# Common questions have short, practical answers *Common PRP Questions | PRP Glendale* > Straight answers for PRP Glendale readers about relief, timing, knee soreness, cortisone, insurance, home care, and when a medical exam makes sense. The joint may feel easier today with gentle movement and less strain. Soreness that keeps returning is worth an exam. ## Sources 1. 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. 2. 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. 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](https://pubmed.ncbi.nlm.nih.gov/34812863/). *JAMA*, 2021. DOI: 10.1001/jama.2021.19415. 4. The ESSKA-ICRS consensus applied the RAND/UCLA appropriateness method to 216 clinical scenarios for intra-articular PRP in knee OA. Only 84 scenarios (38.9%) were rated appropriate, 9 (4.2%) inappropriate and 123 (56.9%) uncertain. PRP was judged appropriate in patients aged 80 or under with KL grade 0-III osteoarthritis AFTER failed conservative non-injective or injective treatment; it was NOT considered appropriate as a first treatment, nor in KL grade IV (bone-on-bone) osteoarthritis, where 91.7% and 87.5% of scenarios respectively were uncertain. Kon E, de Girolamo L, Laver L, et al. — [Platelet-rich plasma injections for the management of knee osteoarthritis: The ESSKA-ICRS consensus. Recommendations using the RAND/UCLA appropriateness method for different clinical scenarios](https://pubmed.ncbi.nlm.nih.gov/38961773/). *Knee Surgery, Sports Traumatology, Arthroscopy*, 2024. DOI: 10.1002/ksa.12320. 5. 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. 6. 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)](https://www.cms.gov/medicare/coverage/evidence/plasma). *CMS.gov*, 2024. 7. FDA states verbatim of stem cell, stromal vascular fraction, umbilical cord blood, Wharton's jelly, amniotic fluid and exosome products: 'None of these products have been approved for the treatment of any orthopedic condition, such as osteoarthritis, tendonitis, disc disease, tennis elbow, back pain, hip pain, knee pain, neck pain, or shoulder pain.' The only FDA-approved stem cell products in the United States are blood-forming cells from umbilical cord blood, approved only for disorders of blood production, and there are no FDA-approved exosome products. PRP is a different product from all of these and the categories must not be blurred in either direction. U.S. Food and Drug Administration — [Consumer Alert on Regenerative Medicine Products Including Stem Cells and Exosomes](https://www.fda.gov/vaccines-blood-biologics/consumers-biologics/consumer-alert-regenerative-medicine-products-including-stem-cells-and-exosomes). *FDA (Center for Biologics Evaluation and Research)*, 2020. 8. A network meta-analysis of 79 randomized trials with 8761 patients compared 11 injectable options for knee osteoarthritis. At 4-6 weeks and 3 months the highest-ranked treatment for WOMAC was high-molecular-weight hyaluronic acid plus corticosteroid; at 6 months the highest-ranked treatment for WOMAC was PRP. Stromal vascular fraction ranked highest for VAS at all time points, on a much thinner evidence base. Anil U, Markus DH, Hurley ET, et al. — [The efficacy of intra-articular injections in the treatment of knee osteoarthritis: A network meta-analysis of randomized controlled trials](https://pubmed.ncbi.nlm.nih.gov/34500430/). *The Knee*, 2021. DOI: 10.1016/j.knee.2021.08.008. ## Is there anything better than PRP? Cortisone may ease swelling sooner. Physical therapy, gentle exercise, a brace, or less daily strain may also help without a shot. PRP stands for platelet-rich plasma, made when staff spin drawn blood and save liquid holding many platelets. Your body uses those platelets to begin repairing a cut, and the liquid is placed where your joint or tendon hurts. ## Is PRP better than a cortisone shot? Neither is better every time. Cortisone often helps within days, while PRP groups sometimes reported more relief several months later. For elbow tendons, cortisone did better before two months and PRP did better after six months. Ask the examiner when improvement from either shot would be checked. ## Is PRP worth considering for a sore knee? A knee discussion may make sense after simpler care hasn’t eased the soreness enough. Some tests found PRP groups felt better than cortisone or gel groups months later. In a large test, both PRP and salt-water groups improved a little. The PRP group didn’t report extra relief after twelve months. ## How long can PRP relief last? No clinic can promise a set length of relief. Some knee comparisons found PRP beat cortisone for several months. Another large knee test found PRP and salt water brought about the same relief. Tendon results also differ by the sore body part. ## Why isn’t PRP recommended for everyone? Clinics don’t all prepare PRP the same way. Some keep more platelets or white blood cells, which can change early soreness and may affect results. No one yet knows which mix works best for every sore joint or tendon. An exam also shows whether severe wear calls for another choice. ## What can I try before PRP? Try lighter activity, gentle movement, and cold or warmth as the joint prefers. Supportive shoes, a cane, or a brace can also reduce strain. Physical therapy can improve strength and motion over time. Review any medicine choice against your current prescriptions and health conditions. ## Does PRP therapy work for arthritis? Knee tests don’t all give the same answer. One found PRP and salt water brought about the same relief after twelve months. Hip-joint and ankle tests also found no added relief over salt water. You don’t need to choose a study; the examiner can explain what fits the sore joint. ## Does insurance cover PRP in Arizona? Health plans commonly don’t cover PRP for soreness in joints or tendons. Cortisone, physical therapy, braces, and common medicine are more often covered. Get the clinic’s price in writing, then speak with your plan ahead of the visit. Confirm prior approval, the deductible, and the share you must pay. ## A visit begins with an exam of the sore joint QC Kinetix offers consultations and regenerative treatments, meaning non-surgical blood care prepared on site and intended to support the body’s repair response after an exam. Book a free consultation: --- What may ease the soreness and when an exam helps. Help for knee, shoulder, hip, elbow, heel, or ankle soreness in Glendale, with home care, visit timing, PRP, cortisone, costs, and nearby clinics. Plain Glendale guidance about joint soreness, home care, visits, and treatment choices. This site is operated by the owners of the QC Kinetix clinics serving the Phoenix area, including the Peoria and Banner Estrella offices these pages send readers to, so read it as first-party writing from a business that benefits when you book - and check the sources for yourself. Copyright 2026 The Glendale Injection Desk. General education about joint and tendon injections, not medical advice about your own joint; talk to a clinician who can examine it.