Efficacy and safety of mesenchymal stem cell injections for knee osteoarthritis: A systematic review and meta-analysis.

Background: There have not been any clear studies on the use of mesenchymal stem cells (MSCs) to treat osteoarthritis (OA) in the knee.

Materials and methods: This study investigates the effects of different MSC dosages on pain alleviation in individuals with OA in the knee by conducting a meta-analysis of existing randomized controlled trials. Electronic resources such as Google Scholar, PubMed, Cochrane Library, and Web of Science were searched up until June 2023. Treatment effect sizes were computed using the knee osteoarthritis outcome score (KOOS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Knee Society Score (KSS). Random or fixed effect models were applied to aggregate the data. We performed a subgroup analysis according to dosage level. The heterogeneity of the research was investigated using the Chi-square test and the I2 index.

Results: The meta-analysis included 26 studies with a total sample size of 739 patients. A significant reduction in pain was observed 1 year and 2 years following the injection of MSCs into the injured joint, as indicated by the Visual Analogue Scale, WOMAC, KOOS, and KSS indexes (P < 0.05). Patients on MSCs reported much reduced pain after 1 and 2 years compared to the control group (P < 0.05). Subgroup and meta-regression analyses revealed no statistically significant variations in the effectiveness of MSC dosage (P < 0.05). The studies did not report any adverse effects.

Conclusion: Different dosages of MSCs had the same pain-relieving effects on patients with OA in the knee. MSC injections were safe and beneficial in such cases.