Cartilage Restoration: Knee Renewal Instead of Replacement

When you cut yourself or break a bone, your body immediately works to heal that injury, sending nutrients through the bloodstream to repair and restore the damaged tissue. But if your cartilage is damaged, you’re out of luck. This soft, flexible tissue that cushions the joints has no direct blood supply and thus little ability to heal itself.

Cartilage is the smooth protective covering lining the ends of the bones at the joints, and is very important within the knee joint, particularly. "Normally, cartilage acts as an effective shock absorber, tough enough to survive both the wear and tear of daily activities and high level sports,” explains Dr. Steven Hale, orthopaedic specialist with Center for Orthopaedics. "It has an extremely low friction surface that enables the knee to bend and move easily and painlessly.”

However, cartilage can become damaged through injury or as a result of the wear and tear that occurs over years, according to Dr. Hale. "A traumatic injury, such as falling and twisting your knee, usually causes a more localized type of cartilage injury. Damage due to wear and tear, otherwise known as degenerative arthritis, or osteoarthritis, occurs over a lifetime. In many cases, it may start as a localized area of damage, but progress to involve larger areas of cartilage damage, leading to further wearing away of cartilage, bone damage and painful movement.”

Dr. Hale says articular cartilage defects, small areas of injury, have been notoriously difficult to treat, and can lead to persistent pain in an otherwise healthy knee. "We know that if we can treat these types of small defects successfully, we can prevent more extensive damage from occurring within the joint, which could require more complex procedures to restore pain-free movement, such as a joint replacement. "

"A good way to think about cartilage restoration is to compare the injured cartilage surface to a damaged road,” says Dr. Hale. "If the road is completely damaged all the way across, the best way to fix it is to clear out all the damage and replace it with a completely new surface. If the injury is just a small pothole, then that one spot can be repaired. In the knee, our goal is to mimic this same approach to successfully repair small cartilage defects whenever possible. New innovative technology is allowing us to do this with more and more success.”

Microfracture has long been the traditional treatment for cartilage defects, according to Dr. Hale. This procedure allows the body’s own bone marrow stem cells to "fill-in” a defect, producing a scar tissue patch. This effectively repairs the damaged site and aids in protecting the adjacent cartilage from progressive damage. The surgeon creates small holes into the bone underneath the damaged cartilage in order to allow blood and marrow healing elements into the area of missing cartilage. However, while scar tissue, called fibrocartilage, fills the area where the cartilage is missing, it does not have the same strength and resiliency as normal articular cartilage. Fibrocartilage does not usually stand up over time and typically wears down after a few years, and may require a repeat procedure.

Over the past decade, new techniques have been developed to improve upon microfracture, allowing doctors to renew and restore healthy cartilage. Center for Orthopaedics’ physicians have been involved in multiple FDA Phase II clinical trials to evaluate various restoration techniques and Dr. Hale says the results are very positive.

"Biocartilage grafting is one technique that we are using with a great deal of success,” says Dr. Hale. "It is used in conjunction with traditional microfracture, but instead of a repair based only on fibrocartilage growth, we are able to generate the growth of real articular cartilage by implanting a paste of micronized allograft dehydrated cartilage mixed with platelet-rich plasma into the small microfracture openings. This approach has been shown to improve the strength and stability of the regenerate cartilage.”

Dr. Hale says Biocartilage is just one of numerous new cartilage restoration techniques that are dramatically improving the treatment of cartilage defects. "This is a rapidly evolving field so the data available only goes back several years, but the results are very promising and give us more options to offer our patients than ever before. The technology is very exciting and basically allows us to harness the body’s ability to heal itself in new ways.”