腓骨高位截骨对膝关节应力改变的三维有限元分析

Three-dimensional finite element analysis of stress changes in knee joint with high fibular osteotomy

目的采用三维有限元分析腓骨高位截骨对膝关节应力改变的影响,为临床采用腓骨高位截骨术治疗合并内翻畸形的膝关节骨性关节炎提供生物力学依据。方法采集1例膝关节骨性关节炎合并内翻畸形(内翻15°)患者的CT、X线片,采用Super-Sap 93软件建立个体化的膝关节三维有限元模型,经过对膝关节模型设定边界条件、加载组织材料弹性性能、载荷设置、计算机模拟腓骨高位截骨术,计算腓骨高位截骨手术前后膝关节内部任意节点的冯米斯应力(MS)。结果正常情况下内侧半月板MS应力值明显高于外侧半月板,在腓骨高位截骨去除腓骨支撑后,内、外侧半月板MS应力值均减少,且内侧半月板MS应力值减小幅度大于外侧半月板,截除腓骨后的内侧半月板应力值依然大于外侧半月板。正常情况下内侧胫骨平台所受的MS应力值高于外侧胫骨平台,在腓骨高位截骨去除腓骨支撑后,内侧胫骨平台的MS应力值减小,而外侧胫骨平台的MS应力值改变不明显,内外侧趋于平衡。结论采用腓骨高位截骨术治疗轻中度内翻型膝关节骨性关节炎够改变膝关节的力学环境,降低膝关节内侧间室的应力,从而平衡内外侧间室所受到的压力。

Objective To analyze the effect of high fibular osteotomy on the stress change of the knee joint with threedimensional finite element in order to provide a biomechanical basis for the clinical use of high fibular osteotomy for knee osteoarthritis with genu varum. Methods The CT and X-ray films of one patient with osteoarthritis of knee joint （genu varum 15°） were collected, and the Super-Sap 93 software was used to establish an individual three-dimensional finite element model of the knee joint. By setting the boundary condition, loading the elasticity of the tissue material, setting the load, using the computer to simulate the high fibula osteotomy, the Von Mises Stress （MS） of any node in the knee was obtained. Results Under normal circumstances, the stress value of the medial meniscus Was significantly higher than that of the lateral meniscus. After the removal of part of the fibula, the MS of the medial and lateral meniscus were reduced, the medial meniscus＇s MS reduction was significantly greater than the lateral meniscus, but the average stress of the medial meniscus was still greater than the lateral. In the normal case, the medial tibial plateau received higher MS than the lateral tibial plateau. After high fibular osteotomy, the MS value of the medial tibial plateau decreased, while the MS plateau value of the lateral tibial plateau did not change significantly. The inner and outer sides tended to balance. Conclusion The high fibular osteotomy for knee osteoarthritis with mild to moderate genu varum can change the knee joint mechanics environment, reduce medial interventricular stress, and therefore balance medial and lateral interventricular stress.