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ACL Stem Cell Surgery: Do You Need Knee Surgery to Get an Injection?

POSTED ON IN ACL Procedure Outcomes Latest News Regenexx-SD BY Chris Centeno


I’m a pretty practical guy. At the end of the day, I try and relate everything to the real world, as in medicine, it’s easy to get caught up in the “medical bubble.” What do I mean? To get too caught up in the business or science of medicine and forget about how medical decisions impact patients. In fact, I love a saying by Confucius that intersects with that concept: “Never use a cannon to kill a fly.” Today I was e-mailed by a European professional footballer who tore his ACL and was offered a same-day stem cell injection, but the procedure would be an ACL stem cell surgery to accomplish an injection? Huh?

Developing a Procedure to Heal Knee ACLs with Stem Cells

We invented a procedure many years back that used a same-day stem cell injection to heal the knee ACL. The first times we tried injecting the torn ACL, it wasn’t a reliable procedure. By this, I mean that sometimes we would hit the ligament and sometimes it would be a miss. We tried it both with fluoroscopic and ultrasound guidance and decided that using the X-ray was a better way to go. We also tried using a min-arthroscopy procedure to guide the needle, but in the end, as our injection techniques using fluoroscopy got better and better, we didn’t need the surgical approach. In fact, it just added risk without adding benefit.

Why would an injection with X-ray be better than an ACL stem cell surgery? After all, since the ACL ligament stabilizes the knee and lives deep in the middle of the joint and it can be easily seen using arthroscopic knee surgery, shouldn’t this be better? The problem with injecting this ligament with surgical visualization is that you have no idea how the cells are spreading inside the ligament. However, with fluoroscopy, you can see the contrast dye spread through the ligament. Why is this critical?

Since we developed this procedure, we’ve treated more ACLs with stem cells than any other clinic on earth. We’ve also had a chance to compare the results of how the injection spreads through the ligament. When we see complete coverage to all of both parts of the ligament, we see better healing on MRIs and overall success after the procedure. Hence, having a way to document that the cells are hitting all areas is essential.

The Real Regenexx ACL Stem Cell Treatment vs. a Copy of a Copy

The professional football athlete (what we call soccer here in the U.S.) who contacted me was told by a clinic outside the U.S. that he was a candidate for ACL stem cell surgery to perform an “injection” where arthroscopic surgery would be used to guide the needle. I know the clinic that told him he was a candidate for that procedure. They do a good job, but in this area, they can’t match our experience level with this technique. Hence, I told this athlete to send me his MRI films. This is where what he was offered was very different from what we do in a Regenexx ACL procedure.

  1. Candidacy: Through the years, we’ve figured out who is a good candidate and who is more likely to have this procedure fail. This is based on how the ligament appears on MRI and a very particular set of measurements. If this value is more than 6 or 7 mm, the procedure is likely to fail. In this patient’s case, that measurement was a 12! The likelihood that this procedure could regenerate and heal the ACL tear was very, very small.
  2. Injection: While the surgeon who was going to inject this ACL is excellent, he doesn’t know how to perform this procedure and has no way using arthroscopy to see which parts of the ligament are getting cells and which parts have no cells. Finally, injecting stem cells into the water-based environment of arthroscopy will dilute the strength of the injection, which isn’t a problem when the knee is injected using fluoroscopy. Also, even if you can stick the ligament many times in many areas, another issue is that the surgery adds risk without benefit. Hence, this provider doesn’t have the needed skill set or tools to maximize the chances of success for this patient. The good news is that the Interventional Orthopedics Foundation has courses on how to perform the ACL injection procedure under fluoroscopy guidance, so training is available.
  3. HD-BMC: An ACL ligament can’t hold more than a few ccs of stem cells. However, most commercial systems can’t concentrate stem cells to that high a level. In fact, no commercial system or manual system can concentrate stem cells to the same level as Regenexx. This is why we call what we inject, HD-BMC, or high-dose bone marrow concentrate.

The upshot? You don’t need knee surgery to get your ACL injected! In fact, this will only add risk and reduce the overall quality of the injection. However, injecting this ligament without surgery is difficult to do properly. So if someone tells you they can do this without having taken the IOF training and passed that course, they’re not qualified to do the injection. Make sure your doctor is properly trained! And one more thing, never use a cannon to kill a fly!




    Artee Lewis says

    Does your procedure help with Chrondramalsia? I have a grade 4.


    Chris Centeno says


    Yes, These case studies are the same patient. Please see: and and and and


    Rod Olsen says

    Hello Regenexx!

    Am I a viable candidate?

    68 years young - R medial meniscus surgery 1972 - L medial meniscus surgery 1975 - diagnosed with torn R ACL in 2003 (diagnosed as an "old" injury - no surgery as I was referring Division I Soccer and other than a occasional hitch in my giddy up)

    currently experience pain on insides of both knees and according to family and friends I look like I am struggling.

    I walk 3+ miles/day and stopped running 3 years ago when I saw how much space I had lost in my x-rays.

    would like not to have surgery if possible

    am healthy and wonder if I am a candidate for your treatment?

    Please advise.


    Chris Centeno says


    It's likely, as you fit into the profile of many of our knee patients. However our Candidacy process requires one of our Physicians to read the MRI of your knees rather than the report, and a full medical history, etc. Please submit the Candidate form if you'd like us to take a look:


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    About the Author

    Chris Centeno

    Christopher J. Centeno, M.D. is an international expert and specialist in regenerative medicine and the clinical use of mesenchymal stem cells in orthopedics. He is board certified in physical medicine as well as rehabilitation and in pain management through The American Board of Physical Medicine and Rehabilitation.…

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