3D打印多孔钛钢板一体化植入体修复髋臼后壁粉碎性骨折合并骨缺损的初步研究

目的 :探讨应用计算机辅助设计(computer aided design,CAD)结合3D打印技术对髋臼后壁粉碎性骨折合并骨软骨缺损进行修复重建的可行性,评估多孔钛合金支架钢板一体化植入体复合氮化钛生物陶瓷涂层的生物力学性能。方法:基于连续断层CT图像,利用CAD软件来构建具有特定三维内部结构的多孔钛钢板一体化植入体数字模型,以Ti6Al4V粉末为原材料打印出实体并于其关节面复合氮化钛涂层,观察植入体与髋臼匹配和贴附情况;利用Ansys软件进行有限元建模,分析正常组、传统组及植入体组髋臼在相同载荷状态下的应力分布、应力传导及形变位移等情况,验证植入体的生物力学性能。结果:植入体的多孔钛合金支架与髋臼匹配程度良好,钢板形态基本与骨表面贴附,根据Matta复位标准评定为优。有限元分析结果显示:植入体重建后髋臼在Von Mises应力峰值13.38 MPa接近正常组13.11 MPa,小于传统组15.66 MPa;植入体重建后的髋臼在应力分布和传导与正常组基本一致,稍优于传统组;植入体的最大相对位移为0.166 mm,处于可以接受的范围。结论:3D技术制备的多孔钛合金支架钢板一体化植入体复合氮化钛涂层具备优良的匹配度和生物力学性能;解剖重建使后壁头臼应力分布及传导恢复比较理想,接近正常的髋关节,其为临床治疗髋臼后壁粉碎性骨折合并严重骨缺损的病例提供新选择。

A preliminary study of three-dimensional printed porous titanium plate integrated implant for the repair of comminuted acetabular posterior wall fracture with bone defect

Objective:To explore the feasibility of using computer-aided design(CAD) combined with 3D printing technology to repair and reconstruct the comminuted fracture of the posterior wall of acetabulum with osteochondral defect,to evaluate the biomechanical properties of composite titanium nitride bioceramic coatings with porous titanium alloy scaffolds and steel plate integrated implants.Methods:Based on CT images of continuous tomography,the computer-aided design software was used to construct a digital model of porous titanium alloy plate implant with a specially open cellular three-dimensional structure,and the three-dimensional implant was prepared with Ti6Vl4V powder by using the 3D printing technology,following by titanium nitride coating on its articular surface. The degree of matching and attachment between the implant and acetabulum were observed;Ansys software was used for finite element modeling to analyze the stress distribution,stress conduction and deformation displacement of the acetabulum of the normal group,the traditional group and the implant group under the same load state,and to verify the biomechanical properties of the implant.Results:The porous titanium alloy implant fit well with the acetabular bone defects,the shape of the plate was well attached to the bone surface,and it was rated as excellent according to the Matta criteria. The Von Mises stress peak of the implant group 13.38 MPa was close to the normal group 13.11 MPa and smaller than that in the traditional group 15.66 MPa. The Von Mises stress distribution and conduction of implant group were basically consistent with the normal group,slightly better than the traditional group;the maximum relative displacement of the implant was 0.166 mm,according to the finite element analysis.Conclusion:The porous titanium alloy stent plate implant with titanium nitride coating prepared by 3D technology has excellent matching degree and biomechanical properties;the anatomical reconstruction makes the stress distribution and conduction recovery well,close to normal hip joints,which provides a new option for the clinical treatment of comminuted posterior acetabular wall fractures with severe bone defects.