Knee Implant

One kind of knee problem is injury or damage to the articular cartilage. The condition may occur from sudden twisting, blunt trauma to the knee or wear and tear of the cartilage. Patients may experience knee pain and swelling, "locking" of the knee or "clicking" sounds during movement. When articular cartilage is damaged, it doesn't heal well. In fact, instead of a repair, the damage is more likely to spread. Eventually, the bones in the joint will start to rub against each other, causing more pain, inflammation, stiffness and loss of joint mobility. Initially, doctors may try conservation measures to treat knee pain from an articular cartilage injury.

Physical therapy and anti-inflammatory medications help to reduce symptoms and provide some healing. If that therapy fails, arthroscopic surgery (through small incisions) may be performed to trim away damaged areas of cartilage.

Another type of treatment is arthroscopic microfracture. Small holes are made into the uncovered areas of bone. This initiates a repair process. Cells from the bone marrow move through the holes and into the area where cartilage has been lost. The cells form a covering that resembles articular cartilage.

Sometimes traditional techniques don't work for patients with articular cartilage defects. Eventually, the damage becomes so severe, osteoarthritis develops and knee replacement may be required. Another technique for repairing articular defects in the knee is Carticel®, or autologous cartilage cell implantation. The procedure uses some of the patient's own cartilage cells to repair the damage and stimulate healing.

Carticel treatment is done through two separate procedures, one to retrieve cells and a second to place them back in. First, a small incision is made into the knee. Then, a small amount of cells are removed from a non-weight bearing, healthy area of the cartilage. The cells are sent to a laboratory where they are processed and placed in a growth medium. Here, they multiply, increasing in number to about 12 million. The cultured cells are then shipped back to the physician for implantation.

In the second stage of Carticel placement, another small incision is made into the knee. The damaged cartilage is removed and the defect is cleaned. A small patch of tissue covering the shin bone (called periosteum) is removed and sutured over the top of the injury site. Then, the cultured cartilage cells are injected under the periosteum patch. The patch forms a water-tight seal and holds the transplanted cells in place. Over time, the new cells will form cartilage that is very similar to normal articular cartilage.

After surgery, patients undergo an aggressive rehabilitation program, starting with the use of a continuous passive motion machine (a device that mechanically bends and straightens the knee) while in recovery. Andrew S. Levy, M.D., an Orthopaedic Surgeon with the Center for Advanced Sports Medicine in Harrison, NJ, says he has seen about a 95 percent success rate with Carticel. For younger, active patients, Carticel may enable them to once again participate in some sports activities and avoid the need for a knee replacement at a young age. For less active or older patients, Carticel can reduce pain, return function and improve quality of life.

Since the procedure uses a patient's own cells, there is no risk of rejection. It can be repeated if other areas of the articular cartilage are damaged. And, if future problems develop, patients can still undergo other types of treatments, including a knee replacement. Carticel is approved for use in patients who have failed other types of arthroscopic or surgical treatments and continue to have symptoms. It is not for patients who have already developed osteoarthritis. In a 2006 study, researchers reported about 3.8 percent of adverse effects associated with Carticel, most notably transplant failure, delamination (separation of layers of tissue) and tissue overgrowth.

For information about Carticel®, or to find a nearby surgeon: http://www.carticel.com/patients