Sensitivity of Trabecular Bone Strength to Morphological Change of Plate-like Elements

Bone remodelling is a continuous and necessary process to avoid damage accumulation and to ensure bone architecture is optimised to deal with loading. However, as humans age, the rate of bone resorption eclipses that of bone generation making osteoporosis unavoidable in the elderly. As osteoporosis progresses, trabecular bone transitions from a largely plate-like structure to predominantly rod-like. This shift in composition is conducive to a loss in mechanical strength. Cancellous bone is difficult to model due to the heterogeneity of its structure. Rods and plates are important micro-architectural features in determining mechanical properties of trabecular bone and can, therefore, be used to model bone in a manner which can be analysed for mechanical properties. Through abstraction of plate like elements it is possible to create an idealised finite element model that requires less computational power than other micro-computed tomography (µCT) scanned models and is less destructive than mechanically testing samples. A tetrakaidekahedral, idealised plate-like structure was used to model trabecular bone in this study. The influence of changing the geometry of the tetrakaidekahedral structure was assessed by studying parameters such as trabecular separation (Tb.Sp), trabecular thickness (Tb.Th) and bone volume density (BV/TV). The yield stress, strain and effective modulus (E*) results were comparable to those determined through mechanical testing of trabecular bone. It is anticipated that this study will provide a basis of information which can be built upon for the creation of increasingly complex models, capable of accurately and reliably predicting the mechanical consequence of osteoporosis on a patient specific basis.