There’s yet another new entry into the lameness treatment field. This one is a preparation that’s made from the horse’s own blood (as is IRAP), and, like most things, it comes with a lot of “promise” but very little in the way of good evidence. It’s the latest thing: it has been performed a good bit in human athletes, too. It is known as Platelet-Rich Plasma (PRP).
Platelets are the cells that help plug up blood vessels when horses start to bleed. But platelets also contain numerous growth factors, substances in the body that stimulate cell growth. Because of these factors, the sports medicine and athletic communities have looked at PRP, and other, similar products, as a way to potentially help healing There is increasing interest in the sports medicine and athletic community about providing endogenous growth factors directly to the injury site, using autologous blood products such as PRP, to potentially help speed up healing of tendon and ligament injuries (which are notoriously slow to heal), and help get horses back to work faster, and with better outcomes (it’s the same rationale as is used for stem cells).
PRP is obtained by spinning whole blood down in a tube. When you do that, you concentrate the cells at the bottom of the tube – the heavier cells pack into the bottom, below the lighter liquid portion of the blood. The PRP has a higher concentration of platelets in it than does whole blood.
It all sounds great. But, in spite of what-seems-to-be pretty widespread interest, and what seems to be pretty widespread use (especially in human athletes), good evidence that looks at how well the treatment actually works is sorely lacking (in humans AND horses). There’s basic science that’s been done, and a few animal studies, but the fact is that the few randomized controlled clinical trials (RCTs – the “gold standard” of scientific research) that have looked at the effectiveness of PRP injections have all failed to show that PRP injections are actually effective.
When it comes to PRP injections, the cart is very far out in front of the horse. Good trials need to be conducted before people start paying large amounts of money for a treatment that hasn’t been shown to do anything. Veterinarians need to know about which injuries may benefit, the effectiveness, and the safety of PRP. And that’s not all:
1) Nobody knows what the “right” volume of injection is
2) Nobody knows what (if any) is the most effective preparation (there are several ways to make the product)
4) Nobody knows the optimum timing of the injections in relation to the time of injury
5) Nobody knows if 1 PRP injection is enough, or if a series of injections would be better
6) Nobody knows the most effective rehabilitation protocol to use after PRP injection.
With PRP, you have a treatment of unknown benefits, and a sure cost. There’s not currently any indication that PRP injections offer any benefits over a good rehabilitation program. Fortunately, based on the few publications out there, the risks of PRP injections seem to be very low, however, the benefits
remain unproven at this point in time.
No therapy is completely successful, and all carry some degree of risk. However, personally, I think that medicine should be more than, “You pays your money and you takes your chances.” Currently, with PRP, you’re paying for a lot of promise, but no actual demonstrable results.