Stem cell therapy for Knees has been a growing area of research for treating knee osteoarthritis (OA), especially with the use of Mesenchymal Stem Cells (MSCs). These cells have the potential to repair damaged tissues, reduce inflammation, and potentially even regenerate cartilage. Here’s some of the key studies from the last few years, both positive and negative.

If you want to look more into treatment processes and clinics that treat Knee issues, check out our article on Stem Cell Therapy for Knee’s.

Best Stem Cell Therapy clinics for Knee Treatments

We don’t let any clinic just sign up or pay to be listed.

We speak to every clinic directly and review their medical team, the treatments they offer, how their stem cells are sourced and how they follow up with patients after treatment.

We also review licensing documents to confirm they meet the legal and medical standards of the country they operate in. For example, whether cells are processed in a GMP-certified facility or if they provide documentation on stem cell quality.

Clinics must also agree to let us collect and publish independent patient reviews. Both positive and negative.

Why Use Alt Treatment?

We don’t just list clinics, we help you choose the right one, get the best pricing and support you through the entire journey. For free.

Compare with Confidence: Get clinic matches based on your condition, location, and budget.

Ask the Right Questions: Know what to ask before committing

Save on Treatment: Unlock exclusive discounts on vetted clinics and follow-up care.

We’re With You After Treatment: We check in post-treatment and help resolve any issues.

Travel & Visa Help: Need to travel for care? We can help with logistics, documents, and local tips.

Found a Clinic Elsewhere? We’ll check their licensing and track record for you, free of charge.

No Strings Attached: Even if you choose a clinic we don’t partner with, we’re still here to help you make the best decision.

Top Stem Cell Therapy Clinics in Dubai for Knee Treatments

Orthopaedic Specialists Autologous Stem Cells Umbilical Cord Derived Stem Cells Certified Lab Higher Dosage Treatment

Excellency Center is a specialized clinic focused on orthopaedic and sports medicine, helping people recover from pain, injuries, and movement issues that affect their everyday life.  They offer both autologous stem cells (from your own body) and allogenic stem cells (donor-based), depending on what’s best for your condition. All treatments come with full certifications of quality and safety.

View Full Profile

Top Stem Cell Therapy Clinics in Colombia for Knee Treatments

Umbilical Cord Derived Stem Cells Higher Dosage Treatments Certified Lab

Alevy specializes in stem cell and exosome therapy, using umbilical cord-derived MSCs to treat a wide variety of conditions, from Diabetes, Multiple Sclerosis to Osteoarthritis & Orthopaedic injuries. Their medical team brings over 15 years of experience in pain management, tissue regeneration, and immune system modulation. With three world-class clinics in Medellín, Bogotá, and Pereira, you have options on where you want treatment!

View Full Profile

Umbilical Cord Derived Stem Cells Higher Dosage Treatments Certified Lab

Kyron Stem Cells is a Stem Cell Therapy clinic that focuses on a variety of treatments, including joint pain, chronic fatigue, autoimmune issues, and overall wellness. The clinic is led by Dr. Carlos Rojas, who has been working with stem cells since 1991 and has over a decade of experience in functional and hormone-based medicine. He is known for creating treatment plans that are genuinely personalized, based on each patient’s biology and lab results.

View Full Profile

Current Trials

Institute of Bone and Joint Research Trial on Knee OA: Australia

You can read more about the study here.

The Sculptor trial is a major research study run by the University of Sydney and led by Professor David Hunter. It’s designed to find out if stem cell injections can actually reduce pain, improve movement, and protect knee cartilage in people with mild to moderate knee osteoarthritis, compared to a placebo.

Start Date and Expected Completion Date

• Recruitment Closed: November 14, 2023

• Start Date: March 15, 2021 (first participant enrolled)

• Expected Completion: December 31, 2025 (last data collection point for 24-month follow-up.
• Participants: 321 participants aged older then 40 who have been diagnosed with  mild to moderate knee osteoarthritis (KL grade 2-3)

Procedure:

• Delivery Method
  Three ultrasound-guided intra-articular injections directly into the knee joint
• Injection Timing:
  
  • Dose 1: Baseline
  • Dose 2: Week 3
  • Dose 3: Week 52 (12-month mark)
• Cell Dosage: 2.5 × 10⁷ MSCs (25 million cells) per injection
• Cell Type Used: Allogenic Mesenchymal Stem Cells (MSCs)
  Specifically: Mesenchymoangioblast-derived MSCs (lab-grown stem cells made by turning early adult cells like a skin cell into mesenchymal stem cells in a controlled, high-purity process.)
• How Cells Were Prepared
  • Source: The cells came from a healthy adult and were grown in the lab to create a master cell bank
  • Manufacturing: The cells are grown using a carefully controlled process, tested for safety and quality, to make sure every batch is consistent and meets medical standards.
    

Next Steps

• Follow-up ongoing for all participants through 24 months after their final injection (i.e., into late 2025)
  
• Primary outcomes (pain reduction and cartilage thickness changes) to be assessed at 24 months
  
• Secondary outcomes include quality of life, MRI-based structural changes, economic analysis (QALYs), and participant-reported outcomes
  
• Results are not yet published; final analysis expected after study wraps up in 2025

Previous Research on Stem Cells treating Knee issues

1. Autologous Stem Cell Knee Treatment on meniscus tears with 5 Year Follow Up: Japan

You can read more about the study here.

Researchers at Tokyo Medical and Dental University conducted a five-year study to test the long-term safety of using stem cells taken from a patient’s own knee (called autologous MSCs) after surgery for degenerative meniscus tears.  A common wear-and-tear injury often linked to early osteoarthritis.

While healing was observed, the main goal was to find out if a small genetic change in some of the stem cells (trisomy 7) made them unsafe to use.

Study Details:

• Participants: 10 adults (average age 45) with degenerative meniscus tears in their knees. 3 of the 10 patients had stem cells where a small portion contained an extra copy of chromosome 7 (a condition called trisomy 7). (trisomy 7).  All received stem cell treatment during or after surgical repair. 

• Procedure: The stem cells were directly applied into the knee joint during surgery, onto the repaired meniscus. Patients stayed in position for 10 minutes to let the cells stick, then started movement the next day.

• Cell Type:Autologous mesenchymal stem cells (MSCs) taken from each patient’s own knee synovial tissue (the inner lining of the joint). These are adult stem cells known for helping with cartilage repair.

• How Cells were prepared:The joint lining was broken down with enzymes, and the stem cells were grown using the patient’s own blood.
  Cells were only used at Passage 0 (their first lab culture).
  

Results:

• After 5 years, no serious side effects or tumors were found in any patient.
• Even the 3 patients with trisomy 7-positive cells had no negative outcomes.
• In one patient, an MRI scan taken three years after treatment showed that the meniscus tear was no longer visible, suggesting possible tissue healing.

What we DON’T know

• The exact number of cells used per patient wasn’t shared.
• No data on how long the cells stayed active in the joint.
• The study only used 10 people, so large-scale effects remain unknown.
• This study did not include a comparison group that received surgery without stem cells, so it’s unclear how much of the healing was due to the cells vs. the surgery itself

If you’re looking at getting Knee treatment, this study doesn’t really provide anything apart from it’s safe!

2. Magellan Mag200 Knee Trial: Australia

You can read more about the study here

Magellan Stem Cells, based in Australia, conducted a trial on the use of allogeneic MSCs (from donors) to treat moderate knee osteoarthritis.

Study Details:

• Participants: 40 patients with moderate OA. (KL Grade 2–3).
• Procedure:
  A single injection directly into the knee joint, guided by ultrasound for accuracy.
  Doses tested:10M, 20M, 50M, 100M cells
  Along with a Placebo  group
• After the injection, patients were advised to rest, use a compression bandage, and take pain relief if needed.
• Doctors monitored their progress for 12 months
• The stem cells came from one healthy donor and were specially prepared so the body wouldn’t see them as foreign or reject them.
• Cell Type Used: Allogeneic adipose-derived mesenchymal stem cells (ADMSCs)
  

How Cells Were Prepared

• The stem cells were taken from donated fat using liposuction, then treated with enzymes to separate the stem cells from the rest of the fat tissue. 
• They were then cultured to passage 4 
• After culturing, they were tested using ISCT criteria:
  • Positive: CD105, CD90, CD73. These markers confirm the cells are true mesenchymal stem cells, with over 95% showing the expected regenerative identity.
  • Negative: CD45, CD14, CD34, CD19. These markers are found on blood and immune cells, so having less than 2% means the stem cell sample was very pure and not contaminated with unwanted cell types.
• The cells were checked to make sure they were free from contamination (bacteria, hidden infections, toxins), and that their DNA was stable and hadn’t mutated during lab growth aka: Sterility, MycoPlasma, Endotoxins, Karyotype stability
• The stem cells were then frozen and stored in 1 mL vials, each containing 10 million cells, using a special solution (CryoStor® CS10) that protects them during freezing.
• Delivered in blinded syringes to prevent trial bias

Results:

• No serious adverse events across any dose group

Dose	% Responders	Pain ↓ (NPRS)	Function ↑ (KOOS-ADL)
Placebo	50%	-1.55	+9.99
MAG200 10M	62.5%	-3.80	+16.47
MAG200 20M	100%	-2.62	+20.12
MAG200 50M	62.5%	-2.78	+8.87
MAG200 100M	75%	-3.25	+20.80

• Overall, 75% of the people who received the stem cell treatment saw meaningful improvement in pain or function.
  

Magellan Also tracked results from MRI’s too:

• MRI scans taken 12 months later showed that people in the placebo group had lost cartilage in their knees, meaning their osteoarthritis got worse over time.
• People who received the stem cell treatment generally kept more of their knee cartilage, especially in one key area of the joint (the lateral femoral condyle). The 20 million cell group showed a clear, statistically significant benefit in that spot.
• The MRI didn’t show clear, measurable regrowth of cartilage across the whole knee that was strong enough to rule out chance. So while some areas improved, the overall joint didn’t show proven cartilage regrowth.

How Cells Worked

• The stem cells likely worked by sending healing signals, not by turning into new tissue themselves. These signals helped reduce inflammation, calm the immune system, and support the body’s natural repair process. 
• There’s no evidence in this trial that they worked by becoming cartilage-producing cells (differentiation).
• What we Don’t Know
• The study didn’t include any tests to track what happened to the stem cells in the body . So we don’t know if they stayed in the joint, survived long-term, or turned into cartilage
• We don’t know what happens after 12 months

What happens next?

• This was a solid, thoughtfully run study with some genuinely interesting results. Magellan Stem Cells is now gearing up for phase three clinical trials this year (2025) with the support of a $7 million research grant from the Australian Government.

3. Autologous Adipose Stem Cell Treatment for Knee OA: South Korea

You can read more about the study here.

This study set out to test whether a single injection of a patient’s own fat-derived stem cells (AD-MSCs) into the knee could safely reduce pain and improve function in people with osteoarthritis. It was a Phase IIb clinical trial.

Study Details:

• Participants: 24 Patients with an average age of 62 with Knee OA (KL Grade 2-4). 75% were female. They had a Mean baseline WOMAC score: 60.0 (MSC Group).
  The WOMAC score is a 0–100 scale that measures how much joint pain, stiffness, and difficulty with daily activities a person has due to osteoarthritis.  Higher scores mean worse symptoms
• Procedure: Split into 2 Groups: 12 knees treated with AD-MSCs, 12 knees treated with saline
• Delivery method: Single intra-articular injection into the knee joint
• Cell used: Autologous adipose-derived mesenchymal stem cells (AD-MSCs)
• Source:Fat was taken from under the skin of the belly using a gentle liposuction procedure.
• Dosage:​​ Each patient received 100 million stem cells, mixed into 3 milliliters of saline), which was then injected into their knee. (saline ensures the stem cells stay alive, stable, and safe during injection)
• Control group: This group received 3 mL saline only
• Blinding: Neither the patients nor the doctors knew who received the real stem cell treatment and who got the placebo.
• Follow-up: 1, 3, and 6 months
  

How Cells were Prepared:

• Culture Method:
  • The fat tissue was broken down using an enzyme called collagenase so that the stem cells could be separated from the rest of the material.
  • The stem cells were grown in a nutrient-rich liquid (Keratinocyte-SFM media with rEGF, FBS) that helped them multiply, containing ingredients like growth factors, proteins, and vitamins to keep them healthy and active.
  • Passage: Cells used at Passage 3
• Positive markers: CD73, CD90. These markers confirm the cells are true mesenchymal stem cells (One thing to note is strictly, the ISCT says that true mesenchymal stem cells must have all three markers: CD73, CD90, and CD105.) 
• Negative markers: CD31, CD34, CD45.
  CD31, CD34, and CD45 are proteins found on blood or immune cells, so if stem cells don’t have them, it shows the sample is clean and not mixed with the wrong types of cells. (The ISCT says other markers like CD14, CD19, and HLA-DR should also be checked to make sure the stem cells aren’t mixed with immune cells, which could cause unwanted reactions or reduce the treatment’s effectiveness.
• Viability: On the day of injection, nearly all the stem cells were alive and healthy. With about 93% survival on average, which means they were in good condition to work effectively
• Sterility tests: The cells were tested to make sure they were clean and free from bacteria, fungi, and other harmful contaminants before injection.
• Storage: Frozen at −196°C and thawed on day of use
  

Results

• Primary outcome (WOMAC score):
  The group that received stem cells had a 55% improvement in symptoms. Their average score dropped from 60 to 26.7  and the result was statistically very strong (p < .001), meaning it’s very unlikely to be due to chance.
  Control group: No significant change
• VAS pain score: MSC group dropped from 6.8 → 3.4 (p < .001). (The VAS pain score is a simple 0 to 10 scale where patients rate their pain)
• KOOS scores: All subscales improved significantly in MSC group only. (a questionnaire that measures how knee problems affect someone’s pain, daily activities, sports ability, and quality of life.)
• MRI cartilage defect:
  • MRI scans showed that the stem cell group’s cartilage damage stayed the same, while the placebo group’s cartilage damage got noticeably worse 
  • Meaning the Stem Cells helped stop further cartilage loss.
  • People who received stem cells were able to move their knee more easily after treatment, their range of motion improved
•  Adverse events:No Serious events were reported!

How Cells Worked

• The stem cells helped by sending out healing signals that reduced inflammation and supported tissue repair.
• They did not turn into new cartilage cells themselves. 
• MRI scans showed that the damaged cartilage didn’t get worse, but it also didn’t grow back within 6 months.

What we Don’t Know

• Long-term effects beyond 6 months are unknown.

Conclusion
This study shows that a single stem cell injection can safely reduce pain, improve movement, and help stop further knee damage in people with osteoarthritis. BUT it doesn’t regrow cartilage, at least not within 6 months.

4. Study looking at effects 2 years Post Stem Cell Treatment at Kyung Hee University Hospital: South Korea

You can read more about the study here.

A follow-up study was conducted to observe the long-term effects of autologous MSC injections after high tibial osteotomy (a surgical procedure for knee OA). This randomized controlled trial focused on the regeneration of cartilage two years post-treatment.

Study Details:

• Participants: 26 patients with Medial compartment knee osteoarthritis. (KL grade 2-4)
• Surgical treatment: All patients underwent Medial Open-Wedge High Tibial Osteotomy (MOWHTO) (surgical procedure used to treat knee osteoarthritis, especially when it’s more severe on the inner (medial) side of the knee and the patient has bow-legged (varus) alignment.

Procedure:

• Split into 2 groups: 13 Received Stem Cells & 13 didn’t
• Local Stem Cell injection into the joint (intra-articular), guided by ultrasound
• Timing: Injected 1 week after surgery
• Cells Used: Adipose-Derived Mesenchymal Stem Cells (ADMSCs derived from Fat)
• Dose:  Each patient received 100 million stem cells, mixed into 3 milliliters of saline), which was then injected into their knee. (saline ensures the stem cells stay alive, stable, and safe during injection)
• Control group: Received MOWHTO only (no injection)
• How Cells Were Prepared: Fat was taken from under the skin of the belly using a gentle liposuction procedure.

Culture Method

• The fat tissue was broken down using an enzyme called collagenase so that the stem cells could be separated from the rest of the material.
• The stem cells were separated &  grown in a nutrient-rich liquid  (Keratinocyte-SFM media with rEGF, FBS) that helped them multiply, containing ingredients like growth factors and proteins to keep them healthy and active
• Expansion: Cultured to passage 3

Testing Before Injection

• On the day of injection, more than 80% of the stem cells were alive and healthy. Meaning they were in good condition to function properly and support cartilage repair over the next several days.
•  The cells were tested to make sure they were clean and free from bacteria, fungi, and other harmful contaminants before injection.
• Negative for CD31, CD34, CD45. CD31, CD34, and CD45 are proteins found on blood or immune cells, so if stem cells don’t have them, it shows the sample is clean and not mixed with the wrong types of cells. (The ISCT says other markers like CD14, CD19, and HLA-DR should also be checked to make sure the stem cells aren’t mixed with immune cells, which could cause unwanted reactions or reduce the treatment’s effectiveness.)
• Positive for CD73, CD90. These markers confirm the cells are true mesenchymal stem cells (One thing to note is strictly, the ISCT says that true mesenchymal stem cells must have all three markers: CD73, CD90, and CD105.) 

Results

• Follow-up period: 24 months (serial MRIs at 3, 6, 18, and 24 months)
• Cartilage regeneration:
  • At 24 months, the group that received stem cells showed 81% cartilage regeneration on MRI, compared to 44% in the surgery only group. This means new cartilage grew in the damaged areas!  But the doctors didn’t test the tissue directly, so they don’t know if it was the same strong cartilage you’re born with or a weaker type.
  • The ADMSC group had significantly higher MOCART 2.0 scores. Meaning the new cartilage they grew looked more complete and healthier on MRI compared to the surgery-only group.
  • The new cartilage looked healthier and more complete on MRI in the stem cell group, with 69.2% of patients showing total cartilage regeneration, compared to just 23.1% in the surgery-only group. While it looked closer to normal on scans, the doctors didn’t test the tissue directly, so it’s unclear whether it was the strong, original type of cartilage or a weaker version.
• KOOS-ADL scores significantly improved in ADMSC group at 18 and 24 months. ((a questionnaire that measures how knee problems affect someone’s pain, daily activities, sports ability, and quality of life.)
  
• Patients who received stem cells had better WOMAC scores, meaning they reported less pain and stiffness. But the difference wasn’t strong enough to prove it was definitely due to the stem cells.
• Adverse Events: No Serious adverse events reported!

How Cells Worked

• The researchers believe the stem cells helped by releasing healing signals, not by turning into cartilage themselves. They suggested that molecules like TSP-2, which the stem cells naturally release, likely triggered the body’s own repair process.

What we don’t know

• Small sample size and limited demographic diversity. Everyone was Korean.
• It’s unclear how strong or long-lasting the new cartilage is, since the type of tissue wasn’t confirmed under a microscope

Conclusion

•  Adding stem cells to knee surgery helped patients grow back more cartilage and the new tissue looked healthier on scans compared to surgery alone.
• While the cartilage type wasn’t confirmed under a microscope, the results suggest stem cells may support joint repair by sending healing signals, not by becoming cartilage themselves. 
• Patients in the stem cell group also reported feeling slightly better, though this wasn’t strong enough to prove. Overall, the treatment appeared safe and showed promising signs of better recovery.
  
  

5. 2023 Phase 3 Clinical Trial Comparing Stem Cell Therapy and Cortisone Injections for Knee OA: USA

You can read more about the study here or here.

This study was led by doctors and researchers from Emory University, Duke University, Sanford Health, and Georgia Tech, with support from the FDA and funding from the Marcus Foundation. The team ran a large clinical trial to compare the effectiveness and safety of different stem cell injections versus standard steroid injections for treating knee osteoarthritis. Their goal was to find out whether any of the cell-based treatments worked better than steroids for relieving knee pain.

Study Details

• Participants: 480 patients randomized; 440 completed treatment.Average age of 58.3 years with Knee OA. (KL Grade 2-4)
• Procedure: Patients were split into three groups to test different types of stem cells, and each of those groups also included a smaller set of patients who got steroid injections for comparison.
• Delivery Method: All treatments were injected directly into the knee joint under ultrasound guidance.
• Cells Used:
  • BMAC: Autologous bone marrow aspirate concentrate (minimally manipulated MSC-containing mixture)
  • SVF: Autologous adipose-derived stromal vascular fraction (includes MSCs and other regenerative cells)
  • UCT-MSCs: Allogeneic (donor-derived) human umbilical cord tissue mesenchymal stromal cells
• Dosage: The study didn’t report the exact number of cells used in the bone marrow or fat-derived stem cell treatments, 
  • Patients in the umbilical cord stem cell group received a consistent dose of 20 million

Culture Method

Bone Marrow:

• Harvest: Doctors collected bone marrow from the back of the patient’s hip bone using a needle to draw out stem cells for same-day injection.
• Processing: The bone marrow was spun in an FDA-approved machine to concentrate a mix of cells. Not to isolate Mesenchymal stem cells. So the final product includes a small number of MSCs along with many other cell types.
• Testing: Before the stem cell mixture was injected, it was checked to make sure it had enough total cells, that the cells were alive and healthy, and that it was free from harmful contamination like bacterial toxins.
• However, they did not test whether the cells had specific stem cell markers (like CD105, CD90, or CD73). So they didn’t confirm how many of the cells were actually MSCs.
  

Fat Derived Cells

• Harvest: Doctors used a gentle liposuction procedure to collect a small amount of fat from the patient to prepare the stem cell injection.
• Processing: The fat was processed to extract a mix of healing cells (called stromal vascular fraction) but it didn’t isolate just the stem cells. The final injection contained a variety of cell types, including some MSCs.
• Testing: Like BMAC, it was checked to make sure it had enough total cells, that the cells were alive and healthy, and that it was free from harmful contamination like bacterial toxins.
• However, they did not test whether the cells had specific stem cell markers (like CD105, CD90, or CD73). So they didn’t confirm how many of the cells were actually MSCs.

Umbilical Cord Derived MSC Cells

• Cultured and expanded in a GMP-certified lab
• Grown to Passage 2
• The umbilical cord stem cells were frozen and preserved in a special solution (Plasmalyte A with 5% human protein) and stored in cryobags. Small, sterile containers, at extremely low temperatures using liquid nitrogen to keep the cells alive until they were ready to use
• Before injection, the umbilical cord stem cell batches were tested to ensure the cells were alive, safe, and free from contamination. However, the study didn’t report standard stem cell surface markers (like CD73, CD90, or CD105).
• Instead, they analyzed 8 samples using single-cell RNA sequencing, which confirmed the cells had a consistent MSC gene profile, suggesting good purity and quality.

Results: Follow-up duration: 12 months

Primary outcome: VAS Pain Score ( a 0–100 scale where lower numbers mean less pain)

• The stem cell groups all showed meaningful improvements in pain:
  • BMAC group dropped from 58.1 → 33.8 (a –24.3 point change)
  • SVF group dropped from 53.8 → 34.4 (–19.4)
  • UCT group dropped from 54.3 → 34.2 (–20.1)
  • Steroid group dropped from 59.9 → 39.0 (–20.9)
  • All groups improved, but none of the stem cell groups were statistically better than steroids (P > 0.19 in all cases)
    

KOOS pain score (Function & Quality of Life):

• BMAC group: Increased by +19.1 points
• SVF group: +17.2
• UCT group: +16.2
• Steroid group: +17.7
  Again, no significant difference between any of the treatments (P-values all > 0.44)

MRI cartilage damage:

• MRI scans showed no structural improvement in cartilage in any group, and no major worsening either.
• No treatment prevented or reversed cartilage loss over 12 months.

Safety:

• No serious adverse events
• Minor side effects (e.g., swelling, bruising) were more common in SVF group

How Cells Worked

• No direct proof of differentiation into cartilage or other knee tissues.
• The stem cells appeared to work by sending signals that reduce inflammation and support the joint environment, rather than by turning into new cartilage

What we don’t know

• Long-term outcomes beyond 12 months  the study did not assess durability or delayed benefits.
  
• Dose–response relationship  especially for autologous groups, exact MSC counts were not standardized or disclosed.

Researchers Thoughts

• All treatments, including stem cells and steroids, improved pain and knee function at 12 months.
• No stem cell treatment (BMAC, SVF, or UCT) was better or worse than corticosteroids (CSI) in reducing pain or improving quality of life.
• MRI scans showed no structural improvement in joint cartilage for any group.
• The researchers concluded that while stem cell therapies are safe, they do not offer better results than steroid injections after 1 year.

2020 R Bio Phase 3 JointStem Trial: South Korea

You can read more on the study here

Participants:

• Sample size: 261 patients with Knee OA (KL grade 3).
  
• Demographics: Adults aged 20 to 100 years; both sexes; all Korean study population

Procedure:

• Delivery method: Intra-articular injection into the knee joint
  
• Dosage: 1 × 10⁸ cells (100 million cells), single injection
  
• Control Group: Received saline placebo injection
  
• Blinding: Double-blind (patient and investigator)

Cell Type Used

• Cell type: Autologous adipose-derived mesenchymal stem cells (ADMSCs)
  
• Source: The stem cells were collected from their own fat tissue using a small liposuction procedure. 

How Cells Were Prepared

• Isolation: The fat tissue was broken down using enzymes to separate the stem cells (MSCs) from the rest of the material, allowing them to be expanded in the lab and later injected into the knee.
  
• Expansion: Cells were culture-expanded under GMP conditions to reach the target dose

Full Results and Success Rates

Primary outcomes (6-month follow-up):

• VAS Pain Score Improvement (a simple 0 to 10 scale where patients rate their pain):
  • Patients who received the stem cell treatment reported a 25.2 mm drop in pain on a 100 mm scale.
  • Those who got the placebo still improved, but only by 15.5 mm.
  • The difference was statistically significant, meaning the stem cells clearly worked better than placebo.

• WOMAC Total Score Improvement (a 0–100 scale that measures how much joint pain, stiffness, and difficulty with daily activities a person has due to osteoarthritis.  Higher scores mean worse symptoms):
  • Patients treated with stem cells showed a 21.7-point improvement in knee function.
  • The placebo group improved too, but only by 14.3 points.
  • This difference was statistically significant, showing that stem cells led to better functional results.

• Clinical significance: The stem cell group didn’t just improve more on average. More of them improved enough that it really made a difference in their daily lives.
  
• Adverse events: No serious treatment-related adverse events reported
  
• Radiologic outcomes (MRI): There were no clear signs that the stem cells helped regrow cartilage or improve joint structure on MRI or X-rays.

How Cells Worked

• The stem cells likely helped by sending healing signals, not by rebuilding cartilage.
• Even though scans didn’t show new cartilage growth, patients still felt less pain and moved better.
• These improvements probably came from the stem cells reducing inflammation, supporting joint health, and calming the immune system.

What we don’t Know

• Cartilage regeneration not proven: Despite clinical gains, no MRI evidence of tissue regrowth at 6 months
  
• Duration of effect unknown: Only 6-month follow-up; long-term benefits and durability are untested
  
• No structural outcome changes: No measurable improvements in joint space width or bone alignment

7. Patella Tendonitis Study Comparing STC to PRP: Spain

You can read more about the study here

Participants:

• Sample size: 20 male patients (aged 18–48) with Chronic unilateral patellar tendinopathy (knee tendonitis) who haven’t responded to rehab
  
• Design: The study was carefully designed to fairly compare stem cells and PRP by randomly assigning treatments and keeping both patients and doctors unaware of who got which one.
  
• Location: Institut de Teràpia Regenerativa Tissular (ITRT), Teknon Medical Center, Spain

Procedure:

• Delivery method: Single ultrasound-guided injection directly into the affected portion of the patellar tendon
• The patients were split into 2 groups of 10. One group received the BM-MSC’s and one group received Lp-PRP

Cell Type Used

• Autologous BM-MSCs (Bone Marrow-Derived Mesenchymal Stromal Cells from the patients own body)
• Compared against leukocyte-poor Platelet-Rich Plasma (Lp-PRP)

How Cells Were Prepared

• Source: Doctors used a needle to draw bone marrow from the back of the hip, where it’s safe and easy to access a good supply of stem cells.
• Processing:
  • MSCs were isolated and culture-expanded ex vivo in a GMP facility
    
  • Expansion occurred over ~2–3 weeks
    
  • Dose: 20 million viable MSCs (2 × 10⁷) per injection
    
  • Positive markers: CD73, CD90, CD105. These markers confirm the cells are true mesenchymal stem cells (One thing to note is strictly, the ISCT says that true mesenchymal stem cells must have all three markers: CD73, CD90, and CD105.)

Results

• Follow-up Duration: 12 months
• Structural Healing (UTC Imaging):
  • In the group that received stem cells (BM-MSC), the amount of healthy, organized tendon tissue (called echo-type I) increased from 57.5% at the start to 66.9% after 12 months. A 9.4% improvement. In contrast, the PRP group started at 61.0% and slightly dropped to 60.4%, showing no real improvement.
    
  • For damaged or disorganized tissue (echo-type III), the stem cell group improved from 20.6% down to 14.1%, a 6.5% reduction in unhealthy tendon fibers. The PRP group actually got slightly worse, going from 17.6% to 18.4% over the same time.
    
  • This shows that stem cells clearly helped the tendon heal, while PRP had little to no effect.
• Pain:
  • Patients who received stem cell treatment (BM-MSC) saw their pain scores drop from 3.56 to 0.00 over 12 months, meaning they reported no pain at all by the end of the study. 
  • In comparison, the PRP group started with a higher pain score of 4.67, which dropped to 1.22. A meaningful improvement, but they still experienced some lingering pain after a year.
• Function
  • Strength recovery (via isometric testing) improved faster and more consistently in the MSC groupS
• Side Effects: None major reported; procedure well-tolerated

How Cells Worked

• The stem cells worked by sending out healing signals that triggered the body to repair the tendon. 
• They didn’t turn into new tendon cells themselves 

What we don’t know

• Cell fate not tracked. No biopsy or imaging to confirm if MSCs survived long-term
  
• No data on repeat dosing or long-term outcomes beyond 1 year
  
• Small sample size (n=10 per group) limits statistical power

Reviews looking at Stem Cells treating Knee issues

2023 Review on MSC’s treating OA, with a heavy focus on Knee OA: Brazil

You can read more about the review here.

A team of scientists from Italy and Brazil came together to figure out whether stem cell therapy really works for people with osteoarthritis, especially in the knees. Led by researchers from top medical centers like IRCCS Istituto Ortopedico Galeazzi in Milan and the Federal University of Ceará in Brazil, their review was published in the International Journal of Molecular Sciences in 2023.

What they looked at:

• 35 clinical trials using mesenchymal stem cell (MSC) therapies to treat osteoarthritis (OA), with a strong focus on knee OA.
  
• Trials spanned different MSC sources, delivery methods, doses, and outcome measures.
  
• Types of MSCs reviewed:
  • Bone Marrow MSCs (BM-MSCs)
  • Adipose-Derived MSCs (AD-MSCs: Fat Derived)
  • Synovium-Derived MSCs (SD-MSCs: Stem cells taken from the joint lining (synovium), known for their high ability to form cartilage and natural compatibility with the joint environment.)
  • Peripheral Blood MSCs (PBMSCs: Stem cells collected from the bloodstream after stimulation with growth factors, offering a less invasive alternative for treating large cartilage defects.)
  • Human Umbilical Cord/Placenta MSCs (hUCB-MSCs, PLMSCs)

What they’re trying to find out:

• Whether MSC therapies are effective for treating OA, particularly in terms of cartilage regeneration and symptom relief.
  
• Which types of MSCs, doses, and delivery approaches yield the best outcomes.
  
• Whether any standardized pattern exists for clinical success.
  
• What mechanisms underlie MSC effectiveness: differentiation vs. signaling/trophic effects.

What they found:

1. Effectiveness:

• In 67% of the 35 clinical trials reviewed (about 23 trials), patients treated with MSCs experienced more than double the improvement in pain and physical function scores compared to what would typically be expected without treatment or from baseline.
  
• In 71% of the stem cell therapy trials (about 25 out of 35), patients reported feeling significantly better. With at least a 17-point improvement on the WOMAC scale, which is a widely used tool to measure pain, stiffness, and joint function in people with osteoarthritis.
  
• In about 63% of trials, MRI scans showed actual cartilage healing after stem cell therapy. Suggesting the treatment may do more than just mask symptoms; it may help repair the joint itself.
• 2 trials showed no significant improvement in either symptoms or structure.

2. Mechanisms of Action

• Mesenchymal stem cells (MSCs) help the body heal by sending out signals that reduce inflammation and encourage tissue repair. Not by turning into cartilage themselves.
  
• Instead of becoming new cells, they create a healing environment that supports the body’s natural regeneration process.
  

3. MSC Source Comparison:

• Adipose-derived MSCs (AD-MSCs): Safe, easy to harvest, promising early results; effective even in high doses.
  
• Bone marrow MSCs (BM-MSCs): Most used, generally effective, but outcomes vary.
  
• Synovium MSCs: More chondrogenic; promising results but fewer trials.
  
• Umbilical cord MSCs: Encouraging long-term results in small studies.
  
• BMAC (non-cultured): Generally less effective; did not outperform saline in some trials.
  

4. Dosing Insights

• No consistent dose-response relationship. Higher cell counts did not always yield better outcomes.
  
• Repeated dosing performed better than a single high dose.
  
• The quality of the cells, the stage of the disease, and how the cells were delivered mattered more than just giving a high dose. Bigger isn’t always better if the cells are weak, or the joint is too damaged.

5. Safety

• MSC therapies were consistently safe across all trials.
  
• No severe adverse events or tumor formation observed.
  
• Allogeneic MSCs (from donors) were well tolerated.

6.Limitations Across Trials:

• Most trials were small (only 29% had >50 patients).
  
• Short follow-up periods (only 5 studies had ≥3-year follow-up).
  
• Variable methodology, lack of standardized outcome measures, and inconsistent imaging quality.
  
• Cell preparation varied widely between studies, including differences in donor source (self vs. donor), culture conditions (like serum type and oxygen levels), passage number (how many times cells were grown in the lab), and final product formulation (such as the fluid used to carry the cells and the total cell dose given).

What they Concluded:

• MSC therapy is safe and shows promise for reducing symptoms and potentially regenerating cartilage in OA, particularly knee OA.
  
• Paracrine signaling (not cell differentiation) is the primary mechanism of therapeutic benefit.
  
• No one MSC source or dose is definitively superior, but repeated injections appear favorable.
  
• BMAC may not be sufficient for cartilage regeneration, especially in moderate to severe OA.
  
• There is a need for:
  • Standardized trial designs
    
  • Larger, long-term, controlled studies
    
  • Quality-controlled MSC products
    
  • Better metrics for cartilage repair

2023 Review on MSC Cells treating Knee OsteoArthritis: China

A team of doctors from Jiujiang, China, specialists in orthopedics, spine surgery & dermatology, came together to tackle one big question: do stem cells actually help people with knee osteoarthritis? Led by Rong-hui Xie and Shi-guo Gong, they dug into 16 clinical trials to find out how well these therapies work and which types of stem cells perform best.

What they were looking at

The researchers reviewed and analyzed data from 16 clinical trials involving 875 people with knee osteoarthritis (KOA). These studies tested how well mesenchymal stromal cells (MSCs), a type of regenerative stem cell taken from bone marrow, fat tissue, or umbilical cord, worked compared to standard treatments like hyaluronic acid, platelet-rich plasma (PRP), or placebo.

They examined:

• Pain levels (using VAS)
  
• Joint function (WOMAC, LKSS, Lequesne Index)
  
• Structural changes in the knee (WORMS via MRI)
  
• Safety outcomes
  
• Differences by stem cell source (autologous vs allogeneic, adipose vs bone marrow vs cord
  

What They’re Trying to Find Out

• Whether MSC therapy is effective in reducing pain and improving joint function in KOA patients.
• Which stem cell source is most effective (adipose, bone marrow, or umbilical cord).
• Whether the therapy is safe and well-tolerated.
• Whether MSC therapy contributes to cartilage repair, as assessed by MRI.
• Whether combining MSCs with other treatments (e.g., hyaluronic acid or PRP) influences outcomes.

What They Found

1. Pain Relief

Pain Reduction – Visual Analog Scale (VAS) for pain:

• Average pooled effect size at 12 months: −0.94 (after 12 months, people who received MSC therapy had substantially less pain than those who didn’t)
• Effect sizes at:
  • 6 months: −0.65
    
  • 3 months: −0.50
    
  • 1 month: −0.14 (not statistically significant)
• Best Pain Relief Came from:
  • Umbilical cord-derived MSCs (at 3 and 6 months)
  • Adipose-derived MSCs (ADSCs) (at 1 and 12 months)

2. Improved Function

• WOMAC, Lequesne, and LKSS scores showed statistically significant functional improvement in the MSC groups. (WOMAC looks at overall pain, stiffness, and how well the knee works day-to-day, Lequesne measures how severe the knee problem is and how much it affects daily life, and LKSS checks how well the knee moves and functions during specific activities.)
  
• Autologous ADSCs were most effective for joint function recovery.

3. No Structural Cartilage Regeneration

• MRI-based WORMS scores showed no significant cartilage repair, even at high doses.
• Suggests MSCs did not differentiate into cartilage in meaningful ways.

4. No Added Benefit from PRP/HA Combinations

• MSC combined with PRP or hyaluronic acid did not significantly outperform MSC alone.

5. Cell Source & Dose Matter

• Autologous ADSCs outperformed allogeneic ones.
  
• Higher doses (e.g., 400 million cells) correlated with stronger pain and function outcomes.
  
• However, no formal dose-response curve was performed.

6. Mechanism of Action

• The benefits likely came from the stem cells sending helpful signals to reduce inflammation and support healing, rather than turning into new cartilage themselves.

7. Safety

• MSC therapy was well tolerated, with no major adverse events. Some short-term swelling/pain was reported post-injection.

Limitations they identified

• The researchers point out that many of the studies didn’t follow the same standards for preparing stem cells. So in some cases, it’s unclear whether the cells were actually isolated, tested and confirmed to be true MSCs before being used.
• Many trials only tracked patients for a few months to a year, so the long-term safety and durability of MSC therapy is still unknown.

2024 Review on MSC Cells treating Knee OA: Canada & Iran

You can read the review here

A team of researchers from McMaster University in Canada, along with collaborators from Iran and the Netherlands, set out to answer a big question: Do stem cell injections actually help people with knee arthritis feel better? Backed by experts in pain medicine, anesthesia, and evidence-based health research, they reviewed the best clinical trials available to find out.

What they were looking at

A team of international researchers reviewed 16 randomized trials (807 patients total) to evaluate:

• Whether mesenchymal stem cell (MSC) injections help people with chronic knee pain caused by osteoarthritis (OA).
  
• Trials included patients getting MSC injections vs. placebo, usual care, or sham treatments.
  

They focused on real outcomes patients care about, like:

• Pain relief
  
• Improved physical function
  
• Emotional well-being
  
• Adverse effects

What They Were Trying to Find Out

1. Do stem cell injections relieve chronic knee pain better than placebo or usual care?
   
2. Do they improve physical functioning or quality of life?
   
3. Are there any safety concerns (e.g., joint swelling, pain, complications)?
   
4. Does the type of cell, preparation method, or trial quality affect the outcome?

What They Found

• At 3–6 months, MSC injections reduced pain by −0.74 cm on a 10 cm scale, and at 12 months by −0.73 cm, both with moderate certainty. However, these improvements were not clinically meaningful, as they fell below the 1.5 cm threshold patients would notice.
• In Other Words: Stem cell injections for knee arthritis showed only a tiny improvement in pain too small for most people to actually feel a difference.
• Note: In total, 14 trials reported short-term pain outcomes, but only 6 high-quality trials were trusted for the final conclusion.
• Physical Functioning:
  • At 3–6 months, stem cell injections improved physical function by just +2.23 points on a 100-point scale, which is not enough to matter to patients (10 points is the minimum meaningful change). At 12 months, the improvement was larger (+19.36 points), but the evidence was uncertain and low quality, so the result may not be reliable.
  • Basically, function improved slightly in some lower-quality studies, but better studies showed no real benefit.
• Adverse Events: One case required overnight hospitalization; otherwise, side effects were non-serious but more common with MSC.
  

What Influenced the Results?:

• When all 16 trials were pooled, it looked like MSCs helped.
• But most of those trials had biases (bad blinding, industry funding, poor design).
• When limited to only 4–7 high-quality trials, the benefits disappeared.

What they concluded

• Short-term (3–6 months): MSC injections probably do not improve pain or function in any meaningful way.
• Long-term (12 months): They still don’t significantly reduce pain, and might improve function slightly, but the evidence is weak.
• Overall, MSC injections are not supported by high-quality evidence as an effective treatment for chronic knee OA pain.

2024 Review on Umbilical Cord Derived MSC Cells treating Knee problems: China

You can read more about the review here

This review was written by a team of researchers and doctors from several traditional medicine clinics and universities in Hangzhou, China, including the Hangzhou Fuyang Hospital of TCM Orthopedics, Tongjuntang Second TCM Clinic, and Zhejiang Chinese Medical University. Led by Zhijian Xiao and Lihua Luo.

The team set out to explore whether stem cells from umbilical cords could offer real relief for people suffering from knee osteoarthritis. 

What they were looking at

• The authors set out to find out if umbilical cord mesenchymal stem cells (UC-MSCs) could actually help people with knee osteoarthritis (KOA)
• They wanted to know:
  •  Do these stem cells reduce pain?
  • Do they improve how well the knee works compared to standard treatments like hyaluronic acid (HA) or saline (NS)?
• They used two well-established clinical tools to measure outcomes:
  • WOMAC (Measures pain, stiffness, and physical function in people with osteoarthritis.)
  • KLS (Focuses on knee stability and performance, often used to track recovery after knee injuries or treatments.)

They analyzed three randomized controlled trials (RCTs) involving 101 patients, comparing UC-MSC treatment to conventional options like hyaluronic acid (HA) or normal saline (NS).

What they were trying to find out:

The study aimed to answer a few important questions:

• Do UC-MSC injections actually help?
  Are they effective at relieving pain, reducing stiffness, and improving knee function in people with osteoarthritis?
  
• How do they stack up against standard treatments?
  The researchers compared UC-MSCs to common alternatives like hyaluronic acid (HA) and saline injections.
  
• Are the benefits real and reliable?
  They wanted to know if the positive results from clinical trials were statistically significant (not just due to chance) and clinically meaningful (actually useful in real life).
  
• Are the results consistent and safe?
  They looked for patterns to see if UC-MSCs worked well across different studies and whether they caused any side effects.
  
• Were the studies themselves trustworthy?
  To judge quality, they used tools like the PEDro scale (which scores how well a study is designed), the Egger test (which checks for publication bias), and sensitivity analysis (to see if results hold up when one study is removed).

What they found

• WOMAC Scores
  •  People who got UC-MSC injections had a big improvement. Their WOMAC scores dropped by 25.85 points, which means less pain and better knee function.
  • This result was statistically significant (P = .001),
  • But there was a lot of variation between the studies (I² = 88%), so results weren’t totally consistent.
• Knee Lysholm Score
  • UC-MSCs also helped people move better. Their KLS scores increased by 18.33 points, showing strong improvement in knee performance.
  • This result was very strong and consistent (P < .00001, I² = 0%),
  • Which means the studies agreed closely on this benefit.
• Publication Bias (Egger’s Test):
  •  The authors checked whether only “positive” studies were published (which can skew results).
  • The Egger’s test score was 0.583, showing no sign of bias in how the data was reported.
  • Sensitivity Analysis: Showed that the results were robust and stable, even when removing studies one at a time.
• PEDro Quality Scores:
  • Matas et al.: 10/10 (excellent quality)
  • Sun et al.: 7/10 (good)
  • Wang et al.: 6/10 (good)
• Injection Protocol
  • Only Matas et al. used repeated injections and reported better outcomes compared to single dosing and HA.
  • The other two studies likely used single injections.
• Cell Preparation Details: The review did not provide detailed information on UC-MSCs preparation (e.g., passage number, surface markers, or lab protocols), which limits biological comparability.

What they concluded

• Intra-articular UC-MSC injections show significant improvement in pain and function for KOA patients compared to conventional treatments.
  
• UC-MSCs are safe, with only transient, mild adverse effects (e.g., temporary joint pain or effusion) reported in two studies.
  
• Repeated injections (as in Matas et al.) may be more effective than single-dose protocols.
  
• Despite promising results, only three small-scale RCTs were included, all single-center, which limits generalizability.
  
• There is a need for larger, multi-center RCTs with standardized protocols to confirm long-term safety and efficacy.
  
• The study suggests UC-MSCs could become a valuable non-surgical option for managing knee osteoarthritis, but further validation is essential.

Real-world evidence of mesenchymal stem cell therapy in knee osteoarthritis. A large prospective two-year case series: Australia

You can read more about this evidence study here.

This is a two‑year real‑world evidence study looking at how well stem cell therapy works for knee osteoarthritis when used in everyday clinical practice. It wasn’t a tightly controlled lab trial. Patients paid for the treatment themselves and came from a range of ages, severities, and occupations. The work was led by Magellan Stem Cells and Melbourne Stem Cell Centre Research in Australia, with university oversight to keep things safe and credible.

Participants
329 adults (ages 23–85, mean age 58.6; 60.6% male) with mild to severe knee osteoarthritis. All had failed conservative management (painkillers, exercise, weight loss). Patients came from a mix of occupational backgrounds, and ~31% were classified as obese.

Treatment Procedure
Two ultrasound-guided intra-articular injections (baseline and 6 months) into the knee joint. Each dose: 50 million ADMSCs, suspended in 4 mL of either autologous conditioned serum, platelet lysate, or saline.

Cell Type Used
Adipose-derived mesenchymal stem cells (ADMSCs). Autologous (from the patient’s own fat).

How Cells Were Prepared

• Fat harvested via liposuction (“lipoharvest”) from the abdomen or thigh.
• Cells were cultured in a cleanroom to reach 100 million total dose, expanded to a max of passage 4, and tested for viability (≥90%).
  • Meaning at least 90% of the stem cells were alive and healthy at the time of injection.
• Identity Markers: CD90+, CD105+, CD73+; CD14/19/34/45–.
  • One thing to note is strictly, the ISCT says that true mesenchymal stem cells must have all three markers: CD73, CD90, and CD105.
  • And markers like CD14, CD19, CD34 & CD45 should be checked to make sure they’re not present. These are proteins found on blood or immune cells. So if stem cells don’t have them, it shows the sample is clean and not mixed with the wrong types of cells
• The stem cells were frozen and stored in liquid nitrogen (around –196 °C) to keep them fresh, then carefully thawed and rinsed with saline right before injection to make sure they were safe and viable.

Full Results and Success Rates

• Pain dropped by 54% on average (NPRS: 5.2 → 2.4).
  
• 88% reported improvement (PGIC), with 11% feeling fully recovered.
  
• 70.5% reached clinically meaningful improvements across KOOS/WOMAC.
  
• TKR avoided in 90% of high-risk working patients.
  
• No serious adverse events. Mild pain, swelling, and stiffness were common but self-limiting.
  
• Effect consistent across age and BMI groups.
  
• Most improvement occurred in the first 12 months and was maintained through 24.

How Cells worked

• The authors believe the stem cells worked mainly by calming inflammation and reducing pain signals, not by regrowing cartilage. 
• The cells help by lowering harmful chemicals in the joint (like IL-1, IL-6, and TNFα) and changing immune cells to be less aggressive. 
• Because even people with “bone-on-bone” arthritis felt relief, the treatment likely helped by soothing the nerves and inflammation rather than rebuilding the joint.

What We Don’t Know

• No MRI follow-up at 24 months  so we don’t know if cartilage regrew or stabilized.
  
• No control group, can’t fully rule out placebo effect.

Negatives: What Do the Studies Not Tell Us Stem Cell Knee Treatments?

While these studies highlight promising results, it’s essential to recognize some of the limitations and concerns surrounding stem cell therapy for knees:

1. Lack of Large-Scale Studies: Most of the trials conducted so far involve small sample sizes, typically under 50 participants. Larger, more diverse studies are needed to confirm these findings on a broader scale.
2. Uncertain Long-Term Effects: Although follow-up studies like the one from South Korea provide insights into short-term improvements, the long-term benefits and safety of stem cell therapy are still unclear. Many studies lack data beyond five years, which is crucial for understanding whether MSC therapy can sustain knee function over time.
3. Mixed Results in Cartilage Regeneration: While some patients experience cartilage regeneration, not all studies show consistent results in this area. For instance, although some trials demonstrate improved cartilage health, others show little to no changes in cartilage thickness.
4. Cost and Accessibility: Stem cell therapies, particularly those using allogenic MSCs, can be expensive and are not widely available in many regions. In some countries, regulations and approvals for these treatments remain stringent, limiting accessibility for patients.

Conclusion

• Most research comes from South Korea and Australia, with additional studies from the USA, Japan, China, Spain, and Brazil.
• Adipose-derived stem cells (from fat) are the most commonly tested type, followed by bone marrow-derived cells.
• Umbilical cord-derived cells are promising but tested less frequently.

Success rates are mostly positive:

• Most studies show reduced pain, improved movement, and slowed joint damage.
  
• Cartilage regrowth is rare and inconsistent across trials.

How it works:

• In every study and review, stem cells helped by sending healing signals (called paracrine signaling).
  
• They did not become new cartilage or tissue.

 Safety is strong across the board, with no serious side effects reported in any trial.

If you’re considering stem cell treatment for your knee, keep in mind that real-world clinics may not follow the strict safety and quality protocols used in clinical trials.

These studies showed mixed methods and inconsistent results. So while many people improved, there’s no guarantee it will work the same for you.

Cartistem Research

5 Year Follow up On Cartistem Treatment: Medipost (South Korea)

This study tested whether Cartistem, a treatment made from donor stem cells taken from umbilical cord blood, could safely repair knee cartilage, reduce pain, and improve movement in older adults with serious joint damage.

It was a large, carefully controlled trial (Phase III) where patients were randomly given either Cartistem or standard surgery. Doctors then followed their results for 5 years.

The full study is posted here.

Who Conducted this study?

This was a Phase III, randomized controlled trial led by researchers in South Korea, specifically:

• Lead institution: Seoul National University Bundang Hospital
  
• Principal authors:
  • Chul-Won Ha, MD (Department of Orthopaedic Surgery)
  • Joo Hyun Park, MD, and others from the same department
    

• The study was sponsored by Medipost, the company who produces Cartistem. 

Study Details

Participants: 114 adults (average age ~56) with large (2–9 cm²), full-thickness knee cartilage defects.

• Most patients had mild to moderate osteoarthritis based on X-rays. In the stem cell (Cartistem) group, 10 had grade 1, 18 had grade 2 and 22 had grade 3 arthritis. In the microfracture group, 21 had grade 2 and 21 had grade 3.
  
• Around 40% had multicompartmental osteoarthritis, meaning cartilage damage was present in more than one area of the knee.
  
• Treatment was applied only to the most painful and damaged compartment, usually the medial side of the knee.

Study Design:

• Randomized into 2 groups
  
• Treatment group received umbilical cord blood–derived MSCs + 4% hyaluronic acid (Cartistem)
  
• Control group received microfracture surgery

Primary Outcome Testing:

• Doctors checked how well the knee cartilage had healed by doing a second-look arthroscopy (a small camera procedure) at 48 weeks. They graded the cartilage restoration using the ICRS scoring system, which measures how smooth, full, and well-integrated the new cartilage is.

Secondary Outcome Testing:

• Pain (VAS), function (WOMAC, IKDC) and histologic cartilage quality
• Long-term safety and symptom tracking up to 5 years

Procedure:

• Cartistem was delivered via mini-arthrotomy directly into 5-mm drill holes at the cartilage defect site.
• Microfracture group received standard arthroscopic treatment.

Cells Used (Cartistem):

• Allogeneic (donor) umbilical cord blood–derived mesenchymal stem cells (UCB-MSCs)
• Combined with 4% hyaluronic acid gel for structure and delivery

Doseage:

• 7.5 million MSCs per 1.5 mL of gel, injected directly into the defect site
• The gel helped the cells stay in place and supported integration into the knee

Blinding:

• Outcomes were assessed blindly by surgeons and histologists who did not know the treatment group
• Patients and surgeons could not be fully blinded due to visible surgical differences

Cell Preparation:

• Cells were grown in culture from screened donor cord blood
• Tested for potency, sterility, mycoplasma, and endotoxins
• Final dose was thawed and delivered on the day of surgery

Results:

• Primary Outcome (Cartilage Restoration):
  • 97.7% of patients who received the stem cell treatment (Cartistem) showed improvement of at least one cartilage grade on the ICRS scoring system at 48 weeks. Meaning their knee cartilage looked visibly healthier during the second-look arthroscopy compared to before treatment.
  • In comparison, only 71.7% of patients who had microfracture surgery (the control group) showed the same level of improvement 
• Biopsy Results (48 Weeks)
  • Treated cartilage showed:
    – High levels of type II collagen
    – The repaired cartilage contained abundant glycosaminoglycans, which are essential molecules that help healthy cartilage stay cushioned, hydrated, and flexible. A strong sign that the new tissue was high quality.
    – The new cartilage had a strong, organized structure and was well-integrated with the surrounding tissue, meaning it blended in smoothly and looked more like natural, healthy cartilage.
  • The new tissue that grew after treatment looked and behaved more like real, healthy cartilage (called hyaline cartilage) instead of weaker, less functional scar tissue (called fibrocartilage).
• VAS Pain Score (0–100 scale)
  This measures how much pain the patient feels (higher = more pain):
  • Cartistem Group: Pain score dropped from 44 → 29.1
  • Microfracture Group: Pain score dropped only slightly from 44.6 → 43.5
  • P-value: 0.003 (statistically significant difference. Cartistem clearly better)
• WOMAC Score
  This measures pain, stiffness, and physical function in people with knee OA (lower = better):
  • Cartistem Group: Score improved from 37.4 → 26.9
  • Microfracture Group: Score improved slightly from 40.4 → 36.2
  • P-value: 0.020 (statistically significant – Cartistem better)
• IKDC Score
  This measures overall knee function (higher = better):
  • Cartistem Group: Score increased from 42.7 → 54.7
  • Microfracture Group: Score increased from 41.8 → 47.1
  • P-value: 0.007 (statistically significant – Cartistem better)
    
• Across all three major measures of knee pain and function Cartistem showed significantly greater improvements than standard microfracture surgery
• Improvements were maintained at 5 years in Cartistem group
• Microfracture patients’ gains faded after year

MRI Not Used for Primary Imaging:

• Assessment was done via second-look arthroscopy and tissue biopsy
• No MRI-based cartilage volume metrics included

Adverse Events

• No immune reactions or rejection (despite donor cells)
  
• No major safety issues
  
• Serious events (e.g., knee replacement) were rare and similar between groups

How Cells Worked:

• The UCB-MSCs helped by sending out anti-inflammatory and healing signals to the surrounding joint tissue (paracrine effect).
• There was no evidence the cells directly turned into cartilage.
• Instead, they likely stimulated the patient’s own repair processes and improved the environment for regeneration.

What We Don’t Know

• Long-term cartilage durability beyond 5 years
• Whether non-surgical delivery methods (e.g., injection) would be as effective

Conclusion

This study shows that Cartistem can safely restore cartilage structure, improve pain + knee function and help avoid further knee damage in older adults with serious joint defects.

While the cells didn’t directly become new cartilage, they created a powerful healing environment, leading to better outcomes than microfracture and those results lasted 5 years.

2-Year Follow-Up on Cartistem Treatment vs. Microdrilling + HTO: Yonsei University (South Korea)

This study compared two cartilage repair treatments:

1)  Cartistem (a stem cell therapy made from donor umbilical cord blood) 

2) Microdrilling

Researchers wanted to see which worked better at regenerating cartilage, reducing pain, and improving knee function.

All patients had serious arthritis on the inner side of the knee (medial OA) and bowed-leg alignment. To correct this, everyone also had a procedure called high tibial osteotomy (HTO), which shifts pressure away from the damaged area to reduce stress and support healing.

This article in Nature covers the study in full detail.

Who Conducted The Study

• This was a prospective comparative study (not randomized) led by orthopedic researchers at Yonsei University College of Medicine, Seoul, South Korea
• Principal Authors:
  • Se-Han Jung, MD
  • Bum-Joon Nam, MD
  • Sung-Hwan Kim, MD (corresponding author)

• They used Cartistem, supplied by MediPost.  The study was independent with no declared competing interests or corporate sponsorship.

Study Details

Participants:

• 54 patients (60 knees) with advanced medial knee OA
• Divided into two treatment groups:
  • Cartistem group: 27 knees
  • Microdrilling group: 33 knees

All Had:

• Near or full-thickness cartilage damage (ICRS Grade 3–4).
  • Grade 3: Severe cartilage damage with deep lesions but not yet fully exposed bone
  • Grade 4: means the cartilage is completely worn away, exposing the underlying bone. A condition often described as “bone-on-bone.”
• These patients had also failed to improve with conservative (non-surgical) treatments.
• The patient’s legs were bowed inward (called varus alignment), which puts too much pressure on the inner (medial) part of the knee.
  • To fix this, surgeons performed a procedure called High Tibial Osteotomy (HTO) to realign the leg, shifting weight away from the damaged area of the joint.
• All patients had arthritis only on the inner side of the knee (medial compartment), and the outer side (lateral compartment) was still healthy.

Treatment Design:

• Cartistem group: Cartistem implanted during HTO
• Control group: Microdrilling during HTO
• All patients received second-look arthroscopy ~12 months post-op. (a surgical procedure where a doctor inserts a tiny camera into the knee to look inside and examine the cartilage, bone, and other tissues.)

Results:

Primary Outcomes:

• Cartilage Quality, evaluated by ICRS CRA score during second-look arthroscopy.
  • ICRS CRA score is a way for doctors to grade how good the new cartilage looks when they check the knee with a camera. Higher scores mean smoother, fuller, better-healed cartilage:
    • Cartistem® group: 9.41
    • Microdrilling group: 7.94
    • P = .021
  • This means more complete, better-integrated cartilage was visible in the Cartistem group.

Other Outcomes:

• Pain dropped from 48 → 15.2
  (VAS: In the Cartistem group, pain scores fell from 48 to 15.2 out of 100 at 24 months.)
  In contrast, the microdrilling group improved from 52.2 → 28.6.
  (P = 0.016 — statistically significant)
• Function improved from 36.6 → 58.5
  (IKDC: In the Cartistem group, knee function scores rose from 36.6 to 58.5 out of 100.)
  This was significantly better than the microdrilling group (which improved from 35.8 → 50.3).
  (P = 0.038)
  Patients reported better walking, stair climbing, and daily mobility.
• No significant difference in MRI cartilage appearance
  (MOCART 2.0 scores: Cartistem group averaged 53.7; microdrilling group 53.04 on a 100-point scale)
  (P = 0.85 — not statistically significant)
  This suggests both groups had a similar amount of visible cartilage fill on MRI after one year.

• Anterior lesions healed best
  Patients with anterior cartilage damage (front part of the knee) showed higher cartilage scores than those with middle or posterior lesions. Especially with Cartistem.
• No major safety concerns
  No infections, allergic reactions, or serious adverse events were reported in either group.
  The Cartistem product used was allogeneic (donor-derived) but showed no immune complications.

How the Cells Worked

• While the researchers did not directly test how the cells functioned inside the knee, they highlighted several important characteristics:
  • Low immunogenicity: Cartistem is made from donor cells, but it has a low risk of triggering an immune response or rejection.
  • Lab expansion and consistency: The cells can be easily grown in the lab to therapeutic doses and prepared as an off-the-shelf product.
  • Effective even in older patients: Unlike stem cells from a person’s own body Cartistem stem cells retain high regenerative potential regardless of patient age.
• However, the study did not specify whether the cells turned into cartilage themselves (a process called differentiation) or worked by sending out healing and anti-inflammatory signals
  

Conclusion

This study found that in older adults with arthritis on the inner side of the knee and bowed-leg alignment, Cartistem  led to better cartilage healing, less pain, and improved knee function than microdrilling when both were combined with high tibial osteotomy (HTO).

Although both treatments helped, Cartistem provided significantly better results, especially in:

• Patient-reported pain and mobility
• Cartilage quality seen during follow-up knee camera exams
• The MRI scans showed similar amounts of cartilage in both groups, but Cartistem patients had smoother, more natural-looking tissue under direct inspection.

The results suggest that Cartistem, when used with HTO, may be a more effective option than microdrilling for patients with serious medial knee osteoarthritis and bow-legged alignment.

Real-world evidence of umbilical cord stem cell implantation for knee osteoarthritis: a two-year clinical case series from Korea

This was a two-year retrospective study tracking real-life outcomes of patients with moderate knee osteoarthritis who received Cartistem. Unlike a lab-controlled trial, this was based on real-world orthopedic surgical practice in South Korea. Patients came from a wide range of ages, BMIs, and severity levels. The work was led by surgeons at Gangnam JS Hospital and The Catholic University of Korea.

This real word study is documented in Pubmed.

Participants:

128 adults with moderate knee osteoarthritis:

• Age range: 40–78 (mean: 56.5); 67% female
  
• All had full-thickness cartilage damage (ICRS grade 4, meaning the cartilage was completely worn down and the underlying bone was exposed) and had failed conservative care. This is otherwise known as “Bone-on-Bone”
  
• 61 patients (nearly 50%) had two or more cartilage lesions, suggesting multicompartmental disease
  
• 96 also had microfracture on the tibial plateau, and over 85% had meniscus problems

Treatment Procedure

A single surgical implantation of Cartistem into the defect site:

• Surgeons created 4 mm-deep holes in damaged cartilage using an arthroscopic burr
• The procedure used Cartistem, a product containing 7.5 million stem cells per 1.5 mL

Cell Type Used: CartiStem:

• Umbilical Cord Derived Mesenchymal Stem Cells
• Mixed with hyaluronic acid at the time of surgery

How Cells Were Prepared:

Cartistem is produced by Medipost, a Korean biotech company:

• Umbilical cord blood was collected with maternal consent and processed in a GMP facility
  
• Cells were expanded and cryopreserved, then thawed and injected fresh on surgery day
  
• The dose was personalized based on the size of the cartilage damage, with about 5 million stem cells per milliliter. For every 1 cm² of damaged cartilage, doctors injected 0.5 mL of the stem cell mixture, so larger areas received more cells.
  For example, a 4 cm² defect would receive 2 mL, or about 10 million stem cells in total.
  
• Cell identity verified per regulatory standards, though ISCT surface marker data were not reported

Full Results and Success Rates:

• Pain dropped from 7.0 → 2.0 (VAS: After treatments, patients reported their pain as 2 out 10)
  
• Function improved from 32.5 → 61.2 (IKDC: Function scores nearly doubled.Rising from 32.5 to 61.2 (out of 100) on the IKDC scale. Meaning patients could walk, climb stairs, and move more easily after treatment.)
• WOMAC scores improved by 65%, on average. (This means that, on average, patients’ symptoms decreased by 65% compared to where they started.)
  
• All improvements were statistically significant (P < 0.001)
  
• Effect was consistent across all age, BMI, lesion size, and lesion count groups
  
• Trochlear lesions (front part of the knee) had slightly better outcomes than medial femoral condyle ones (inner part of the knee joint)
  
• No infections, allergic reactions, or serious adverse events reported

How Cartilage Was Assessed

34 of the 128 patients agreed to post-op MRIs:

• MRI scans showed that damaged cartilage areas were gradually filling in with new tissue. On a 100-point scale, healing improved from a score of 30.6 to 55.4 over a year. Meaning most patients had visible cartilage regrowth, even if it wasn’t complete.
• This implies visible defect filling, but:
  • No histological biopsy was done
  • The study did not report how many patients had full vs. partial coverage
  • No evaluation of cartilage strength or type (e.g., hyaline vs. fibrocartilage)
    

How Cells Might Have Worked

This is what the researchers concluded about how these cells worked:

• It’s not known whether hUCB-MSCs repair cartilage by turning into new cells or by sending signals to help healing.
• However, we believe these stem cells are more useful than other types because of their advantages.

What We Don’t Know

• No long-term data past 2 years
• No detailed analysis of cartilage composition or durability
• Only 25% of patients underwent MRI, and MOCART subscores (e.g., surface, signal, integration) were not disclosed

Cartistem Conclusion

Cartistem is a stem cell treatment that has shown strong and lasting results in people with moderate to severe knee osteoarthritis. In a major 5-year clinical study, patients who received Cartistem had better pain relief, stronger knee function, and healthier cartilage compared to those who had traditional surgery. These improvements weren’t just short-term,they lasted for years and fewer people needed follow-up procedures.

Tissue samples from treated patients showed that the new cartilage looked and acted more like healthy, natural cartilage, not weak scar tissue. Real-world data from over 1,000 people in Korea confirmed that Cartistem works well for a wide range of patients, no matter their age, weight, or how severe their condition was.
It also helped people with damage in multiple parts of the knee, something that usually makes treatment harder.

Cartistem works by sending powerful healing and anti-inflammatory signals into the joint, helping the body repair itself. Instead of becoming cartilage directly, the stem cells create a supportive environment where natural cartilage can regrow in a smoother, healthier way.

What makes Cartistem different isn’t just how well it works, but also how it got approved. It’s the first Korean stem cell product allowed to skip early clinical trials in Japan because of its strong results in Korea.

Now, Cartistem is in Phase 3 trials in Japan and preparing to start trials in the U.S.
Medipost is also talking to global pharmaceutical companies to bring this therapy to more people worldwide. With growing interest from aging populations and proven long-term benefits, Cartistem is leading the way in a new generation of knee osteoarthritis treatments.