退行性关节炎与骨质疏松性股骨颈骨小梁的有限元分析

Finite element analysis of femoral neck trabecular bone in OA and OP patients

目的以生物力学的观点探讨分析退行性关节炎(OA)及骨质疏松(OP)的临床病变表现。方法建立OA及OP患者股骨颈骨小梁的有限元模型,分别计算指标参数,并利用骨小梁分布密度,配合有限元法计算得到骨小梁组织真正的材料性质,重新模拟破坏的情形,观察不同模型的应变分布,并探讨各指标参数及材料性质对骨小梁强度的影响。结果骨小梁的数量越多、密度越高,达到屈服应变的比例就越低。骨小梁的间隔越大,则达到屈服应变的比例就越高。而骨小梁的表面积比及厚度与结构强度无关。试件的结构刚度、剪切模量及骨小梁组织的弹性模量等材料性质越高,其达到屈服应变的元素的比例就会越低。结论虽然几何外形也是影响材料性质的因素之一,但材料性质对骨小梁强度的影响要比几何外形明显。

Objective To compare the clinical pathological changes of osteoarthritis （OA） and osteoporosis （OP） from the biomechanical point of view. Methods OA and OP femoral neck trabecular models were established for finite element analysis. The indexes and trabecular distributive densities were compared. Real material properties of trabecular tissue were found. Failure simulations were conducted to observe yielding strain distribution in different models. The influences of indexes on material properties were also investigated. Results The results showed that lower distributions of yielding strain were caused by more trabeculae and higher density of trabecula. Increase of trabecular interval resulted in increase of yielding strain. Relative bone surfaces and thickness of trabecula seemed to have no significant relation to structural strengths. Ratio of yielding strain would be lower as long as material properties, such as stiffness, shear modulus and Young＇s modulus of trabecular tissue, were stronger. Conclusion Although geometry is also one of the factors that influence material properties, trabecular strength is influenced more by material properties than by geometries.