两种股骨柄在骨缺损翻修中应用的有限元分析研究

Finite element analysis on the femoral revision with two types of revision hip stems

目的比较钴铬合金广泛涂层柱形柄和钛合金带脊锥形股骨柄行骨缺损翻修后股骨应力分布差异。方法通过Mimics软件、Geomagic Studio软件、Solidworks软件中建立股骨、钴铬合金广泛涂层柱形柄、钛合金带脊锥形股骨柄三维实体模型。在Solidworks软件中根据Parprosky骨缺损分型建立IIA、IIB、IIC、IIIA股骨骨缺损实体模型,并模拟手术将2种假体与4类不同程度股骨骨缺损模型装配,得到8个翻修手术实体模型,分为钛合金锥形柄组和钴铬合金柱形柄组,最后导入到软件ANSYS Workbench进行有限元分析,比较股骨Von Mises应力值。结果相同骨缺损程度下,钛合金锥形柄组较钴铬合金柱形柄组在股骨骨缺损区有更高应力分布(P<0.05);并且钛合金锥形柄组股骨中上段应力分布均匀,钴铬合金柱形柄组应力分布不均;钴铬合金柱形柄组假体涂层末端区域存在应力集中,钛合金锥形柄组未见。结论钴铬合金广泛涂层柱形股骨柄相对钛合金带脊锥形股骨柄在骨缺损区应力遮挡较重,并且在涂层末端区域存在应力集中。

To compare the stress distribution on the femur after femoral revision for bone defect using extensively porous-coated cylindrical cobalt-chromium stems and tapered fluted titanium stems.The 3D solid models of the femur,extensively porous-coated cylindrical cobalt-chromium stems and tapered fluted titanium stems was established through software Mimics,Geomagic Studio and Solidworks.In SolidWorks,type IIA,IIB,IIC and IIIA femur bone defect models were established according to the Parprosky classification.Then,2 types of prosthesis and 4 different degree of bone defect model were assembled together to obtain 8 femoral revision models that were divided into extensively porous-coated cylindrical cobalt-chromium stem group and tapered fluted titanium stem group.Finally,femoral revision models were imported to ANSYS Workbench for finite element analysis.von Mises stress value of femur was compared.Under the condition of the same degree of bone defect,tapered fluted titanium stem group had higher von Mises stress value than extensively porous-coated cylindrical cobalt-chromium stems group in bone defect regions(P<0.05).Besides,Von Mises stress was distributed more regularly in upper and middle femur in tapered fluted titanium stem group while extensively porous-coated cylindrical cobalt-chromium stems group showed uneven.Furthermore,there was stress concentration at the distal area of the porous coating region in extensively porous-coated cylindrical cobalt-chromium stems group while it was not observed in the tapered fluted titanium stem group.Extensively porous-coated cylindrical cobalt-chromium stems have more serious stress shielding in bone defect zone and stress concentration at the distal part when compared to tapered fluted titanium stem.