# Common questions about a sore joint *Straight Answers — Orthobiologics Scottsdale Blood and Marrow Care* > Orthobiologics Scottsdale refers to care using blood or marrow; get plain answers about soreness, studies and home relief. These answers cover the questions people often ask about joint soreness and blood or marrow treatments. The study results apply mostly to sore knees with mild or moderate arthritis. Your exam may show that a different choice makes more sense. If an answer isn’t clear, take the question to your visit. ## Sources 1. RESTORE, the largest and most rigorously blinded placebo-controlled PRP trial in knee OA (n=288, participant-, injector- and assessor-blinded), gave three weekly injections of a commercial leukocyte-poor PRP or saline. At 12 months the change in knee pain was -2.1 vs -1.8 points (difference -0.4; 95% CI -0.9 to 0.2; P=.17) and the change in medial tibial cartilage volume was -1.4% vs -1.2% (difference -0.2%; P=.81). Twenty-nine of 31 prespecified secondary outcomes showed no between-group difference. The authors concluded the findings do not support the use of PRP for knee OA. Bennell KL, 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 meta-analysis of 27 Level I studies (1,042 PRP, 226 BMAC, 1,128 HA patients) found significantly better post-injection WOMAC, VAS and subjective IKDC scores for BOTH PRP and BMAC compared with hyaluronic acid - and NO significant difference between PRP and BMAC on any outcome score. This is the clearest published statement that the two most-marketed orthobiologics perform the same as each other in the knee. Belk JW, et al. — [Patients With Knee Osteoarthritis Who Receive Platelet-Rich Plasma or Bone Marrow Aspirate Concentrate Injections Have Better Outcomes Than Patients Who Receive Hyaluronic Acid: Systematic Review and Meta-analysis.](https://pubmed.ncbi.nlm.nih.gov/36913992/). *Arthroscopy*, 2023. DOI: 10.1016/j.arthro.2023.03.001. 3. A meta-analysis of 8 trials (648 patients, judged at low risk of bias overall) comparing intra-articular PRP with intra-articular corticosteroid found PRP significantly better for pain, stiffness and function at 3, 6 and 9 months (P<0.01), with the largest effects at 6 months (SMD -0.78) and 9 months (SMD -1.63). Three PRP injections a week apart outperformed a single injection over 12 months. McLarnon M, Heron N. — [Intra-articular platelet-rich plasma injections versus intra-articular corticosteroid injections for symptomatic management of knee osteoarthritis: systematic review and meta-analysis.](https://pubmed.ncbi.nlm.nih.gov/34134679/). *BMC Musculoskeletal Disorders*, 2021. DOI: 10.1186/s12891-021-04308-3. 4. Medicare's national coverage determination states that CMS covers autologous platelet-rich plasma ONLY for patients with chronic non-healing diabetic, pressure and/or venous wounds, and only inside an approved coverage-with-evidence-development clinical study. Every approved study listed under the NCD is a wound-healing study. There is no Medicare national coverage for PRP in osteoarthritis or tendinopathy, which is why these injections are billed to the patient. Centers for Medicare & Medicaid Services — [Autologous Platelet-rich Plasma (Coverage with Evidence Development)](https://www.cms.gov/medicare/coverage/evidence/plasma). *CMS.gov*, 2024. 5. FDA states verbatim of stem cell products, stromal vascular fraction (adipose-derived cells), 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 (hematopoietic progenitor) cells derived from umbilical cord blood, approved only for disorders of blood production, and there are currently NO FDA-approved exosome products. 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. 6. The largest head-to-head trial of cell-based orthobiologics to date randomised 480 patients with KL II-IV knee OA across four arms: autologous bone marrow aspirate concentrate, autologous adipose stromal vascular fraction, allogeneic umbilical cord tissue-derived MSCs, and a corticosteroid injection control. At 12 months NONE of the three orthobiologic injections was superior to another or to the corticosteroid control on either co-primary endpoint (VAS pain, KOOS pain), and none of the four groups showed a significant change in MRI osteoarthritis score from baseline. No procedure-related serious adverse events were reported. Mautner K, et al. — [Cell-based versus corticosteroid injections for knee pain in osteoarthritis: a randomized phase 3 trial.](https://pubmed.ncbi.nlm.nih.gov/37919438/). *Nature Medicine*, 2023. DOI: 10.1038/s41591-023-02632-w. ## What does PRP mean, and can it help a sore knee? The letters PRP stand for platelet-rich plasma, made by spinning blood and saving plasma with extra platelets. Platelets are blood parts involved in healing. In the largest study, both the PRP and salt-water groups reported less pain after twelve months. The difference was too small to show PRP worked better, while other knee studies found more relief. ## Is BMAC marrow treatment better than PRP blood treatment? BMAC means bone marrow aspirate concentrate, made from marrow taken at the back of the pelvis. PRP means platelet-rich plasma, made by spinning drawn blood and saving plasma with extra platelets. A review of twenty-seven knee studies found less soreness in both groups, but no score clearly favored BMAC. The harder marrow procedure hasn’t proved better. ## How long can PRP blood treatment help? There isn’t one set length of relief. A review of eight knee studies found more relief with PRP than cortisone at three, six and nine months. A separate study found no clear difference from salt water after twelve months. Ask which study included joints most like yours. ## Is PRP blood treatment better than a cortisone shot? Cortisone may help sooner, often within two to six weeks. A review of eight knee studies found more relief from PRP at three, six and nine months. Those studies used different scoring scales, so the review doesn’t give one plain number of pain points. Neither choice works the same for everyone. ## What can I do at home for joint soreness? Cut back on the activity that started the soreness, but avoid a full day of rest. Cold may soothe warmth or swelling after use. Gentle heat can ease stiffness before movement. Stop and seek care if pain turns sharp, your knee buckles or swelling keeps growing. ## When does joint soreness need quick care? Seek help quickly if the joint becomes hot, red or swollen very fast. Fever, a joint that looks out of place or being unable to stand also matters. New numbness or marked weakness shouldn’t wait. These signs aren’t part of a mild arthritis flare. ## Bring your questions to the consultation Write down where the joint hurts and which motions bring on soreness. List every medicine you take and bring any earlier X-ray report. You can use the visit to discuss the choices and their limits. Book a free consultation: --- Clear answers for a sore joint. Plain help for knee, hip and shoulder soreness, with ways to ease it, signs needing care and local choices. Plain Scottsdale guidance for understanding joint soreness and the choices that may follow. For clarity, this site is operated by the owners of the Phoenix-area QC Kinetix clinics. © 2026 Scottsdale Orthobiologics Field Guide