Platelet-rich plasma injection “no more effective than saltwater”

Well, this was probably inevitable.

Last summer a reader asked me what I think of platelet-rich plasma (PRP) injections — the injection of a concentrated preparation of your own blood into irritated tissue, usually a tendinitis or similar condition like iliotibial band syndrome or plantar fasciitis — to stimulate healing. I replied quite optimistically at the time:

Incredibly, I have no strong objection to PRP. This is rare! I am a grump and not easily impressed. The huge majority of therapies I get asked about strike me as mostly pointless shots in the dark. By contrast, PRP injections seem like they have a reasonable rationale, there’s a bunch of promising evidence, and they are quite unlikely to have any significant risks. Wow. Cool.

Of course, I would caution you against singing its praises: there’s a huge gap between “promising” and “proven.” If it works for you, great! But don’t promote it as a treatment that “works” — one experience means nothing. For all we know, future research will show significant problems and limitations. This is precisely what has happened with countless other therapies.

And that is precisely what just happened to PRP, only a few months later. Yesterday, the New York Times reported bad science news for platelet-rich plasma injection, and I am now once again just as unimpressed by PRP as I am by most other too-good-to-be-true treatments:

Now, though, the first rigorous study asking whether the platelet injections actually work finds they are no more effective than saltwater.

So another treatment bites the dust. I don’t want to completely dismiss a treatment like PRP just because one good study was clearly negative, but the results immediately and seriously afflict PRP with the how-good-can-it-possibly-be problem — how good can it be if it fails the best testing so far? Initially promising in many ways, PRP will now undoubtedly now be mired in years of controversy. Wait and see, check the evidence in five years: it will be a mess of contradictions and no clear answers. PRP will probably die a slow death, only beaten into submission over many years by a growing pile of underwhelming evidence, even as its proponents continue to overconfidently sell the service.

• “Platelet-Rich Plasma Injection for Chronic Achilles Tendinopathy: A Randomized Controlled Trial,” an article in Journal of the American Medical Association, 2010.
• “A Case Study In Aggressive Quackery Marketing,” a webpage on ScienceBasedMedicine.org.
• “Popular Blood Therapy May Not Work,” a webpage on New York Times.