Department of Mechanical Systems Engineering, School of Engineering, Nagoya University, Japan.
Department of Mechanical Systems Engineering, School of Engineering, Nagoya University, Japan.
J Biomech. 2022 Sep;142:111262. doi: 10.1016/j.jbiomech.2022.111262. Epub 2022 Aug 17.
Hip fractures caused by falls are important health problems for the elderly. Many studies used finite element (FE) models of the femur and its surroundings to evaluate the hip fracture risk during the impact phase in a fall. In this study, the whole-body human FE model (THUMS) of a small female was applied from the descent to the impact phase in a fall to understand the effect of the whole body. Brosh's material model was used for the soft tissue of the hip. A low-BMI and high-BMI model were developed based on THUMS (middle-BMI). For the middle-BMI model, the torso angle and the pelvis impact velocity were 45.2° and 2.62 m/s at the time of pelvis impact. The effective mass changed with time, and was 18.3 kg when the femoral neck force was maximum. The femoral neck force was 2.11 kN for the low-BMI model. The femoral neck forces when wearing a soft and a hard hip protector, and when falling on an energy-absorbing floor were compared for the FE models of human and a hip protector testing system. Though the force attenuation of the protective devices was 32.0-44.3 % in the testing system, the force attenuation in the middle-BMI was 0.1-22.2 %. In the low-BMI model, the attenuation of the soft protector was limited (4.2 %) because the hip protector protruded from the outer surface, so the contact force was concentrated at the hip region. This research suggests the importance of including the whole body to evaluate the hip fracture risk.
髋部骨折是老年人的重要健康问题。许多研究使用股骨及其周围的有限元 (FE) 模型来评估跌倒时冲击阶段的髋部骨折风险。在这项研究中，应用了小女性的全身人体 FE 模型 (THUMS) 来评估跌倒过程中的下降和冲击阶段，以了解整个身体的影响。Brosh 材料模型用于髋部的软组织。基于 THUMS 开发了低 BMI 和高 BMI 模型（中 BMI）。对于中 BMI 模型，在骨盆撞击时，躯干角度和骨盆撞击速度分别为 45.2°和 2.62 m/s。有效质量随时间变化，当股骨颈力最大时为 18.3kg。低 BMI 模型的股骨颈力为 2.11 kN。比较了人体 FE 模型和髋保护器测试系统的软髋保护器和硬髋保护器以及在能量吸收地板上跌倒时的股骨颈力。虽然在测试系统中防护设备的力衰减为 32.0-44.3%，但在中 BMI 中力衰减为 0.1-22.2%。在低 BMI 模型中，由于髋保护器从外表面突出，因此软保护器的衰减有限（4.2%），使接触力集中在髋部区域。这项研究表明，评估髋部骨折风险时纳入整个身体的重要性。
