MEMPHIS, Tenn. — A new type of surgery involves grafting healthy cartilage from non-weight-bearing areas of the knee and implanting it on weight-bearing points where the original cartilage is damaged.

The specialist who performed the operation, Dr. Randall Holcomb, is one of two surgeons with OrthoMemphis — an orthopedic group specializing in sports medicine, joint replacement, physical therapy and other services — selected to enroll patients in a four-year nationwide study comparing the new Cartilage Autograft Implantation System with traditional treatment. The other OrthoMemphis surgeon in the study is Dr. Kenneth Weiss.

Knee pain and arthritis from cartilage damage does more than restrict people from participating in sports and healthy activities. It also is a leading cause of disability and lost time at work, Holcomb said.

It happens because of subtle, long-term changes in the one-eighth-inch-thick cartilage coating the bones at the joint. This living tissue absorbs the stresses borne by the knees, compressing and then bouncing back to prevent the bones from rubbing together.

In the experimental process, surgeons look along the peripheral areas where the natural knee cartilage isn't bearing weight. There, they scrape fine fragments of cartilage and collect them to be implanted in the damaged, weight-bearing areas.