轴向微动接骨板固定股骨骨折的生物力学有限元分析

Finite element analysis of femoral fracture fixation by axial micromotion bone plate

目的通过有限元方法探讨轴向微动接骨板固定股骨骨折的生物力学特性,为新型骨植入物的研发和临床应用提供生物力学基础。方法选取1名健康成年男性志愿者,行CT扫描后三维重建股骨模型及10mm骨折;构建1mm轴向微动接骨板,通过700N轴向、10N·m扭转、250N前后四点弯曲和250N内外四点弯曲4种工况有限元仿真,比较轴向微动接骨板和传统锁定接骨板的生物力学特性。结果四种工况下,轴向微动接骨板应力均值均小于传统锁定接骨板(31.15MPa vs 46.51MPa,12.92MPa vs 18.25MPa,3.67MPa vs 4.23MPa,4.51MPa vs 4.94MPa);微动接骨板疲劳寿命略小于锁定接骨板,但超出设计使用寿命34.7%;微动接骨板模型中螺钉平均应力小于锁定接骨板模型,且股骨应力最大值和平均值均小于锁定接骨板模型。结论新型轴向微动接骨板具有更加仿生的生物力学性能,不但可以分散接骨板和螺钉结合处的应力集中,减少断钉风险,同时可以降低股骨所受应力,具有进一步开发的潜力。

Objective To explore the biomechanical properties of axial micromotion bone plate for fixation of femoral fractures by means of finite element method,and to provide a biomechanical basis for the development of new bone implants ant their clinical application.Methods A healthy adult male volunteer underwent CTscanningg to create a three-dimensional reconstruction of the femur model and a 10-mm fracture.A 1-mm axial micromotion plate was constructed and its biomechanical properties were compared to those of a traditional locking plate under four working conditions:700N axial and 10N·m torsion.Finite element simulation was used to compare the biomechanical properties of the axial micromotion plate and the traditional locking plate.The study evaluated the stress val⁃ues of axial micromanipulation splints and conventional locking splints under different loads,including 700N axial,10N-m torsion,250N anterior/posterior four-point bending,and 250N internal/external four-point bending.Results The average stress values of the axial micromotion plate were lower than those of the conventional locking plate.Specifically,the stress values were 31.15 MPa and 46.51 MPa for axial loads,12.92 MPa and 18.25 MPa for torsion loads,3.67 MPa and 4.23 MPa for anterior-posterior bending loads,and 4.51 MPa and 4.94 MPa for internal-external bending loads,respectively.The micromotion plate exhibited a slightly lower fatigue life than the loc⁃king plate,but 34.7%higher than the design life.The average screw stress in the micromotion plate was less than that in the locking plate,and the maximum and average femoral stresses were smaller than those in the locking plate model.Conclusion The newly de⁃signed axial micromotion plate possess biomimetic biomechanical properties.These properties disperse stress concentration at the combi⁃nation of the splints and screws,reducing the risk of screw breakage.Additionally,they decrease stress on the femur,which may lead to further development.