基于有限元生物力学模型研究前交叉韧带重建术中最佳骨道定位

Optimal bone tunnel location in anterior cruciate ligament reconstruction based on finite element biomechanical model

目的基于三维有限元生物力学模型,模拟计算前交叉韧带(ACL)重建术中选择不同骨道后移植物的应力,探讨重建术中最佳骨道定位。方法选择中国数字化人体5号数据集(CVH-5)膝关节的连续横断面断层图像,对膝关节结构进行分割、三维重建、模型优化和网格划分,并设置材料参数和边界条件,完成膝关节三维有限元模型的建立和验证。找到ACL在股骨和胫骨上的中心点,在膝关节屈曲90°时于胫骨止点中心点及与中心点间隔2 mm向前、后、内、外4个方向取点作为移植物胫骨骨道定位点;以股骨止点中心点及与中心点间隔2 mm向前、后、上、下4个方向取点作为移植物股骨骨道定位点,在膝关节屈曲0°、30°、60°、90°和120°时,模拟25种骨道定位的力学仿真,测量ACL重建术中选择不同骨道点后移植物的应力分布,并进行计算和分析。结果本研究成功建立了膝关节三维有限元模型,包含膝关节骨、软骨、内外侧半月板、前后交叉韧带和内外侧副韧带等14个部件,总计53866个单元。力学仿真结果显示,ACL重建术后骨道移植物在膝关节屈伸活动过程中所受应力主要集中在股骨止点及胫骨止点,在股骨止点下部及胫骨止点后部形成峰值,并呈波浪状向四周逐渐减小,移植物中部所受应力相对较小。重建后移植物应力值及变化范围最小的骨道为T1-F3,该骨道在膝关节屈曲0°~120°时的应力值在股骨止点为(14.11±5.38)MPa,在胫骨止点为(6.30±3.22)MPa。结论本研究利用有限元生物力学模型分析得出ACL重建术中最佳骨道定位点为T1-F3,为临床解剖学和生物力学提供了理论依据和参考数据。

Objective Based on the three-dimensional finite element biomechanical model,the stress of the graft after selecting different bone tunnels in anterior cruciate ligament(ACL)reconstruction was simulated and calculated to explore the optimal bone tunnel location during ACL reconstruction.Methods The continuous cross-sectional tomographic images of the knee joint from Chinese Visible Human 5(CVH-5)were selected to conduct segmentation,three-dimensional reconstruction,model optimization and meshing of the knee joint structure,and to set the material parameters and boundary conditions to complete the establishment and verification of the three-dimensional finite element model of the knee joint.The center points of ACL on femur and tibia were found.When the knee joint was flexed at 90°,the center point of the tibial insertion and the anterior,posterior,internal and external directions with an interval of 2 mm from the center point were taken as the tibial bone tunnel location point of the graft;the central point of the femoral insertion and the anterior,posterior,superior and inferior directions with an interval of 2 mm from the center point were taken as the femoral bone tunnel location point of the graft.Mechanical simulation was performed by simulating 25 kinds of bone tunnel location when the knee joint was flexed at 0°,30°,60°,90°and 120°,and the stress distribution of the graft after selecting different bone tunnels in ACL reconstruction was measured,calculated and analyzed.ResultsIn this study,the three-dimensional finite element model of knee joint was successfully established,including 14 parts of knee joint bone,cartilage,internal and external meniscus,anterior and posterior cruciate ligaments,and medial and lateral collateral ligaments,with a total of 53866 elements.The mechanical simulation results showed that the stress of bone tunnel graft during the process of knee flexion and extension after ACL reconstruction was mainly concentrated on the femoral insertion and tibial insertion,and the peak was formed at the lower part of femoral insertion and the rear of tibial insertion,which gradually decreased around in a wavy shape,and the stress in the middle part of the graft was relatively small.The bone tunnel with the smallest graft stress value and variation range after reconstruction was T1-F3,the stress value of this bone tunnel at the femoral insertion was(14.11±5.38)MPa,and the stress value at the tibial insertion was(6.30±3.22)MPa when the knee joint was flexed from 0°to 120°.Conclusion In this study,the optimal bone tunnel location point in ACL reconstruction was T1-F3 by using the finite element biomechanical model,which can provide theoretical basis and reference data for clinical anatomy and biomechanics.