Q: Is it ever too late to have surgery for a hole in the knee cartilage? I'm 43 and too young for a knee replacement but is there something else they can do for this before my entire knee is torn up with arthritis?

A: A hole in the knee cartilage usually refers to damage in the articular cartilage. This area of the joint is a smooth, fibrous covering over the two bones that form a joint. If you were to look at this structure on a chicken leg, it is the equivalent of the gristle at the end of the drumstick.

The purpose of the articular cartilage is to protect the bone while making it possible for the knee joint to slide and glide as it bends and straightens. Damage to this part of the joint can create cracks and even holes called defects that must be treated to prevent erosion of the underlying bone. Without treatment, the eventual outcome is painful knee osteoarthritis.

There are three main surgical treatment techniques for this type of condition: 1) osteochondral autologous transplantation (OAT), 2) microfracture (MF), and 3) autologous chondrocyte implantation (ACI).

Microfracture is a way to repair the defect. The surgeon drills tiny holes through the articular cartilage into the bone. This causes bleeding and the formation of tiny blood clots to fill the defect. The body then sets up a healing response that causes new chondrocytes (cartilage cells) to form. Transplantation and implantation are restorative techniques. The surgeon uses a plug of cartilage and bone taken from a healthy area of the patient's own cartilage for the transplantation procedure or the patient's own cartilage for implantation procedures to fill in the hole.

According to a recent review of the evidence supporting these procedures, you can expect to get good results no matter what procedure is used. Reduced pain and improved knee function are routinely reported. Studies show that repair with microfracture seems best for small lesions (less than 2.5 cm2).

The osteochondral autologous transplantation (OAT) transferring a plug of cartilage and bone into the defect works better than microfracture for medium-sized defects (2.8 cm2). And restorative techniques with transplantation or implantation have the best results when used with the more active patients.

Age does make a difference in selecting the best treatment technique. Patients under 30 seem to respond better than patients 30 and older no matter what treatment was used. But there are other factors to consider such as the location of the defect, your body mass index, and the type of training your surgeon has received in treating these types of lesions.

Reference:

Joris E. Bekkers, MD, et al. Treatment Selection in Articular Cartilage Lesions of the Knee. A Systematic Review. In The American Journal of Sports Medicine. November 2009. Vol. 37. Suppl. 1. Pp. 148S-155S.