Dealing with knee osteoarthritis can be frustrating, turning simple activities into painful tasks. If you’re looking for a solution, you’ve likely heard about stem cell therapy for knees. It’s a promising option, and I want to show you what the research says. We’ll look at published studies from the Darrow Stem Cell Institute on using bone marrow-derived stem cells as a stem cell treatment for knee pain. My goal is to explain what this stem cell for knee arthritis treatment involves and what the results could mean for you. Have a question about your knee pain? Ask me directly using the form below.

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.

Understanding Knee Osteoarthritis and Its Impact

Just How Common Is Knee Pain?

If you’re dealing with knee pain, you are certainly not alone. It’s one of the most common reasons people experience chronic pain and disability, especially as they get older. In fact, research shows that knee osteoarthritis affects a significant portion of the population, with some studies indicating that about 10% of people over 60 live with painful symptoms. This isn’t just a minor inconvenience; it’s a condition that can deeply impact your quality of life. Simple, everyday movements like walking up a flight of stairs, getting out of a car, or enjoying a walk in the park can become difficult. This constant discomfort can limit your mobility and independence, which is why many people explore regenerative treatments to address the underlying issue and get back to the activities they love.

A Closer Look: Short-Term Results of Stem Cell Injections for Knees

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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How Does Stem Cell Therapy for Knees Work?

When you’re dealing with chronic knee pain from osteoarthritis, it can feel like your options are limited to managing symptoms or facing major surgery. But what if you could tap into your body’s own healing system to repair the damage? That’s the fundamental idea behind stem cell therapy. Think of stem cells as your body’s internal repair crew. These unique, powerful cells have the ability to develop into many different types of specialized cells, including the cartilage cells that cushion your knee joint. When your knee cartilage wears down from osteoarthritis, it leads to that familiar grinding, inflammation, and pain that can stop you from living your life fully.

The treatment process is designed to address this issue at its source. By carefully injecting a concentrated solution of stem cells directly into the knee joint, we deliver that repair crew right where it’s needed most. Once there, these cells get to work. They can help calm the chronic inflammation that causes so much of the pain, protect the existing cartilage from further breakdown, and signal your body to begin its own repair processes. The ultimate goal is to encourage the growth of new, healthy cartilage tissue, creating a stronger, more functional joint from within. It’s a minimally invasive approach that works with your body’s natural mechanics, offering a path toward lasting relief without the long recovery of surgery.

Where Do the Stem Cells Come From?

A common and important question we hear from patients is, “Where exactly do these powerful stem cells come from?” The source of the cells is a critical part of the therapy’s safety and effectiveness. Generally, stem cells are sourced in one of two ways: either from your own body or from a donor. At the Stem Cell Institute, we exclusively use autologous stem cells, which means they are harvested directly from you, the patient. This is the gold standard for ensuring safety and compatibility. As our own published research on knee osteoarthritis has shown, we have seen promising results using cells derived from the patient’s own bone marrow.

Autologous vs. Allogeneic Stem Cells

Let’s break down the difference. Autologous means “from the self.” We perform a simple procedure to collect stem cells from your own bone marrow. These cells are then concentrated and prepared for injection back into your knee. Because the cells are your own, your body recognizes them, and the risk of rejection or an adverse immune reaction is virtually eliminated. In contrast, allogeneic cells come from an outside source, like a screened donor’s umbilical cord tissue. While this method is used in some settings, it introduces variables and potential complications that we believe are unnecessary. By using your body’s own resources, we stick to a treatment philosophy that is as natural and safe as possible.

What Does the Latest Research Say About Stem Cells for Knees?

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.

The Current State of Scientific Understanding

The scientific community is increasingly optimistic about using stem cells for knee osteoarthritis. Recent studies highlight that injections using bone marrow-derived stem cells can be a safe and encouraging option for cartilage repair. Researchers point to the unique ability of these cells to self-renew and reduce inflammation, which helps to significantly improve pain and daily function. A large review of over 1,000 cases confirmed that stem cell therapy is a feasible option that leads to remarkable improvements in clinical outcomes, especially for patients in the earlier stages of joint degeneration. The consensus is that these treatments can meaningfully enhance a person’s quality of life, though more long-term research is always welcome to build on these positive findings.

Potential Risks and Considerations

As with any medical procedure, it’s wise to consider all aspects before moving forward. While stem cell therapy is generally considered safe, there is a minimal risk of complications such as infection, localized pain, or irritation at the injection site. The best way to mitigate these risks is to work with a highly qualified physician with extensive experience in regenerative medicine. Another practical point to consider is the cost, as most insurance companies do not currently cover stem cell procedures for orthopedic conditions. Discussing these factors with a specialist like Dr. Marc Darrow can help you weigh the incredible potential benefits against the risks and financial investment, ensuring you feel confident and informed in your decision.

Study Confirms: Stem Cells Offer Significant Knee Pain Relief

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.”

Stem Cell Therapy vs. Other Knee Treatments

When you’re dealing with chronic knee pain from osteoarthritis, it can feel like your options are limited and often extreme. Many people believe they have to choose between temporarily masking the pain with injections or committing to a major surgery like a total knee replacement. However, regenerative medicine offers a different path—one that aims to work with your body’s own healing mechanisms. Unlike treatments that simply manage symptoms, the goal of stem cell therapy is to address the underlying damage, potentially slowing cartilage degeneration and improving mobility. It’s a fundamentally different approach that focuses on repair and regeneration rather than replacement.

Understanding where stem cell therapy fits among your choices is key to making an informed decision about your health. It’s not about finding a magic bullet, but about exploring all avenues for lasting relief and improved function. For many, the idea of using their own cells to heal their joints is a compelling alternative to more invasive procedures. By comparing stem cell therapy directly with traditional options like surgery and other injections, you can get a clearer picture of the potential benefits and decide if this innovative treatment aligns with your personal health goals.

Comparing Stem Cells to Total Knee Replacement Surgery

The most significant difference between stem cell therapy and total knee replacement surgery lies in their core philosophy: repair versus replacement. A knee replacement is a major invasive surgery where the damaged joint is removed and replaced with a prosthetic implant. While effective for many, it comes with significant downtime, a lengthy rehabilitation process, and the risks associated with any major surgery. In contrast, stem cell therapy is a minimally invasive procedure. As research from Georgia Regents University highlights, cellular therapies “have the potential to regenerate the lost cartilage, combat cartilage degeneration, provide pain relief, and improve patient mobility.” The focus is on helping your body heal itself, which can be a powerful alternative for those wishing to avoid going under the knife.

How It Stacks Up Against Other Injections and Therapies

Beyond surgery, many people with knee pain are familiar with other injections, such as corticosteroids or hyaluronic acid. While these can provide temporary relief, they don’t typically address the root cause of cartilage degeneration. Corticosteroids reduce inflammation, but their effects are often short-lived and repeated use can potentially harm cartilage over time. Regenerative treatments like stem cell therapy and PRP therapy operate differently. A comprehensive review in the *Archives of Orthopaedic and Trauma Surgery* found that stem cell injections for knee osteoarthritis are a “feasible option, leading to an overall remarkable improvement” in clinical outcomes. This suggests that stem cells may offer more than just temporary symptom management by supporting a better healing environment within the joint.

Navigating the Cost of Stem Cell Therapy

Once you understand the potential benefits of stem cell therapy, the next logical question is about the cost. It’s a practical and important consideration for anyone exploring treatment options. The financial aspect of regenerative medicine can seem complex, primarily because it’s an evolving field. Unlike traditional treatments that have been standard for decades, procedures like stem cell therapy are still considered cutting-edge by many institutions, including insurance providers. This directly impacts how these treatments are paid for. It’s essential to go into the process with a clear understanding of what to expect financially so you can plan accordingly and focus on what matters most: your health and recovery.

Before making any decisions, it’s wise to have a direct conversation with the clinic providing the treatment. They can offer a clear breakdown of the costs involved and discuss any available payment or financing options. At the Stem Cell Institute, we believe in transparency and are committed to helping patients understand every aspect of their care plan. You can always contact our office to get specific information related to your circumstances. Having this knowledge upfront removes uncertainty and empowers you to make a choice that feels right for both your physical and financial well-being.

Does Insurance Cover Stem Cell Injections for Knees?

This is one of the most common questions patients ask, and the answer is usually straightforward: No, most insurance companies do not cover stem cell therapy for knee osteoarthritis. According to Resilience Orthopedics, a resource on the topic, “Most health insurance companies do not cover stem cell therapy or PRP (Platelet-Rich Plasma) injections for joint pain or orthopedic conditions.” This means that patients should generally expect the procedure to be an out-of-pocket expense. While this can be disappointing news, understanding it from the start helps you set realistic expectations and explore other financial avenues without the frustration of a denied insurance claim.

Understanding Why It’s Often an Out-of-Pocket Expense

The reason insurance providers typically deny coverage for stem cell therapy is that they classify it as “experimental” or “investigational.” While a growing body of research—including the studies mentioned earlier—shows promising results, insurance companies often wait for a massive volume of long-term, large-scale clinical trials before they consider a treatment “proven.” This is a slow-moving process that can take many years. In the meantime, clinics led by experienced physicians like Dr. Marc Darrow continue to offer these treatments based on current positive evidence and successful patient outcomes, giving people access to innovative care now rather than later.

Is Stem Cell Therapy for Knees Right for You?

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.

  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. 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
  3. 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.
  4. 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.
  5. 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.
  6. 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.
  7. Chang YH, Liu HW, Wu KC, Ding DC. Mesenchymal stem cells and their clinical applications in osteoarthritis. Cell Transplant. 2015 Dec 18.

What to Expect During Recovery

One of the first questions people ask about any medical procedure is, “What’s the recovery like?” With stem cell therapy, the process is designed to be minimally disruptive. As a non-surgical injection, most people go home the same day and can return to their usual daily activities within days. Research co-authored by our own Dr. Marc Darrow shows patients often experience significant improvements in pain and function after just the first treatment. The goal is to help your body heal itself, and that process unfolds over time. Studies show impressive results, with patients reporting an average 84% decrease in resting pain and a 67% total overall improvement after a series of treatments.

Functionality also sees a major upswing, making it easier to perform daily tasks that were once challenging. While you’ll need to wait a few months before returning to more intense physical activities, the steady progress in pain reduction and mobility can be incredibly encouraging as your body works to repair the damaged tissue. This gradual improvement allows you to regain strength and confidence without the extensive downtime associated with surgery, helping you get back to the life you enjoy.

Frequently Asked Questions

How is stem cell therapy different from a cortisone shot? Think of it as repair versus a temporary patch. A cortisone shot is a powerful anti-inflammatory that can reduce pain for a short time, but it doesn’t address the underlying cartilage damage. In fact, repeated cortisone injections can sometimes weaken tissues over time. Stem cell therapy works differently by using your body’s own repair cells to target the source of the problem. The goal is to reduce inflammation naturally and create an environment that supports the healing of damaged tissue for more sustainable relief.

How long does it take to see results from the treatment? The timeline for relief is a gradual process. Our research shows that many patients feel an immediate improvement in their ability to perform daily activities after the first treatment. Significant pain reduction, especially pain while at rest, tends to build with each successive injection over a couple of months. The idea is that each treatment builds on the progress of the last, allowing your body the time it needs to repair the joint from the inside out.

Why does your research suggest multiple injections instead of just one? Our clinical findings showed that a series of treatments delivered better and more significant results. While a single injection can be helpful, we found that patients experienced a greater overall improvement in pain and function after completing the full series. Each injection seems to amplify the healing response, leading to a more comprehensive and lasting outcome. This approach allows for a steady, cumulative effect that helps patients achieve more complete relief.

Am I too old for my own stem cells to be effective? This is a common and completely valid question. While the concentration of stem cells in our bodies can decrease with age, there are still plenty of powerful, viable cells available for treatment. The key is having an experienced physician who uses precise techniques to harvest and concentrate these cells. A skilled doctor can ensure a high-quality sample is prepared, giving you an effective treatment that leverages your body’s own healing potential, regardless of your age.

What is the recovery process actually like after an injection? Recovery is one of the most appealing aspects of this treatment. Because it’s a minimally invasive injection and not a major surgery, there is very little downtime. Most people are able to go home shortly after the procedure and can resume their normal, light daily activities within a day or two. We advise you to listen to your body and avoid strenuous exercise for a few weeks to give the cells the best possible environment to work. The goal is to get you back to your life quickly, without the long and demanding rehabilitation period that follows surgery.

Key Takeaways

  • It’s a research-backed option for pain relief: Studies, including those from the Darrow Stem Cell Institute, show that using your own bone marrow stem cells can significantly reduce knee pain from osteoarthritis and improve your ability to handle daily activities.
  • The treatment works with your body: This therapy uses your own cells to target inflammation and support natural repair. Research suggests a series of treatments may be more effective for achieving lasting results.
  • Prepare for the cost: Since stem cell therapy is rarely covered by insurance, you should plan for it to be an out-of-pocket expense. A direct conversation with the clinic is the best way to understand the financial investment.

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