Mesenchymal Stem Cells for Treatment of Tendon and Ligament Injuries-clinical Evidence

INTRODUCTION: Sport injuries, most of the time affect muscles, tendons, ligaments, cartilage and bones and range from very mild to severe, prompting different therapeutic approaches. Overuse is the most common cause of sports injuries and half of those injuries affect tendon, tendon sheet and tendon insertion to the bone. The number of ligament injuries, particularly anterior cruciate ligament (ACL) increasing. AIM: We were searching PubMed, Google Scholar and Medline focusing on human clinical studies related to stem cell therapy for tendinopathies and ligament injuries. Considering small number of published articles, we accepted papers with all level of evidence without following strict PRISMA guidelines. RESULTS: The number of studies related to ligament injuries is very low compared to tendon injuries. In human clinical trials there have been only a few studies published so far. In double blind randomized control trial (RCT) Wang and coauthors combined allogenic precursor mesenchymal stem cells (MPC) with hyaluronic acid (HA) and compared with hyaluronic acid alone in 17 patients underwent ACL reconstruction. Intensity of pain and quality of life were assessed by Knee Injury and Osteoarthritis Outcome Score (KOOS) and SF-36v2 scores. A width of joint space, volume of cartilage and bone were recorded by magnetic resonance imaging (MRI). Moderate arthralgia and swelling were detected within 24 hours after the injection in 4 out of 11 patients in the group receiving MSC+HA. In the group receiving only HA, there were no adverse reactions. The signs of slowing down of regenerative process were presented on MRI by preserving joint space and reducing degradation of cartilage volume. CONCLUSION: Clinical application of MSCs for treatment of tendon and ligament injuries might be good alternative option for athletes. Published clinical studies confirmed clinical improvement and integrity of impaired tissues. However, RTCs are needed to confirm real potential of cell therapy and their advantages comparing to other treatment options.