Osteoporotic fracture models.

Animal models are widely used to investigate the pathogenesis of osteoporosis and for the clinical testing of anti-resorptive drugs. However, osteoporotic fracture models designed to investigate novel ways to treat fractures of osteoporotic bone must fulfil requirements distinct from those of pharmacological testing. Bone strength and toughness, implant fixation and osteointegration and fracture repair are of particular interest. Osteoporotic models should reflect the underlying clinical scenario be that primary type 1 (post-menopausal) osteoporosis, primary type 2 (senile) osteoporosis or secondary osteoporosis. In each scenario, small and large animal models have been developed. While rodent models facilitate the study of fractures in strains specifically established to facilitate understanding of the pathologic basis of disease, concerns remain about the relevance of small animal fracture models to the human situation. There is currently no all-encompassing model, and the choice of species and model must be individualized to the scientific question being addressed.