Lower limb injures are frequently observed in passenger car traffic accidents.Previous studies of the injuries focus on long bone fractures by using either cadaver component tests or simulations of the long bone kinem...Lower limb injures are frequently observed in passenger car traffic accidents.Previous studies of the injuries focus on long bone fractures by using either cadaver component tests or simulations of the long bone kinematics,which lack in-depth study on the fractures in stress analysis.This paper aims to investigate lower limb impact biomechanics in real-world car to pedestrian accidents and to predict fractures of long bones in term of stress parameter for femur,tibia,and fibula.For the above purposes,a 3D finite element(FE) model of human body lower limb(HBM-LL) is developed based on human anatomy.The model consists of the pelvis,femur,tibia,fibula,patella,foot bones,primary tendons,knee joint capsule,meniscus,and ligaments.The FE model is validated by comparing the results from a lateral impact between simulations and tests with cadaver lower limb specimens.Two real-world accidents are selected from an in-depth accident database with detailed information about the accident scene,car impact speed,damage to the car,and pedestrian injuries.Multi-body system(MBS) models are used to reconstruct the kinematics of the pedestrians in the two accidents and the impact conditions are calculated for initial impact velocity and orientations of the car and pedestrian during the collision.The FE model is used to perform injury reconstructions and predict the fractures by using physical parameters,such as von Mises stress of long bones.The calculated failure level of the long bones is correlated with the injury outcomes observed from the two accident cases.The reconstruction result shows that the HBM-LL FE model has acceptable biofidelity and can be applied to predict the risk of long bone fractures.This study provides an efficient methodology to investigate the long bone fracture suffered from vehicle traffic collisions.展开更多
目的研究社区老年2型糖尿病(type 2 diabetes mellitus,T2DM)对骨密度(bone mineral density,BMD)、下肢肌功能、跌倒及骨折的影响。方法选取上海市5家社区卫生服务中心的60岁以上老年人9 584例,其中T2DM组1 201例,对照组8 383例;T2DM...目的研究社区老年2型糖尿病(type 2 diabetes mellitus,T2DM)对骨密度(bone mineral density,BMD)、下肢肌功能、跌倒及骨折的影响。方法选取上海市5家社区卫生服务中心的60岁以上老年人9 584例,其中T2DM组1 201例,对照组8 383例;T2DM患者分为骨折组184例,非骨折组1 017例。分别记录受试者的年龄、性别、身高及体质量,计算出体质量指数(body mass index,BMI),起立行走计时测试(the timed up and go,TUG)评估下肢肌力情况,询问受试者骨折史,吸烟、饮酒情况,1年内跌倒及骨折情况,父母发生髋部骨折史,并询问T2DM患者的病程,药物治疗情况。利用跟骨超声骨密度仪(quantitative ultrasound system-bone mineral density,QUS-BMD)测量骨密度值。比较T2DM与对照组的一般基础资料及发生跌倒和骨折情况,比较T2DM患者骨折组与非骨折组各临床指标。结果 T2DM组吸烟率20.4%明显高于对照组17.8%(P=0.030),完成TUG所需中位数时间10.75 s明显高于对照组10.12 s(P=0.000),BMD(0.920±0.040)g/cm^2高于对照组(0.790±0.030)g/cm^2(P=0.000),1年内跌倒发生率10.1%高于对照组7.1%(P=0.000),1年内骨折发生率15.3%高于对照组12.1%(P=0.080);T2DM患者中,与非骨折组相比,骨折组女性的比例高(89.1%vs.52.1%,P=0.000)、糖尿病病程长[(11.6±0.6)年vs.(9.6±0.2)年,P=0.000]、吸烟比率高(95.1%vs.67.9%,P=0.000)、饮酒比率高(93.5%vs.80.7%,P=0.000)、使用胰岛素比率高(23.9%vs.14.9%,P=0.002)、父母髋部骨折史高(9.2%vs.3.7%,P=0.001)、1年内发生跌倒率高(20.7%vs.8.3%,P=0.000)、跌倒风险评分高[(2.98±0.01)分vs.(1.8±0.01)分,P=0.000]、TUG高(10.92 s vs.10.34 s,P=0.000)、骨密度低[(0.635±0.026)g/cm^2vs.(0.780±0.030)g/cm^2,P=0.000]。结论与对照组相比,患T2DM的老年人虽然BMD高,但是下肢肌功能降低、跌倒及骨折的发生率明显增高,揭示T2DM降低了老年人肌肉功能,增加了跌倒和骨折的发生,且该作用独立于BMD以外。展开更多
基金supported by National Hi-tech Research and Development Program of China (863 Program,Grant No. 2006AA110101)"111 Program" of Ministry of Education and State Administration of Foreign Experts Affairs of China (Grant No. 111-2-11)+1 种基金General Motors Research and Development Center (Grant No. RD-209)Project of State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body,Hunan University,China (Grant No. 60870004)
文摘Lower limb injures are frequently observed in passenger car traffic accidents.Previous studies of the injuries focus on long bone fractures by using either cadaver component tests or simulations of the long bone kinematics,which lack in-depth study on the fractures in stress analysis.This paper aims to investigate lower limb impact biomechanics in real-world car to pedestrian accidents and to predict fractures of long bones in term of stress parameter for femur,tibia,and fibula.For the above purposes,a 3D finite element(FE) model of human body lower limb(HBM-LL) is developed based on human anatomy.The model consists of the pelvis,femur,tibia,fibula,patella,foot bones,primary tendons,knee joint capsule,meniscus,and ligaments.The FE model is validated by comparing the results from a lateral impact between simulations and tests with cadaver lower limb specimens.Two real-world accidents are selected from an in-depth accident database with detailed information about the accident scene,car impact speed,damage to the car,and pedestrian injuries.Multi-body system(MBS) models are used to reconstruct the kinematics of the pedestrians in the two accidents and the impact conditions are calculated for initial impact velocity and orientations of the car and pedestrian during the collision.The FE model is used to perform injury reconstructions and predict the fractures by using physical parameters,such as von Mises stress of long bones.The calculated failure level of the long bones is correlated with the injury outcomes observed from the two accident cases.The reconstruction result shows that the HBM-LL FE model has acceptable biofidelity and can be applied to predict the risk of long bone fractures.This study provides an efficient methodology to investigate the long bone fracture suffered from vehicle traffic collisions.
文摘目的研究社区老年2型糖尿病(type 2 diabetes mellitus,T2DM)对骨密度(bone mineral density,BMD)、下肢肌功能、跌倒及骨折的影响。方法选取上海市5家社区卫生服务中心的60岁以上老年人9 584例,其中T2DM组1 201例,对照组8 383例;T2DM患者分为骨折组184例,非骨折组1 017例。分别记录受试者的年龄、性别、身高及体质量,计算出体质量指数(body mass index,BMI),起立行走计时测试(the timed up and go,TUG)评估下肢肌力情况,询问受试者骨折史,吸烟、饮酒情况,1年内跌倒及骨折情况,父母发生髋部骨折史,并询问T2DM患者的病程,药物治疗情况。利用跟骨超声骨密度仪(quantitative ultrasound system-bone mineral density,QUS-BMD)测量骨密度值。比较T2DM与对照组的一般基础资料及发生跌倒和骨折情况,比较T2DM患者骨折组与非骨折组各临床指标。结果 T2DM组吸烟率20.4%明显高于对照组17.8%(P=0.030),完成TUG所需中位数时间10.75 s明显高于对照组10.12 s(P=0.000),BMD(0.920±0.040)g/cm^2高于对照组(0.790±0.030)g/cm^2(P=0.000),1年内跌倒发生率10.1%高于对照组7.1%(P=0.000),1年内骨折发生率15.3%高于对照组12.1%(P=0.080);T2DM患者中,与非骨折组相比,骨折组女性的比例高(89.1%vs.52.1%,P=0.000)、糖尿病病程长[(11.6±0.6)年vs.(9.6±0.2)年,P=0.000]、吸烟比率高(95.1%vs.67.9%,P=0.000)、饮酒比率高(93.5%vs.80.7%,P=0.000)、使用胰岛素比率高(23.9%vs.14.9%,P=0.002)、父母髋部骨折史高(9.2%vs.3.7%,P=0.001)、1年内发生跌倒率高(20.7%vs.8.3%,P=0.000)、跌倒风险评分高[(2.98±0.01)分vs.(1.8±0.01)分,P=0.000]、TUG高(10.92 s vs.10.34 s,P=0.000)、骨密度低[(0.635±0.026)g/cm^2vs.(0.780±0.030)g/cm^2,P=0.000]。结论与对照组相比,患T2DM的老年人虽然BMD高,但是下肢肌功能降低、跌倒及骨折的发生率明显增高,揭示T2DM降低了老年人肌肉功能,增加了跌倒和骨折的发生,且该作用独立于BMD以外。
