Keyak J H, Rossi S A, Jones K A, Skinner H B
Department of Orthopaedic Surgery, University of California Irvine Medical Center, Orange 92868-5382, USA.
J Biomech. 1998 Feb;31(2):125-33. doi: 10.1016/s0021-9290(97)00123-1.
Hip fracture is an important cause of morbidity and mortality among the elderly. Current methods of assessing a patient's risk of hip fracture involve local estimates of bone density (densitometry), and are limited by their inability to account for the complex structural features of the femur. In an effort to improve clinical and research tools for assessing hip fracture risk, this study investigated whether automatically generated, computed tomographic (CT) scan-based finite element (FE) models can be used to estimate femoral fracture load in vitro. Eighteen pairs of femora were examined under two loading conditions one similar to loading during the stance phase of gait, and one simulating impact from a fall. The femora were then mechanically tested to failure and regression analyses between measured fracture load and FE-predicted fracture load were performed. For comparison, densitometry measures were also examined. Significant relationships were found between measured fracture load and FE-predicted fracture load (r = 0.87, stance; r = 0.95, fall; r = 0.97, stance and fall data pooled) and between measured fracture load and densitometry data (r = 0.78, stance; r = 0.91, fall). These results indicate that this sophisticated technique, which is still early in its development, can achieve precision comparable to that of densitometry and can predict femoral fracture load to within -40% to +60% with 95% confidence. Therefore, clinical use of this approach, which would require additional X-ray exposure and expenditure for a CT scan, is not justified at this point. Even so, the potential advantages of this CT/FE technique support further research in this area.
髋部骨折是老年人发病和死亡的重要原因。目前评估患者髋部骨折风险的方法涉及对骨密度的局部估计（骨密度测量），并且由于无法考虑股骨的复杂结构特征而受到限制。为了改进评估髋部骨折风险的临床和研究工具，本研究调查了基于计算机断层扫描（CT）扫描自动生成的有限元（FE）模型是否可用于体外估计股骨骨折负荷。在两种加载条件下检查了18对股骨，一种类似于步态站立阶段的加载，另一种模拟跌倒的冲击。然后对股骨进行机械测试直至失效，并对测量的骨折负荷与FE预测的骨折负荷之间进行回归分析。为了进行比较，还检查了骨密度测量指标。在测量的骨折负荷与FE预测的骨折负荷之间（站立时r = 0.87；跌倒时r = 0.95；站立和跌倒数据合并时r = 0.97）以及测量的骨折负荷与骨密度测量数据之间（站立时r = 0.78；跌倒时r = 0.91）发现了显著相关性。这些结果表明，这种仍处于发展初期的复杂技术可以达到与骨密度测量相当的精度，并且可以在95%的置信度下将股骨骨折负荷预测在-40%至+60%的范围内。因此，此时这种需要额外的X射线照射和CT扫描费用的方法在临床上的应用并不合理。即便如此，这种CT/FE技术的潜在优势支持在该领域进行进一步研究。
