Editorial Commentary: Biologic Augmentation of Meniscus Repair Is Complex

In the setting of biological augmentation for meniscus repair, it is extremely important to evaluate all aspects, including effectiveness, costs, potential risks, benefits, and limitations. It seems that everything matters in healing: the aspirate source of the bioactive agents, cell content, presence of stem cells and their type, growth factors, cytokines, biomechanical scaffold, and the quality of the tissue. There are several differences among mesenchymal, adipose, and peripheral blood stem cells, with the cell origin affecting the differentiation potential towards bone, cartilage and ligament. Moreover, different aspirate sources and fibrin clots have different content in cells, growth factors, and cytokines. In this equation, it is not as simple as the more the better. Different doses of growth factors may have different effects in the different cell types. And as this was not complicated enough, synergistic phenomena between cells and between growth factors can play a huge role. Add to that the role of the biomechanical environment, the proper timing of the healing phases and the inherent patient characteristics. There is very, very much to learn, and finally, we acknowledge that not all menisci repairs can always heal.