Management of articular cartilage defects of the knee.

Articular cartilage has a poor intrinsic capacity for healing. The goal of surgical techniques to repair articular cartilage injuries is to achieve the regeneration of organized hyaline cartilage. Microfracture and other bone marrow stimulation techniques involve penetration of the subchondral plate in order to recruit mesenchymal stem cells into the chondral defect. The formation of a stable clot that fills the lesion is of paramount importance to achieve a successful outcome. Mosaicplasty is a viable option with which to address osteochondral lesions of the knee and offers the advantage of transplanting hyaline cartilage. However, limited graft availability and donor site morbidity are concerns. Transplantation of an osteochondral allograft consisting of intact, viable articular cartilage and its underlying subchondral bone offers the ability to address large osteochondral defects of the knee, including those involving an entire compartment. The primary theoretical advantage of autologous chondrocyte implantation is the development of hyaline-like cartilage rather than fibrocartilage in the defect, which presumably leads to better long-term outcomes and longevity of the healing tissue. Use of synthetic scaffolds is a potentially attractive alternative to traditional cartilage procedures as they are readily available and, unlike allogeneic tissue transplants, are associated with no risk of disease transmission. Their efficacy, however, has not been proven clinically.