2023, Vol. 27 ›› Issue (36): 5766-5770

Difference in mechanical properties of osteoporotic bone trabecular 3D models with different gray thresholds

Wu Minhui1, Tang Changye1, Dai Yuexing1, Zheng Liqin1, 2, Li Zhihong1, Li Shaobin1, Lin Ziling3   

Abstract: BACKGROUND: Brittle fractures occur in patients with osteoporosis, and the 3D bone trabecular simulation model compression test is rarely used to elucidate the mechanism of its occurrence and development.  
OBJECTIVE: To establish 3D models of osteoporotic bone trabeculae with different gray thresholds, and to compare and analyze the differences in microstructure and mechanical properties of osteoporotic bone trabeculae through mechanical compression experiments.
METHODS: A 69-year-old elderly female patient with osteoporotic unilateral intertrochanteric fracture was selected. Three-dimensional bone trabecular models with different gray thresholds were established by GE64 slice spiral CT scanning of bilateral hip joints from the acetabulum to the upper middle femur and micro-CT reconstruction. Its microstructure parameters were obtained. Mechanical properties were obtained by mechanical compression experiment and compared.
RESULTS AND CONCLUSION: (1) 3D models of osteoporotic bone trabeculae with different gray thresholds were successfully established. With the increase of gray thresholds, the bone volume fraction decreased; the bone surface area density decreased; the trabecular number decreased, and trabecular separation increased. (2) With the increase of the gray threshold of the bone trabecula, its elastic modulus diminished. It could be seen that the yield strength, compressive strength and maximum pressure also exhibited such a trend. (3) It is indicated that the 3D bone trabecular simulation model printed with different gray threshold values has significant differences in the bone fine structure parameters and mechanical property parameters, which provides a new method for the occurrence and development of brittle fractures in osteoporosis in terms of material mechanics.

Key words: osteoporosis, 3D printing, bone trabecula, gray threshold, bone volume fraction