At 45, with two serious knee injuries in her medical history, Jennifer Wyche is a textbook candidate for osteoarthritis. Joint injury dramatically increases the odds of getting the disease, which usually shows up after age 45. But Wyche, a former health-food store manager from Los Angeles, hopes to avoid that fate. Five years ago, after her second injury, she underwent what was then a novel bioengineered approach to repairing bum knees and torn cartilage. The method, using laboratory-grown cartilage cells, is but one of an array of treatments doctors are using to deal with this difficult but common ailment. So far, Wyche's left knee is fine. "I ride my bike. I can skate. I can dance again without pain, which makes me very happy," she says.
With active baby boomers pounding away on their aging joints, researchers are hurriedly looking for ways to repair injured cartilage before it can lead to osteoarthritis. They also are searching for treatments to ease the pain and slow the degenerative progress in people destined to get the disease because of genetics or poor joint alignment.
In osteoarthritis, the cartilage that lines the joints slowly wears away, leaving bone rubbing against bone. A major obstacle in dealing with this problem has always been that cartilage has little ability to repair itself. It lacks a good blood supply, and its very density keeps repair cells away. Thus, much of the research is focusing on ways to build cartilage in the laboratory.
In Wyche's treatment, Dr. Bert Mandelbaum, team physician for the U.S. Men's National Soccer Team, used a small incision and arthroscope to remove a bit of healthy cartilage--about the size of a raisin--from her femur and sent it to Genzyme in Cambridge, Mass. The biotech company's lab then coaxed the seed cartilage into producing millions of new cartilage cells, a process that usually takes about a month.
Wyche returned for a second, more invasive surgery. Her doctor cut open her knee, sewed a casing made from bone lining over an area with damaged cartilage, and injected the lab-generated cells. About 4,000 Americans have undergone this surgery, called chondrocyte (or cartilage cell) transplantation. Doctors say 85% to 90% of patients report significant improvement, though the procedure hasn't been around long enough to know how well the patches hold up over time.
The surgery is recommended only for those with localized cartilage injuries. Research is under way to build larger, three-dimensional pieces that could be used to repair an entire joint surface, says Dr. David Menche, a New York orthopedic surgeon who, as a medical resident in the early 1980s, took part in the initial research that led to chondrocyte transplants.
Researchers also are working to get stem cells taken from bone marrow--even fat cells--to grow into cartilage. Farshid Guilak, the PhD leading the fat-cell research at Duke University Medical Center in Durham, N.C., says he expects no problem finding fat, which he now gets from liposuction patients but which could easily be provided by most middle-aged patients.
DIET HELP. Meanwhile, a study funded by the National Institutes of Health is weighing the benefits of a commonly used dietary supplement, glucosamine chondroitin. Smaller studies have shown that the over-the-counter pills, which cost $20 to $30 for a month's supply, relieve joint pain from injury or osteoarthritis. There is even some evidence that glucosamine by itself may slow cartilage degeneration. Since glucosamine and chondroitin are components of human cartilage, one theory is that ingesting them may slow cartilage loss the same way calcium supplements help those suffering the bone loss of osteoporosis. Because the supplement has no known side effects, many orthopedists advise nondiabetic patients to try it.
In another treatment, called viscosupplementation, a fluid similar to that found in the knee but made from rooster combs is injected into the knee joint to relieve pain. "That's basically like greasing a joint," explains Dr. Thomas Einhorn, chairman of the American Academy of Orthopaedic Surgeons' Council on Research.
These options are only the first wave of improved joint repair. With 41% of the U.S. population expected to be 45 or older by 2020, you can bet the race to relieve aching knees will get more crowded.
By Carol Marie Cropper