I’m getting ready to have a big hole in my knee cartilage filled in with some healthy cells harvested from normal cartilage in the same knee. I’ve been told it takes four-to-six weeks to grow enough cells to fill a hole this size. I’ve been looking on-line to find out what the long-term results are of this procedure. Everything I read seems pretty positive. Are there any downsides to this treatment?

It sounds like you are describing a two-step procedure called autologous chondrocyte implantation. Autologous means the surgeon will use chondrocytes (cartilage cells) harvested from healthy tissue along the outside rim of the joint where there is less load and less wear and tear.

The first-step is the arthroscopic inspection. The surgeon takes a look inside the joint to see what’s going on and make the diagnosis. At that time, chondrocyte harvesting can be done and the cells sent to a lab where they will be expanded enough to fill the hole. The cells are then placed in the hole and covered over with a flap of bone or tissue membrane to form a smooth joint surface.

The goal is to form a long-lasting repair that will hold up under normal load and wear. Painfree joint motion with a return to all former activities provides improved quality of life for the patient. Things can go wrong with any surgery. With this particular procedure, sometimes pain persists. Chronic swelling and overgrowth of cartilage can lead to crepitus (crunching sound made by rough joint surfaces rubbing against each other).

Long-term studies have also shown that the harvested and implanted chondrocytes when expanded tend to lose their ability to remain chondrocyte cells. They start to become unstable and lose their form and structure, a process called dedifferentiation. The end-result is joint breakdown again and early arthritis.

Researchers are working on a solution to this problem. One approach is called cell therapy. With cell therapy, the autologous cells are treated (processed) in a special way to preserve the cells’ ability to remain stable and unchanged after implantation into the knee. This cell therapy procedure called a characterized chondrocyte implantation (CCI) is a slight variation of the autologous chondrocyte implantation (ACI).

As you research this topic, form a list of questions for your surgeon. The surgeon will be able to answer your questions based on factors such as your age, activity level, type of knee joint damage, and length of time from injury to surgery. The surgeon can speak from personal experience as well based on observed or reported adverse and/or long-term effects of this procedure for your type of injury.