I am a sports enthusiast — not just watching on TV but playing every sport that comes along. The problem is I’ve developed a hole in my right knee cartilage that is going to require surgery. The surgeon is going to plug the hole with a new collage treatment they are using in other countries. I’m going to ask at my next appointment about how soon I can be active again. But I thought I’d check on-line and see what I could find out. What do you people advise?

You might find the results of a recent study of interest. In this study, orthopedic surgeons from Italy explored the use of a minimally invasive, one-step osteochondral scaffold to repair damage to the surface of the knee joint. The level of evidence is low (rated four on a scale from one-to-four) because it was a case series. But the information about results is still valuable for the type of treatment you are considering.

The condition you described (a hole in the cartilage) is known as osteochondritis dissecans or OCD. As you have experienced from your activities, this is an acquired injury from repetitive microtrauma. A lack of blood supply to the damaged area causes separation of the first two layers of the knee joint: the cartilage that lines the joint (articular cartilage) and the subchondral bone (bone just under the cartilage).

The end-result is a hole (referred to as a “lesion” or “defect”) in the knee joint cartilage that goes down to the bone. The defect is on the bottom of the femur (thigh bone) where the femur comes in contact with the tibia (lower leg bone). Instability of the articular cartilage causes pain, swelling, and loss of knee motion and knee function. Left untreated, uneven contact of the joint eventually causes further degeneration of the joint and arthritis.

The most effective treatment (especially for large lesions) is surgical with a wide variety of procedures currently in use. The goal of surgery is to restore the joint surface to as normal as possible (anatomically). Placing collagen tissue (the basic building block of cartilage and bone) into the defect is one of the techniques under investigation.

In this study, a three-layer scaffold made of type I collagen fibers was placed in the defect. The idea was to stimulate the body to fill in the scaffold as part of the natural healing process. All measures of function improved for each patient over the two-year period. In fact, continued improvements were observed between year one and year two. And the more active patients had a faster recovery.

Your surgeon will outline a post-operative plan of recovery for you. This usually starts on the second (or even the first) day after surgery. A physical therapist will guide you through a series of movements and beginning exercises. Compression of the joint is carefully controlled through these supervised activities. You will likely be on crutches for several weeks and perhaps involved in a pool therapy program (again under the careful eye of the physical therapist).

When there is no sign of swelling and the knee can extend (straighten) fully, your program will be advanced to include full weight-bearing and strengthening exercises. Your return-to-sports should not be premature and only after completing sports-specific skills as part of the rehabilitation program. Your release date will be determined by the physician in coordination with the physical therapist based on your clinical progress. Your cooperation and compliance with all aspects of the program will be an important key to the most successful results.