What makes recommendations for regenerative therapies such as platelet-rich plasma (PRP) inexact is that these approaches are based in biology, not chemistry, said Lisa A. Fortier, DVM, PhD, Dipl. ACVS, of Cornell. Each preparation is just as variable and unique as one horse is to the next. Recognizing this can go a long way in setting clients’ expectations for treatment success using these therapies and also in understanding the controversy that surrounds the best ways to use them. All veterinarians can do for the moment is choose cases carefully, extrapolate from current evidence when formulating treatment plans, and be sure to use traditional rehabilitation techniques as well.

“These are not drugs, they are not perfect, and they are not going to work when all of your other approaches fail,” said Fortier, who is professor of large animal surgery at the university’s vet school, in Ithaca, New York. She summarized current research on PRP and what she’s learned using it at the 2014 American Association of Equine Practitioners Convention, held Dec. 6-10 in Salt Lake City, Utah.

The “tremendous degree of variability” among PRP preparations has to do with platelet and leukocyte (a type of specialized white blood cell that aids in healing) concentrations. Current evidence suggests that PRP preparations with platelet concentrations two- to fourfold over what’s found in blood and low numbers of leukocytes are optimal for increased tissue repair.

Veterinarians initially used PRP for treating tendons and ligament injuries, but Fortier said there is now evidence it can help heal joint injuries as well. Research