Knee Replacement After Stem Cell Treatment: How Often Does It Happen?

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knee replacement after stem cell treatment

Do you have knee arthritis, and have you been told you need, or will soon need, a knee replacement? Perhaps you are considering a nonsurgical stem cell treatment instead but want to know what the chances are that you’ll still need to undergo a knee replacement after stem cell treatment. Most of our knee arthritis patients fall into the knee replacement category, and since they are seeking a nonsurgical alternative to a radical and highly invasive surgery, this is a common question in our clinic.

To answer this question, we utilize a registry to track the numbers of patients who go on to get a knee replacement after stem cell treatment in our clinic. Let’s take a look at the percentage of patients who had to convert to a knee replacement after a precise injection of their stem cells with our Regenexx-SD procedure.

What Percentage of Patients Get a Knee Replacement After Stem Cell Treatment?                      

In the fall of 2014, I engaged our Regenexx Twitter followers in a friendly guessing competition for a chance to win $1,000 off a stem cell procedure. Using the hashtag #SatStats to respond, our fans were asked to guess the percentage of patients who had to undergo a knee replacement despite a Regenexx-SD procedure. The responses were all over the board, but what was that actual number?

Right now we have 5,852 patients who have received a knee stem cell or biologic procedure and 3,450 of those who received a same-day stem cell procedure for knee arthritis. Only 3.57% of patients reported that they had converted to a knee replacement after stem cell treatment. However, that number is likely too low. Let me explain.

What About the Patients Who Didn’t Report?

Good question! It’s important to put this percentage into context. This is a treatment registry, and as such, we depend on patient response. Despite our best efforts (e-mailing, calling, offering prizes, etc.), as with any registry, we have patients who just don’t respond. Hence, the actual rate is likely higher.

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Getting to 100% Response

Recently, as part of another research project, I asked our research team to track down 100 patients and get 100% to respond. The goal was to see how many patients we were missing who actually got a knee replacement by two years out from their stem cell procedure.

Of these patients who were a knee replacement candidate at the time of the procedure, our biostatistics staff divided these into right and left knees. Of the 71 right knees, 6 (8.5%) later received total knee replacements (TKRs) at an average of 11 months post-treatment. Of the 64 left knees, 2 (3.1%) received TKRs at an average of 6 months post-treatment. One patient underwent bilateral TKRs.

What Do the Numbers Mean?

The rate of patients who get a knee replacement despite our very specific protocol of same-day stem cell injections is low. That’s good because there’s little doubt that a knee replacement is drastically more invasive and has more complications than a stem cell injection. How many patients have we helped avoid a knee replacement? Using this random sample and applying that to the 5,000 knee-arthritis patients we’re tracking now, we have likely saved thousands from needing this invasive surgery.

The upshot? How often does knee replacement after stem cell treatment happen? Not often, but it does happen. We believe in transparency, which is why you won’t see these numbers published by any other stem cell clinic. For many clinics, it’s all magic and everyone has a miracle, which simply isn’t true. This is a procedure that can produce great results, like most patients dodging the bullet and not needing a knee replacement by two years after the procedure, but like all medical procedures, it can also fail to work.

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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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Category: Knee, Regenexx-SD

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27 thoughts on “Knee Replacement After Stem Cell Treatment: How Often Does It Happen?

  1. Ron Anderson

    As an athlete, how much down time after stem cell treatment?

    1. Regenexx Team Post author

      It depends. What would you be treating?

  2. mary kauflin

    One year out and doing good. Glad I had it done.

  3. Patti

    How does PRP compare with stem cells for knee arthritis?
    Can PRP “stand alone” as an effective treatment?

    1. Regenexx Team Post author


      It can be. What’s important is matching the right treatment to the right issue. Regenexx SCP, is much more powerful than PRP, and is often used for mild knee arthritis. What these platelet procedures do is to work as an “espresso shot” for the local stem cells, waking them up and getting them to work. With more severe arthritis, there is a lack of stem cells, so waking them up won’t help, instead a whole new supply is needed, which are the cases for which we use precise image guided injections of your stem cells to the specific areas they are needed. Please see:

  4. Vickie Sandusky

    Do you have to wear a brace after Regenexx?

    1. Regenexx Team Post author


      It depends on what’s done. Most knee and ankle stem cell patients wear a brace during the 3 appointment protocol, and your doctor decides whether it needs to be used afterwards and for how long. Generally, we like patients to move normally as soon as possible as it helps stem cells to differentiate. ACL patients generally wear the brace for the longest, which is usually about 6 weeks, (compared to up to 2 years for surgery) Please see:

  5. Bob Wagner

    How many get hip replacement after stem cell injections?

    1. Regenexx Team Post author


      The stats aren’t currently broken down that way. Put in a request, and given that they are actively tracking more than 9,000 patients, it will take some time.

  6. Mike Nelli

    Dr. Centeno, have you done the same study regarding the Regenexx-C procedure? Fortunately I was able to get that done in CO in ’08 and ’09, and am still going strong with basketball and ultimate Frisbee. Still can’t thank you enough…

    1. Regenexx Team Post author

      Great to hear you’re still kickin’it! We’ve not actually broken down the data, but something we will do in the future…

  7. DavePG

    Thanks for this blog and great information. Question: does Regenexx (and/or providers in your network) do PRP, PL and/or Stem Cell treatments for what I believe may be case of, at least at this point, fairly mild, occasional but stubborn peroneal tendonitis or tendonosis? X-rays and a bone scan were negative for fracture in the intermittently sore area (near base of the 5th metatarsal where this meets the peroneal brevis tendon) that seems to flare after harder (running) workouts (I’m a very active older amateur athlete). And would I need an MRI or could you diagnose this by ultrasound or something else? Finally, if applicable and generally speaking of course, what would be the downtime for a PRP or PL procedure for this (e.g return to activity, would I have to wear a boot etc.)? Many thanks!

    1. Regenexx Team Post author

      Yes, we do. Just make sure that you choose a Regenexx Provider who has foot/ankle on their list of area’s treated. This was a similar case done here in Colorado, though what procedures are needed and the treatment plan for each case is unique: Interactive Regenexx Provider List:

  8. Susan Ellis

    I had a RegenexxSD stem cell treatment last February on my right knee. I was told before the procedure that I was a marginal candidate but elected to have it anyway. I had a booster injection at the end of April and again in November. Unfortunately, I am still having significant pain and difficulty going about my daily activities. I have made an appointment with an orthopedic surgeon to have my knee replaced in May. I have tried everything I can think of to avoid surgery but I am tired of the pain and disability. That being said I would do it all again. Dr Amaroso was great to work with and I’m sorry by knee did not cooperate!

    1. Regenexx Team Post author

      It’s important to do all you can do before a joint replacement. You have! We are hoping the very best for you…a smooth procedure and great recovery. When in May?

  9. Dale Price

    I had regenexx-sd performed on both knees in January, 2017. I am now 3 weeks and 2 days from the 3rd day protocol…. Is it possible that I would actually notice a marked improvement in being able to walk without limp, and less popping sound when getting up from sitting? or, is it just purely in my mind? I want this to work so badly, and I could swear it is.. Thank you for your research into an alternative to knee amputation replaced with a prosthetic (I refuse to call this barbaric procedure a “knee replacement “) God bless you and your entire team!

    1. Regenexx Team Post author

      It is! Take it slow though as soon you might experience some temporary returned instabiity as the internal swelling goes down and the stem cells are busy doing there thing. But that kind of response that early is great news!

    2. PattyL

      @Dale Price – I was told by an ortho that all three of my knee compartments were significantly degenerated, several bone spurs, significant/obvious crepitus, etc, etc. Two orthos were ready to do a total knee on me.
      I had my stem cell tx Thanksgiving week, and after the first couple of days, once the initial (pretty significant) swelling from the treatment itself went down, I noticed a very significant decrease in pain that soon. Obviously, cartilage regeneration doesn’t occur in two days, but maybe my knee felt so much better so quickly because stem cells have such significant anti-inflammatory properties. Not sure.
      Also, just a few days in I started noticing my extension improving. Pre-treatment, I couldn’t extend w/out extreme medial pain, so as a result I didn’t extend my knee when I walked (and had a hideous gait). I still walk with a limp, but much less pronounced. Flexion and extension have both improved quite a bit. I also don’t hear the crackling in my knee hardly at all anymore.
      So far I’m pleased and hoping for continued improvement. (But addressing your question, my improvement also started a lot sooner post-procedure than I expected.)

      1. Regenexx Team Post author


        Great news! Sometimes the knee is so void of healthy stem cells it’s like getting water in a desert!

  10. Venetia Santichen

    I have grade 2 osteoarthritis in my right knee. I have pain daily. Could I be a candidate at this stage?

    1. Regenexx Team Post author

      Yes. Stage 2 knee osteoarthritis is comparatively mild, so an exam is important track down the source of pain. Please see: You can get this type of exam at these locations: If not local to those locations, you can submit the “Are You a Candidate” form, which will allow you to upload MRI’s and medical history and speakt one of our Physicians to establish Candidacy.

  11. Cynthia Finley

    I had meniscus surgery in 1969. I was told that all of the meniscus was removed. I have significant daily pain and have to take steps one at a time. I’ve been told by 2 doctors that I need TKR. Am I a good candidate for stem cell treatment?

    1. Regenexx Team Post author

      Forty eight years with no meniscus is remarkable, but we’d need to see a recent MRI to answer that question. There are two main issues with the removal of a meniscus. It leaves the knee unstable which leads to more wear and tear, and without the shock absorption and the protection the meniscus provides the knee cartilage, there is nothing to protect it against that wear and tear. If you’d like to upload your MRI, speak to one of our Physicians and see if you’d be a good Candidate, you’ll find the Candidate form here:

  12. Phil

    How long do the results typically last?

    1. Regenexx Team Post author

      Most patients get a single knee stem cell procedure. Some require an update or two. Here is one of our knee patients who commented about their knee procedure recently: and

  13. Martha

    Hi I had poliyo In one leg since, birth and which developed arthritis in my right knee I’m I the Candidate for stem cell therapy I’m only 25 I wants to avoid TKR plz help me out of this situation I’m very worried about my condition.

    1. Regenexx Team Post author

      There is a process to gather the information needed to see if someone is a Candidate. To do that, please submit the “Are You a Candidate” Form at this link:

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