Age-related changes in trabecular bone microstructures: global and local morphometry.

INTRODUCTION: A recently developed method allows investigating trabecular bone on an elemental (rod/plate) level. With this method, it is possible to measure local morphometric parameters such as thickness or orientation directly on the extracted rods and plates. Age-related changes of trabecular microarchitecture can thus be investigated on an elemental level, which may help to improve the understanding of age-related bone failure mechanism as well as the effect of pharmaceutical intervention in the prevention of such fractures.
METHODS: Autopsies from femoral heads (FH) and lumbar spine (LS) were analyzed by global morphometry. Additionally, the trabecular structures were decomposed into rods and plates for the analysis with local morphometry. These morphometric indices were related to age using an analysis of covariance to test for gender differences and linearity with age.
RESULTS: In this study, age-related changes showed no gender but site differences. In LS, rods were thinned in aging and finally vanish from the structure, causing a transformation of the trabecular bone structure to longer and, on average, thicker rods. In FH, changes were expressed by a simultaneous thinning and loss of interconnecting trabeculae and perforation of plates leading to new plates and rods. Results were mostly in agreement with earlier findings using descriptive analysis of the aging process.
CONCLUSION: Here we present for the first time preliminary quantitative evidence of changes in the local microstructure, i.e., individual rods and plates. Nevertheless, the number of samples was too small to make for ready conclusions. We conclude that the combination of local and global morphometry is a useful method for a detailed and quantitative description of age-related changes in bone microstructure.