Straight answers about sore joints and blood-based PRP shots

Sources

1. A randomized controlled trial of acute hamstring injury found patients treated with a single autologous PRP injection plus a rehabilitation programme returned to play significantly earlier than those doing rehabilitation alone (26.7 +/- 7.0 days versus 42.5 +/- 20.6 days; P=.02), with lower pain severity scores throughout.

   A Hamid MS, Mohamed Ali MR, Yusof A, et al. — Platelet-rich plasma injections for the treatment of hamstring injuries: a randomized controlled trial. American Journal of Sports Medicine, 2014. DOI: 10.1177/0363546514541540.

2. A systematic review and meta-analysis with best-worst case analysis found statistically NON-significant evidence that PRP with or without physical therapy reduced mean time to return to play or reinjury rates for hamstring injuries compared with no treatment or physical therapy alone, in short-term follow-up. Complication rates (postinjection discomfort, pain or sciatic nerve irritation) averaged 5.2% +/- 2.9%. The pooled picture does not support the single positive trial.

   Seow D, Shimozono Y, Tengku Yusof TNB, et al. — Platelet-Rich Plasma Injection for the Treatment of Hamstring Injuries: A Systematic Review and Meta-analysis With Best-Worst Case Analysis. American Journal of Sports Medicine, 2021. DOI: 10.1177/0363546520916729.

3. A systematic review and meta-analysis of adverse events in randomized trials of intra-articular PRP for knee osteoarthritis found PRP associated with mild, transient adverse events - knee pain and swelling - that typically resolve without intervention, and more frequent with LEUKOCYTE-RICH formulations. Leukocyte-poor PRP had a safety profile similar to hyaluronic acid. Knee stiffness was more frequent with PRP than with normal saline (P=.031). No severe adverse events were reported in any group.

   Nakagawa HF, Kim J, Rabinowitz J, et al. — Assessment of adverse events and safety associated with intra-articular platelet-rich plasma injections compared to other injectates for knee osteoarthritis: A systematic review and meta-analysis. PM&R, 2026. DOI: 10.1002/pmrj.70141.

4. The DEPA classification was built because platelet and leukocyte counts alone do not describe an injection. Applied retrospectively to 20 published PRP preparations, the dose of injected platelets ranged from 0.21 billion to 5.43 billion - a 25-fold spread. No device recovered more than 90% of the platelets in the blood drawn, and most preparations were contaminated with red blood cells: only three of the devices reached a purity score corresponding to more than 90% platelets relative to red cells and leukocytes.

   Magalon J, Chateau AL, Bertrand B, et al. — DEPA classification: a proposal for standardising PRP use and a retrospective application of available devices. BMJ Open Sport & Exercise Medicine, 2016. DOI: 10.1136/bmjsem-2015-000060.

5. Medicare's national coverage policy covers autologous platelet-rich plasma ONLY for patients with chronic non-healing diabetic, pressure and/or venous wounds, and only within an approved coverage-with-evidence-development clinical study. There is no Medicare national coverage for PRP in osteoarthritis or tendinopathy, which is why these injections are billed to the patient as cash-pay.

   Centers for Medicare & Medicaid Services — Autologous Platelet-rich Plasma (Coverage with Evidence Development). CMS.gov, 2024.

6. In a double-blind, placebo-controlled trial of 54 patients with chronic midportion Achilles tendinopathy, all doing eccentric exercises, VISA-A scores improved 21.7 points with PRP and 20.5 points with saline over 24 weeks - an adjusted between-group difference of -0.9 (95% CI -12.4 to 10.6), excluding the predefined relevant difference of 12 points. PRP added nothing to eccentric loading.

   de Vos RJ, Weir A, van Schie HT, et al. — Platelet-rich plasma injection for chronic Achilles tendinopathy: a randomized controlled trial. JAMA, 2010. DOI: 10.1001/jama.2009.1986.

7. A placebo-controlled, double-blind randomized trial of 40 patients with chronic rotator cuff tendinopathy compared a single ultrasound-guided subacromial injection of 5 mL PRP with 5 mL saline, with both groups completing a 6-week standard exercise programme and follow-up to one year. PRP did not produce better outcomes than saline on any measure - a reminder that the exercise programme, not the injectate, carried the improvement.

   Kesikburun S, Tan AK, Yilmaz B, et al. — Platelet-rich plasma injections in the treatment of chronic rotator cuff tendinopathy: a randomized controlled trial with 1-year follow-up. American Journal of Sports Medicine, 2013. DOI: 10.1177/0363546513496542.

8. A prospective fixed-sequence controlled laboratory study in healthy men found that daily low-dose aspirin significantly reduced release of VEGF, PDGF-AB and TGF-beta1 from freshly isolated leukocyte-rich PRP when activated with arachidonic acid. This is the mechanistic basis for the routine instruction to review antiplatelet and NSAID use before a PRP draw - and the authors noted clinical studies are still needed to establish how much this matters in vivo.

   Jayaram P, Yeh P, Patel SJ, et al. — Effects of Aspirin on Growth Factor Release From Freshly Isolated Leukocyte-Rich Platelet-Rich Plasma in Healthy Men: A Prospective Fixed-Sequence Controlled Laboratory Study. American Journal of Sports Medicine, 2019. DOI: 10.1177/0363546519827294.

9. The devices used to spin PRP at the point of care are cleared by FDA as clinical centrifuges, product code JQC, a Class I device under 21 CFR 862.2050 - for example the Biomet GPS Platelet Separation Kit (K030555, cleared 2003) and the Harvest SmartPrep2 / SmartPrep Platelet Concentration System (K103340, cleared 2010). That clearance covers the equipment that separates blood. It is not an FDA approval of platelet-rich plasma as a treatment for osteoarthritis, tendinopathy or any other orthopedic condition, and copy must never blur the two.

   U.S. Food and Drug Administration (Center for Devices and Radiological Health) — 510(k) Premarket Notification database and Product Classification: JQC, Centrifuges (Micro, Ultra, Refrigerated) For Clinical Use, 21 CFR 862.2050. FDA accessdata (CDRH device databases), 2003.