What is platelet-rich plasma therapy?
PRP therapy involves the removal of a couple of tablespoons of blood from a patient who has a soft-tissue injury. The blood is spun in a centrifuge, which leaves a highly concentrated sample of platelets. These platelets contain proteins known as growth factors, which promote cell growth and, thus, are beneficial to areas that normally are slow to heal, such as tendons. The platelets are then injected directly into the injury. The process takes about an hour.
That part of PRP therapy is pretty much standard. But there are other differences that could explain divergent results in the studies.
"There are a lot of controversies about this," Johnson says. "No one knows exactly how to use it. No one knows what the protocol is.
"I was in Europe last year. Some people use it every week for three weeks, some people use it two times for five weeks. (There are differences in) how to deliver it. Some add calcium to it — the addition of calcium is probably one of the major controversial points."
PRP therapy has been used in several areas, according to Johnson's paper, from implantology to vascular ulcers. But in recent years it has become popular in the field of sports medicine and arthroscopy.
"The Spanish were the first to start this," Johnson explains, "with dental surgeons who would use this to improve the healing of bone graft procedures that were done with implants in the jaw. They started that 15, maybe 20 years ago. They have a long history of it."
More recently, amateur and professional athletes have been drawn to the therapy. Tiger Woods was reported to have undergone the treatment during his 2009 recovery from knee surgery. Perhaps the biggest boost came in last year's Super Bowl, in which Pittsburgh receiver Hines Ward was able to play only two weeks after suffering a sprained medial collateral ligament in his right knee. PRP treatment was credited with speeding his healing.
"It became a very hot item when Hines Ward used it," says Dr. Anthony Lavenda, an orthopedic surgeon with the Lakeshore Bone and Joint Institute, headquartered in Chesterton, Ind. "So patients started asking me about it more and more. Who's to say whether it helped (the Steelers) win the Super Bowl, but it definitely got (the procedure) exposure."
Lavenda says that when patients express an interest in the therapy, he gives them information and suggests they do additional research on their own. Many of his patients are runners, he says, who suffer from patella tendinitis or Achilles tendinitis.
"With that, it's rest or change your activities, and they don't want to change," he says. "So a lot of them are willing to do whatever it takes to continue to do the sport they love."
He himself has used the treatment. He has tennis elbow in both elbows — not from tennis, he explains, but from working out and from his orthopedic work — and has had cortisone injections. He had a PRP treatment in his left elbow, but not his right.
"My left one has not bothered me at all; the right one still bothers me occasionally," he says. "I haven't done the other injection, but I'm considering it."
Some eyebrows were raised in January when the Journal of the American Medical Association reported that platelet-rich plasma therapy, which over the last couple of years has been promoted as a promising treatment for tendon, ligament, muscle and joint injuries, had failed a key test.
The JAMA article cited a Dutch study of patients with chronic Achilles tendinopathy. It found that PRP therapy was no better than a placebo, raising questions about the procedure's effectiveness.
But a month later came a review article in the Journal of Arthroscopy, which cited other studies that seemed to contradict the first. And since then there have been other studies that support PRP therapy. So it remains a topic of discussion — and considerable interest.
"Just about everybody else I know is doing a study on this stuff," says Dr. Don Johnson of the Department of Orthopaedic Surgery at the University of Ottawa, who co-wrote the Journal of Arthroscopy article. "Everybody is interested in PRP, and there has been a lot of misinformation, so what we tried to do was gather what is known about PRP, what studies have been done that we felt were good studies. It's called a systematic review of the literature available."
Then in March, four new studies were presented at the annual meeting of the American Academy of Orthopaedic Surgeons in New Orleans. Three showed promising results — in the treatment of knee injuries, chronic tennis elbow and chronic Achilles tendinitis. The fourth found it did not significantly affect pain management in arthroscopic rotator cuff repair.
And even the lead author of the Dutch study says there may be something to PRP therapy.
"This negative result does not write off platelet injections altogether because the therapy could have different effects on different injuries," wrote Dr. Johannes Tol. "Indeed, studies are currently under way to assess the effectiveness of PRP for treating knee, rotator cuff tendon injuries and plantar fasciitis."