(HealthDay News) — Intramuscular platelet-rich plasma (PRP) injections do not provide clinical benefit for acute hamstring injuries, according to a correspondence piece published June 26 in the New England Journal of Medicine.

Gustaaf Reurink, MD, from Erasmus Medical Center in the Netherlands, and colleagues randomized 80 competitive and recreational athletes with acute hamstring muscle injuries (confirmed on magnetic resonance imaging) to receive intramuscular injections of PRP (two 3ml injections via a sterile ultrasonography-guided technique, with the first injection within five days after the injury and the second five to seven days later) or isotonic saline as a placebo. All patients performed an identical, daily, progressively phased, criteria-based rehabilitation program.

The researchers found that the median time to resumption of sports activity was 42 days in both groups (hazard ratio in the PRP group, 0.96; 95% confidence interval [CI], 0.61–1.51; P=0.66). In the PRP group, the reinjury rate was 16% vs. 14% in the placebo group (odds ratio, 1.17; 95% CI, 0.33–4.18; P=0.81). There were no serious adverse events.

“Although the 95% confidence interval still allows for a small chance that there was a clinically relevant between-group difference, our study demonstrated no benefit for intramuscular PRP injections, as compared with placebo injections, in patients with acute hamstring injuries,” the authors write.

The study was funded in part by Arthrex Medizinische Instrumente.

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