Platelet-rich-plasma (PRP) injections have emerged in recent years as a treatment for a variety of sports injuries, ranging from severe tendonitis to muscle tears. As with any new treatment, there are few studies reporting on the effectiveness of PRP, and even those that have been published are debated by experts, leading the American Academy of Orthopaedic Surgeons to the "hottest topic in orthopedics."
As a companion piece to Keith Cronin's excellent article on the use of PRP in which the both sides of the debate about PRP are presented, and based on a point-counterpoint debate conducted via email between the two experts whose views are expressed in Keith's piece, Dr. Nathan Mall, associate physician for the St. Louis Cardinals and Director for the St. Louis Center for Cartilage Restoration and Repair Regeneration Orthopedics , and Andrew M. Blecher MD, a Primary Care Sports Medicine physician and Medical Director of the Center for Rehabilitation Medicine  at the Southern California Orthopedic Institute in Van Nuys, California, here are what Drs. Mall and Blecher have to say about the current state of the research on PRP.
Dr. Mall recently completed researching the topic of PRP injections. Based on that review of the literature, he notes the following:
While he agrees with many of Dr. Mall's general statements about PRP in the companion article, including that it is expensive, not covered by insurance, may not be the most cost-effective first line treatment and is often used when all other conservative treatments fail," and "that much more research needs to be done in order to establish the optimal concentrations, protocols and procedure techniques for the various musculoskeletal indications for which PRP is being used," Dr. Blecher differs in his interpretation of the research studies conducted so far.
"In regards to the current research, Dr Mall states that we have no evidence that PRP works for any musculoskeletal conditions. He cites to studies that have low numbers of patients, don't report platelet concentrations and lack control groups. While I agree that much of the research out there for PRP is less than desirable, I think it important to cite to some studies as a counterpoint which do have large numbers, platelet concentrations and control groups.
He points to research by a Stanford University researcher, Allan K. Mishra, who has studied PRP for years, whose in his most recent published research includes a large multicenter study  involving a host of well-respected orthopedic surgeons around the country who followed 230 patients in a double-blind randomized control study [the gold standard for medical research]. "The study showed with level 1 evidence that PRP was more effective than control for tennis elbow," says Blecher.Another popularly used indication for PRP is knee osteoarthritis (admittedly, not a condition ordinarily found in youth athletes, but to which those who have undergone ACL reconstruction surgery are more prone later in life). Blecher notes that two large prospective studies of PRP vs. control [9,10] have yielded level I and II evidence that PRP is more effective than control for treating the condition.
In response to Dr. Blecher, Dr. Mall emphasized, as previously stated, that of all the PRP data, the best is for lateral epicondylitis. "However, when critically looking at the Mishra article,"  Dr. Mall points to the fact that it found that 37% of PRP patients still had pain compared with 48% of the control group." Dr. Mall also argues that the Mishra study contains "multiple flaws," among them inadequate controls over inclusion of patients whose pain was not controlled by one of three more conservative treatments: NSAIDS, PT, or cortisone. "If someone went to two therapy visits," Mall notes, "then they would have been considered a failure and then would be eligible for the study. Therefore they may have gotten better regardless."
Dr. Mall also observed that only 119 patients were available for follow-up at 24 weeks, which is where the biggest difference was noted. There are many reasons for errors, one of which is not having appropriate follow-up. "Only having 119 of 231 patients follow up basically negates the findings of the study. Most good quality studies require 80% follow-up; the MIshra study only had 51%. Therefore, we have no idea how the other 49% are doing and they may not have followed up because they weren't any better after spending a lot of money on PRP injections."
With respect to the study on baseball pitchers, Dr. Mall observes that it says absolutely nothing about the speed at which these players got back to playing sports, and that, because there was no control group, "we don't know if these kids would have gotten better by simply resting an additional six weeks and then starting a return to throwing program."
"The study by Kon et al, when looked at critically, is simply saying that 3 PRP injections costing $2,400-$5,000 or more is equivalent to hyaluronic acid injection, which is covered by insurance plans. Therefore patients are paying out of pocket to get an equivalent result, I find it difficult to recommend this."
"The study by Patel has multiple errors in the methodology, which are outlined by Fillardo, Giuseppe et al in a letter to the editor of the American Journal of Sports Medicine in September 2013. Plus, the study compares PRP to saline or salt water, so it is basically saying that PRP is better than doing nothing, but not comparing it to standard treatments covered by insurance."
"The key," argues Dr. Mall, "is to look critically at the data, as the study may not really be able to say what the authors are suggesting it does. None of the studies cited prove without a reasonable doubt that PRP works or doesn't work. I am not saying PRP does not have a role, because I do use it in certain situations. However, parents and patients really need to understand that there is no proof that PRP will prevent surgery, relieve their symptoms, or be better than standard treatment options. This is a lot of money to spend for a treatment that has not been proven and I think it is irresponsible to recommend this treatment to patients without a full and upfront discussion that must include that there is still little to no data that show that this will do anything. If Dr. Blecher and other physicians have had such great results with this treatment I would encourage them to publish these results so that we can better educate our patients."
Dr. Blecher offers his final (promise) thoughts:
"As previously stated, I agree that the PRP studies are less than perfect. Despite Dr. Mall's critiques, however, they do show statistically significant improvements with PRP therapy. We could discuss the merits of each study ad infinitum because perfect studies on new treatments rarely occur. But it should be noted that such flawless studies do not exist for many of the alternative treatments that Dr Mall suggests including the benefit of:
In fact, treatments such as physical therapy, steroid injections and even surgery often lack this type of evidence to substantiate their use for many of the indications for which they and PRP are used. I think it is safe to say that we agree that PRP treatment is not a panacea for all musculoskeletal conditions and should be used only in appropriate situations. It is up to each practitioner to synthesize the available evidence and determine how it will affect his or her practice.
I, for one, do find a growing role for PRP in my sports medicine practice. Dr Mall states that he has used it as well, which suggests that he must believe in its potential benefit to some degree. He is not alone. There are a growing number of well-informed patients who have tried and failed other treatments and seek out PRP therapy as an option of last resort. This includes patients who have failed surgery as well.
As with any procedure (surgery and PRP included), it is important that the patient have informed consent as to the potential risks and benefits of the treatment as well as the other treatment options available to them. If a practitioner does not believe enough in the potential benefits of a treatment until it is proven "beyond a reasonable doubt", then they will simply not offer that treatment.
But we should be aware that many of the alternative treatments listed above have not reached that same threshold of proof either and therefore to suggest one over another is somewhat arbitrary, and may just reflect the practitioners relative lack of experience with that particular treatment or may be based solely on cost. Treatments such as corticosteroid injection have never been shown to provide long term benefit and, in fact, have been shown to be detrimental to cartilage, tendon and ligament cells, yet they are commonly used because they are cheap, easy and provide quick pain relief.
These "standard treatments covered by medical insurance" continue to fail for many patients. If we as practitioners continue to stick with cheap and easy until something that is more expensive is proven beyond a reasonable doubt, then we are just as bad as the insurance companies who continue to deny coverage on certain procedures until they have become the standard of practice.
I believe that PRP will one day have the preponderance of evidence in its favor when used appropriately, and insurance companies will realize that it is cheaper than surgery and requires little to no down time or missed work. In fact, there are now some worker's compensation insurance carriers that have started covering PRP treatments, as they too become convinced of its cost-effectiveness.
Injuries to professional athletes are covered by worker's compensation insurers and, as evidenced in the media, there are a growing number of athletes undergoing these procedures. Although all of my athletic patients are not professional or elite athletes, I certainly try to treat them as such. If treatments such as PRP have been shown to provide benefits in certain situations, then I will continue to offer these treatments to all of my well-educated patients, even though cost may be a barrier to some.
Ultimately we as doctors are educators. We educate our patients as to our beliefs as to what treatments would benefit them. The educated patient choses to agree or disagree with our recommendations. Hopefully articles such as this provide patients with more information to make those choices."
1. Podesta L, Crow SA, Volkmer D, Bert T, Yocum LA. Treatment of Partial Ulnar Collateral Ligament Tears in the Elbow With Platelet-Rich Plasma.Am J Sports Med. 2013;20(10). DOI: 1177/0363546513487979.
2. Filardo G, Dhillon MS, Di Matteo B, Kon E, Patel S, and Marwaha N. Platelet-Rich Plasma for Knee Osteoarthritis: Letter to the Editor.Am J Sports Med 2013 41: NP42. DOI: 10.1177/0363546513502635.
3. Mishra A, Harmon K, Woodall J, Vieira A. Sports medicine applications of platelet rich plasma. Curr Pharm Biotechnol. 2012;13(7):1185-1195.
4. Peerbooms JC, Sluimer J, Bruijn DJ, Gosens T. Positive effect of an autologous platelet concentrate in lateral epicondylitis in a doubleblind randomized controlled trial: platelet-rich plasma versus corticosteroid injection with a 1-year follow-up. Am J Sports Med. 2010;38(2):255-262.
5. Krogh TP, Stengaard-Pederson K, Christensen R, Jensen P, Ellingsen T. Treatment of Lateral Epicondylitis With Platelet-Rich Plasma, Glucocorticoid, or Saline: A Randomized, Double-Blind, Placebo-Controlled Trial. Am J Sports Med. 2013;20(10). doi:10.1177/036354612472975.
6. Gaweda K, Tarczynska M, Krzyzanowski W. Treatment of Achilles tendinopathy with platelet-rich plasma. Int J Sports Med. 2010 Aug;31(8):577-83. doi: 10.1055/s-0030-1255028. Epub 2010 Jun 9.
7. de Vos RJ, Weir A, van Schie HT, Bierma-Zeinstra SM, Verhaar JA, Weinans H, Tol JL. Platelet-rich plasma injection for chronic Achilles tendinopathy: a randomized controlled trial.JAMA. 2010;303(2):144-9. doi: 10.1001/jama.2009.1986.
8. Mishra AK, Skrepnik NV, et al. Platelet-Rich Plasma Significantly Improves Clinical Outcomes in Patients With Chronic Tennis Elbow: A Double-Blind, Prospective, Multicenter, Controlled Trial of 230 Patients. Am J Sports Med. 2013; 20(10).DOI: 10.1177/0363546513494359 (epub July 3, 2013).
9. Kon E, Mandelbaum B, et al. Platelet-rich plasma intra-articular injection versus hyaluronic acid viscosupplementation as treatments for cartilage pathology: from early degeneration to osteoarthritis.Arthroscopy. 2011;;27(11):1490-501. doi: 10.1016/j.arthro.2011.05.011. (epub Aug 10, 2011).
10. Patel S, Dhillon MS, Aggarwal S, Marwaha N, Jain A. Treatment with platelet-rich plasma is more effective than placebo for knee osteoarthritis: a prospective, double-blind, randomized trial. Am J Sports Med. 2013; 41(2):356-64. doi: 10.1177/0363546512471299. (epub Jan 8, 2013)
Posted October 10, 2013; updated October 18, 2013 to include Dr. Blecher's final comments