Study Summary

Ten studies including 818 patients with knee osteoarthritis (KOA) were included in this systematic review and meta-analysis comparing intra-articular mesenchymal stem cell (MSC) injection versus hyaluronic acid (HA) injection. Pooled outcomes of interest included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score, WOMAC subscales (pain, stiffness, function), visual analog scale (VAS), Whole-Organ Magnetic Resonance Imaging Score (WORMS), and adverse events. MSCs demonstrated significantly greater improvements in pain, function, and cartilage repair outcomes compared with HA at multiple time points, while adverse event rates were similar between groups. Overall, MSC injections provided superior clinical and structural outcomes without increased safety risk, suggesting MSCs offer a more effective regenerative treatment option for KOA.