Finite Element Investigation of Out-of-Position Failure Modes for the Knee-Thigh-Hip of a 50^th Percentile Male During a Frontal Car Crash

The introduction of air bags has reduced injuries to the upper region of the body for occupants of vehicles in frontal crashes, such as head and thorax. Airbags have not, however, improved the safety of occupants with respect to injuries to the lower extremities. Though lower extremity injuries are usually not life threatening, they can have long lasting physical and psychosocial consequences. A validated Knee-Thigh-Hip (KTH) finite element model of a 50^th percentile male was used to investigate injury mechanisms during frontal car crashes with the occupant in different positions. Simulations of frontal impacts were performed with the Knee-Thigh-Hip joints at different angles of thigh flexion, adduction and abduction. Results show that the failure mechanism can significantly depend on the occupant position prior to impact. Failure mechanisms in the simulations were compared to results found in literature to ensure the model provides a useful tool for predicting fractures in the lower limb resulting from out-of-position frontal vehicle crashes.