Platelet-rich plasma does not enhance return to play in hamstring injuries: a randomised controlled trial

Background To evaluate the efficacy of a single platelet-rich plasma (PRP) injection in reducing the return to sport duration in male athletes, following an acute hamstring injury. Methods A randomised, three-arm (double-blind for the injection arms), parallel-group trial, in which 90 professional athletes with MRI positive hamstring injuries were randomised to injection with PRP-intervention, platelet-poor plasma (PPP-control) or no injection. All received an intensive standardised rehabilitation programme. The primary outcome measure was time to return to play, with secondary measures including reinjury rate after 2 and 6 months. Results The adjusted HR for the PRP group compared with the PPP group was 2.29 (95% CI 1.30 to 4.04) p=0.004; for the PRP group compared with the no injection group 1.48 (95% CI 0.869 to 2.520) p=0.15, and for the PPP group compared with the no injection group 1.57 (95% CI 0.88 to -2.80) p=0.13. The adjusted difference for time to return to sports between the PRP and PPP groups was -5.7 days (95% CI -10.1 to -1.4) p=0.01; between the PRP and no injection groups -2.9 days (95% CI -7.2 to 1.4) p=0.189 and between the PPP and no injection groups 2.8 days (95% CI -1.6 to 7.2) p=0.210. There was no significant difference for the secondary outcome measures. No adverse effects were reported. Conclusions Our findings indicate that there is no benefit of a single PRP injection over intensive rehabilitation in athletes who have sustained acute, MRI positive hamstring injuries. Intensive physiotherapy led rehabilitation remains the primary means of ensuring an optimal return to sport following muscle injury.