The Initial Study On The Application Of 3D Printed Porous Titanium Alloy/plate Implant For The Repairment Of Comminuted Posterior Acetabular Wall Fractures With Bone Defect

Objective: To investigate the feasibility of comminuted posterior acetabular wall fractures with bone/cartilage defect repaired by using computer-aided design(CAD)combined with 3D printing technology and evaluate the biomechanical properties of 3D-printed porous titanium alloy/plate implant combined with titanium nitride bioceramic coating.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 Ti6Vl4 V 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(13.38MPa)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 the comminuted posterior acetabular wall fractures with severe bone defects.