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Single MSC Injection Provides Functional improvements and Pain Relief for Knee Osteoarthritis Patients

Review of “Intra-Articular Injection of Autologous Adipose tissue-derived Mesenchymal Stem Cells for the Treatment of Knee Osteoarthritis: a Phase 2b Randomized Placebo Controlled Clinical Trial” from STEM CELLS Translational Medicine by Stuart P. Atkinson 

The ability of mesenchymal stem cells (MSCs) to differentiate into cartilage tissue and their paracrine anti‐inflammatory and immunomodulatory effects has led to their application as a therapeutic approach to knee osteoarthritis. While successful pain relief, functional improvement, and cartilage regeneration have been reported in response to the intra‐articular injection of MSCs for knee osteoarthritis, only one relevant study employed randomization, blinding, and a comparative group [1]. 

Researchers from the laboratory of Kang‐Il Kim (Kyung Hee University, Seoul, Republic of Korea) previously reported clinical efficacy and safety in a phase I/IIa trial of the intra‐articular injection of high dose autologous adipose tissue‐derived MSCs. However, this study employed the intra‐articular injection of MSCs after washing the joint space in the operating room, which may result in performance bias as clinical and structural improvements would be affected by surgical procedures [2] (Check out this great STEM CELLS article here!).

Now, the team returns with the results of a new and improved trial in a recent STEM CELLS Translational Medicine article [3]. In this phase IIb clinical trial, Lee at al. assessed the efficacy and safety of a single intra‐articular injection of high‐dose autologous adipose-derived MSCs in patients with knee osteoarthritis as part of a prospective randomized, double‐blinded, and placebo‐controlled study in the outpatient setting. Excitingly, the results suggest that this strategy can provide satisfactory functional improvement and pain relief for knee arthritis patients.

  • The trial enrolled 24 patients, with 12 entering each treatment arm (MSC injection vs. saline injection)
    • Patients displayed similar demographics
    • The trial employed no additional surgical interventions or concomitant injections
  • A single intra‐articular injection of 100 million MSCs in the outpatient clinic prompted significant improvements in pain, stiffness, and physical functionality of the treated osteoarthritic knee
    • MSC injection correlated with reductions in the pain score (by 59%), the stiffness score (54%), and physical function score (54%)
    • However, control patients (saline injections) displayed no improvements within the same period
  • The authors failed to observe any serious adverse events in either group during the follow‐up period
  • Magnetic resonance imaging analysis employed to evaluate alterations to the cartilage defect failed to detect any significant changes to the defect over six months
    • However, the defect increased in size in the control patients

While the authors of this article establish that a single intra‐articular injection of autologous adipose tissue‐derived MSCs can provide functional improvements and pain relief for patients with knee osteoarthritis in the outpatient setting, they also highlight limitations to the study. However, they hope to remedy these problems with larger sample size and longer-term follow up in their subsequent trials of this encouraging strategy for the treatment of knee osteoarthritis.

For more on MSC-based treatments for knee osteoarthritis and other conditions, stay tuned to the Stem Cells Portal!


  1. Mokbel AN, El Tookhy OS, Shamaa AA, et al., Homing and reparative effect of intra-articular injection of autologus mesenchymal stem cells in osteoarthritic animal model. BMC Musculoskeletal Disorders 2011;12:259.
  2. Jo CH, Lee YG, Shin WH, et al., Intra-Articular Injection of Mesenchymal Stem Cells for the Treatment of Osteoarthritis of the Knee: A Proof-of-Concept Clinical Trial. STEM CELLS 2014;32:1254-1266.
  3. Lee W-S, Kim HJ, Kim K-I, et al., Intra-Articular Injection of Autologous Adipose Tissue-Derived Mesenchymal Stem Cells for the Treatment of Knee Osteoarthritis: A Phase IIb, Randomized, Placebo-Controlled Clinical Trial. STEM CELLS Translational Medicine 2019;8:504-511.