Safety and efficacy of allogenic placental mesenchymal stem cells for treating knee osteoarthritis: a pilot study

Abstract Objective Knee osteoarthritis (OA) is a common skeletal impairment that can cause many limitations in normal life activities. Stem cell therapy has been studied for decades for its regenerative potency in various diseases. We investigated the safety and efficacy of intra-articular injection of placental mesenchymal stem cells (MSCs) in knee OA healing. Methods In this double-blind, placebo-controlled clinical trial, 20 patients with symptomatic knee OA were randomly divided into two groups to receive intra-articular injection of either 0.5–0.6 × 10 8 allogenic placenta-derived MSCs or normal saline. The visual analogue scale, Knee OA Outcome Score (KOOS) questionnaire, knee flexion range of motion (ROM) and magnetic resonance arthrography were evaluated for 24 weeks post-treatment. Blood laboratory tests were performed before and 2 weeks after treatment. Results Four patients in the MSC group showed mild effusion and increased local pain, which resolved safely within 48–72 h. In 2 weeks post-injection there was no serious adverse effect and all of the laboratory test results were unchanged. Early after treatment, there was a significant knee ROM improvement and pain reduction (effect size, 1.4). Significant improvements were seen in quality of life, activity of daily living, sport/recreational activity and decreased OA symptoms in the MSC-injected group until 8 weeks ( P Conclusion Single intra-articular allogenic placental MSC injection in knee OA is safe and can result in clinical improvements in 24 weeks follow-up. Trial registration number: IRCT2015101823298N.