Cortical Bone Mineralization in the Human Femoral Neck in Cases and Controls from Synchrotron Radiation Study

To compare the degree and distribution of mineralization in femoral neck cortex from 23 women with hip fractures (age 65-96 years) and 17 female controls (age 72-103 years), we obtained 3D data by synchrotron radiation microtomography (SRμCT). Variables were degree of mineralization of bone (DMB) in total cortex (cDMBSRMEAN), osteons (oDMBSRMEAN), and pure interstitial tissue (intDMBSRMEAN). The cortex on SRμCT images was divided into nine to twelve 50-μm zones from the periosteum to the endosteum; cDMBSRMEAN, oDMBSRMEAN, and intDMBSRMEAN were measured in each zone. We used descriptive statistics and t tests, general linear model analyses to compare DMBSR values across zones and individuals, one-way analysis of variance for within-group comparisons of zones. In patients, the variance of mineral content value was not different than in controls, but mean values of degree of mineralization varied across zones. These cross-sectional data suggest that bone fragility may be related to a greater heterogeneity of the distribution of mineralization in femoral neck cortex.