The cartilage in the knee doesn’t heal very well. The cells just don’t seem to be able to repair themselves. If the damage is deep enough to go clear to the bone, there are cells in the bone marrow that can help. Doctors have tried to stimulate the bone marrow to make cells that will become cartilage. They’ve tried drilling, sanding, and putting small cracks in the bone to release these healing cells.
Different kinds of cells make up cartilage, ligaments, and tendons. These are called collagen fibers. Some collagen fibers are harder and stronger than others. Likewise, some collagen tissue is softer and has limited durability. Treatment to stimulate bone marrow is more likely to form tissue that is softer and less stable.
With this in mind, researchers have explored other sources of cartilage cells to promote healing. Animals were used in the 1980s to see whether injecting cartilage cells helped the healing process. Studies are now being done on humans. In one study, cartilage cells were shaved from the patient’s injured knee, washed and cut up, and then injected back into the damaged area. Rehabilitation took place over the next eight weeks. Each patient was followed for five years or more.
Good to excellent results were reported in almost all of the patients. Failures were the most common in patients who had damage to the cartilage and the ligaments of the knee at the same time. Some failures were the result of patients not following the prescribed exercise program.
The use of cartilage harvested from a person’s own knee is a new treatment developed over the last 10 years. It is a much better method of repair in some cases compared to sanding, drilling, or fracturing the damaged area. The repaired cartilage is stiffer and more stable after two years. Patients are able to return to full activities. These good results are present in more than half of all cases, even years later.