Efficacy of mesenchymal stromal cells for the treatment of knee osteoarthritis: a meta-analysis of randomized controlled trials

BACKGROUND: Mesenchymal stromal cells (MSCs) are used as an emerging new option for the treatment of knee osteoarthritis (OA). However, their efficacy remains controversial across studies with different doses of MSCs and cell processing methods. We conducted this meta-analysis to assess the efficacy of MSCs in the treatment of knee OA. METHODS: Randomized controlled trials (RCTs) published in PubMed, Embase, Web of Science, SinoMed (Chinese BioMedical Literature Service System, China), and CNKI (National Knowledge Infrastructure, China) databases were systematically reviewed. The pain level and function improvements were evaluated using visual analog scale (VAS), McMaster Universities Osteoarthritis Index (WOMAC), and International Knee Documentation Committee (IKDC). The pooled estimate was calculated with weighted mean difference (WMD) with 95% confidence intervals (95%CIs). RESULTS: Nine RCTs involving 476 patients were included in this meta-analysis. The pooled estimate showed that the treatment of MSCs significantly reduced VAS, WOMAC pain, WOMAC stiffness, and WOMAC function scores at a long-term follow-up (12 or 24 months). However, for the IKDC and WOMAC total scores, MSCs also showed significant improvement in these outcomes, although this was not statistically significant when compared to the control. CONCLUSION: Based on the current studies, our results suggested that MSCs were a promising option for the treatment of patients with knee OA. However, considering the potential limitations, more well-performed, large-scale RCTs are needed to verify our findings. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13018-020-02128-0.