You may have heard about athletes getting injections that are actually legal these days: Tiger Woods, Rafael Nadal, Kobe Bryant and Troy Polamalu. More and more often, sports medicine's answer to chronic tendon and ligament problems is platelet-rich plasma (PRP) therapy. The procedure takes a small amount of a patient's blood, isolates the platelets and injects the growth factors they release directly into the injured area, where they promote the body's natural healing response.
In the past, when tissues and joints were injured, the common treatment in similar circumstances was a cortisone injection. Cortisone is a steroid that inhibits protein metabolism so inflamed cells that are actively turning over are shut down. This effect reduces swelling and therefore pain.
Unfortunately, it also reduces activity in normal cells and tissues, and leads to weakening of the tissues and occasional tendon ruptures. Joints that are repeatedly injected with cortisone show damage to the articular cartilage surfaces, which protect the ends of bones. Rather than work to actively heal the damaged tissue, a cortisone injection unfortunately only serves to mask the injury, allowing the athlete to continue to play, often causing more damage.
PRP therapy is a promising alternative to cortisone. It is a relatively simple procedure to administer whereby platelets are harvested from a small amount of the patient's own blood. A centrifuge spins the blood so fast that it causes the different cells in the blood to separate, concentrating the platelets and releasing their growth factors. (Platelet growth factors are essential in repairing and regenerating connective tissues, and stimulating the healing process.) Once separated, we can extract the part of the blood with the platelets and growth factors and inject it into the site of the injury, whether it's a ligament, a tendon or an arthritic joint.
The preparations of PRP vary, with some containing white cells, and others containing higher or lower concentrations of growth factors. It remains unclear how great the effect is. Philosophically, however, stimulating tissues to heal makes more sense than inhibiting healing with cortisone.
In our practice, we combine PRP with an injection of hyaluronic acid. HA is the natural lubricant found in joints. The lubricant assists in the natural cartilage repair process, decreasing inflammation and reducing the breakdown of damaged cartilage. This lubricant in concentrated form can be injected into a joint to increase lubrication, rather like oiling a machine.
HA injections contain a synthetic version of this natural lubricant of the joint. The injection is actually absorbed within 24 hours but appears to have a lingering effect of improving lubrication by stimulating the synovial lining cells of the joint to produce more HA. Recent data has been mixed on its effect on arthritis, however. We use this PRP-HA injection for injured joints, joints with arthritis, and after articular cartilage repairs and meniscus replacements.
PRP is not new. It has been used for more than 20 years in dentistry, to speed the healing of reconstructive oral surgeries, and by veterinarians to heal animals. While there was some early fear in the sports world that the injections could be a performance-enhancing substance, the fear seems to have been put to rest.
Major League Baseball, the NFL and the NBA, as well as the World Anti-Doping Agency, have all declared that PRP is a safe and legal treatment. So for now, blood doping with your own platelets is legal, though blood doping with whole blood is not.
Dr. Kevin R. Stone is an orthopedic surgeon at The Stone Clinic and chairman of the Stone Research Foundation in San Francisco. He pioneers advanced orthopedic surgical and rehabilitation techniques to repair, regenerate and replace damaged cartilage and ligaments. For more info, visit www.stoneclinic.com.