Does your knee hurt? We need better methods for the repair of worn and aging body parts. With better ways to repair we could keep bodies running far beyond their original design life just like antique cars. The best knee cartilage repair surgery helps some but far from enough.

“A small hole is going turn into a big hole eventually, given enough time," says Riley Williams, M.D., orthopedic surgeon, Sports Medicine and Shoulder Service, Hospital for Special Surgery in New York, and director of the Institute for Cartilage Repair at HSS.

After an initial injury that has caused damage to a specific area of the cartilage, there are few options that can repair the damage which is likely to lead to severe osteoarthritis. The most popular current treatment for such lesions is called the microfracture procedure. In this surgery, a tiny 'pick' spikes holes into the base of the damaged cartilage area to promote bleeding. This allows the patient’s bone marrow cells to come to the surface of the damaged tissue. As a result, the cells then change into fibrocartilage cells and heal the defect.

While microfracture is minimally invasive and very quick, research has found that the defect may not always be fully repaired. The fibrocartilage does not hold up as well under everyday wear and tear as normal cartilage and has a much higher risk of breaking down again. As a result, surgeons in this area continue to pursue new methods of repairing cartilage injuries.

Some improvements in tissue engineering using a patient's own cells might produce a far more lasting layer of replacement cartilage.

A new multi-center clinical trial led by Dr. Williams at Hospital for Special Surgery uses a patient’s own cells to heal damaged cartilage, but in a much different way. First, a small piece of the patient’s healthy cartilage is taken and then the cells are grown in a laboratory. These cells are put into a piece of protein matrix, called NeoCart®, which has an internal structure shaped like a honeycomb. The cells use the NeoCart® as a scaffold and begin to grow over and around the structure. This creates a piece of new cartilage which is then, through a tiny incision, implanted into the patient’s joint over the damaged area, much like a living patch. The hope is that the new cartilage will repair the damage and integrate seamlessly with the surrounding cartilage.

Cell manipulation and tissue engineering technologies will produce much better results in the coming years. Some of the more mechanical parts of the body such as joints are lower lying fruit for repair and rejuvenation.

My biggest concern with the clinical trial above has to do with the age of the patients. Will the cells of older patients grow vigorously enough to create enough replacement cartilage? Will we need to wait for rejuvenating therapies for cells before an elderly patient's own cells can build replacement parts? The odds of success might be higher the younger you are.