Bone Transplantation

Abstract

Bone transplantation (bone grafting) is frequently used in association with internal fixation of fractures and nonunions. Transplanted bone functions to enhance fracture healing in three ways. The transplanted bone is a source of osteoprogenitor cells. Surface cells on transplanted autogenous cancellous bone will survive under optimal conditions and participate in the total early osteogenic response around the graft. The transplanted bone stimulates the formation of new bones of host origin by recruitment and differentiation of the host mesenchymal cells. This process of osteoinduction is modulated by bone-inducing factors present in the matrix. The transplanted bone also serves as a trellis for the ingrowth of capillaries, perivascular tissue, and osteoprogenitor cells, a process called osteoconduction. In addition, transplanted cortical bone serves as a mechanical support for the fracture and internal fixation.