2023, Vol. 27 ›› Issue (9): 1313-1318

Microstructural indexes that determine the trabecular bone maximum stress of micro-finite element models

Zhong Yizheng1, Huang Peizhen2, Cai Qunbin2, Zheng Liqin3, He Xingpeng3, Dong Hang2   

Abstract: BACKGROUND: The mechanical response of trabecular bone under loading can be studied using micro-CT based micro-finite element. It is generally considered that bone volume fraction in animal specimens is the most important index that determines the compressive strength of trabecular bone. However, in the micro-CT based finite element model, the microstructural index leading to stress concentration or determining the maximum stress is not clear.
OBJECTIVE: To investigate the microstructural indexes that affect the maximum stress of trabecular bone micro-finite element model.
METHODS: The microstructural indexes of trabecular bone of 10 normal rats from bilateral femoral metaphysis region of interest were obtained and the differences of trabecular bone in bilateral regions of interest were compared. The 20 trabecular bone finite element models were constructed and loaded. The average stress values of the ranking 5%, 2%, 1% and 0.5% of stress value were taken as the maximum stress value. The reliability of the models was verified according to the stress and effective strain. Finally, with the maximum stress value as the dependent variable and the trabeculae microstructural index as the independent variable, the key factor affecting the maximum stress of trabeculae micro-finite element model was explored by multiple linear stepwise regression method.
RESULTS AND CONCLUSION: There was homogeneity in trabecular bone microstructure of bilateral femoral metaphysis (P > 0.05), and then data were combined. The average number of elements and nodes of 20 trabeculae finite element models was 232 813 and 606 82. The average stress of the ranking 5%, 2%, 1% and 0.5% elements was 31.91, 41.96, 50.86 and 61.23 MPa, respectively, and the average effective strain was 3.28%. The results of multiple linear stepwise regression analysis indicated that the structure model index was the most important factor influencing the maximum stress of trabeculae finite element model (P < 0.001, R2=0.807). It is indicated that the trabecular bone structure model index is the most important bone microstructure index that affects the stress concentration of the trabecular bone micro-finite element model.
Key words: trabecular bone, microstructure, maximum stress, stress concentration, finite element, biomechanics, trabecular bone structure model index