The treatment has become so popular that patients with orthopedic injuries are demanding it, willing to pay $1,000 or more out of their own pocket. Its appeal only soared higher when professional athletes like Tiger Woods and the football players Troy Polamalu and Hines Ward reported that it cured them.  It is a new procedure, based on an idea that once seemed revolutionary: Inject people with their own blood, concentrated so it is mostly platelets, the tiny colorless bodies that release substances that help repair tissues.  Soon the treatment, platelet-rich plasma, or P.R.P., was extended to so many uses  treating muscle sprains and tendon pulls and tears, arthritis, bone fractures and surgical wounds  that Dr. Bruce Reider, editor of The American Journal of Sports Medicine, said in a recent editorial that perhaps it should be called “platelet-rich panacea.”  Thousands of doctors and about 500 hospitals are offering the treatment, said Frank Stephenson, vice president for marketing and sales of Harvest Technologies, among several companies selling equipment for concentrating blood platelets.  Now, though, the first rigorous study asking whether the platelet injections actually work finds they are no more effective than saltwater. The study, reported in the Jan. 13 issue of The Journal of the American Medical Association, involved people with injured Achilles’ tendons, fibrous tissue that connects the calf to the heel bone.  “We are sorry for the patients,” Johannes Tol, the lead researcher and a professor of orthopedic research at the Hague Medical Center in the Netherlands, said in an interview this week. “There still is no good treatment.”  Achilles’ tendon injuries are among the hardest to treat; fewer than half of patients are pain-free a year after the injury, Dr. Tol said.  But Dr. Tol and others say it is too soon to write off the platelet injections. The injections may have different effects on different injuries, they suggest, or there may be techniques that make the injections more effective.  And another study, to be published next month in The American Journal of Sports Medicine, concludes that platelet injections may help tennis elbow, a degeneration of the tendons attaching the forearm muscles on the outside of the arm to the elbow. But some say that study had a design flaw that leads them to question its conclusions.  “The underlying rationale for P.R.P. makes sense,” said Dr. Scott A. Rodeo, an orthopedist at the Hospital for Special Surgery in New York and author of a review of the treatment. But, Dr. Rodeo added, “We don’t know the most fundamental things about the causes of tendinopathy,” the degenerative changes in tendons underlying many injuries.  Insurers generally decline to pay for the injections. But patients, eager for relief, have paid $1,000 or more for an injection; some even get a second or third.  Tendon disorders, the focus of the two new studies, account for as many as half of sports injuries. Distance runners, Dr. Tol reports, have a 52 percent chance of tendon injury. Tendons heal slowly, if at all, and may keep people away from their sport for long periods.  In their study, Dr. Tol, Dr. Robert J. de Vos of the Hague Medical Center and colleagues recruited 54 people with Achilles’ tendons that had been hurting at least two months. On average, they had symptoms for more than six months and had stopped doing their sport for three months.  The participants were randomly assigned to have an injection of platelets or saline. They also were instructed to use the only treatment shown to be at all effective: eccentric contraction exercises  in this case, standing on a step and lowering the heel, which they were to do 180 times a day.  Six months later, patients in both groups had improved. Their pain was an average of 20 points less on a 100 point scale. Two-thirds to three-quarters had returned to their sport. But there was no difference between saline and the platelet injections.  The other study, of tennis elbow, compared platelet injections with injections of a steroid. After three months, patients who had a steroid injection reported less pain and disability than those who had platelets. Then patients who had received steroids started doing worse. Six months after the study began, those who had gotten platelet injections were better off.  “We not only proved that P.R.P. gives better results, but we proved that steroids did not change pain and disability,” said Dr. Taco Gosens, an orthopedic surgeon at St. Elisabeth Hospital in Tilberg, the Netherlands, who conducted the study.  But Dr. Freddie H. Fu, an orthopedist at the University of Pittsburgh Medical Center, said the study stacked the deck in favor of platelet injections. Steroid injections temporarily soothe pain but slow healing, Dr. Fu said. In the end, patients getting steroids were worse than if they had received no treatment.  Although 73 percent of patients given platelet injections improved after a year, compared with 54 percent for steroid injections, Dr. Fu said that was not much success. “Any time you touch a patient, you get 70 percent success,” he said, adding that even placebos give that rate over time.  Dr. Gosens said it would have been ethically difficult to ask patients to be randomly assigned to a treatment that might include a saline injection because steroid injections are a standard of care. He also said the difference in the two studies might be traced to the difference in the tendons. The Achilles’ tendon gets almost no blood, making healing more difficult, as compared with the smaller elbow tendon.  Meanwhile, researchers are asking fundamental questions: Should injections be done immediately or after time has passed? Do the injected platelets quickly diffuse? If so, can they be held in place? How long should they stay in the injured area? Do people need more than one injection?  Research now under way includes a study by Dr. Gosens of plantar fasciitis, heel pain caused by damage to tissue connecting the heel to the toes. Another center in the Netherlands is studying knee tendon injuries. Dr. Rodeo is studying platelet injections during surgery to repair rotator cuff tendons in the shoulder. And researchers like Dr. Rodeo and Dr. Tol are doing more basic research on the biology of platelet injections.  In the meantime, Dr. Tol said, doctors in the Netherlands, who learned about the two studies at a recent conference, are starting to turn away from the platelet injections.  As for Dr. Fu, he said he was keeping an open mind but still did not offer platelet injections. “I just do not have the heart to ask patients to pay for an unproven therapy,” he said.
A rigorous study found that a procedure known as platelet-rich plasma and used to treat orthopedic injuries was no more effective than salt water injections.