What people ask about a sore joint

Sources

1. Arnold Caplan, who NAMED mesenchymal stem cells more than 25 years earlier, argued in Stem Cells Translational Medicine that the name should be changed. His stated reason is exactly the marketing problem: because MSCs are called 'stem cells', patients infer they will receive direct medical benefit, imagining the cells will differentiate into regenerating tissue-producing cells - and hundreds of clinics and trials now use human MSCs with very few focusing on the in vitro multipotential capacities the name refers to.

   Caplan AI, et al. — Mesenchymal Stem Cells: Time to Change the Name!. Stem cells translational medicine, 2017. DOI: 10.1002/sctm.17-0051.

2. A Nature comment by Sipp, Robey and Turner arguing that loose use of 'mesenchymal stem cell' across an enormous range of unrelated cell preparations has produced a scientific and commercial mess, and calling for the terminology and the evidentiary standards to be tightened. Included because the objection to the word comes from inside stem cell science, not from its critics.

   Sipp D, et al. — Clear up this stem-cell mess.. Nature, 2018. DOI: 10.1038/d41586-018-06756-9.

3. A dual systematic review compared the RCT evidence on injectable orthobiologics for knee OA with how news media describe it. Of 14 qualifying RCTs, 8 showed significant pain improvement and 10 function improvement, with frequent heterogeneity and risk of bias. Of 124 news articles: 79.0% highlighted benefits, only 29.8% mentioned drawbacks, 37.1% used the term 'stem cell' without specifying the product, 35.5% mentioned commercial entities with no disclosure, and 66.1% were favourable in tone. The authors conclude this disconnect encourages unrealistic expectations.

   Zhang EJX, et al. — Disparities in Evidence and Media Portrayal of Injectable Orthobiologics for Knee Osteoarthritis: A Systematic Review of Randomized Trials and News Media.. Orthopaedic journal of sports medicine, 2026. DOI: 10.1177/23259671261443876.

4. A JBJS systematic review screened 420 papers on intra-articular cellular therapy for knee OA and focal cartilage defects and found only SIX at Level III evidence or higher (4 Level II, 2 Level III), covering 300 knees, with wide variation in cell source, cell characterisation, adjuvant therapy and outcome assessment - meaning no consensus exists on indications, cell sources, preparation or delivery. Two products called 'stem cell therapy' at two clinics may share almost nothing.

   Chahla J, et al. — Intra-Articular Cellular Therapy for Osteoarthritis and Focal Cartilage Defects of the Knee: A Systematic Review of the Literature and Study Quality Analysis.. The Journal of bone and joint surgery. American volume, 2016. DOI: 10.2106/JBJS.15.01495.

5. FDA states plainly that no stem cell, exosome, stromal vascular fraction, umbilical cord blood, Wharton's jelly or amniotic-fluid product has been approved for the treatment of ANY orthopedic condition - it names osteoarthritis, tendonitis, disc disease, tennis elbow, back pain, hip pain, knee pain, neck pain and shoulder pain individually. The only FDA-approved stem cell products in the United States are cord-blood-derived blood-forming stem cells for disorders of the hematopoietic system, and there are currently no FDA-approved exosome products.

   US Food and Drug Administration, Center for Biologics Evaluation and Research — Consumer Alert on Regenerative Medicine Products Including Stem Cells and Exosomes. FDA, 2020.

6. Medicare's National Coverage Determination covers autologous platelet-rich plasma ONLY for chronic non-healing diabetic, pressure or venous WOUNDS, and only under Coverage with Evidence Development inside an approved clinical research study. There is no Medicare coverage pathway for PRP as a treatment for osteoarthritis or any other joint indication, which is why these injections are quoted as cash prices.

   Centers for Medicare & Medicaid Services — Autologous Platelet-rich Plasma (Coverage with Evidence Development). CMS.gov, 2012.

7. The RESTORE trial - a participant-, injector- and assessor-blinded RCT of 288 adults aged 50+ with symptomatic medial knee OA (Kellgren-Lawrence 2-3) - compared three weekly intra-articular PRP injections against saline placebo, with co-primary endpoints of 12-month knee pain and medial tibial cartilage volume on MRI. PRP did not beat placebo on either. It is the single best-designed test of the specific claim that PRP changes joint structure, and it was negative.

   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.. JAMA, 2021. DOI: 10.1001/jama.2021.19415.

8. A four-arm, multicentre, single-blind phase 2/3 randomized trial of 480 knee OA patients (KL II-IV) compared autologous bone marrow aspirate concentrate, autologous adipose stromal vascular fraction and allogeneic umbilical-cord-tissue mesenchymal stromal cells against a corticosteroid injection control. At 12 months NONE of the three orthobiologic injections was superior to another, or to the corticosteroid control, and none of the four groups showed a significant change in MRI osteoarthritis score from baseline. No procedure-related serious adverse events occurred.

   Mautner K, et al. — Cell-based versus corticosteroid injections for knee pain in osteoarthritis: a randomized phase 3 trial.. Nature medicine, 2023. DOI: 10.1038/s41591-023-02632-w.