Introduction

Knee osteoarthritis (OA) is a common degenerative disease, affecting approximately 13% of women and 10% of men over 60 years of age. Mesenchymal stem cells (MSCs) show strong potential for cartilage repair, and allogeneic MSCs help overcome the limitations associated with autologous sources.

Aim

To evaluate efficacy and safety of allogeneic MSC implantation versus placebo in knee OA patients. 

Patient Profile

• Patients with knee osteoarthritis
• Mean age 54.2 years

Methods

• Systematic review 
• Included 7 studies (RCTs) investigating the outcomes of allogeneic MSC implantations in patients with knee OA. 
• 356 OA patients ; 177 received MSCs.
• The average follow‐up period was between 12 & 24 months.
• Data on clinical outcomes, such as subjective scores such as VAS and WOMAC, radiological outcomes, such as cartilage thickness &histological outcomes, such as ICRSII score, were extracted.

Results

Clinical Outcomes 

• Significant pain reduction was observed, with VAS scores improving by ~30.4 points at 12 months.
• Functional outcomes improved markedly, with WOMAC scores decreasing by ~40 points, indicating better pain, stiffness, and mobility.
• Imaging and histology confirmed cartilage regeneration, with increased cartilage thickness and improved ICRSII scores (32.0 to 23.9)

Table 1:Baseline vs Follow-up Outcomes (12 months)

 MRI and Histological Outcomes 

• Imaging studies showed increased cartilage thickness in knee joint areas after treatment.
• There was a reduction in damaged cartilage areas (better cartilage quality on T2 MRI)

• Histology analysis showed improved cartilage structure and surface quality.
• Overall cartilage score (ICRS II) improved from 32.0 ± 21.6 at baseline to 55.9 ± 23.2 at 6 months (p<0.05)

Safety Outcomes

Conclusion

• Allogeneic MSCs provide significant pain relief, functional improvement, and cartilage restoration
• Treatment was safe with minimal adverse effects up to 12 months.

Reference

J Exp Orthop. 2025;12:e70437