PREMIER ORTHOPAEDICS-Cartilage Implant Surgery

Cartilage Implant Surgery Brings
Life Back to "Old" Knees
Article courtesy of South Jersey Health System "Family and Friends", Spring 2000 Edition

Cartilage - It's smooth as silk, stronger than steel and the secret to properly functioning pain-free joints in the human body. Unfortunately, it is not indestructible.

In the knee joint, cartilage - articular cartilage to be precise - covers the ends of the femur and tibia that, along with the patella (knee cap), form the knee joint. Without the protection provided by this thin layer of cartilage, the femur and tibia would mercilessly scrape against one another, destroying the joint in the process.

In fact, this occurs in varying degrees when cartilage is damaged from injury or repetitive use, or when a congenital defect exists, explained Thomas Dwyer, M.D., a board certified orthopedic surgeon with fellowship training in Sports Medicine. Dr Dwyer's experience with athletics also includes a year spent working with the Pittsburgh Steelers. He joined the SJH Medical Staff in 1996

"Until recently, orthopedic surgeons basically had one option - knee replacement", explained Dr. Dwyer.

"Now, we have an exciting new procedure that involves taking cartilage cells from the patient, growing them in a laboratory and implanting them back into the knee.

"Cartilage is just one of many extraordinary materials found in the human body. Medical science hasn't even come close to producing a synthetic material with its tremendous strength and friction-fighting ability," said Dr. Dwyer.

For many patients under age 50, the cartilage implantation procedure offers many benefits over traditional joint replacement.

Dr. Dwyer explains, "The procedure is less invasive, there are fewer complications and, most importantly, early indications lead us to believe that cartilage replacement will avoid the necessity of an artificial knee joint. Even with the best artificial knee, an active person can wear it out in five years."

In contrast, doctors are hopeful that cartilage implantation will last for decades and perhaps a lifetime.

Although the ability to culture certain types of cells has existed for a long time, cartilage cells have only been propagated in laboratories for about a decade. The first implantation procedure of cultured articular cartilage into a human knee was performed about 10 years ago in Sweden.

"We have pretty good data for up to four years post implantation," said Dr. Dwyer. "A majority of these patients are still pain free and there are no signs of rejection or other complications."

The actual process involves two surgical procedures. First, a minor outpatient procedure is used to harvest the patient's cartilage cells. Guided by an arthroscope (a flexible fiber optic tube equipped with a miniature video camera) the surgeon removes microscopic cartilage cells with a curette-like surgical tool. The sample is then prepared for shipment and sent to a lab in Boston. Under strictly controlled conditions, the cells are then cultured, or grown, until enough cartilage is formed to fill the defect. This usually take about four weeks.

After receiving the cartilage back from the lab, the surgeon performs the second procedure. This involves implanting the cartilage into the damaged area and covering the defect with a thin circular piece of periosteum (a thin membrane that covers the non-joint areas of bones), which is taken from the patient's shin bone. This procedure requires a one-night stay in the hospital.

The final step is an aggressive rehabilitation program designed to help the patient regain lost function and to minimize the risk of further injury to the knee. It takes approximately one year for the cartilage to fully integrate into the bone.

Dr. Dwyer received special training for this procedure while working with the Pittsburgh Steelers and was the first surgeon in the region to perform this state-of-the art technique.

He is hopeful that cartilage implantation will soon be approved for other joints such as the ankle and shoulder as well as for larger defects. Currently, only defects smaller than a 50-cent peice are approved for the procedure.

"This procedure is revolutionizing the treatment of cartilage damage," said Dr. Dwyer. "We now have a very effective procedure that can help many younger people return to an active pain-free lifestyle

	STEP 1- An Arthroscopic Biopsy First, the surgeon examines your knee through an arthroscope - a small device that allows the doctor to see into your knee joint. If a lesion is detected, a tiny biopsy of healthy cartilage tissue will be removed
STEP 2 - Cell Culture Processing The cartilage sample is then sent to Genzyme Tissue Repair (GTR), where it is cultured. Cell culturing takes about 4-5 weeks, during which time your cells multiply significantly. About 12 million cells will be supplied to your surgeon at the time of your operation.
	STEP 3 A surgical procedure is performed, and the damaged cartilage is removed
STEP 4 Periosteum, a skin that covers the bone, is sutured over the prepared defect.
	STEP 5 - Surgical Implantation The cultured cells are then implanted into the lesion. Here, the cells may continue to multiply and integrate with surrounding cartilage. With time, the cells will mature and fill in the lesion with hyaline cartilage.
Illustrations courtesy of Genzyme Tissue Repair