Management of osteochondral injuries of the knee.

The management of articular cartilage lesions has yet to reveal a "right answer." Instead, it must be recognized as a multifactorial clinical challenge that requires the physician to consider surgical, biomechanical, and physiologic implications of the management chosen. The goal is to restore normal type II cartilage to the area of concern. Falling short of that, we must strive for the most reasonable of the facsimiles currently available. The science certainly will advance to assist our understanding of articular cartilage and the best way to approximate or replicate its properties. Continued research must examine which of the many variables are essential to address in contemplating these challenging cases. Basic science research appears to be the area of greatest promise. Perhaps elucidating the roles of Cartilage Derived Morphogenetic Proteins (CDMP) and other polyclonal stimulators of mesenchymal stem cells, and refining techniques of cartilage autotransplantation, should be included in the areas of focus. Studies evaluating stem cells as progenitors to cartilage-forming cells will bear watching. Long-term follow-up studies of all of the techniques reviewed are needed to give definitive answers about the durability of the repair and transplanted tissues. The orthopaedist taking care of these lesions is well served to have more than one option in managing these challenging clinical problems.