个性化3D打印多孔钛合金加强块重建重度髋臼骨缺损的有限元分析

摘要

目的 建立个性化3D打印多孔钛合金加强块重建重度髋臼骨缺损有限元模型,分析个性化3D打印多孔钛合金加强块、螺钉以及骨的生物力学和临床应用安全性.方法 利用1例PaproskyⅢA型髋臼骨缺损病人的骨盆CT数据建立完整的个性化3D打印多孔钛合金加强块重建重度髋臼骨缺损有限元模型,模拟1倍体重(单足站立)、4倍体重(步行)和6倍体重(慢跑)加载负荷下分析加强块、螺钉以及骨的应力分布.结果 个性化3D打印多孔钛合金加强块的最大应力分布为10.130 MPa(1倍体重)、40.706 MPa(4倍体重)和61.213 MPa(6倍体重),固定加强块的螺钉最大应力分布为12.424 MPa(1倍体重)、50.250 MPa(4倍体重)和75.860 MPa(6倍体重),骨面应力分布最大应力分布为10.439 MPa(1倍体重)、42.627 MPa(4倍体重)和64.554 MPa(6倍体重).结论 有限元模拟术后即刻完全负重站立时所有部件的应力分布均小于其屈服强度,不会发生失效;但是于步行和慢跑加载负荷下,与加强块和螺钉接触骨面的部分区域松质骨会发生失效.因此从有限元分析角度考虑,病人术后即刻可以进行完全负重站立康复锻炼,但是不能进行完全负重的步行或慢跑康复运动.%Objective To establish the finite element model of acetabular bone defect reconstructed by 3D printed porous Ti6Al4V augment and further analyze the stress distribution and clinical safety of augment, screws and bone. Methods The finite element model of acetabular bone defect reconstructed by 3D printed porous Ti6Al4V augment was established by the CT data of a patient with PaproskyⅢA defect. The von Mises stress of augment, screws and bone were analyzed by a vertical load applied in 3 increments (500 N, 2000 N and 3000 N). Results The peak von Mises stresses under 500 N load in the porous augment, screws and cortical bone were 10.130, 12.424 and 10.439 MPa respectively, those were 40.706, 50.250 and 42.627 MPa respectively under 2000 N load, and those were 61.213, 75.860 and 64.554 MPa respectively under 3000 N load. Conclusion The finite element analysis shows that all the components will be intact under 500 N (full weight-bearing standing). However, partial cancellous bone contacted with porous augment and screws will be failed under 2000 N (walking) and 3000 N (jogging). So we recommend that patients can stand under full bearing, but cannot walk or jog immediately after surgery.