Platelet-Rich Plasma Therapy: Much Ado about Nothing?

Platelet-rich plasma (PRP) therapy became a hot topic among professional and recreational athletes after some studies suggested it could hasten wound healing and several high-profile athletes reported using it as they rehabbed from various injuries.  But recently, the news hasn’t been quite so good. For those not in the know, let’s do a quick review of the subject.

PRP therapy involves extracting and centrifuging a person’s blood to create a concentrated broth of growth factors and white cells, and then then injecting the stew directly into injured tissue. The growth factors supposedly promote healing.

PRP therapy has been used for numerous conditions including tennis elbow and pulls, sprains and strains of dozens of different muscles, tendons and whatnot.

The treatment became buzzworthy after animal studies showed that it fostered collagen and new blood vessel formation in the tendons of animals that had been surgically injured by scientists.

The buzz grew after reports surfaced that Tiger Woods used PRP therapy to treat a sore knee, NFL player Chris Canty used it for a hamstring injury, and itinerant MLB pitcher Cliff Lee used it for an abdominal strain. After these high-profile athletes claimed to be satisfied with the results, recreational athletes began demanding PRP therapy for themselves, even though it cost $1,000 per shot and isn’t covered by most insurance plans.

Alas, recent scientific studies of PRP therapy should dampen that enthusiasm, at least a bit. It just doesn’t seem to work in humans with overuse injuries and strains, according to these studies.

This month for example, S. de Jonge and colleagues at Erasmus University (Rotterdam) published one-year follow-up data on their placebo-controlled trial of PRP therapy for Achilles tendinopathy. Their original report showed no benefits at 6 months, and the extended follow-up showed the same thing (no benefit). de Jonge’s group concluded there is “no evidence for the use of platelet-rich plasma” therapy in this particular condition.

A second paper by Leon Creaney and colleagues, which is in the publication queue at the British Journal of Sports Medicine, reportedly found that PRP therapy was not more effective (indeed, it was quite possibly less effective) than injections of un-centrifuged blood for the treatment of tennis elbow.

How do we reconcile the outcomes of the favorable animal studies with those from the human trials, which were negative? One theory is that the animal studies involved acute injuries, which provoke a vigorous inflammatory response that may well be enhanced by PRP therapy. By contrast, overuse injuries, strains, sprains and pulled muscles provoke a less robust response. PRP therapy seems unable to enhance the healing process in such instances. Of course, it may also be the case that animals just respond differently to PRP therapy than humans.

In any case, it’s clear that scientists don’t yet understand the mechanisms by which PRP therapy works, if and when it does. This uncertainty has prompted the International Olympic Committee to issue the following note of caution regarding PRP therapy: “We believe more work on the basic science needs to be undertaken,” and until such work is complete, athletes should “proceed with caution in the use of” PRP therapy for the treatment of sports-related injuries.

Your doctor or trainer knows best, but perhaps good old-fashioned physical therapy and RICE (rest, ice, compression, elevation) is the best way to go.