Abstract
Background
The porous structure of bone tissue is essential for maintaining the physiological functions and overall health of bone cells. The lacunar-canalicular system (LCS), a microscopic porous structure within bone units, facilitates the transport of nutrients and signaling molecules through interstitial fluid flow. However, the transient behavior of fluid flow within these micro-pores under dynamic loading conditions has not been extensively studied.
Methods
This study constructs a fluid-solid coupling model that aligns with the micro-porous structure of bone, including the Haversian canal, canaliculi, lacunae, and interstitial fluid, to examine interstitial fluid flow within the LCS under dynamic loading with varying frequencies and amplitudes. For the first time, the study explores the relationship between changes in LCS pore volume and fluid velocity and pressure.
Results
The results demonstrate that increasing strain amplitude leads to significant changes in LCS pore volume, which in turn significantly enhances interstitial fluid flow velocity and pressure within the LCS. When the loading amplitudes are 1500 µε, 2000 µε, and 2500 µε, the LCS pore volume changes to 998.4‰, 997.8‰, and 997.3‰ of the original volume, respectively. The average flow velocity at the center of the superficial bone lacuna at these amplitudes is 136%, 177%, and 214% of that at 1000 µε, respectively. Additionally, at a loading amplitude of 1000 µε under three different loading frequencies, the average flow velocities at the center of the superficial bone lacuna are 0.60 µm/s, 1.04 µm/s, and 1.54 µm/s, respectively. This indicates that high-frequency and high-amplitude dynamic loading can promote more vigorous fluid flow and pressure fluctuations.
Conclusions
Dynamic mechanical loading can significantly enhance interstitial fluid flow within the bone lacunae and canaliculi, which positively impacts the normal metabolism and bone remodeling processes of bone cells.