A simulation study on marrow fat effect on biomechanics of vertebra bone.

Trabecular bone and bone marrow are main components of cancellous bone. Most mechanical studies for bone mainly focus on hard tissues, while if bone marrow contributes to bone biomechanics is not clear yet. This study was proposed to investigate marrow fat effect on trabecular bone biomechanics by simulation. Finite element (FE) bone models were established based on quantitative CT images at L3 lumbar spine, from which trabecular structures with and without marrow fat were investigated respectively. Auni-static compressive test was applied on the proposed models until to the appearance of fracture. Simulation results showed that trabecular models filled with marrow fat had about 3%-9% less maximum stress in volume than models with only trabeculae. However, its average stress in volume was about 9%-56% larger than those with only trabeculae. The strain energy density of the bone model with marrow fat showed a more uniformed distribution. As a conclusion, marrow fat has contributions to the bone mechanics. It can balance the stress distribution of the bone tissue, which may reduce bone deformation under a compressive loading. The mixture of trabecular structure and marrow fat would be against higher compress load before the failure point.