Platelet-rich plasma (PRP) has become a familiar name in the treatment of chronic musculoskeletal injuries — tendinopathies, ligament sprains, and degenerative joint pain. But acute muscle injuries, like a torn hamstring, are a different question entirely. Does injecting concentrated platelets into freshly damaged muscle tissue actually get athletes back on the field faster?
For years, the honest answer was "probably not." A newly published systematic review is starting to change that answer — with an important caveat.
The New Study: PRP May Shorten Return-to-Play, With a Catch
A systematic review and meta-analysis published in the British Journal of Sports Medicine (Nakagawa et al., 2026) set out to answer this question as rigorously as possible. The researchers searched Embase, MEDLINE, Web of Science, Elsevier, and Cochrane Central through March 2025, and applied a strict inclusion standard: only randomized controlled trials (RCTs) comparing PRP to a control treatment for acute hamstring injuries qualified. Non-randomized studies and chronic tendinopathy research were excluded outright.
Six RCTs met that bar, covering 277 patients total. The findings:
- Return-to-play time was shorter with PRP — a mean difference of 8.6 days (21.4 days for PRP versus 30.0 days for control), a statistically significant result.
- Reinjury rates were essentially identical between groups (15% PRP vs. 16% control).
- Adverse events were rare and similar between groups (1% vs. 0%).
- Critically, the review noted PRP's benefit appeared to be especially pronounced when the injection was image-guided — meaning delivered under ultrasound visualization directly to the site of the tear, rather than administered blindly.
The authors were candid about the limitations: certainty of evidence was rated low to moderate, and heterogeneity between the six trials was high (I² = 94.1%), meaning the studies didn't all measure or report things the same way. Their conclusion was appropriately measured: PRP may shorten return-to-play in acute hamstring injuries, particularly with image guidance, but larger and more standardized trials are still needed.
Why This Result Is a Bit of a Reversal
Here's what makes this finding worth paying attention to: it cuts against a decade of more skeptical evidence.
An earlier and frequently cited meta-analysis in the same journal, led by Pas et al. (2015), reviewed 10 RCTs on conservative treatments for acute hamstring injury and found that PRP showed no measurable effect on return-to-play time compared to control.
A 2018 meta-analysis in Sports Medicine (Grassi et al.) reached a more nuanced version of the same conclusion. Across all six included RCTs, PRP did show a significantly shorter return-to-play time overall — but when the analysis was narrowed to only the double-blind studies, or only the studies specifically involving hamstring injuries, that advantage disappeared.
A 2017 review in Arthroscopy (Sheth et al.) found a similar split: PRP showed a significantly earlier return to sport across all grade I–II muscle strains pooled together, but that benefit vanished in the hamstring-only subgroup.
Even a 2020 meta-analysis in the American Journal of Sports Medicine (Seow et al.), which pooled 10 studies and 356 patients, could only describe its favorable return-to-play finding (a 5.67-day advantage) as a non-significant trend, not a proven effect.
So for most of the last decade, the honest clinical summary was: PRP looks biologically promising for acute hamstring injury, but the RCT evidence specific to hamstrings hasn't held up under scrutiny.
What's Different Now
A 2025 meta-analysis in the Journal of Sport Rehabilitation (Liu et al.), pooling eight studies and 330 patients, already hinted at a shift — finding a smaller but statistically significant return-to-play benefit (2.29 days) for PRP combined with physical therapy versus physical therapy alone.
The new BJSM review pushes that signal further, and its emphasis on image guidance is likely the key variable. Many of the earlier, more skeptical trials didn't consistently confirm that PRP was delivered precisely to the injury site. An ultrasound-guided injection targets the exact zone of muscle fiber disruption — arguably where the biological rationale for platelet-derived growth factors actually applies. A blind injection into the general hamstring region, by contrast, may miss the injury site entirely, diluting any real effect in the data.
This is a pattern seen elsewhere in orthobiologics research too: as injection technique becomes more precise and standardized, treatment effects that were previously "non-significant" start to emerge more clearly. It's a reminder that a negative RCT doesn't always mean a treatment doesn't work — sometimes it means the treatment wasn't delivered the way it needs to be.
The Takeaway
The current best evidence suggests PRP is not a guaranteed fix for acute hamstring injuries, but it may offer a real, modest reduction in return-to-play time — particularly when injected under image guidance by someone experienced in precisely localizing the injury. Reinjury risk does not appear to be affected either way, and the treatment continues to show a favorable safety profile.
For athletes and active patients, the clinical takeaway is less "should I get PRP for my hamstring strain" and more "if I'm considering PRP for an acute muscle injury, how is it being delivered, and by whom." Precision may matter more than the biologic itself.