A Drop Tower Protocol with Advanced Pulse Shaping for Hip Fracture Simulation

Force traces from isolated pelvis impact tests [1] have a bimodal behaviour with each local maximum having nearly the same magnitude, but the first having a lower duration. We believe that the initial force peak in this data was caused by the inertia of the femoral head and lateral pelvis, which are almost rigidly connected to the femoral neck. To date, test apparatuses used to model falls to the side have not reproduced the inertia of these structures but instead have focused on modelling the inertia of the body delivered through the pelvis. The rate of loading will affect the strain rate in the femoral neck; since bone properties are influence by strain rate, we believe that this initial, high-rate pulse could be critical to modelling and understanding the behaviour of the proximal femur in a sideways fall. To this end, we sought to include models of the tissues and structures surrounding the femur in a drop tower simulation of a sideways fall, replicating their inertial effects and elastic properties.