Cortical bone: a target for fracture prevention?

In young individuals, cortical porosity is 3–5% and tends to be homogeneously distributed. From about age 40 years, cortical porosity begins to increase, and can approach 20% in the femur and humerus by age 80 years. However, these values underestimate true bone loss because much of the resorption occurs along the endocortical surface, and as the porosities coalesce, that bone is completely lost. In The Lancet today, Roger Zebaze and colleagues 1 Zebaze RMD Ghasem-Zadeh A Bohte A et al. Intracortical remodelling and porosity in the distal radius and post-mortem femurs of women: a cross-sectional study. Lancet. 2010; 375: 1729-1736 Summary Full Text Full Text PDF PubMed Scopus (607) Google Scholar propose that the age-related increase in cortical porosity is routinely underestimated by methods that measure bone density. They suggest that cortical porosity is a crucial factor determining the bone fragility that underlies non-vertebral fracture risk in women older than 65 years, and that it should be a target for therapeutic intervention. Intracortical remodelling and porosity in the distal radius and post-mortem femurs of women: a cross-sectional studyAccurate assessment of bone structure, especially porosity producing cortical remnants, could improve identification of individuals at high and low risk of fracture and therefore assist targeting of treatment. Full-Text PDF