Lotz J C, Hayes W C
Department of Orthopaedic Surgery, Charles A. Dana Research Institute, Beth Israel Hospital, Boston, Massachusetts 02115.
J Bone Joint Surg Am. 1990 Jun;72(5):689-700.
We conducted an in vitro investigation of the loads and energies needed to fracture the proximal part of the femur in twelve fresh cadavera under loading conditions simulating one particular type of fall. The fracture loads ranged from 778 to 4,040 newtons and the work to fracture, from five to fifty-one joules. We also investigated the relationship between the fracture loads and several potential indices of bone strength, which were measured non-invasively at the subcapital, basic-cervical, and intertrochanteric regions with quantitative computed tomography. A very high positive correlation with the fracture load resulted from use of an intertrochanteric index--the product of the average trabecular computed-tomography number and the total cross-sectional area of the bone (R2 = 0.93, standard error of estimate = 295 newtons, and p less than 0.00001). We expect the use of this parameter to result in improved assessments of the degree of osteoporosis and of the component of risk of fracture of the hip that is associated with bone strength. However, the measured work to fracture for the isolated femur was an order of magnitude smaller than estimates of the energy available during a typical fall (about 450 joules), suggesting that energy absorbed during falling and impact, rather than bone strength, may be the dominant factors in the biomechanics of fracture of the hip.
我们在十二个新鲜尸体上进行了一项体外研究，模拟一种特定类型的跌倒加载条件，以确定使股骨近端骨折所需的负荷和能量。骨折负荷范围为778至4040牛顿，骨折功为5至51焦耳。我们还研究了骨折负荷与几个潜在的骨强度指标之间的关系，这些指标通过定量计算机断层扫描在股骨头下、基底部和转子间区域进行无创测量。使用转子间指数（平均小梁计算机断层扫描数与骨的总横截面积的乘积）与骨折负荷呈现出非常高的正相关性（R2 = 0.93，估计标准误差 = 295牛顿，p小于0.00001）。我们期望使用这个参数能够改进对骨质疏松程度以及与骨强度相关的髋部骨折风险成分的评估。然而，孤立股骨的测量骨折功比典型跌倒过程中可用能量的估计值小一个数量级（约450焦耳），这表明跌倒和撞击过程中吸收的能量而非骨强度可能是髋部骨折生物力学中的主导因素。
