BACKGROUND: With the ability to bear up to five times a person's weight, the knee is the largest and strongest joint in the body. Regardless of its strength, it is not unsusceptible to damage. Cartilage cells, called chondrocytes, are one of the few types of cells in the body that can survive in areas with low blood supply; however their distance from a blood supply makes it difficult to regenerate after sustaining damage. If left untreated, it can progress to the more serious osteoarthritis, a degenerative disease that gradually breaks down protective cartilage.

More than 800,000 people injure their knees every year. Whether to correct an injury from a sports game or normal wear and tear, approximately 266,000 patients seek knee replacement surgery a year. Older patients turn to this option more often. In the procedure, metal and plastic implants take the place of damaged portions of the knee, mimicking the natural structure of the joint.

REGENERATING NEW CARTILAGE: Instead of knee replacements, physicians are using new cartilage regeneration and transplantation techniques to repair early cartilage damage, potentially helping patients avoid joint replacements. The technique is especially appealing to younger individuals. Today, orthopaedic surgeons are using autologous chondrocyte implantation to fix the damaged articular cartilage that covers the ends of bones. Cartilage tissue is harvested from a patient's own knee and then cultured in a lab in order to produce millions of new cartilage cells. Those cells are then implanted into the damaged areas of the knee, where they can continue to multiply. Prior to this technique, patients would have to wait and deal with their pain, but the new method allows cartilage to regenerate before it degenerates further. For larger defects that involve bone and cartilage loss, an allograft may be necessary. Allografts involve using implants obtained from freshly donated cadaver cartilage and bone. The advantage to this method is that the implant includes both bone and fully developed cartilage. The downside is there may be some risk of infection.

SCALING NEW HEIGHTS: Often knee injuries involve the two menisci, which consist of rough cartilage and rest between the thigh and shin bones. Their job is to distribute body weight across the knee joint. Without the menisci, body weight would be unevenly distributed. Historically, treatment involved removing the entire meniscus; however with the advent of arthoscopy, standard treatment involves removing only damaged cartilage from the knee joint. Today, many orthopaedic surgeons believe the first line of treatment is to attempt to repair it and do so using the implantation method.

FOR MORE INFORMATION, PLEASE CONTACT:
Sharon Butler, Media Relations
Rush University Medical Center
Chicago, IL
(312) 942-7816
Sharon_Butler@rush.edu