Platelet-rich Plasma Does Not Enhance Return to Play in Hamstring Injuries: a Randomized Controlled Trial
Hamilton B, Tol JL, Alusa E, Boukarroum S, Eirale C, Farooq A, Whiteley R, & Chalabi H. Br J Sports Med. 2015; 49: 943-950. Doi:10.1136/bjsports-2015-094603.
Take Home Message: Compared to intensive rehabilitation alone, a single injection of platelet-rich plasma (PRP) does not reduce the time to return to sports (RTS) among professional male athletes with acute hamstring injuries.
To date, there is insufficient evidence to support the use of platelet-rich plasma (PRP) in the treatment of musculoskeletal soft tissue injuries despite the rapid expansion of its use in the field of “Regenerative Medicine.” Specifically for hamstring injuries, there is a lack of well-designed clinical trials to demonstrate effectiveness despite its commonplace use. The authors of this article conducted a randomized clinical trial to investigate whether PRP reduced the time to return to sports (RTS) among male professional athletes with acute grade I or II hamstring injuries. Ninety professional athletes with MRI-positive, acute hamstring injuries were randomized to a single PRP injection, a single platelet poor plasma (PPP) injection or no injection. All three groups then received physical therapy according to a standardized protocol. The primary outcome measure was the time to RTS. Adverse outcomes and reinjury rates within 2 months and 6 months were measured as secondary outcomes. Comparing the PRP and no injection groups, the adjusted average difference for time to RTS was -2.9 days; but, for a typical professional athlete we may expect a difference for time to RTS between -7.2 to 1.4 days. Comparing the PRP and PPP groups, there was an average difference for time to RTS by -5.7 days; but, for a typical professional athlete we may expect a difference for time to RTS between -1.6 to 7.2 days. Thus, on average an athlete who receives a PRP injection is unlikely to RTS faster than an athlete who receives PPP or no injection. There was no difference in reinjury rates among all groups and there were no adverse outcomes.
The use of PRP to enhance soft tissue healing is controversial due to the small amount of high quality studies in the literature. Healthcare professionals are using PRP for a variety of different injuries in an attempt to get athletes back to sports faster. This study adds significantly to the available literature on the use of PRP; however, there are some limitations. First, the authors looked strictly at professional athletes; hence, the findings may not apply to the general population with similar injuries. Secondly, as with all studies involving PRP, there is variability regarding preparation and subsequent concentration. Perhaps the platelet concentration is an important variable when assessing efficacy of PRP injections. Third, in this study, sonographic guidance was not used to demonstrate that the injectate was delivered directly in the area of pathology. In addition, the authors looked only at patients with acute injuries. Hence, these findings are primarily applicable to professional athletes with an acute hamstring injury that are going to receive similar PRP preparations (for example, PRP with no activating agent). While the design of this study may limit how we can interpret the study there were some strengths. The authors attempted to provide a more appropriate placebo than saline, as used in a prior study, by using PPP. The difference between RTS between PRP versus PPP and PRP versus no injection again highlights the lack of understanding about the mechanism of action and efficacy of PRP injections. As the authors emphasize, all of these potential factors need “further evaluation before PRP can be routinely recommended for use.” For now, intensive physiotherapy led rehabilitation remains the best treatment for acute grade I or II hamstring injuries in reducing time lost from sport due to injury.
Questions for Discussion: Have you seen positive results from PRP injections used to treat hamstring injuries in your practice? Other than cost, have you seen disadvantages to trying PRP injections?
Written by: Emily Levy, MD & Marc I. Harwood, MD
Reviewed by: Jeffrey Driban