Bone morphology and mechanical Behavior: New insights into cortical and trabecular failure under compression

Bone is a heterogeneous, dynamic tissue that plays a crucial role in structural support and load bearing. Cortical bone, with its dense and organized structure, exhibits greater strength and rigidity compared to trabecular bone, which is more porous and spongier. The interaction between these two bone types significantly influences overall biomechanical behavior and failure resistance. However, the precise correlation between bone microstructure and mechanical performance remains incompletely understood, particularly at the microscale level. This study aims to identify the relevant morphometric characteristics of both cortical and trabecular bone and their relationship to whole-bone mechanical behavior and failure mechanisms under loading. Mechanical compression tests were conducted on pig rib bone slices containing both cortical and trabecular components. Digital image correlation (DIC) was used to track local displacements and failure sites during loading. Load-deformation behavior was recorded for each slice. Prior to testing, the bone slices were scanned using micro-CT, and their morphometric parameters were analyzed with Dragonfly software. The findings reveal that key bone parameters, primarily related to total bone mass and cortical bone morphology, strongly influence mechanical behavior, including elastic properties, stiffness, and strength after structural collapse. Failure analysis indicated that fractures predominantly occur in regions where the trabecular bone is less organized and has a lower density.