"It takes 30 to 40 stitches about as thin as a hair," Mirzayan says.
Studying growth factors
The third area of research into cartilage regeneration -- studying growth factors -- will take a big step in the next few months with the start of several clinical trials, one based in Santa Monica, Mandelbaum says.
Growth factors are substances that promote cell division. The trials will evaluate the role of growth factor BMP-7 (bone morphogenetic protein 7) in enhancing regeneration of cartilage and inhibiting degeneration of the knee joint.
Already, the three areas of research are starting to overlap, as Mandelbaum says they should.
The rat-tail ACI merges new scaffolding and cellular techniques. Beyen says his company plans to try seeding plugs with the "super-chondrocytes" produced by ChondroCelect. And Caborn says he's already had good results in experimenting with "seeding" TruFit plugs with chondrocytes. "And you could also seed the cells with growth factors," he says. "It's like adding fertilizer to a plug in your lawn."
But in all the excitement over these new knee procedures, Mirzayan sounds a reminder about a procedure that's been around the block a few times.
"Knee replacement surgery, if done in the right patient at the right time, is still one of the most successful operations we can offer as orthopedic surgeons," he says.
The right patient is older, probably over 60. At that point, damage to the knee is most likely caused by generalized arthritis. That means the new procedures couldn't even work, because they're only suited to very localized damage.
But just as the new procedures aren't suited to most older patients, knee replacements aren't suited to most younger ones.
"They don't last forever, only about 15 to 20 years," Mirzayan says. After that, the patient needs another, but each time the surgery is repeated it's less effective.
In his practice, Mirzayan only sees young people with early arthritis. "I try to do something before they end up needing knee replacement," he says. "The longer they can wait, the better the chances that they'll only need one."