Zimmer, for its part, is poised to keep grabbing market share, boosting hip and knee sales by closer to 10% a year.
The stocks of Zimmer and its rivals, such as Stryker (SYK), Johnson & Johnson's (JNJ) DePuy division and Britain's Smith & Nephew (SNN), all have been enjoying long-term ascents. Between 2002 and 2004, Zimmer's share price more than doubled; the rally continued, albeit at a slower pace, right up to last fall.
At that point, the Justice Department accused the industry of using phony consulting contracts to pay off surgeons using its products. Zimmer and its peers settled, paid a fine and agreed to have external monitors oversee surgeon contracts. (Gutowski, my surgeon in Princeton, says he has no financial interest in Zimmer.)
Zimmer shares, which had traded as high as 91 before the controversy, tumbled to 64. Now, with the scandal diminished, the shares are back up to about 70 -- and demographics still favor long-term growth. The stock could well keep climbing: The consensus among analysts is that it will rise about 20% over the next 12 months, to 85 -- and some bulls figure it will top 90.

JIM CRINES, THE CFO, points out that there is considerable pent-up demand for Zimmer's wares. Many people who haven't had hip or knee replacements are candidates, but are putting off operations out of fear, he says. "We are working to lessen the trauma of surgery," which could attract the fence sitters, he predicts.
My own experience shows that a knee replacement isn't as scary as it might seem. I was struck more by the sheer ingenuity of the engineering. The operation started with a spinal anesthetic and six-inch incision down the front of my knee. After the muscles, nerves, blood vessels and knee cap were carefully pushed aside, Gutowski leveled off the top of my tibia (shin bone) and, using a special cement, inserted a flat metal plate with a plug going down the center of the bone.

The sides and bottom of my femur (thigh bone) were then shaved to specific angles using precision instruments and, again, cemented to a kind of metal cap. This fits to -- and rotates on -- a polyethylene surface attached to the top of the tibia plate. In a decade or so, this by-then worn insert can be easily replaced with minor surgery, thus avoiding a complete new operation.

Because the operation leaves the muscles and nerves uncut, recovery is relatively swift and I was walking with a crutch the evening of the surgery. Pain was occasionally acute, but easily alleviated by medication. Now, after a series of admittedly tough sessions with my physical therapist, I am walking a couple of miles a day without pain. Stairs, especially coming down, remain a challenge, but this is sure to get easier with time. I have every confidence in my NexGen LPS-Flex Fixed Bearing Knee.

Of course, Zimmer has other knees in its pipeline.