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. I also invite you to ask your questions using the form below about your knee pain.

Before we get to new 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 January 2020 (2) study from Loughborough University in the United Kingdom suggests:

“Pre-clinical studies have demonstrated successful, safe and encouraging results for articular cartilage repair and regeneration (with intra-articular injections of bone marrow derived mesenchymal stem cells). This is concluded to be due to the multilineage differential potential, immunosuppressive and self-renewal capabilities of bone marrow derived mesenchymal stem cells, which have shown to augment pain and improve functional outcomes.

Subsequently, clinical applications of intra-articular injections of bone marrow derived mesenchymal stem cells are steadily increasing, with most studies demonstrating a decrease in poor cartilage index, improvements in pain, function and Quality of Life; with moderate-to-high level evidence regarding safety for therapeutic administration . . .

Overall, the benefits of intra-articular injections of bone marrow derived mesenchymal stem cells were deemed to outweigh the adverse effects; thus, this treatment be considered as a future therapy strategy. To realise this, long-term large-scale randomised clinical trials are required to enable improved interpretations, to determine the validity of efficacy in future studies.”

A study published in the Archives of orthopaedic and trauma surgery (3) 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 (4) , 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,(5) 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.

Do you have questions? Ask Dr. Darrow



A leading provider of stem cell therapy, platelet rich plasma and prolotherapy
11645 WILSHIRE BOULEVARD SUITE 120, LOS ANGELES, CA 90025

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.

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 InjectionsClin Med Insights Arthritis Musculoskelet Disord. 2018 Jun 18;11:1179544118781080. doi: 10.1177/1179544118781080. PMID: 29977117; PMCID: PMC6024328.
2 Doyle EC, Wragg NM, Wilson SL. Intraarticular injection of bone marrow-derived mesenchymal stem cells enhances regeneration in knee osteoarthritis [published online ahead of print, 2020 Jan 31]. Knee Surg Sports Traumatol Arthrosc. 2020;10.1007/s00167-020-05859-z. doi:10.1007/s00167-020-05859-z
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.
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.
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.
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.
Chang YH, Liu HW, Wu KC, Ding DC. Mesenchymal stem cells and their clinical applications in osteoarthritis. Cell Transplant. 2015 Dec 18.