What to ask about a PRP success rate

What to ask when the number sounds certain

Ask which joint was studied and what people could do later. Some studies give points for soreness and movement. Those points may shift even when your walking feels the same. You’ll want to know when people were checked again. The ache can ease on its own, so a better day doesn’t prove the shot helped.

A percentage alone won’t answer your question.

What to ask about the comparison

One study group gets PRP, while another gets a salt-water dummy shot or follows the same exercise plan without PRP, so researchers can compare how each group feels and moves. If the groups improve about the same, PRP didn’t add clear help. At QC Kinetix, your visit can include a joint exam and a talk about regenerative treatments. These are office options, including PRP, that begin with material from your body. Your result still can’t be known ahead of time.

Ask the clinician this: did PRP help people with my joint problem more than the other care did?

What to bring when you ask

Take any X-ray you already have and a current list of medicines. Name the motion that’s hard and say how long your soreness lasts. Ask whether the study included people with the same cause of soreness. Then choose a result you’d notice, such as climbing steps with less trouble or walking farther. Don’t accept “better” without knowing what it meant in daily life.

If success isn’t clear, the rate can’t guide you.

Sources

1. A meta-analysis of 73 articles covering 5,895 patients quantified the PLACEBO response to intra-articular injection in knee osteoarthritis: statistically and clinically significant improvements in pain, function and quality of life at 1, 3 and 6 months, with responder rates above 50% at each of those points, declining by 12 months. The placebo response was stronger in trials with more female participants and in more recently published trials. This is why an uncontrolled 'our patients improved' figure carries almost no information.

   Previtali D, Boffa A, Di Laura Frattura G, et al. — Placebo response to intra-articular injections in knee osteoarthritis: magnitude, evolution over time, and influencing factors. A systematic review and meta-analysis with meta-regression. EFORT Open Reviews, 2025. DOI: 10.1530/EOR-2025-0022.

2. A Bayesian network meta-analysis restricted to LARGE randomized trials (at least 100 patients per group; 57 trials, 22,795 participants, 18 intra-articular interventions) found treatment effects were larger in the 35 high-risk-of-bias trials than in the 22 low/unclear-risk trials. Excluding high-risk trials, the effects of 16 of the 18 intra-articular interventions in knee or hip OA were smaller than the minimal clinically important difference and most were consistent with placebo effects; triamcinolone had the highest probability of exceeding the MID at weeks 2-6.

   Pereira TV, Saadat P, Bobos P, et al. — Effectiveness and safety of intra-articular interventions for knee and hip osteoarthritis based on large randomized trials: A systematic review and network meta-analysis. Osteoarthritis and Cartilage, 2025. DOI: 10.1016/j.joca.2024.08.014.

3. 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.

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 Delphi consensus of 24 invited experts produced the Minimum Information for Studies Evaluating Biologics in Orthopaedics (MIBO) checklists: 58 items reached consensus for PRP and were compiled into a 23-statement reporting checklist, with a parallel 25-statement checklist for mesenchymal stem cells. The need for it was identified because clinical studies of PRP and MSCs are 'limited by inadequate reporting of scientific details critical to outcome'.

   Murray IR, Geeslin AG, Goudie EB, et al. — Minimum Information for Studies Evaluating Biologics in Orthopaedics (MIBO): Platelet-Rich Plasma and Mesenchymal Stem Cells. Journal of Bone and Joint Surgery (American), 2017. DOI: 10.2106/JBJS.16.00793.

7. 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.