Does Umbilical Cord Stem Cell Therapy Work for Knee Arthritis?
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By Dr. Jeffrey Peng, MD · Published March 6, 2026 · 7 min read
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Stem cell therapy continues to generate excitement as a potential treatment for chronic joint pain. Among the various sources of stem cells being studied, umbilical cord-derived mesenchymal stem cells have emerged as a particularly interesting option. Unlike bone marrow or adipose-derived stem cells — which are harvested from the patient's own body — umbilical cord stem cells come from donated tissue after delivery, offering a theoretically unlimited supply of young, potent cells.
As a sports medicine physician who specializes in orthobiologic treatments, I have been closely following the research on these newer cell-based therapies. In this post, I will break down what umbilical cord stem cells are, how they are obtained, and what a recent systematic review tells us about whether they actually work for knee arthritis.
What Are Umbilical Cord Stem Cells?
Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) are a type of cell harvested from tissue that would otherwise be discarded after childbirth. There are two primary methods for obtaining these cells.
The first method involves isolating cells directly from the placenta — the organ that provides oxygen and nutrients to the developing baby. After delivery, the placenta is normally discarded. Pharmaceutical companies can take this tissue and process the cells under sterile conditions to create an injectable product suitable for treating arthritic joints.
The second method involves collecting stem cell-rich cord blood and processing the blood products obtained from it. This is conceptually similar to drawing blood to produce platelet-rich plasma (PRP), except the source material comes from the umbilical cord rather than the patient's veins. The cells are then cultured, expanded, and sterilized for clinical use.
Why Consider Umbilical Cord Stem Cells Over Other Sources?
One of the main advantages of umbilical cord-derived stem cells is that they are not limited by the patient's age. As we get older, our own stem cell counts decline. For elderly patients with chronic orthopedic conditions — the population most likely to benefit from regenerative treatments — lower cell counts from their own bone marrow or fat tissue may translate to reduced effectiveness.
Umbilical cord stem cells bypass this limitation entirely. They provide a rich source of cells and growth factors regardless of the patient's age or medical comorbidities. Additionally, some research suggests that these cells may have greater proliferative capacity than cells obtained from bone marrow or adipose tissue, meaning they may be able to multiply and differentiate more effectively.
Does Umbilical Cord Stem Cell Therapy Work for Knee Arthritis?
A systematic review published in the Orthopaedic Journal of Sports Medicine examined this question by analyzing seven studies with a total of 385 patients. The mean follow-up period was approximately two years.
Injection protocols varied considerably across the included studies. Four studies administered a single injection. One study combined a single stem cell injection with two subsequent hyaluronic acid injections. Another gave a second injection at six weeks if pain had not improved. The final study administered injections at baseline and again at six months.
In terms of outcomes, four of the five studies that reported WOMAC scores — a widely used functional scoring system for osteoarthritis — demonstrated significant improvement from pretreatment to the latest follow-up. Results using the IKDC scoring system were more mixed: two of four studies found statistically significant improvement, while the other two showed trends toward improvement without reaching statistical significance. VAS pain scores followed a similar pattern, with two studies reaching significance and two showing favorable trends.
What Are the Side Effects of Umbilical Cord Stem Cell Injections?
An important consideration with any allogeneic (donor-derived) injection is the risk of adverse reactions, since a foreign substance is being introduced into the joint. The systematic review found that the most commonly reported side effect was post-injection pain — a reaction that is typical of any intra-articular injection. There were no reports of allergic reactions or infections. In three of the seven studies, no adverse reactions of any kind were reported.
What Do We Still Need to Know?
While these early results are encouraging, several important limitations remain. The total sample size of 385 patients across seven studies is relatively small. Injection protocols varied widely between studies, making direct comparisons difficult. Most critically, we lack head-to-head comparative data between umbilical cord stem cells and other established treatments such as bone marrow-derived stem cells or PRP.
The authors of the systematic review concluded that patients treated with hUC-MSCs for knee osteoarthritis might be expected to experience clinical improvements, but that additional high-quality randomized studies are needed to better determine their efficacy.
Are Umbilical Cord Stem Cell Injections FDA Approved?
It is important to understand that human umbilical cord-derived stem cells are currently not approved by the FDA for the treatment of osteoarthritis. Because of this, physicians in the United States cannot perform these treatments outside of an active clinical trial. Patients should be cautious of any clinic offering umbilical cord stem cell injections outside of a research setting, as these products are not regulated for clinical use.
Moving Beyond Cortisone: The Future of Orthobiologic Treatments
Despite the current limitations, research into umbilical cord stem cells represents an important step forward in the field of regenerative medicine. We are learning more every year about how different orthobiologic treatments — including PRP, bone marrow-derived stem cells, adipose-derived stem cells, and now umbilical cord stem cells — can benefit patients suffering from knee arthritis.
The key questions that need to be answered are: Which injection source is most effective? What is the optimal treatment protocol? How do these therapies compare to each other in well-designed head-to-head trials? What is their long-term safety profile?
What is increasingly clear is that the field of orthobiologics is moving away from repeat cortisone injections, and treatments like PRP and stem cell therapy offer promising alternatives. If you are interested in learning more about nonsurgical treatment options for knee arthritis, I encourage you to schedule a consultation to discuss which approach may be right for you.
References
1. Dhillon J, Kraeutler MJ, Belk JW, Scillia AJ. Umbilical Cord-Derived Stem Cells for the Treatment of Knee Osteoarthritis: A Systematic Review. Orthop J Sports Med. 2022;10(7):23259671221104409. doi:10.1177/23259671221104409
Medical Disclaimer: This content is for educational purposes only and does not substitute for the medical advice of a physician. Always consult your healthcare provider before beginning any new treatment program. The information presented reflects the opinion of Dr. Jeffrey Peng and does not represent the views of his employers or affiliated hospital systems.
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