How to Stop Knee Pain: Why PRP and Stem Cells Beat A2M Injections

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For many patients, slowing the progression of arthritis is a great way to help stop knee pain in its tracks. One of the newest methods now offered by physicians involves A2M, a naturally occurring chemical in the blood that has been shown to slow arthritis progression in animals. But do you need to seek an A2M-specific treatment–or is A2M already a part of the platelet rich plasma (PRP) and stem cell procedures that are currently available for knee pain? First let’s learn about A2M–then we’ll be able to answer this question clearly so you can decide what type of treatment is best for you.

What is A2M?

A2M stands for alpha-2-macroglobulin. We’ve known about this chemical–officially classified a cytokine–for over 50 years, so it’s not a new discovery. In fact, it’s circulating in your blood right now. What’s new is the idea that A2M might help slow arthritis progression.

One of the hallmarks of arthritis is that the cartilage breaks down and wears away. One of the cytokines in the joint that’s responsible for chewing up healthy cartilage goes by the moniker of MMP (matrix matelloproteinase). There are many of these MMPs in the joint, and some of them can cause your cartilage to degrade. We’ll call MMPs the “bad guys” since they’ll destroy a joint if left unchecked. Chronic inflammation also plays a part in this chemical dance as it enhances the ability of the bad guys to kill cartilage. So think of inflammation as an accomplice–someone who provides the bad guys with the tools they need to commit the crime.

Where does A2M fit into all of this? Think of A2M as a good guy whose job is to bust the bad guy. Basically, it helps block MMPs, which in turn prevents cartilage breakdown. If you have healthy knees, it’s likely that you already have high levels of A2M keeping the MMPs in check. In addition to A2M, many other types of good guys exist to help fight cartilage degradation, like IRAP and TIMP. An arthritic joint may be caused by deficiencies in A2M, IRAP, and/or TIMP.

Can A2M Shots Stop Knee Pain?

Current research says that A2M can help block cartilage breakdown. In an animal study, when researchers found that there wasn’t enough A2M already in the blood to block cartilage breakdown, they injected more A2M around the joint and found a decrease in arthritis progression. Through their research, they discovered the concentration level of A2M that was needed in order to stop arthritis in the joints.

We now have two systems that doctors can use to concentrate A2M in the blood so that it can be injected into a joint. The doctors buying these machines believe they can treat arthritis with this A2M-specific method. In addition, we have many other types of biologic injections being prescribed such as platelet-rich plasma (PRP), platelet-poor plasma (PPP), and bone marrow concentrate (BMC), which all also seem to help arthritis. But could it be that they, too, contain a healthy concentration of A2M?

The video above is fairly complex, but I’ve mixed in a some slides that help keep it simple to understand. It shows that when we measured A2M levels in the common biologics that are being injected to treat knee arthritis, all had fairly high levels of A2M–much more than the minimum amount needed to block cartilage breakdown. Lastly, when we compared the amount of A2M that was already in the joints of patients before our stem cell procedure at Regenexx, the levels of A2M in the joint after the treatment all far exceeded the amount needed to block cartilage breakdown. At this point, there seems to be little rationale for concentrating A2M with one of the new systems coming onto the market, as PRP and stem cell injections already have high concentrations of the stuff, with all of the additional benefits offered by these biologic treatments.

Perhaps one day someone will prove that concentrated A2M helps arthritis more than other cytokines do, but we don’t have evidence of that right now. As far as I’m aware, there are no studies underway that are designed to answer that question as they don’t compare A2M injections to more common treatments, like PRP.

The upshot? If you have mild arthritis, your best bet is likely a PRP injection. If you have severe arthritis, you’ll likely benefit even more from a bone marrow stem cell procedure. On the latter topic, I can say with great confidence that the amount of A2M in your knee will likely rise to much higher levels after our patented knee stem cell procedure.

Hopefully this has helped shed some light on your options for treating knee pain. While we agree with recent research on A2M’s critical role in keeping your knees healthy, we advise against procedures focused only on injecting concentrated A2M. Since PRP and stem cell injections already raise A2m levels in your joints, help reduce knee pain, and slow the progression of arthritis, it’s likely the most reliable option for you on your journey to reclaim your health.

To find out if you might be a candidate for a Regenexx stem cell procedure, complete our Regenexx Procedure Candidate Form online.

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.

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33 thoughts on “How to Stop Knee Pain: Why PRP and Stem Cells Beat A2M Injections

  1. maureen morley

    how much does the bone marrow stem cell injections cost please I am bone on bone both knees thankyou Maureen Morley

    1. Regenexx Team Post author

      Lisa is correct. Whether you’re a candidate or not needs to be established first. Then because these are medical procedures, treatment plans are based on exam, and therefore prices can’t be quoted. The Platelet Procedures (which are enough for some) are in the $1500 range. The range for Regenexx SD (our stem cell procedure) would likely be in the $5500 – $7000 range, it could be a bit higher, depending on what needs to be done, which is approximately the out of pocket cost of a knee replacement without the serious risks and complications.

  2. daryl

    how about painful hip doesn’t work there

    1. Regenexx Team Post author

      Yes, we treat painful hips regularly. Please see:

    2. Regenexx Team Post author

      Yes we treat hips as well:

  3. David Watson

    I use to run marathons and run 40-60 miles a week… Now at 71 my right knee is kaput( torn meniscus cartilage loss, etc. Had one steroid shoot and it worked for 5 weeks and now back to pain. what benefit can i expect to get from stem cells therapy?. How safe is the therapy. Is there a chance it will cause tumors?

    1. Regenexx Team Post author

      The problem with Steroid shots is they kill off the local stem cells, making the situation worse, not better. A catabolic joint stew takes hold and causes further breakdown of cartilage which eventually affects the bone itself if not stopped. Stem cells on the other hand correct the chemical environment in the knee and bring in the repairmen: Bone marrow stem therapy does not cause tumors (that’s an embryonic stem cells), and can even be used in patients WITH cancer: No major complications have been reported.

  4. Rick

    Yes please answer how much is stem cell or A 2M injections?

    1. Regenexx Team Post author

      We don’t do A2M injections. Lisa is correct. Whether you’re a candidate or not needs to be established first. Then because these are medical procedures, treatment plans are based on exam, and therefore prices can’t be quoted. The Platelet Procedures (which are enough for some) are in the $1500 range. The range for Regenexx SD (our stem cell procedure) would likely be in the $5500 – $7000 range, could be a bit higher, depending on what needs to be done, which is approximately the out of pocket cost of a knee replacement, but without the serious risks and complications.

  5. Lisa

    Rick and Maureen, there is no way the doctors can quote you a price until you have an MRI, have them review it and let you know if you are even a candidate. I can tell you that it is not covered by insurance. If you have coverage for an MRI that will be covered but stem cell, PRP and I am assuming A2M injections are not covered either. If you don’t have discretionary cash available of 5 to 10 K in your banking account you should not consider it unles you can take out a loan. I will tell you that it was worth every penny. I had a hip replacement then I found out about stem cell and PRP. I had both done on my knee and I couldn’t be happier. I will never get another joint replaced. With stem cell you keep your own parts, it is much faster, easier and you will be happier. Whatever you do, DO NOT get a cortisone shot if you are even considering stem cell.

  6. Carol

    Who is NOT a candidate for stem cell therapy of knees? Thanks.

    1. Regenexx Team Post author

      Like all medical procedures Regenexx has success and failure rates. That said, knees respond especially well to Regenexx SD (our stem cell procedure). Cases where less robust response would be expected are cases in which the patient has arthritis in many joints:, or has poor blood sugar control. While a good percentage of our patients are knee replacement candidates and do very well, it is possible for the joint to be damaged beyond repair.

  7. Beth

    Do you do PRP or Stem Cell therapy for a torn meniscus on the inside of my knee? How about for tendon injuries in the wrist or elbow.?

  8. Pia Diaconescu

    Do you have any statistics with the results of this procedure?

    1. Regenexx Team Post author

      We have outcome information for all of our procedures, and many peer reviewed published studies. What particular procedure, and on what joint, are you inquiring about?

  9. Rebecca

    Does bone-on-bone arthritis in one compartment (and almost two compartments now) respond to PRP or is it too late.

    What are the odds from studies? And the same question for regenerexx.

    1. Regenexx Team Post author

      Generally, for what is referred to as “Bone on Bone” Arthritis, Stem Cells rather than PRP are needed as the regenerative potential is greater.

  10. Junglee Koirala

    Some places in the USA are performing bone marrow aspirate injection in the knee joint for less than $2000 . Does Regenexx uses more advanced equipment than those places to justify $10000+ price? Thanks

    1. Regenexx Team Post author

      The price point is not accurate, A Regenexx SD stem cell procedure costs closer to half that. Regenexx procedures are very different than other stem cell procedures being offered. A simple BMAC or “bone marrow aspirate injection” from clinic X, is just that: bone marrow aspirated, and re-injected. Regenexx procedures are the most studied stem cell procedures in the world, are the result of 11 years of ongoing research, our doctors are trained more extensively than any other in the regenerative medicine field, and we’ve done and published 33% of the world’s peer reviewed research on the use of bone marrow derived stem cells for orthopedic use, which all account for the difference in our results. Importantly though, each person needs to find what they’re comfortable with…

  11. Jim

    I have chronic low back pain for about twenty years and have been diagnosed with disc degeneration and arthritis; not overweight and exercise regularly. Still an avid golfer at 57 and mostly walk rather than cart, but it is becoming more difficult. Over the years I have tried all the standard treatments and even received a couple of treatments with Regenexx PRP over the last six months, but still no relief. Are stem cell treatments (or any new treatments) available or being developed to treat this type of persistent back problem?

    1. Regenexx Team Post author

      If you’ve had a full workup and Regenexx PL-Disc and Regenexx DDD has not given the level of relief you need the next step would either be stem cells, or in more extreme cases the cultured procedure, Regenexx-C, which is only available in Grand Cayman. I wish I could say any one of the things being brought to market like Mesoblast and others hold any promise, but unfortunately they just don’t.

  12. Gayle Todhunter

    What is the recovery time involved after a Stem cell injection of the knee

    1. Regenexx Team Post author

      That depends on many variables but the results generally become apparent in 1-3 months and in some patients can take 6-9 months.

  13. Jim

    Thanks for the info. There is no MRI evidence my pain is from a disc. A diagnostic procedure under xray guidance determined the specific location but not a definitive cause of the pain. It may be an arthritic facet joint, but that is not certain. The plan is to move forward with an injection of stem cells into this location. I am hopeful the stem cells being more effective than PRP will help alleviate the pain. Although I am optimistic, if this does not succeed I am not sure if there is anything further to pursue? Thanks for providing this website. There is no other place I know that has this information, and can help ordinary people make better informed choices about such critical decisions.

    1. Regenexx Team Post author

      What was the procedure used to determine the location of the pain? Is the planned stem cell procedure a Regenexx stem cell procedure? There are other things to pursue if the current plan is unsuccessful, but I would need the answers to the questions to suggest what could be the next logical step.

  14. Jim

    Flouroscope guidance was used to inject a temporary numbing agent into the location believed to be the source of the pain near the L4-L5 vertebrae. Immediately after the injection I was asked to stand and move around a bit and the pain was almost completely gone. The planned procedure is a Regenexx stem cell procedure performed by a Regenexx doctor listed in your network. The plan is to inject this location with stem cells and hopefully they will provide healing to what is causing the pain. I have also been working with physical/sports training therapists over the past four months on stretching and strengthening with a primary focus on core strength. Workouts have gradually increased to fairly intense with strength and flexibility gaining measured improvement. After four months I had hoped to see some pain improvement but unfortunately it has not diminished at all. However, I plan to continue workouts as I can only see them to be beneficial. The program is monitored by physical therapists and I do not think I am over doing it.

  15. Donna

    This article is misleading regarding A2M injections and the benefits of A2M over PRP. There is quite a bit of research regarding this.

    1. Regenexx Team Post author

      If you can send peer reviewed published research from a reputable journal comparing A2M to PRP, or stem cells, we’d be glad to review it.

  16. Tara

    I would love the see the video (slides) referenced in this article, but I can’t see it.

    1. Regenexx Team

      Hi Tara,
      Just checked and the Video is working. Refreshing the page may help.

  17. Claudia Bondila

    I was recently proposed an injection in the knee, PRP and A2M combined. From your article I understand that PRP injections provide already enough A2M. The injection is supposed to help with pain and stiffness due to meniscus repair and some arthritis. Should I stick only to PRP?

    1. Regenexx Team

      Not all PRP is the same. Where are the injections being done?

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