By Jana Soeldner Danger
Chronic knee pain can make life miserable. Sufferers often need to cut back on or abandon their participation in athletics or fitness programs, and even day-to-day activities like walking can be uncomfortable.
Some bad news: Osteoarthritis, the major cause of joint deterioration, is happening in younger people. “The average age for diagnosis now is about 50,” says Dr. Frank McCormick, an orthopedic sports medicine surgeon at Holy Cross Hospital in Fort Lauderdale. “It used to be the mid-60s. It’s partly because many Americans today are more active than in the past, and also because many of them are heavier.”
“Cartilage injuries have been a health problem forever,” says Dr. John Malloy, an orthopedic surgeon with Broward Health. “Cartilage is avascular [meaning it doesn’t have a blood supply], so repair cells can’t get to it to heal it.”
Until recently, a mechanical replacement was pretty much the only remedy for deteriorating knee joints. But this surgical procedure can be painful and require lengthy recovery times.
The good news: Today there are new, less invasive treatments to get an individual back to work and onto the playing field or jogging trail. Two approaches showing excellent results are cartilage transplants and stem cell injections.
With transplantation, the physician performs a biopsy to remove a small piece of cartilage from a non-weight-bearing part of the knee. “It’s about the size of a Tic Tac,” Dr. McCormick says.
The physician sends the biopsied tissue to a lab, where the cells are expanded, then loaded onto a collagen scaffold and returned so they can be implanted into the patient’s knee through a small incision. “Over the next six months or so, they turn into normal cartilage cells and fill the ‘potholes,’” says Dr. McCormick.
If the patient doesn’t have healthy cartilage to remove, tissue may be transplanted from a cadaver. Because cartilage is immunoprivileged, meaning the body won’t try to reject the tissue, the patient does not have to take suppressants as is necessary with most other kinds of transplants. And new technology allows donor cartilage to be freeze-dried and stored for up to five years.
But the supply is still limited. “You need a donor with healthy cartilage,” says Dr. Malloy.
The procedure has been around for more than 20 years, and results last indefinitely. But currently, cartilage transplantation is usually reserved for younger patients. A newer technique, stem cell therapy, is appropriate for adults of all ages and seems to get better results, says Dr. Malloy.
It works like this: The physician harvests cells from the patient’s own blood, bone marrow, or fat. They are put into a centrifuge, which separates the different kinds of cells. “Then we skim off the stem cell layer and inject them back into the knee using an arthroscope,” says Dr. Malloy, who has performed the procedure on both young patients and elderly ones. “We harvest them, isolate and concentrate them, and redeliver them.”
Although the much newer procedure is showing good results, it has not yet been proven. “We don’t know why it works, but it works very well,” says Dr. McCormick. “Symptoms improve and the patient feels better.”
“The evidence so far is mostly anecdotal,” says Dr. Malloy, who is currently participating in three studies involving the procedure. “We need better science on it, but what we think is happening is that when the stem cells find damaged tissue, they repair it, because that’s their job. This is regenerative medicine.”