Effects of Moisture Content and Loading Profile on Changing Properties of Bone Micro-Biomechanical Characteristics

Abstract

BackgroundOur study explored the influences of hydration conditions and loading methods on the mechanical properties of cortical bones and cancellous bones.Material/MethodsElastic modulus and hardness of human cortical bones and cancellous bones that contained different moisture levels (20%, 30%, 40%, 50%, and 60%) were measured with nanoindentation with different peak loads and loading rates. Cortical bones with 20% and 60% moisture were tested with 30 nm, 40 nm, and 50 nm peak loads at 6 nm/s, 8 nm/s, and 10 nm/s loading rates, respectively. Cancellous bones with 5% or 40% moisture percentages were tested with 600 μN, 750 μN, and 1000 μN peak loads at 200 μN/s, 250 μN/s, and 333 μN/s loading rates, respectively.ResultsUnder the same loading condition, specimens with higher moisture contents showed decreased elastic modulus and hardness. Under different loading conditions, the loading modes had little influence on elastic modulus and hardness of cortical bone and cancellous bone with low moisture, but had significant influence on specimens with higher moistures.ConclusionsThe elastic modulus and bone hardness were affected by the moisture content and the loading conditions in cortical and cancellous bones with high hydration condition but not in those with low hydration condition.

A Tool for Studying the Mechanical Behavior of the Bone–Endoprosthesis System Based on Multi-scale Simulation

“…15a), it was established that the hardness of the undrained bone tissue specimen was 55 MPa, while the hardness of the fluid-saturated bone was 47 MPa, and the elastic moduli were 3.9 and 3.6 GPa, respectively. The results obtained correspond qualitatively to the data on the influence of fluid on the mechanical response of bone tissue by other authors [72][73][74].…”

The Hydration State of Bone Tissue Affects Contrast in Neutron Tomographic Images

“…The mechanical properties were expected to be affected by the hydration state, as dried bone is expected to become stiffer and more brittle (Smith and Walmsley, 1959;Broz et al, 1993;Conrad et al, 1993;Nyman et al, 2006;Lievers et al, 2010;Granke et al, 2015;Lin, 2016;Wang et al, 2018). Conrad et al (1993) assessed changes in mechanical behavior of trabecular bone due to freezedrying and found that freeze-drying followed by rehydration for 24 h caused a 24% increase in stiffness compared to freshly frozen controls and that non-rehydrated freeze-dried specimens were 33% stiffer than rehydrated specimens (Conrad et al, 1993).…”

“…The mechanical properties of bone are dependent on the hydration state of the tissue and drying alters the mechanical behavior in terms of increased stiffness and brittleness on the nano-, meso-and macro-scales (Smith and Walmsley, 1959;Broz et al, 1993;Conrad et al, 1993;Nyman et al, 2006;Lievers et al, 2010;Granke et al, 2015;Lin, 2016;Wang et al, 2018). Hence, for physiologically relevant assessment of the mechanical properties, the specimen should be hydrated when tested mechanically.…”