Strain Response in Osteocyte Lacuna Due to Mechanical Loading - a Parametric Finite Element Study Using FEBio

Abstract

Osteocytes are the major type of living cells in bone and are known to be responsible for the biomechanosensory functions within the bone matrix. Osteocytes are activated by mechanical forces and regulates both osteoclasts and osteoblasts for bone resorption/formation. Not all the osteocytes are activated due to the applied mechanical loading because of many factors such as variation in size, position and orientation of them with respect to the loading surface. Strain response of osteocyte to the applied loading is of importance in estimating the bone resorption/formation. Although previously there were many studies that investigated strain responses at the osteocyte lacuna, very few were finite element studies and were limited to 2-dimensional models. Here in this study, a finite element model was created using FEBio at the microscale level and osteocyte lacunar and perilacunar responses were calculated based on three studies: 1) variation in lacunar position, 2) variation in lacunar orientation and 3) variation in lacunar size. A parametric study was performed by varying the elastic modulus of the perilacunar matrix which resulted in a decrease of maximum strain in lacuna with an increase in perilacunar modulus from 5GPa to 20GPa. Then, the model was scaled down to nanometer range and the lacunar responses were investigated and the results were compared with a previous study. Finally, a 3-dimensional osteocyte model was developed using MIMICS and 3-Matic softwares using confocal image stack of mouse femurs.