Commonality in the microarchitecture of trabecular bone: A preliminary study

Understanding the relationship between the microstructure and mechanical function of trabecular bone is critical for prediction and prevention of bone fragility fractures. However, a detailed understanding of the structural design of trabecular microarchitecture is still missing. This study hypothesized that there exists a commonality in the underlying probabilistic distributions of microstructural features of trabecular bones, whereas the microstructural differences among individuals are primarily describe by a set of scalar parameters. To test the hypothesis, twenty-three trabecular bone specimens were obtained from two anatomic locations (i.e., femoral neck and vertebral body) and a diverse group of seventeen donors of different age and sex. The number, size, spatial location, and orientation of individual plates and rods in the trabecular bone specimens were determined via volumetric decomposition of 3D μCT images using the Individual Trabecula Segmentation (ITS) technique. Then, m/n bootstrap Kolmogorov-Smirnov tests were performed to compare the normalized distributions of size, orientation, and spatial arrangement of trabecular plates and rods in the specimens. The results showed that 100% of the twenty-three normalized distributions of each microstructural feature were statistically equivalent irrespective of individual differences among the bone specimens, except the distributions of rod spatial arrangement (<100%). On the other hand, nonparametric Mann-Whitney U tests showed that a set of scalar parameters (i.e., the number, average size, and average nearest neighbor distance of trabecular plates and rods) were statistically different among the individual specimens (p<0.05). Due to the commonality of the underlying distributions, the individual differences in the trabecular microstructure among the specimens seemed to be reflected primarily by changes in the scalar parameters. The above results strongly support the hypothesis of this study and may shed more light on understanding the natural design of trabecular bone microstructures.