Does PRP work? What to ask for your sore area

What to ask about mixed knee results

Some knee studies found less soreness after PRP. Others found that PRP and saline, plain salt water used for a dummy shot, worked about alike. So PRP didn’t show clear extra help there. A good visit begins with your exam, the amount of arthritis and the task you’d like back. Ask how likely relief is, when it may come and what care costs.

Mixed results deserve a straight answer.

What to ask about a shoulder, hip or Achilles tendon

For the Achilles tendon problems studied, PRP didn’t help more than a dummy procedure. In one shoulder study, both groups followed the same exercise plan; one group also got PRP, but didn’t gain clear extra help. Hip studies compared PRP with other shots and found no clear extra help either. These findings can’t tell what causes your soreness. QC Kinetix can examine your sore area and discuss regenerative treatments, which are office options made from blood or other material from your body.

Ask a plain question: what did my exam find, and was that same problem studied?

What to settle before care starts

Name the task you need to do more easily, perhaps reaching a shelf, walking or sleeping on one side. Ask how the clinic makes its concentrated PRP and why you’re being offered that method. Find out which exercise continues and when you’ll check your daily movement. Joint preservation means exercise, braces or other care used to delay surgery. It may come up along with PRP, but neither choice brings a promised result.

Don’t decide until the possible gain, cost and unknowns make sense.

Sources

1. In the RESTORE trial - the largest placebo-controlled PRP trial in knee osteoarthritis - 288 adults aged 50+ with symptomatic Kellgren-Lawrence grade 2-3 medial knee OA received three weekly intra-articular injections of leukocyte-poor PRP from a commercial system or saline placebo. At 12 months the mean change in knee pain was -2.1 points with PRP versus -1.8 with saline (difference -0.4; 95% CI -0.9 to 0.2; P=.17) against a minimum clinically important difference of 1.8, and the change in medial tibial cartilage volume was -1.4% versus -1.2% (difference -0.2%; 95% CI -1.9% to 1.5%; P=.81). Twenty-nine of 31 prespecified secondary outcomes showed no significant between-group difference. The authors concluded the findings do not support use of PRP for knee OA.

   Bennell KL, Paterson KL, Metcalf BR, et al. — Effect of Intra-articular Platelet-Rich Plasma vs Placebo Injection on Pain and Medial Tibial Cartilage Volume in Patients With Knee Osteoarthritis: The RESTORE Randomized Clinical Trial. JAMA, 2021. DOI: 10.1001/jama.2021.19415.

2. A meta-analysis of 34 randomized trials (1403 PRP knees, 1426 control knees) found WOMAC favoured PRP over placebo at 12 months (P=.02) and over hyaluronic acid at 6 and 12 months (P<.001), and favoured PRP over steroids on VAS pain and KOOS at 6 months. Critically, the authors reported that the superiority of PRP did NOT reach the minimal clinically important difference for any outcome, and graded the quality of evidence as low.

   Filardo G, Previtali D, Napoli F, et al. — PRP Injections for the Treatment of Knee Osteoarthritis: A Meta-Analysis of Randomized Controlled Trials. Cartilage, 2021. DOI: 10.1177/1947603520931170.

3. The American Academy of Physical Medicine and Rehabilitation convened a technical expert panel that ran a structured literature review (2023, updated through June 2025) and a modified Delphi process, and issued five evidence-based clinical recommendations plus 11 consensus-based best practices for PRP in knee osteoarthritis. The statement is explicit that orthobiologic therapies 'remain an evolving area of practice' and that robust, dose-dependent randomized controlled trials are still needed to establish PRP's clinical effects.

   Borg-Stein J, Jayaram P, Colorado BS, et al. — AAPM&R guidance statement on platelet rich plasma for knee osteoarthritis. PM&R, 2026. DOI: 10.1002/pmrj.70144.

4. A 24-site, 240-patient participant-blinded randomized trial of a single intratendinous PRP injection versus a sham (subcutaneous dry needle) for chronic midportion Achilles tendinopathy found VISA-A scores of 54.4 versus 53.4 at six months (adjusted mean difference -2.7; 95% CI -8.8 to 3.3) against a 12-point minimal clinically important difference. The authors stated the findings do not support the use of this treatment for chronic midportion Achilles tendinopathy.

   Kearney RS, Ji C, Warwick J, et al. — Effect of Platelet-Rich Plasma Injection vs Sham Injection on Tendon Dysfunction in Patients With Chronic Midportion Achilles Tendinopathy: A Randomized Clinical Trial. JAMA, 2021. DOI: 10.1001/jama.2021.6986.

5. PATH-2 randomised 230 adults with acute Achilles tendon rupture managed non-surgically to PRP or a placebo dry-needle injection across 19 UK hospitals, with a central laboratory confirming the PRP was of good quality with the expected growth-factor content. At 24 weeks there was no detectable difference in muscle-tendon function (limb symmetry index 34.7% versus 38.5%; adjusted mean difference -3.9%; 95% CI -10.5% to 2.7%) or in any secondary outcome or adverse-event rate.

   Keene DJ, Alsousou J, Harrison P, et al. — Platelet rich plasma injection for acute Achilles tendon rupture: PATH-2 randomised, placebo controlled, superiority trial. BMJ, 2019. DOI: 10.1136/bmj.l6132.

6. 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.

7. A network meta-analysis of 11 randomized trials (1353 patients) with HIP osteoarthritis found that for both pain and function, at 2-4 months and at 6 months, NO intervention - corticosteroid, hyaluronic acid or PRP - significantly outperformed an intra-articular saline placebo injection.

   Gazendam A, Ekhtiari S, Bozzo A, et al. — Intra-articular saline injection is as effective as corticosteroids, platelet-rich plasma and hyaluronic acid for hip osteoarthritis pain: a systematic review and network meta-analysis of randomised controlled trials. British Journal of Sports Medicine, 2021. DOI: 10.1136/bjsports-2020-102179.

8. A systematic review of 105 clinical PRP studies in orthopaedics published 2006-2016 found that only 11 (10%) described the preparation protocol clearly enough for another investigator to repeat it, and only 17 (16%) reported any quantitative metric of the final PRP composition. The authors concluded that the current reporting of PRP preparation and composition does not allow the PRP products actually delivered to patients to be compared between studies.

   Chahla J, Cinque ME, Piuzzi NS, et al. — A Call for Standardization in Platelet-Rich Plasma Preparation Protocols and Composition Reporting: A Systematic Review of the Clinical Orthopaedic Literature. Journal of Bone and Joint Surgery (American), 2017. DOI: 10.2106/JBJS.16.01374.

9. A systematic review that screened 876 studies and extracted standardised data from 33 commercially available PRP systems and protocols found that final product concentrations of platelets, white cells and growth factors varied widely between systems, as did the preparation protocols themselves. Platelet concentration correlated directly with the volume of blood drawn and with the centrifugal force of the device. The authors called the heterogeneity between separation systems something that 'must be resolved for proper study of this promising treatment'.

   Fadadu PP, Mazzola AJ, Hunter CW, et al. — Review of concentration yields in commercially available platelet-rich plasma (PRP) systems: a call for PRP standardization. Regional Anesthesia and Pain Medicine, 2019. DOI: 10.1136/rapm-2018-100356.

10. 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.