Clinical and experimental approaches to knee cartilage lesion repair and mesenchymal stem cell chondrocyte differentiation.

Cartilage has poor regeneration capacity due to the scarcity of endogenous stem cells, its low metabolic activity and the avascular environment. Repair strategies vary widely, including microfracture, autologous or allogenic tissue implantation, and in vitro engineered tissues of autologous origin. However, unlike the advances that have been made over more than two decades with more complex organs, including vascular, cardiac or bone tissues, similar advances in tissue engineering for cartilage repair are lacking. Although the inherent characteristics of cartilage tissue, such as the lack of vascularity and low cellular diversity, suggest that it would be one of the more simple tissues to be engineered, its functional weight-bearing role and implant viability and adaptation make this type of repair more complex. Over the last decade several therapeutic approaches and innovative techniques show promise for lasting and functional regeneration of hyaline cartilage. Here we will analyze the main strategies for cartilage regeneration and discuss our experience.