I have a painful knee from damage to the articular cartilage. What do you recommend for surgical treatment?

Q:  I have a painful knee from damage to the articular cartilage. What do you recommend for surgical treatment?

A:  It sounds like you have a defect or hole in the articular cartilage. This is the cartilage that lines the joint and sits right up against the bone.

We don't know for sure that if left alone, the articular cartilage would eventually heal on its own. The process of what happens over time without intervention or treatment is called the natural history of a condition.

Right now, it's assumed that damage to the articular cartilage leads to arthritis sooner than later. But there's no real evidence to support this view. Most of the studies done so far haven't been on single (isolated) defects of the articular cartilage. Injuries treated have included additional damage to the joint such as an ACL tear (ACL = anterior cruciate ligament).

The articular cartilage doesn't have much of a blood supply of its own. It relies on movement of nutrients in fluids that cross the cartilage bringing supplies like a wagon train. But the fluid can't cross holes in the cartilage and that's a problem. Without a healthy, intact matrix of bone and cartilage, it's like the wagon coming to a canyon with no bridge to get across.

Since that time, three different surgical techniques have been developed and tried for this type of injury: 1) microfracture, 2) autologous chondrocyte implantation (ACI), and 3) osteochondral autograft transplantation (OAT). Here's a brief explanation of each one.

Microfracture involves drilling tiny holes through the cartilage, past the first layer of bone underneath, and into the bone marrow. There's a rich blood supply there and drops of blood well up through the holes to aid the healing process.

Autologous chondrocyte implantation requires removing some of the healthy cartilage cells, taking them to the lab, growing more healthy cells, and then putting them into the holes or defects in the knee.

And osteochondral autograft transplantation refers to harvesting healthy cartilage cells from a part of the knee that doesn't bear weight (and isn't damaged) and using those plugs to repair the damaged area.

Each of these techniques has its own advantages and disadvantages. According to studies done so far, there's no clear winner. But in a recent report by surgeons revisiting the question of which one has the best results it was suggested that microfracture seems to be the best choice for treating articular cartilage defects.

It is a one-step procedure and less expensive than the other treatment methods. Pain levels, function, ability to return-to-sport, cost, and overall failure rates over time were used to compare results.

But your surgeon is the best one to advise you. Some of the treatment choices depend on how much and what type of damage is present. It's a whole different picture if there is any knee instability from ligamentous damage. And your age can make a big difference, too. Younger patients seem to respond better to the osteochondral autologous transplantation (OAT) procedure compared with older adults (30 years old or older).

Reference: Marc R. Safran, MD, and Kenneth Seiber, MD. The Evidence for Surgical Repair of Articular Cartilate in the Knee. In Journal of the American Academy of Orthopaedic Surgeons. May 2010. Vol. 18. No. 5. Pp. 259-266.