Research Summary
Umbilical Cord Stem Cell Injections Beat Hyaluronic Acid for Severe Knee Arthritis in a Small 50-Patient Trial
Repeated injections of umbilical cord stem cells eased pain and improved function more than hyaluronic acid over 1 year in people with severe knee arthritis, a small randomized trial found. The study was published in Stem Cell Research & Therapy in 2026.
What was studied
Researchers in China tested umbilical cord mesenchymal stem cells (UC-MSCs), cells that are thought to calm inflammation and support tissue repair. In a single-center, triple-blind randomized controlled trial, 50 patients with advanced knee osteoarthritis (Kellgren-Lawrence grade III or IV) received either 4 stem cell injections 2 weeks apart (25 patients) or 5 weekly injections of sodium hyaluronate, a common hyaluronic acid "gel" shot (25 patients). Patients were followed for 12 months, including MRI scans.
Key findings
- On a 10-point pain scale, pain fell by about 3.8 points in the stem cell group versus about 2.4 points with hyaluronic acid, and the stem cell group showed no rebound over the year.
- WOMAC arthritis scores improved by 23.2 points with stem cells versus 15.6 points with hyaluronic acid.
- MRI cartilage repair scores improved more with stem cells, and bone marrow swelling (edema) in the thigh bone cleared in 80% of stem cell patients versus 44%.
- No serious side effects, such as joint infection or severe allergic reaction, occurred in either group.
What it means for people with knee pain
For people with severe knee arthritis who want to delay or avoid surgery, this adds early evidence that stem cell injections may help more than hyaluronic acid. It is not yet proof that this treatment should be standard care, so it is worth discussing with an orthopedic specialist before seeking it out.
Limitations
The trial was small, ran at one center, and lasted only 1 year. The two groups got different numbers of injections on different schedules, and there was no placebo group, so it cannot show how stem cells compare with no active treatment. Larger, longer trials are needed to confirm the benefits and long-term safety.
Frequently asked questions
- Do stem cell injections work for severe knee arthritis?
- In this 50-patient trial, umbilical cord stem cell injections gave more pain relief and function improvement over 12 months than hyaluronic acid injections. Because the study was small and single-center, larger trials are needed to confirm the results.
- How many stem cell injections did patients get?
- Patients in the stem cell group received 4 injections into the knee, given 2 weeks apart. The comparison group received 5 weekly hyaluronic acid injections.
- Were there serious side effects?
- No serious adverse events, such as joint infection, severe allergic reaction, tumor growth, or events needing hospital care, were seen in either group during the 12-month study.
Sudden severe pain, swelling, or can't bear weight? Seek medical care promptly. In an emergency call 911.