"We have tried it, and we have some anecdotal evidence that clinically, it doesn't really make much of a difference," said Dr. A. Nick Shamie, an associate clinical professor of orthopaedic surgery at the University of California at Los Angeles.
Shamie and his colleagues injected the PRP treatment in spinal fusion surgery patients, but didn't find much of a difference in the patients' ability to regenerate bone.
"There are so many factors that help [the] healing of tissues, that PRP cannot be held responsible for all," Shamie said.
In a previous study, Shamie and his colleagues tested different chemical secretions in the body -- including the platelet-derived growth factors that "turn on" cells. Of everything they tested, only a protein called BMP, or bone morphogenetic protein, jump-started regenerative bone growth.
"This BMP tells cells that haven't decided what they want to become, to become cells that are cartilage or bone," he said.
But that's not to say the plasma injections may not jump-start healing in other injuries, or for other tissues.
"There's a big difference in making a protein grow more tissue in petri dishes and healing in humans," he said.
More studies of blood plasma injections in humans may tell the difference.