Journal of Bone Research
Open Access

Fractures Online Journals

Fracture healing and bone repair are postnatal processes that mirror many of the ontological events that take place during embryonic development of the skeleton and have been extensively reviewed elsewhere. The recapitulation of these ontological processes is believed to make fracture healing one of the few postnatal processes that is truly regenerative, restoring the damaged skeletal organ to its pre-injury cellular composition, structure and bio- mechanical function. Interestingly, a comparison of the transcriptome of mouse callus tissues across a 21-day period of fracture healing showed that about one-third of the mouse homologues of the genes expressed by human embryonic stem cells are preferentially induced. Many of the homeotic genes that control appendicular limb development also show increased expression during fracture healing.Finally, all the primary morphogenetic pathways that are active during embryonic skeletal development are expressed in fracture calluses,and have therefore become the focal point of efforts to develop new therapies. In this Review, we place these biological processes in the context of how trauma and the immune system, as a component of the injury response, are related to the developmental aspects of fracture healing. We then review the relationships between ontogeny and the recovery of skeletal function. Finally, we focus on specific biophysical, local and systemic therapies that have been used to promote fracture healing and on the various biological processes they promote