Osteochondral allograft transplantation: The rationale and basic science

The use of allograft tissues for orthopedic reconstructions has seen a dramatic rise in the past decade. For example, allograft bone is widely used to fill bone voids, provide temporary structural support, and to induce local tissue repair. One application for the use of allograft tissues is to attempt to reconstruct the articular surface in patients with chondral or osteochondral lesions. As our understanding of the basic science of allograft tissues has grown, we have seen an evolution of its use from primarily a structural entity into one in which these tissues are implanted with the intent of preserving their biological activity and function, as well. Articular cartilage is a particularly good target for allograft transplantation given that it is aneural, avascular, and relatively immuno-priveledged. Reports of allograft osteochondral reconstructions have been performed with excellent results. The procurement, preservation and storage of these allografts are critical factors in maintaining an appropriate balance of tissue availability and chondrocyte viability, while ensuring high standards for safety. Newer therapies which can provide an off-the-shelf option for the treatment of chondral defects have been developed and are available in some areas. More of these products or biologically-active devices can be expected in the years to come. An understanding of the potential benefits and limitations of the use of allograft tissues can help to direct research and clinical applications which optimize their role in articular reconstruction.