Are there stem cells in my knee? Stem Cell Number in the Synovial Fluid Increases after Knee Meniscus Injury

By /

are there stem cells in my knee?

Are there stem cells in my knee? Most patients seem surprised that there are stem cells in their knees. We did a study many years ago where we injected a pro-inflammatory agent into the knee joint and drew off the swelling in the joint. What was in the fluid? When compared to the other knee we didn’t treat, the fluid had many more stem cells. So it’s not a surprise today to see a recent study that shows that the natural stem cell number in the knees is higher when someone tears a meniscus. It’s also fitting that this study comes on the heels of new research showing that surgical treatment for knee meniscus tears doesn’t work.

Why are we seeing more stem cells in knees where the meniscus has been injured? Because these cells normally live in the synovial membrane, the inside lining of the knee joint. When there is an injury, they mobilize from there to the fluid so they can hitch a ride to the injury site (in this case the knee meniscus). This is why younger patients who injure their knees tend to heal more often, they simply have more stem cells that are available in the synovial membrane. I call this the “stem cell reserve”, which naturally declines as we age. Now this process of getting stem cells from the knee joint lining to the injured site (like a meniscus) isn’t that efficient. Many will end up somewhere else in the knee and some won’t attach to the right portion of the meniscus tear. Hence, when performing knee stem cell therapy, this is why exact placement becomes so important. You want to make sure you get the maximum number of cells where they are needed. For example, for a meniscus tear, this takes a high level of expertise in ultrasound guidance of the injection, so the stem cells make it to the parts of the tear where they’re needed. In addition, early studies showing that stem cell injections into the knee may help reduce the progression of arthritis, likely give credence to this concept of replenishing a worn out stem cell reserve with new cells.

The upshot? There are stem cells in your knees and they’re important in helping you heal. So the next time you tweak your knee, know that it’s mobilizing an army of repairmen into the spot. However, because of your age or the size of the injury, this army of cells may need some reinforcements!

Learn about Regenexx procedures for knee conditions.

If you have questions or comments about this blog post, please email us at [email protected]

NOTE: This blog post provides general information to help the reader better understand regenerative medicine, musculoskeletal health, and related subjects. All content provided in this blog, website, or any linked materials, including text, graphics, images, patient profiles, outcomes, and information, are not intended and should not be considered or used as a substitute for medical advice, diagnosis, or treatment. Please always consult with a professional and certified healthcare provider to discuss if a treatment is right for you.

Get Blog Updates by Email

By submitting the form, you are agreeing that you read and consent to our Privacy Policy. We may also contact you via email, phone, and other electronic means to communicate information about our products and services. We do not sell, or share your information to third party vendors.

Category: Knee, Latest News
Copyright © Regenexx 2021. All rights reserved.



9035 Wadsworth Pkwy #1000
Westminster, CO 80021


*DISCLAIMER: Like all medical procedures, Regenexx® Procedures have a success and failure rate. Patient reviews and testimonials on this site should not be interpreted as a statement on the effectiveness of our treatments for anyone else.

Providers listed on the Regenexx website are for informational purposes only and are not a recommendation from Regenexx for a specific provider or a guarantee of the outcome of any treatment you receive.