Participant-specific modelling of the femur during falls: importance of impact dynamics and bone morphology

The mechanical nature of factors influencing hip fracture rates are not fully understood. This study evaluated the influence of fall simulation paradigm (FSP), sex, and trochanteric soft tissue thickness (TSTT) on femoral neck stresses and fracture risk. Through coupling of experimental FSP and tissue level modelling this analysis was sensitive to differences in both skin-surface impact dynamics and underlying femur morphology. FSP incorporating a lateral motion elicited greater impact energy, stresses and fracture risk. Across FSP, impact vector orientation interacted with femur geometry to influence stress distribution. While males experienced greater impact force over the greater trochanter, differences in femur morphology resulted in no differences in stresses nor fracture risk compared to females. In contrast, femur morphology in high-TSTT resulted in lower stresses and fracture risk, despite no differences in skin-surface loading compared to low-TSTT. These results highlight the importance of impact ...