Cartilage Injections Repair Knee Damage

Swedish researchers have found a way to repair damaged cartilage in the knee. The new treatment involves growing patients' cartilage cells in a test tube, then injecting them into the damaged area.
Damaged cartilage often leads to osteoarthritis, the most common form of arthritis. The treatment seems to restore injured cartilage to almost-normal condition. It offers hope of nearly full recovery for young people who suffer cartilage damage in sports injuries.
Cartilage is a tough, slippery, flexible material that covers the ends of bones and lines joints. The material allows bones in joints to slip over each other smoothly, without pain or stiffness.
Cartilage cells, called chondrocytes, are distributed throughout a web of tough fibrous material. Cartilage has no blood vessels or nerves. For reasons that are not entirely clear to scientists, once cartilage is damaged or wears down over time, it does not repair itself.
Damage to cartilage can lead to osteoarthritis, characterized by joint pain and swelling. About 75% of elderly people suffer from osteoarthritis. Eventually the disease can lead to destruction of the entire joint. When this happens, doctors often replace the joint with an artificial one. About 95,000 people in the United States get artificial knees every year.
A recent study was done by Lars Petersen and Anders Lindahl at the Sahlgrenska University Hospital in Goteborg, Sweden, and their colleagues. They reported on 23 patients in the October 6, 1994, issue of the New England Journal of Medicine.
The patients ranged in age from 14 to 48. Most had relatively small knee-cartilage defects that were caused by accidents. "We started with knee injuries because they are the most common and easy to reach," Petersen told the Associated Press. "In principle, we could use this technique in any joint to repair and prevent further damage."

Chrondrocytes

In a preliminary operation, Petersen and Lindahl removed small pieces of healthy cartilage from the knees of their patients. They removed chondrocytes from the fibrous cartilage material and grew the cells in a test tube for 14 to 24 days.
During a second operation, the scientists removed a piece of the tough outer membrane, called periosteum, from a nearby bone. They sewed the periosteum over the damaged area of cartilage. Then they injected the cultured chondrocytes under it. Petersen and Lindahl examined the transplants three months after the second operation and again 12 to 48 months later.
In most cases the transplanted cells had grown into the previously damaged cartilage and formed normal-looking tissue. In all the patients, pain and swelling in the knee subsided to some degree.
Sixteen of the patients had defects in the cartilage that lines the bottom of the thigh bone. Fourteen of the 16 had good to excellent results. The other two required further surgery.
Seven patients had defects in the cartilage at the back of the kneecap. The procedure was less successful with these patients. Of those seven, only two had favorable results. Two others required further surgery.
Most elderly patients develop osteoarthritis due to normal wear and tear on their joints throughout their lives. The operation might not be as successful with them as with young accident victims.
Biosurface Technology Inc. in Cambridge, Massachusetts, is working with the Swedish team to refine the operation. Currently, the procedure requires open-knee surgery. Researchers hope to develop a way to perform the operation arthroscopically, using thin viewing tubes threaded into the knee through small incisions.
Clinical tests of the procedure are scheduled to begin in 1995 at Brigham and Women's Hospital in Boston.