Safety and Efficacy of Injecting Mesenchymal Stem Cells Into a Human Knee Joint To Treat Osteoarthritis: A Systematic Review

Intraarticular stem cell therapy has become increasingly used to treat knee osteoarthritis (KOA) with minimal high-quality evidence to support its use. This study aims to see how well intra-articular injections of mesenchymal stem cells (MSCs) worked and how safe they were for individuals with KOA. A total of 10 studies were extracted using PubMed, Cochrane Library, and PMC from 2017 to 2021 in the English language. An assessment of the risk of bias was applied via the Cochrane Collaborative Bias Risk Tool and Newcastle-Ottawa Quality. Changes in pain and functional outcomes in patients with KOA were measured by a Knee injury and Osteoarthritis Outcome Score (KOOS) scores, Visual Analogue Scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores at baseline, and follow-up evaluation criteria. The magnetic resonance imaging (MRI) was evaluated using the whole-organ magnetic resonance imaging score (WORMS) and cartilage volume changes. A total of six randomized controlled trials (RCTs), three prospective retrospective clinical trials, and one retrospective clinical trial included 723 patients. They were diagnosed with unilateral or bilateral KOA with Kellgren-Lawrence (KL) grade 1-4 KOA and followed up for six, 12, and 24 months. The experimental groups received multipotent MSCs, mesenchymal progenitor cells (MPCs), adipose tissue progenitor stem cells (AD-MPCs), adipose tissue mesenchymal stem cells (AD-MSCs), bone marrow mesenchymal stem cells (BM-MSCs), bone marrow aspiration (BMA), bone marrow aspiration concentration (BMAC), or micro fragmented adipose tissue (MFAT) while the controlled groups received normal saline (NS), hyaluronic acid (HA), placebo, or went through conservative management. In conclusion, significant improvements were noticed in the MSCs groups via different outcome measuring tools like KOOS, VAS, WOMAC, and MRI. Furthermore, no significant adverse events (AEs) have been observed. Therefore, intra-articular injections of MSCs are effective and safe in relieving pain and improving motor function in individuals with KOA in the short term, contrary to earlier research findings.