A Study on the Effect of Age on the Injury Criteria and Modeling of Lower Extremity Long Bone

The incidence and severity of lower extremity fracture increase with age in a vehicle to pedestrian accident, but very little is known about how age-related changes affect the injury mechanisms and injury tolerance, this paper was to study the influence of age on the injury tolerance level of the lower extremity long bone as well as its modeling. The GHBMC lower extremity FE model was used as the basic model, and the age-related bone material parameters were analyzed and adjusted based on the biomechanical tests data, then three different age groups were selected to do the three-point bending virtual tests under the quasi-static and dynamic conditions, and finally the regularity of age-related injury tolerance of lower extremity long bone was found out.The simulation results demonstrate FE models had high biofidelity to accurately estimate tolerance of long bone under various age groups.As the adult aging 10 years, the injury tolerance of femur, tibia and fibula were decreased with age, and the tolerance would decline 27.6Nm, 18Nm and 1.4Nm respectively for the femur, tibia and fibula every 10 years.An updated FE model of lower extremity long bone was built and validated with three-point bending virtual tests under the quasi-static and dynamic conditions, and the effect of age on skeletal material parameters and geometry was studied, based on the virtual tests results and the published past mortal human subject (PMHS) tests data, the regularity of age-related injury tolerance of lower extremity long bone was found out. The lower extremity FE model with age-related property, which built in this study, could be used in the research of injury mechanism in vehicle to elderly people accident.