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Healing Cartilage from the Bone Up

The lining or cartilage of a joint heals better if it is damaged clear to the bone. Damage that only goes through part of the cartilage doesn't heal nearly as fast or as well. Scientists think this is because cartilage needs the healing cells that are on the surface of the bone. An opening all the way through the cartilage allows those cells to come to the injured site.

With osteoarthritis, cartilage loses its normal structure and function, causing rough, irregular joint surfaces. At first, the individual fibers of the cartilage get damaged. As the disease gets worse, cracks or fissures develop. These fissures go deeper and deeper through the cartilage and then into the bone.

Doctors are looking for ways to prevent this loss of joint surface. In the meantime, they are looking for ways to repair the bone. Some surgeons are trying to shave the joint down to the bone to promote repair of the damaged surface. One group of Japanese physicians looked at the effect of surgery to "realign" the leg bones. The purpose of this surgery is to redistribute the weight on the joint more evenly. This kind of operation is used in patients with osteoarthritis on only one side of the joint.

This group of doctors found that even with the corrected leg alignment, the cartilage still couldn't repair itself. Once the damage is done, it is very hard for cartilage to repair itself. Repair of injured cartilage requires the healing cells under the bone. However, surgery to correct alignment did prevent further joint damage.

Researchers have new information about the joint damage that comes with osteoarthritis. Cartilage can't repair itself unless the damage goes clear to the bone. Then cells from the blood and tissue under the bone come to the rescue of the cartilage. Realigning the bones with surgery does not help the repair process, but it does keep the damage from getting worse. This information has led researchers to look for ways to stimulate the joint to repair itself. This may involve cell transplantation, growth factors, and tissue transplants.

References: Shinji Wakabayashi, MD, et al. A Comparison of the Healing Potential of Fibrillated Cartilage Versus Eburnated Bone in Osteoarthritic Knees After High Tibial Osteotomy: An Arthroscopic Study With 1-Year Follow-up. In Arthroscopy. March 2002. Vol. 18. No. 3. Pp. 272-278.

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