Intra-articular injections of mesenchymal stem cells for knee osteoarthritis

Knee osteoarthritis (KOA) represents an enormous societal burden. This review article summarizes the knowledge on the efficacy of using intra-articular injections of mesenchymal stem cells (MSCs) to treat KOA. PubMed (Medline) and the Cochrane Library were searched for literature related to MSC therapy and KOA up until January 31, 2014. The key search terms used were stem cells and knee osteoarthritis. One hundred thirty-five reports were found, but only the 25 fully focused on the topic were used for analysis. Only 3 randomized controlled trials (level II evidence) found pain relief and functional improvement over the short term. The other human studies also reported encouraging results, but their evidence level was very low (IV). Larger randomized controlled trials are needed to support these preliminary encouraging results. The relatively short duration of the studies is also a limitation for the technique at present.