# PRP results change with the joint and the cause of soreness *What Results Say — PRP Therapy Peoria* > Does PRP work for a sore joint? Findings differ. This PRP therapy Peoria page explains knee, shoulder, elbow, and heel-cord results. Here you’ll see what people felt and could do after PRP. A clinician makes PRP by drawing some of your blood, separating its layers, and putting the chosen layer into the sore area. The results aren’t alike for every joint. ## Some people improved, while others did no better One careful knee test compared a PRP shot with a shot of salt water. After a year, people in both groups described about the same change in soreness. Other reviews compared PRP with a steroid shot, which is strong medicine for swelling, or with a gel shot used in joints, and checked people again many months later. Some people then reported less soreness and easier movement with PRP. The amount of change wasn’t steady from one review to another. That’s why “does PRP work” can’t have an honest yes-or-no answer. Shoulder tests also split. In one, PRP beat a steroid shot for soreness and movement. Another found no extra help over salt water when everyone followed the same exercise plan. Tests of the thick cord above the heel found no added strength or movement. For my own knee, I’d ask about work on the same joint problem. ## The PRP mix can change from one office to another Some PRP shots carry more platelets, little parts of blood that gather at a cut. Others keep more white blood cells, which fight germs but may cause added soreness. The number of shots can change as well. These differences may explain some of the split results. They also mean a clinic’s PRP might not match the one tested. Here’s the useful point: a good result isn’t promised. The Peoria QC Kinetix office has regenerative options, meaning non-surgical shots that medical providers prepare from your blood. These are the clinic staff members who check the joint and manage your care. They can see whether your exam resembles those of people in a test. Ask if those people had the same joint trouble. A clinic may count everyone who says later that they improved. That total can’t prove PRP caused the change, since soreness may ease with time, exercise, or other care. Sometimes the fair answer will still be, “We don’t know.” ## 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](https://pubmed.ncbi.nlm.nih.gov/34812863/). *JAMA*, 2021. DOI: 10.1001/jama.2021.19415. 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](https://pubmed.ncbi.nlm.nih.gov/39265924/). *Osteoarthritis and Cartilage*, 2025. DOI: 10.1016/j.joca.2024.08.014. 3. 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](https://pubmed.ncbi.nlm.nih.gov/41031623/). *EFORT Open Reviews*, 2025. DOI: 10.1530/EOR-2025-0022. 4. 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](https://pubmed.ncbi.nlm.nih.gov/29040132/). *Journal of Bone and Joint Surgery (American)*, 2017. DOI: 10.2106/JBJS.16.01374. 5. 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](https://pubmed.ncbi.nlm.nih.gov/30992411/). *Regional Anesthesia and Pain Medicine*, 2019. DOI: 10.1136/rapm-2018-100356. 6. A technical and biological review screened 1379 studies and identified 50 commercial PRP preparation systems in three technical categories (tubes, syringes, bags). Sufficient biological characterisation was available for only 14 of those 50 systems. Comparing the 36 characterised preparations across the seven existing PRP classifications revealed 'a large heterogeneity among the available current PRP commercial systems' and showed the classifications themselves differ in how well they discriminate between preparations. Magalon J, Brandin T, Francois P, et al. — [Technical and biological review of authorized medical devices for platelets-rich plasma preparation in the field of regenerative medicine](https://pubmed.ncbi.nlm.nih.gov/33155867/). *Platelets*, 2021. DOI: 10.1080/09537104.2020.1832653. 7. A systematic review of 132 Level I/II PRP studies across all medical specialties, covering 28 different conditions, found inconsistent reporting of PRP composition in every field of medicine. Musculoskeletal indications - knee osteoarthritis and tendinopathy above all - accounted for the majority of high-level studies. Sixty-one percent of the studies reported PRP as favourable over the control treatment, with no difference in that proportion between musculoskeletal and non-musculoskeletal specialties. Nazaroff J, Oyadomari S, Brown N, et al. — [Reporting in clinical studies on platelet-rich plasma therapy among all medical specialties: A systematic review of Level I and II studies](https://pubmed.ncbi.nlm.nih.gov/33891618/). *PLOS ONE*, 2021. DOI: 10.1371/journal.pone.0250007. 8. 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](https://pubmed.ncbi.nlm.nih.gov/31748208/). *BMJ*, 2019. DOI: 10.1136/bmj.l6132. 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](https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfPCD/classification.cfm?ID=JQC). *FDA accessdata (CDRH device databases)*, 2003. ## Ask what is sore, what may help, and what it costs In Peoria, you can visit QC Kinetix to discuss regenerative options, the clinic’s term for non-surgical shots its medical team makes from your blood after checking what hurts. Bring any X-ray, write down every medicine, and note how your ache started. Ask for the exam result, the choices that fit, and the next step if the first treatment doesn’t help you. Book a free consultation: --- Plain talk about your sore joint. Why a joint stays sore, what may help, and what the Peoria clinic offers. Plain help for Peoria readers whose joint keeps aching. This site is operated by the owners of the QC Kinetix Phoenix-area clinics, including the Peoria location recommended here, so it is first-party educational writing from a business that benefits when a reader books. © 2026 Peoria PRP Ledger. General education only, not medical advice or a diagnosis for your joint or tendon.