The PRP Question.

Platelet-rich plasma (PRP) has been a focus of researchers and clinicians for quite some time with mixed results reported. From stunning laboratory animal success to disappointing clinical studies, a clear picture has not emerged.[2] Yet, the enthusiasm for cell-based therapies is understandable. The potential to unlock a magic array of growth factors from readily available cell sources generates excitement for those treating injuries and musculoskeletal degeneration or performing surgical procedures. Added pressure to use these preparations comes from the public that is well aware of PRP’s potential because of reports like that on the front page of a New York newspaper detailing the miraculous recovery of a Pittsburgh Steeler before the 2009 Super Bowl.[6] Unfortunately, moving the positive developments from laboratory animals and Petri dishes to the patient is a daunting, complex transformation.

Consequently, the need for well-designed PRP translational research has never been more apparent. When moving from the easily controlled environs of the laboratory, the magnitude of the challenge expands. Patients come in all shapes, sizes, and ages. Their medical complexities highlight the challenges of streamlining an environment for a clinical trial. Controlling the multitude of human factors and variables appears almost impossible at times. It takes a monumental effort, usually by an experienced skilled research team, to design a trial that can often only answer one clinical question: Can the therapy improve a patient’s status when confounding variables are controlled?

My hat is off to those who accept the challenge, design a trial, and begin the task of securing funding. The review process for clinical research studies at the federal level is daunting. The time, effort, and commitment are staggering—much more than what most outside of research realize. So, it is no surprise that modern medicine is not as evidence based as most leaders in medical care would like to see. The paucity of properly designed randomized clinical trials is certainly understandable given the resources and effort needed to bring them to fruition.

So, in today’s world, short of randomized clinical trial–generated Level I evidence, practitioners often rely on the best evidence available. This is where a good clinician is invaluable: one who is able to balance the needs of patients with the risks and potential of new therapies. Too often this step is undervalued. This is where knowledge, practical experience, and ethics should merge for patient care. Unfortunately, this is also where the dark side of medicine can appear. Subjecting patients to unproven therapies unnecessarily or failing to balance the risk:benefit ratio because of financial incentives should not happen, but does. Clinicians must always remember their pledge to “do no harm.” When clinicians lose sight of what’s best for the patient, the health care delivery system is harmed, and these events encourage government agency intrusion into the practice of medicine to protect the public. While the regulatory role of the Food and Drug Administration has a place in our medical delivery system, it must not distort the patient-physician relationship that is the basis for modern medicine.

Two initial studies set the stage for the frenzy that now surrounds PRP in sports medicine. The 2006 study by Mishra and Palvelko[4] with resistant elbow tendinosis and the Achilles surgical repair report by Sanchez et al[5] highlighted the potential of these preparations. Consequently, PRP is being added to the treatment protocol for many surgical and nonsurgical problems that involve muscle, tendon, ligament, and bone.

One of the most recent targets of PRP treatment has been the ubiquitous problem of early osteoarthrosis (OA) after joint injury, especially in athletic joint injury. The study by Gobbi et al[3] is an excellent example of the clinical evaluation process in working order: a credible research team with an exciting intervention tackling a daunting, expanding clinical problem—osteoarthritis. As the authors clearly point out, it is not a perfect study because of its limitations: mainly, no control group. The lack of a control group makes it difficult to put this study into perspective. Without a control group of OA patients in the same environment, it is hard to know how much better this PRP treatment was than the natural history of OA. Even so, it’s difficult to dismiss the 6- and 12-month improvement seen in the Knee injury and Osteoarthritis Outcome Score, International Knee Documentation Committee, and Marx scores for males and females, with or without surgery. Similar results were reported very recently in a Level II evidence study by Filardo et al[1] of 144 symptomatic patients treated with 3 PRP injections. Prospective follow-up at 2, 6, and 12 months showed significant clinical improvements.

Are these results too good to be true? I hope not, but we can’t simply rely on this level of proof to justify large-scale inclusion of PRP into OA treatment protocols. These authors did a reasonable job of “translating” the process of clinical research further down the road. We clearly need larger, better-designed studies with adequate controls to fully answer the question of where this sits in the treatment of OA. Level I and II studies can supply better clinical information to help decide if and when PRP has a role in the treatment of OA. Scientific methods of investigation should always be the cornerstone of our research efforts. Balance of the risk:benefit ratios for those in dire straits is frequently difficult because of the “slippery slope” on which many lie. Throughout this process, we must be willing to divulge any potential conflicts to our research endeavors. We are human and capable of bias and poor judgment. If, however, we are transparent in our efforts, others will be capable of fairly judging our work. As physicians, if we don’t follow these principles in deciding treatment protocols, we can expect the decision making to be taken out of our hands. That would be a sad day for modern medicine!