I’m trying to help my brother get some information. He had a bad cartilage tear that went clear to the bone. They did some kind of surgery to repair the problem. Something like a patch of new cartilage was placed over the hole. But it didn’t work — there’s just soft scar tissue there now, so the knee is still unstable. What are his options now?

Cartilage injuries in the knee can be a big problem. Healing is very slow, if it happens at all. That’s because the cartilage in the knee doesn’t have much of a blood supply. These injuries can occur as a result of trauma (usually athletic injuries) or degenerative changes associated with aging.

Surgeons and scientists have worked hard to find ways to enhance or speed up cartilage healing. Two cartilage-stimulating techniques developed in the recent past are microfracture and autologous chondrocyte implantation (ACI). Chondrocytes are cartilage cells.

Microfracture is the drilling of tiny holes in the cartilage to stimulate bleeding and a healing response. Autologous chondrocyte implantation (ACI) is the removal of normal, healthy cartilage cells from the patient. The donor tissue is either removed and expanded (grown) in the lab and then reinjected or it can be harvested from the patient and immediately reinjected directly into the damaged area.

It sounds like your brother had the implantation procedure — perhaps with less than satisfactory results. Soft, spongy fibrous tissue forming in and around the defect isn’t really all that uncommon. If the knee is stable, further treatment may not be needed. But if there are symptoms of pain, swelling, or giving way (knee buckles when standing on it or walking), then a second procedure may be needed.

The best thing to do is encourage your brother to go back to the surgeon for a reevaluation.