Robinovitch S N, Hayes W C, McMahon T A
Department of Orthopedic Surgery, Charles A. Dana Research Institute, Beth Israel Hospital and Harvard Medical School, Boston, MA 02215.
J Biomech Eng. 1991 Nov;113(4):366-74. doi: 10.1115/1.2895414.
A major determinant of the risk of hip fracture in a fall from standing height is the force applied to the femur at impact. This force is determined by the impact velocity of the hip and the effective mass, stiffness, and damping of the body at the moment of contact. We have developed a simple experiment (the pelvis release experiment) to measure the effective stiffness and damping of the body when a step change in force is applied to the lateral aspect of the hip. Results from pelvis release experiments with 14 human subjects suggest that both increased soft tissue thickness over the hip and impacting the ground in a relaxed state can decrease the effective stiffness of the body, and subsequently reduce peak impact forces. Comparison between our fall impact force predictions and in-vitro measures of femoral fracture strength suggest that any fall from standing height producing direct, lateral impact on the greater trochanter can fracture the elderly hip.
从站立高度跌倒时髋部骨折风险的一个主要决定因素是撞击时作用于股骨的力。这个力由髋部的撞击速度以及接触瞬间身体的有效质量、刚度和阻尼决定。我们开发了一个简单的实验（骨盆释放实验）来测量当对髋部外侧施加力的阶跃变化时身体的有效刚度和阻尼。对14名人类受试者进行骨盆释放实验的结果表明，髋部软组织厚度增加以及在放松状态下撞击地面都会降低身体的有效刚度，进而降低峰值冲击力。我们对跌倒冲击力的预测与股骨骨折强度的体外测量结果之间的比较表明，任何从站立高度跌倒并直接横向撞击大转子的情况都可能导致老年人髋部骨折。
