Esses S I, Lotz J C, Hayes W C
Department of Orthopaedic Surgery, Charles A. Dana Research Institute, Beth Israel Hospital, Boston, MA.
J Bone Miner Res. 1989 Oct;4(5):715-22. doi: 10.1002/jbmr.5650040510.
To assess the use of quantitative computed tomography as an in vivo predictor of fracture in the osteoporotic hip, we examined the in vitro relationship between single-energy quantitative computed tomography data, calibrated for scanner drift, and the mechanical properties of trabecular bone from the proximal femur. For 49 samples, the apparent density and ultimate strength were measured and their functional relationship to the computed tomography data determined. Apparent density demonstrated a moderate linear correlation to the computed tomography numbers (R2 = 0.60), and the ultimate strength was related through a power law (R2 = 0.83). In addition, for 8 intact femora, average computed tomographic data from the sub-capital region were moderately correlated to the ultimate fracture load applied under controlled in vitro conditions (R2 = 0.64). The average fracture energy for these femora was 43 J, a value more than an order of magnitude less than the energy available in a fall from standing height, suggesting that fall mechanics are a more important determinant of fracture risk than has been previously thought. The relationship between the energy absorbed to failure and the computed tomography data was best described by a power law (R2 = 0.90). Based on these results, it appears that quantitative computed tomography provides a potentially useful approach for the direct estimate of that component of fracture risk that can be attributed to a reduction in bone strength.
为评估定量计算机断层扫描作为骨质疏松性髋部骨折的体内预测指标的应用，我们研究了经扫描仪漂移校准的单能定量计算机断层扫描数据与股骨近端小梁骨力学性能之间的体外关系。对49个样本测量了表观密度和极限强度，并确定了它们与计算机断层扫描数据的函数关系。表观密度与计算机断层扫描数值呈中度线性相关（R2 = 0.60），极限强度通过幂律相关（R2 = 0.83）。此外，对于8个完整的股骨，股骨头下区域的平均计算机断层扫描数据与体外控制条件下施加的极限骨折负荷呈中度相关（R2 = 0.64）。这些股骨的平均骨折能量为43焦耳，该值比从站立高度跌落时可用能量小一个数量级以上，这表明跌倒力学是比先前认为的更重要的骨折风险决定因素。吸收至破坏的能量与计算机断层扫描数据之间的关系最好用幂律描述（R2 = 0.90）。基于这些结果，定量计算机断层扫描似乎为直接估计可归因于骨强度降低的骨折风险成分提供了一种潜在有用的方法。
