Cell-based regeneration of damaged or diseased articular cartilage still faces significant clinical challenge due to inadequate environmental regulation of stem cell proliferation and chondrogenic differentiation. The role of insulin-like growth factor in critical steps of human bone marrow-derived mesenchymal stem cell chondrogenesis has potential in optimizing the therapeutic use of mesenchymal stem cells in cartilage disorders. In addition to the previously described benefits of recombinant adeno-associated viral vector for in vivo gene therapy, demonstrated by Frisch and colleagues, such vector is also a safe and efficient delivery system for the genetic modification of human bone marrow-derived mesenchymal stem cells via ex vivo insulin-like growth factor 1 gene transfer, so that implanted mesenchymal stem cells continuously release a therapeutic level of insulin-like growth factor 1 to achieve sustained mesenchymal stem cell chondrogenesis for cartilage regeneration.