Scientific evidence may be lacking, but many swear by injections

SEATTLE – Mariners pitcher Cliff Lee isn’t sure how he got the abdominal strain that kept him on the bench early this season.

Was he throwing too hard? Did something rip when he collided with a catcher in spring training?

Likewise, Lee can’t say whether the curious treatment he tried – injecting a therapeutic component of his own blood into the sore spot – accelerated his recovery.

“It seemed like it should help, but who really knows?” said the 2008 American League Cy Young Award winner.

The scientific evidence to support the treatment, called platelet-rich plasma, or PRP, is equally ambiguous.

But that hasn’t kept athletes, both amateur and pro, from clamoring for it. And while some doctors advise caution, others now rely on PRP as one of their main tools to treat patients with stubborn tendon and joint pain.

“We’ve had some amazing successes with it, and we’ve had some people who haven’t gotten better,” said University of Washington sports-medicine specialist Dr. Kim Harmon, who estimates she and her colleagues have administered at least 400 of the injections.

Demand is fueled partly by the examples of high-profile athletes, such as golfer Tiger Woods and Pittsburgh Steelers wide receiver Hines Ward, who both used it for knee problems. Other drivers are the desperation of folks hobbled by their fraying infrastructure, and the frustration of doctors with few other options to offer.

Enthusiasm has so outpaced research that an editorial in the American Journal of Sports Medicine warned PRP has been “elevated to the level of platelet-rich panacea.” Even the cost, which can range from $800 to $1,200 or more and isn’t covered by most insurance, hasn’t proved much of a deterrent.

With a $9 million salary, price was no object for Lee. His goal was to return to the mound as quickly as possible. So when team doctor Ed Khalfayan suggested PRP, Lee did some research and decided it was worth a shot.

“In professional baseball, if you can cut recovery time from three weeks to two-and-a-half weeks, that’s a big deal,” he said.

Spinning blood

In the treatment, a couple of tablespoons of the patient’s blood are spun in a centrifuge to separate out tiny cells called platelets. Best known for their role in blood clotting, platelets also contain dozens of growth factors and other substances that help clear away dead tissue, patch up damaged areas and attract other repair cells to a wound.

In theory, injected platelets should foster, and perhaps speed, healing. The boost could be particularly helpful in tendons and ligaments, which have a poor blood supply and are often slow to mend, Harmon said.

And few side effects are likely from a treatment that simply taps the body’s own healing cells.

Because PRP can contain small amounts of human growth hormones, the International Olympic Committee is investigating whether it might unfairly boost performance. There are no rules against it in professional sports.

The use of PRP dates back nearly 20 years, first to treat injured racehorses, then later to speed bone healing in people who had oral surgery. There’s a wealth of evidence from test-tube and animal experiments that platelet injections can spur collagen production, strengthen tendons and help orchestrate the many steps involved in healing.

But results are mixed from the few rigorous studies in humans. In one of the first, Dutch scientists found PRP no more effective than saline shots at relieving Achilles tendon pain.

Another study concluded that patients treated with PRP for tennis elbow did better than patients who got cortisone shots.

“We really need to figure out if it truly translates into functional improvement,” said UW’s Dr. Brian Krabak, who served as a physician for the 2010 Winter Olympics in Vancouver, B.C.

Lots of research is under way, said Dr. Allan Mishra, adjunct assistant professor of orthopedics at Stanford University. A pioneer in the use of PRP for sports injuries, Mishra is convinced it works, but acknowledges that little is known about the mechanism, which patients might benefit most, or the optimum treatment regimen.

“We are at the very beginning of understanding where this is best applied,” he said.

Best as last resort

For now, PRP seems most appropriate for people with persistent tendon problems who have tried everything else, said Mishra and Harmon.

People like Tony Dodson. The 44-year-old Bellevue firefighter was dogged by a tight hamstring that cramped his training for Ironman triathlons – the kind where the marathon is but a third of the race.

Physical therapy didn’t help, nor did a regimen of muscle-lengthening exercises. He had his hamstring poked with a needle, which is sometimes enough to spark healing. Even an injection of his own whole blood, a similar treatment to PRP, yielded no improvement.

But after receiving two PRP injections from Harmon, Dodson is back at full strength and getting ready for Ironman Canada this summer. “I’ve never had a problem since,” he said.

Dodson has no doubt PRP made the difference.

But it’s easy for medicine to be misled by anecdotes and fads, said Dr. Christopher Wahl, a University of Washington orthopedic surgeon. Several years ago, something called bone morphogenetic proteins, or BMPs, were all the rage. Growth factors that direct stem cells to form bone or cartilage, BMPs were being used for all manner of bone, joint and sports injuries.

“For anything and everything, there was somebody sticking in a needle to inject BMP,” Wahl said. But the promise didn’t pan out. In the long run, BMPs proved useful for only a few specialized applications, such as complex fractures.

Another craze, heating injured shoulder joints to tighten loose ligaments, was abandoned when it became clear it was doing more harm than good.

PRP may have unanticipated side effects, too, Wahl cautioned. In addition to healing factors, platelets can release substances that foster formation of scar tissue.

When he operated recently on the knee of a patient whose PRP treatments hadn’t helped, Wahl said, he found a rock-hard tendon encased in scar tissue. It’s just a single case, with no evidence of cause-and-effect, but Wahl finds it worrying.

There’s also money at stake, for the companies that make the equipment used in PRP treatments and for the doctors who administer the shots.

“The cynical side of me thinks that if there weren’t some profit motive in this, there would be a lot less enthusiasm,” Wahl said.

But Mishra pointed out that physical therapy can easily cost $2,000 or more. The price of surgery to repair damaged tendons or ligaments ranges from $10,000 to $15,000, and success is not guaranteed.

If PRP proves beneficial, it’s likely insurance companies will encourage patients to try it first, he said.

“This may be one novel therapy that may be better and potentially cheaper than the alternatives.”