Injuries are the bane of many triathletes’ existence. If they become chronic, out of desperation athletes may pursue alternative therapies in the hopes of finding something that will help. For the second part of this continuing series on non-traditional treatments for common injuries, I look at platelet-rich plasma or ‘PRP’. If you want to check out part one in which I addressed steroid injections, click here.
The Process Behind PRP
PRP has been investigated since the mid-1980’s. The rationale for its use is rooted in our understanding of the physiology of injury and healing. Unfortunately, in many types of tissues, especially in tissues prone to chronic injuries such as ligaments and cartilage, blood flow is very poor. This makes the repair process exceedingly slow as the oxygen, nutrients and mediators of tissue healing are not adequately available.
After an acute injury, the process of tissue repair occurs in three distinct phases: there is the inflammation phase, the proliferation phase and finally, the remodeling phase. The progression within these phases and from one phase to another is regulated by locally expressed chemicals called cytokines and growth factors. It has long been known that platelets, a component of the blood that plays an important role in blood clotting, also have a very high concentration of many of the same cytokines and growth factors that are necessary for tissue repair.
What, the researchers thought, would happen if we concentrated platelets and simply injected them into injured tissue?
Researchers struck on the idea that an external source of some of these elements, injected into the area of injury, might enhance the healing process. Initial studies were performed on lab animals and the results were pretty encouraging. In mice, rats and rabbits, the use of concentrated platelet solutions seemed to promote healing to injured ligaments and tendons as well as muscles. These results spurred the development of human trials.
Best Tendon Use Cases for PRP
The most compelling evidence for the use of PRP comes from patients who have lateral epicondylitis (tennis elbow). While this is not a common triathlon injury, it is still the injury where PRP has shown the best results. In several well-designed studies, patients treated with PRP were 25% more likely to see improvement in pain than those without PRP. PRP also served patients better than injections with local anesthetics or steroids.
Triathletes are much more likely to sustain injuries to their tendons. The patellar tendon is frequently a source of chronic pain, for example in the condition called jumper’s knee. In studies addressing these types of cases, PRP did show promise by virtue of decreasing symptoms of tendinopathy in the short term. However, in the moderate-to-long term, there was no difference between patients treated with PRP and those treated without it.
Tendinopathy Cases When PRP Falls Short
Another common injury that triathletes suffer from is Achilles tendinopathy. In this case, the evidence has been quite consistent. Researchers have studied the use of PRP to augment surgical repair of Achilles tendon rupture and so far the results have been disappointing showing no benefit at all.
Plantar fasciitis is another frustrating injury for triathletes as it is resistant to most therapies. As I mentioned in the first article, steroid injections may be of some benefit in these cases, but there is an increased risk of fascial rupture. Studies of PRP show equivocal results for plantar fasciitis but indicate some equivalence with steroids in terms of symptom relief. Given the lower incidence of adverse effects, the use of PRP is not a bad idea though it should not be viewed as a catch-all solution.
Finally, rotator cuff tendinitis, a common affliction amongst older triathletes as a result of swimming overuse, has also not shown benefit from PRP. That being said, there is so much variability in how PRP is used, this may change once some consistency in testing is established. For now though, PRP cannot be recommended for this indication based on current evidence.
Additional Non-Tendon Use Cases
Beyond tendinopathies, there are other cases where PRP has been studied and there too the evidence has been positive in some cases, negative in others or mixed.
Osteoarthritis of the knee is not helped by steroid injections but there is some research to suggest that PRP may be beneficial for patients. To date, there is nothing that clearly demonstrates that PRP can restore function. However, some studies show that patients with PRP report improvements in pain and function compared to other kinds of treatment modalities. Long-term benefits have yet to be reported.
Conclusion
The final area with a robust body of research for the use of PRP is in acute injuries such as sprains of the ankle and muscular strains or tears. In both cases, PRP has not been shown to be an effective solution to restore function or reduce pain.
To sum up all of the evidence cited, PRP just has one clear-cut success story: the treatment of tennis elbow. There is likely benefit for its use in osteoarthritis of the knee as well, but beyond this, the benefits become rapidly tenuous and far from certain.
In the next article, I’ll look at dry needling. Until then, train hard, train healthy
Sources
- Martínez-Martínez A, Ruiz-Santiago F, García-Espinosa J. Platelet-rich plasma: Myth or reality? Radiol (English Ed. 2018;60(6):465-475. doi:10.1016/j.rxeng.2018.08.001
- Wu PIK, Diaz R, Borg-Stein J. Platelet-Rich Plasma. Phys Med Rehabil Clin N Am. 2016;27(4):825-853. doi:10.1016/j.pmr.2016.06.002
- Hamid MSA, Yusof A, Mohamed Ali MR. Platelet-rich plasma (PRP) for acute muscle injury: A systematic review. PLoS One. 2014;9(2):1-7. doi:10.1371/journal.pone.0090538
- Le ADK, Enweze L, DeBaun MR, Dragoo JL. Current Clinical Recommendations for Use of Platelet-Rich Plasma. Curr Rev Musculoskelet Med. 2018;11(4):624-634. doi:10.1007/s12178-018-9527-7
