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

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Hamilton, B., Tol, J., Almusa, E., Boukarroum, S., Eirale, C., Farooq, A., Whiteley, R., & Chalabi, H. (2015). Platelet-rich plasma does not enhance return to play in hamstring injuries: a randomised controlled trial British Journal of Sports Medicine, 49 (14), 943-950 DOI: 10.1136/bjsports-2015-094603