University of Pittsburgh Doctor Hoping to Halt Arthritis

By Joe Meloni for Knee1

For years, doctors have studied human cartilage in hopes of developing methods to fully restore damaged tissue. There are several methods to repair the damaged tissue but not to its original strength and flexibility. Damage to cartilage is among the leading causes of osteoarthritis. Developing more effective methods of identifing and treating the damaged tissue is crucial to limit osteoarthritis.

With this in mind, Dr. Constance Chu, director of the Cartilage Restoration Center at the University of Pittsburgh, is testing a new procedure on retired race and rodeo horses. Doctors have succeeded in generating tissue in labs, but have not yet developed a technique to grow the tissue on a human joint. Tissue grown on a human would likely function as natural cartilage does. The hope of the experiment is to develop a technique more effective than microfracture surgery – the most common cartilage regeneration method currently used in the United States.

Currently, osteoarthritis can be treated with medication, but there is no method currently in practice to identify potentially problematic tissue in a patient. Doctors have improved treatment methods over the years, but regenerated cartilage still limits patients. The lesser quality of the regenerated tissue often leads to further problems for patients and, quite frequently, more surgery.

Even more difficult than treating cartilage damage is identifing weakened tissue before serious injury occurs. In fact, the tissue can appear entirely healthy, only to cause the patient further pain and problems down th road, according to Dr. Chu's study published in the Dec. 2009 edition of the American Journal of Sports Medicine.

One of the predictive methods currently in trial is a digital imaging method called optical coherence tomography – the method provides a three-dimensional photo of tissue by dispersing light throughout the cartilage.

As far as treating already damaged tissue, microfracture surgery uses small incisions in the bone around the cartilage. Cells from the bone marrow, which contains stem cells, join with the cartilage and spawn new, healthy cartilage. However, the new tissue is not as strong as the original tissue.

According to Chu, there is not a single method in practice that replaces damaged cartilage with equally strong tissue except cartilage transplant. However, it is very difficult to find healthy cartilage available for transplant.

The experiment involves creating a small injury in a horse’s stifle joint, which resemble the human knee. From there, stem cells are taken from the horse’s own bone marrow and inserted into the cartilage. Another procedure involves removing stem cells from the patient and growing them in a laboratory. The first procedure is preferable because it is faster and requires just one operation.

At this point, 11 of the 12 horses Chu plans to test have had the surgery. They will be monitored over the next three months. If the results are favorable, Chu plans to move the procedure to human trial, which would begin in roughly two years.