidelined by throbbing knees and other worn-out parts, experts expect a boom in joint replacement surgeries in the coming years.
By 2030, the number of knee replacements in the United States is expected to jump 673 percent to 3.48 million, according to a study presented at the American Academy of Orthopaedic Surgeons' annual meeting in March.
Hip replacements are expected to grow 174 percent to 572,000.
"Prior generations lived with a little limp. But baby boomers are the first generation to try to stay active on an aging frame," said Dr. Nicholas DiNubile, an orthopedic surgeon in Philadelphia who has seen the number of patients in their 50s and younger swell in recent years.
"They want to turn back the clock at just about any cost," he said.
It's a mind-set that resonates with Bob Finn, a 58-year-old Defense Department investigator from Edgewater who had both knees replaced in January 2004, mostly so he could return to the baseball field.
"I guess it's a sense we have at our ages that we're going to keep playing and, if something breaks, well, we'll just get a replacement for it," he said.
Today orthopedic surgeons can, in fact, replace most joints in the body. But the vast majority of operations are for knees and hips. Surgeons in the United States performed 638,000 hip and knee replacements in 2003, the most current year for which data are available. That's more than double the number performed in 1993.
Diseases such as rheumatoid arthritis -- a chronic and painful inflammation of the joints -- are responsible for some of the surgeries. So are injuries.
Landis, who at 30 is far younger than the typical joint replacement candidate, suffered a cycling crash three years ago that shattered his right hip and cut off the blood supply to the bone there. Eventually, it withered and died. The condition, known as osteonecrosis, forced professional football and baseball player Bo Jackson to undergo hip replacement surgery in 1992.
But most people who get a joint replaced have osteoarthritis, a degenerative condition resulting from the gradual loss of bone-cushioning cartilage within the joints.
While genes play a role in who develops osteoarthritis, for many patients, it's more about a lifetime of wear and tear. "I see a lot of 55-year-old ex-lacrosse players," said Dr. Frank Ebert, chief of orthopedic surgery at Union Memorial Hospital.
For Stanford Lamberg, a 67-year- old Pikesville dermatologist, it was squash.
Lamberg picked up the game in his 20s, playing three to four times a week for the next three decades. By the time he hit 60, his left knee had begun to throb. "It reached a point where I'd play, and then I'd hobble for three days," he said.
Hoping to delay a knee replacement, he switched to cycling. But by last summer, he had trouble sleeping, required anti-inflammatory cortisone shots in his leg, and could barely bend his knee enough to pedal. He made an appointment for a replacement.
"The whole reason for doing this was to get back on the bike," Lamberg said. "Otherwise, I had a sense I would just get old quickly."
Joint replacement surgery has advanced significantly in the past decade, orthopedists say. Today's prosthetics are composed of advanced plastics, ceramics and alloys that are more durable and easier to install than older models.
Surgical and rehabilitation techniques have also improved. "We used to treat our patients like eggshells," said Dr. David Dalury, a Towson orthopedic surgeon who has been installing new joints for more than 17 years. "Now you're out of bed in a day and out of the hospital in three."
Lamberg had his knee operation in January. "Two days later, I was walking around," he said. "My knee is as good as it's ever been."
That doesn't mean artificial joints come with a lifetime warranty. And as patients get younger, one potential concern is the need for a second replacement.
In recent years, the number of do-overs -- known in the trade as "revision" surgery -- has steadily grown, according to the American Academy of Orthopaedic Surgeons.
"It's like, `Oh my God, how many more times in my life do I have to have this thing done?'" said Jayne Donohoe, 50, an elementary school teacher from Jarrettsville who had both knees replaced in April -- and is already thinking ahead.
The best reliability data show that 90 percent of replacements will last at least 10 years. But many orthopedic surgeons tell patients that they can expect a far longer life for their new joint -- as much as two decades.
Still, "the bottom line is, these devices don't last forever," said Steven Kurtz, a biomedical engineer at Drexel University in Philadelphia who studies artificial joint failure.