Marc Darrow MD, JD 

In this article I will present research on the use of stem cell therapy treatments for knee osteoarthritis. I will discuss published research by the Darrow Stem Cell Institute on the use of bone marrow derived stem cells and discuss the use of amniotic tissue treatments, umbilical cord blood treatments and adipose or fat derived stem cells  We will explore the newest research and clinical applications. I also invite you to ask your questions using the form below about your knee pain.

In our office we offer two types of stem cell treatments:

  • Bone marrow derived stem cell therapy.
  • Umbilical cord blood derived stem cell therapy.
  • WE DO NOT OFFER: Amniotic or Adipose treatments.

Before we get to updates, let’s review the research we conducted at the Darrow Stem Cell Institute in Los Angeles, California on patients with knee osteoarthritis.

Short-Term Outcomes in Treatment of Knee Osteoarthritis With 4 Bone Marrow Concentrate Injections
Brent Shaw, Marc Darrow, MD JD : Darrow Stem Cell Institute, Los Angeles, CA, USA
Armen Derian : Mayo Clinic, Phoenix, AZ, USA
Clinical Medicine Insights: Arthritis and Musculoskeletal Disorders June 18, 2018 (1)

Study synopsis
Preliminary research suggests that bone marrow concentrate (BMC), which contains mesenchymal stem cells and platelets, is a promising treatment for knee osteoarthritis. The aim of this study was to build on this preliminary research by reporting the short-term progress of 15 patients (20 knees) with knee osteoarthritis through 4 BMC (bone marrow derived stem cell treatments.)

The timetable of the four treatments:

  • First treatment
  • Second treatment approximately 14 days after first treatment.
  • Third treatment, approximately 21 days after second treatment, 35 days after first treatment
  • Fourth treatment, approximately 34 days after the third treatment. Approximately 69 days on average after first treatment
  • The last follow-up was conducted a mean 86 days after the first treatment.

What we measured: Overall improvement percentage was compared after each treatment for the following:

  • pain at rest
  • pain during activity
  • functionality scale scores

What we found:

  • Patients experienced statistically significant improvements in active pain and functionality score after the first treatment.
  • Additionally, patients experienced a mean decrease in resting pain after the first treatment, yet outcomes were not statistically significant until after the second treatment.
  • On average, patients experienced:
    • an 84.31% decrease in resting pain,
    • a 61.95% decrease in active pain,
    • and a 55.68% increase in functionality score at the final follow-up.
  • Patients also reported a mean 67% total overall improvement at study conclusion. Outcomes at the final follow-up after the fourth treatment were statistically significant compared to outcomes at baseline, after first treatment, after second treatment, and after third treatment.

In this study we concluded: “These results are promising, and additional research with a larger sample size and longer follow-up is needed to further examine the treatment effectiveness of multiple BMC injections for knee osteoarthritis.”

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Recent research on bone marrow derived stem cells

A study published in the Archives of orthopaedic and trauma surgery (2) in August 2019 offered these observations on improved outcomes after mesenchymal stem cells injections for knee osteoarthritis: results at 12-months follow-up. This was a systematic review of 18 medical studies and 1069 knees offered treatment.

  • 72% of the included studies harvested the stem cells from the iliac crest (bone marrow-derived MSCs),
  • the remaining 28% from the adipose tissue (adipose-derived MSCs).

The investigators woote: “According to the current evidences and the main findings of this systematic review, we reported that MSC infiltrations for knee osteoarthritis can represent a feasible option, leading to an overall remarkable improvement of all clinical and functional considered outcomes, regardless of the cell source. Patients treated at earlier-degeneration stages reported statistically significant greater outcomes. The pain and function scores were improved considerably, thus, leading to a significant improvement of patient participation in recreational activities and quality of life.”

A study in the journal Cytotherapy (3) , examined the injection of  mesenchymal stromal cells (bone marrow derived stem cells) as a treatment for knee osteoarthritis.

The study subjects were randomized into two groups:

  • A single injection of stem cells, or
  • A placebo injection of saline solution

Patients were followed up for 6 months after the injection.

Scores were recorded for :

  • Pain level and function improvements to include: walking distance, painless walking distance, standing time and knee flexion compared with the placebo group at 3 and 6 months

The conclusion of this research was the bone marrow derived stem cell injection demonstrated safety and effectiveness. However more research would be needed to confirm this.

Research: Bone marrow derived stem cell injection provided significant and clinically relevant pain relief over 6 months versus placebo.

In their 2016 study published in the journal Clinical and translational medicine,(4) researchers at Georgia Regents University wrote: “Current pharmacological treatment strategies are ineffective to prevent the osteoarthritic progression; however, cellular therapies have the potential to regenerate the lost cartilage, combat cartilage degeneration, provide pain relief, and improve patient mobility.” They add that among the cellular therapies, bone marrow-derived stem cells which have been shown to  have a higher chondrogenic capability (the ability to make cartilage) than adipose (fat) derived stem cells, and they have been studied more extensively than the fat derived stem cells.

They also note that: “Due to the increasing incidence and prevalence of osteoarthritis, more innovative and effective therapeutic modalities need to be investigated, including MSCs. More randomized clinical trials need to be completed in order to demonstrate the efficacy, safety, and benefits of MSCs in treating patients with osteoarthritis.”

Our conclusions about bone marrow derived stem cells for knee osteoarthritis

Returning to our own published research cited above, I would like to recap the learning points:

  • We found that in the short-term, receiving multiple injections may be more effective than receiving a single Bone Marrow Concentrate stem cell injection.
    • Outcomes at the final follow-up after the fourth treatment were statistically significant compared with outcomes at baseline, after first treatment, after second treatment, and after third treatment.
  • Functionality score increased after first treatment, illustrating that patients experienced an immediate benefit in performing everyday activities with less difficulty.
  • By the second injection, patients began to report improvement with pain at rest. Patients then experienced additional decreases in resting pain with each treatment thereafter.
  • The increase in mean functionality score with successive BMC treatments shows that increasing the number of BMC treatments improves patient performance in daily activities. 

The present findings may provide new clinical insights into treating osteoarthritis with Bone Marrow Concentrate. If Bone Marrow Concentrate treatments become more affordable or covered by insurance companies, there could be an increase in the number of patients receiving multiple Bone Marrow Concentrate treatments for osteoarthritis. If patients who reported improvement to a single injection received multiple, they may experience increased symptomatic relief such as the patients in our study. An additional finding illustrated that patients experienced a greater pain relief when injected with a high-nucleated cell count compared to a lower dose. Our study demonstrates that gradual increase in BMC injections in a short time period may be more effective than a single injection.

We do call on more research to help validate our findings as our small sampling case studies are not definitive.

Side effects

When patients were asked whether they experienced adverse side effects at each follow-up, the most common complaints were pain at the extraction site and inflammation at the injection site. Grinding, popping, and snapping sensations in the knee joint were common with specific movements, as was joint stiffness, especially 1 to 2 days following treatment. However, the stiffness generally resolved by the next follow-up visit.


In 2017, doctors reported their findings in the journal Stem cells translational medicine (5) of a seven-year observation of patients who had received human umbilical cords stem cell therapy for knee osteoarthritis:

Here are the safety learning points of this research:

  • This study revealed that treatment with an allogeneic human umbilical cord blood stem cells is safe.
  • The results of the study show that the patients had no significant adverse effects or undesired effects over the seven years of follow‐up.
  • None of the study participants had substantial permanent degenerative disease.
  • The study found no evidence of abnormal findings suggesting rejection or infection.
  • The researchers suggest that the characteristics of the human umbilical cord blood stem cells such as hypoimmunogenicity (does not cause an immune system reaction) and immunomodulatory (the immune system does not consider these “foreign” cells to be invaders) activity contributed to the lack of the stem cells rejection.
  • There were no cases of osteogenesis (bone mutation) or tumorigenesis over 7 years.

Here are the learning points regarding the outcome of the patient’s human umbilical cord blood stem cells knee osteoarthritis treatment:

Not only did the doctors report that none of the seven patients in the study needed to undergo knee replacement despite the severity of their degenerative knee disease, but umbilical cord blood stem cells appear to be safe and effective for the regeneration of durable articular cartilage in osteoarthritic knees.


In the Chinese journal of reparative and reconstructive surgery, (6) doctors reported on the effects of umbilical cord blood stem cell therapy on their patients. Here are the learning points of their study:

  • Between January 2015 and January 2016, 36 patients with moderate or severe degenerative knee osteoarthritis were randomly divided into 2 groups of 18 patients each.
  • Intra-articular injection of human umbilical cord stem cell suspension was performed once a month for 2 times as a course of treatment in the cell treatment group; sodium hyaluronate by intra-articular injection was used once a week for 5 times as a course of treatment in the control group.
  • All patients of 2 groups received a course of treatment.
  • The patients were followed up for 6 months.
  • In the stem cell treatment group, standardized pain and function scores at 2-6 months after treatment were significantly better when compared with scores before treatment, and no recurrence of knee pain was observed during follow-up.
  • The standardized pain and function scores at 1 and 2 months after treatment between 2 groups were similar but the scores of the cell treatment group were significantly better than those of the control group at 3 and 6 months.

Conclusion: Human umbilical cord stem cells can significantly improve the joint function and quality of life for patients with degenerative knee osteoarthritis. It takes effect after 1 month and the treatment effect can be sustained for 6 months.

A December 2018 study in the medical journal Stem cells translational medicine (11) examined single versus multiple umbilical cord blood stem cell treatments in patients suffering from knee osteoarthritis.

The patients in this study either:

  • Received hyaluronic acid injections at the baseline of the study and at 6 months.
  • Received a single-dose umbilical cord blood stem cell treatment at baseline.
  • Received two umbilical cord blood stem cell treatments at baseline and 6 months.
  • Clinical scores and magnetic resonance images (MRIs) were assessed throughout the 12 months follow-up.
  • No severe adverse events were reported.
  • Only umbilical cord blood stem cell treatment patients experienced significant pain and function improvements from baseline.
  • Patients reached significantly lower levels of pain in the two umbilical cord blood stem cell treatment group as compared with the hyaluronic acid injection group.
  • Repeated umbilical cord blood stem cell treatment is safe and superior to hyaluronic acid injections in knee osteoarthritis at 1-year follow-up.
The controversy surrounding umbilical cord blood stem cell therapy

There is a controversy surrounding umbilical cord blood stem cells therapy offered in the United States. The controversy surrounds the makeup of the injectable solution. There are those in the medical community who insist that the injectable solution contains beneficial and abundant live umbilical cord blood stem cells. There are those who suggest that there were no live umbilical cord blood stem cells in the injectable solution. As of the time this question remains debated. I have tried this treatment on myself, and, on numerous occasions. Once satisfied that I was personally attaining good results, our office slowly began offering it to our patients. We monitored and noted the empirical, observational evidence and found that this treatment would be effective for certain patients. We can report at this time, with confidence, that this treatment is helping people.
Cord blood contains a mixed population of cells, including hematopoietic stem cells and mesenchymal stems cells. These cells have the capacity to self-renew, release growth factors, and further develop into more specialized cells. For the treatment, these cells are prepared as “human tissue allograft,” which means donated cells and material are processed into a liquid solution or a “suspension.” This is what is injected in the treatment.

Adipose (Fat derived) stem cells for knee osteoarthritis

There are numerous studies on the benefit of adipose derived stem cells for knee osteoarthritis. It is for some an effective treatment. Most of the emails we get from people asking us about the difference between adipose derived stem cells and bone marrow derived stem cells are looking for that definitive edge in which treatment they should choose.

In our office we do not use adipose stem cells. A primary reason is the liposuction procedure needed to harvest the stem cells. We are also not convinced that adipose stem cells work better than bone marrow derived stem cells. So three important factors in our decision are extra expense, discomfort of the lipo cell harvest, no clear or definitive benefit of the adipose procedure.

  • Doctors at  Colorado State University wrote in the Journal of orthopaedic research of how patients saw a greater improvement with bone marrow-derived mesenchymal stem cells when compared to adipose-derived (fat) stromal vascular fraction and placebo treatment.(5)
  • Doctors in Taiwan noted that: Mesenchymal stem cells (MSCs) isolated from either bone marrow or adipose tissue show considerable promise for use in cartilage repair. . . MSCs can directly differentiate into chondrocytes (cartilage building cells). . . hey also have immunosuppressive and anti-inflammatory paracrine effects. (They change the joint environment from breakdown to healing by telling the other cells to start repairing.) (6)

Do you have questions? Ask Dr. Darrow

A leading provider of stem cell therapy, platelet rich plasma and prolotherapy

PHONE: (800) 300-9300 or 310-231-7000

Stem cell and PRP injections for musculoskeletal conditions are not FDA approved. We do not treat disease. We do not offer IV treatments. There are no guarantees that this treatment will help you. Prior to our treatment, seek advice from your medical physician. There is controversy in the medical community about whether umbilical cord blood stem cells are alive or dead, and which type of stem cell may be appropriate.

Neither Dr. Darrow, nor any associate, offer medical advice from this transmission. This information is offered for educational purposes only. The transmission of this information does not create a physician-patient relationship between you and Dr. Darrow or any associate. We do not guarantee the accuracy, completeness, usefulness or adequacy of any resource, information, product, or process available from this transmission. We cannot be responsible for the receipt of your email since spam filters and servers often block their receipt. If you have a medical issue, please call our office. If you have a medical emergency, please call 911.

1 Shaw B, Darrow M, Derian A. Short-Term Outcomes in Treatment of Knee Osteoarthritis With 4 Bone Marrow Concentrate Injections. Clin Med Insights Arthritis Musculoskelet Disord. 2018 Jun 18;11:1179544118781080. doi: 10.1177/1179544118781080. PMID: 29977117; PMCID: PMC6024328.
2 Migliorini F, Rath B, Colarossi G, Driessen A, Tingart M, Niewiera M, Eschweiler J. Improved outcomes after mesenchymal stem cells injections for knee osteoarthritis: results at 12-months follow-up: a systematic review of the literature. Archives of orthopaedic and trauma surgery. 2019 Aug 27:1-6.
3 Emadedin M, Labibzadeh N, Liastani MG, Karimi A, Jaroughi N, Bolurieh T, Hosseini SE, Baharvand H, Aghdami N. Intra-articular implantation of autologous bone marrow-derived mesenchymal stromal cells to treat knee osteoarthritis: a randomized, triple-blind, placebo-controlled phase 1/2 clinical trial. Cytotherapy. 2018 Oct 11. pii: S1465-3249(18)30605-4. doi: 10.1016/j.jcyt.2018.08.005. PubMed PMID: 30318332.
4. Burke J, Hunter M, Kolhe R, Isales C, Hamrick M, Fulzele S. Therapeutic potential of mesenchymal stem cell based therapy for osteoarthritis. Clinical and Translational Medicine. 2016;5:27. doi:10.1186/s40169-016-0112-7.
5 Kurtzberg J, Lyerly AD, Sugarman J. Untying the Gordian knot: policies, practices, and ethical issues related to banking of umbilical cord blood. J Clin Invest. 2005;115(10):2592-7.
6 Kurtzberg J. Update on umbilical cord blood transplantation. Curr Opin Pediatr. 2009;21(1):22-9.
7. Frisbie, DD, Kisiday, JD, Kawcak, CE, Werpy, NM, McIlwraith, C. Evaluation of adipose-derived stromal vascular fraction or bone marrow-derived mesenchymal stem cells for treatment of osteoarthritis. J Orthop Res. 2009;27:1675–1680.
8 Chang YH, Liu HW, Wu KC, Ding DC. Mesenchymal stem cells and their clinical applications in osteoarthritis. Cell Transplant. 2015 Dec 18.
9 McIntyre JA, Jones IA, Danilkovich A, Vangsness Jr CT. The placenta: applications in orthopaedic sports medicine. The American journal of sports medicine. 2018 Jan;46(1):234-47.