Introduction
Half of the population sustains at least one fracture during their
lifetime, and the majority of these fractures heal successfully.
Successful fracture healing requires the following five elements; (i)
osteogenic cells (e.g., osteoblasts), (ii) osteoinductive stimuli (e.g.,
bone morphogenetic proteins); (iii) an osteoconductive matrix;
(iv) adequate blood and nutrient supply, and (v) sufficient
mechanical support. One or more elements can be compromised
due to the existence of a bone defect. Bone defects are
treated with bone grafts in order to avoid insufficient fracture
healing. Insufficient fracture healing is encountered in 5–10% of the
fractures, resulting in delayed union, malunion, or non-union
