Dr. Nicholas Cappello

Experts in sports medicine say that if the technique’s early promise is fulfilled, it could eventually improve the treatment of stubborn injuries liketennis elbow and knee tendinitis for athletes of all types.

The method, which is strikingly straightforward and easy to perform, centers on injecting portions of a patient’s blood directly into the injured area, which catalyzes the body’s instincts to repair muscle, bone and other tissue. Most enticing, many doctors said, is that the technique appears to help regenerate ligament and tendon fibers, which could shorten rehabilitation time and possibly obviate surgery.

Research into the effects of platelet-rich plasma therapy has accelerated in recent months, with most doctors cautioning that more rigorous studies are necessary before the therapy can emerge as scientifically proven. But many researchers suspect that the procedure could become an increasingly attractive course of treatment for reasons medical and financial.

“It’s a better option for problems that don’t have a great solution — it’s nonsurgical and uses the body’s own cells to help it heal,” said Dr. Allan Mishra, an assistant professor of orthopedics at Stanford University Medical Center and one of the primary researchers in the field. “I think it’s fair to say that platelet-rich plasma has the potential to revolutionize not just sports medicine but all of orthopedics. It needs a lot more study, but we are obligated to pursue this.”

Dr. Neal ElAttrache, the Los Angeles Dodgers’ team physician, used platelet-rich plasma therapy in July on a partially torn ulnar collateral ligament in the throwing elbow of pitcher Takashi Saito. Surgery would have ended Mr. Saito’s season and shelved him for about 10 to 14 months; he instead returned to pitch in the September pennant race without pain.

Platelet-rich plasma is derived by placing a small amount of the patient’s blood in a filtration system or centrifuge that rotates at high speed, separating red blood cells from the platelets that release proteins and other particles involved in the body’s self-healing process, doctors said. A teaspoon or two of the remaining substance is then injected into the damaged area. The high concentration of platelets — from 3 to 10 times that of normal blood — often catalyzes the growth of new soft-tissue or bone cells. Because the substance is injected where blood would rarely go otherwise, it can deliver the healing instincts of platelets without triggering the clotting response for which platelets are typically known.

“This could be a method to stimulate wound healing in areas that are not well-vascularized, like ligaments and tendons,” said Dr. Gerjo van Osch, a researcher in the department of orthopedics at Erasmus University Medical Center in the Netherlands. “I call it a growth-factor cocktail — that’s how I explain it.”

Dr. van Osch and several other experts said they had used the procedure as a first option before surgery for reasons beyond its early results. There is little chance for rejection or allergic reaction because the substance is autologous, meaning it comes from the patient’s own body; the injection carries far less chance for infection than an incision and leaves no scar, and it takes only about 20 minutes, with a considerably shorter recovery time than after surgery.

Because of those apparent benefits, the consensus among doctors is that the procedure is worth pursuing. However, several doctors emphasized that platelet-rich plasma therapy as it stands now appeared ineffective in about 20 to 40 percent of cases, depending on the injury. But they added that because the procedure costs about $2,000 — compared with $10,000 to $15,000 for surgery — they expected that with more refinement, insurance companies would eventually not only authorize the use of PRP therapy but even require it as a first course of treatment.