Optimization Design And Finite Element Analysis Of Internal Fixation Plates For Distal Radius Fractures

BackgroundDistal radius fractures are one of the most common fractures in clinical.and most of patients can achieve satisfactory results with conservative treatment.However,the open reduction internal fixation is often preferred treatment option for unstable fractures and intra-articular fracture.Due to reduce irritability of dorsal extensor tendons and good angular stability,the volar locking plate has gradually become the mainstream choice for internal fixation of distal radius fractures.Due to improper applications or internal design factors,it violates the original intention of the design and causes a series of complications.The key is how to meet the needs of fracture strain though adjusting the stiffness of the internal fixation.In addition,the mechanical environment of the wrist joint is complex,and there are many forms of combined loads.The ideal volar locking fixation should take the above factors into consideration,especially the need for stability and safety in early rehabilitation individualized functional exercise.ObjectiveIn this study,the topological optimization design of internal fixation plate for distal radius fractures and the adjustment of its stiffness are studied,and the scheme is verified and evaluated with the finite element analysis method,so as to provide a new method for individualized treatment of distal radius fractures and device innovation.Methods1.Validity analysis of finite element model of distal radius fractureThree-dimensional reconstruction was performed based on forearm CT data of a young healthy female,and imported it into the Geomagic Studio for materialization process,then simulated a distal radius fracture in UG.Finally,the calculation and analysis was carried out in the ABAQUS under early rehabilitation load.2.Study on the optimization of volar plate fixation for distal radius fractures under multiple working conditionsOn the base of demonstrating the effectiveness of the finite element model of distal radius fractures,the topological optimization was carried out under the conditions of torsion and compression to obtain maximum stiffness.Furthermore,we compared biomechanical characteristics between the optimized scheme and the conventional locking plate.3.Topology optimization and numerical simulation of locking plate for personalized stiffness requirementsBased on the stiffness control strategy of displacement constraint,the topology optimization method was used to locking steel plate redesign in order to meet the specific stiffness requirements.Results1.The equivalent finite element model of distal radius fracture was established.The axial compression,dorsal bending,and volar bending stiffness were 331.02,18.16,and 18.16 N/mm respectively.The model can be used in the follow-up study of this project,which lays a foundation for further optimization design of internal plates of distal radius fractures.2.The strain energy of the optimized plate under axial and torsional load had been significantly reduced by 21.4%and 16.28%,respectively,and the stress amplitude and distribution were also more uniform than conventional plate.The optimization goal of maximum stiffness was achieved preliminarily.3.Based on the stiffness control strategy of displacement constraint,after optimization,the axial stiffness of steel plate was reduced by 19.7%(optimization target 33.3%),and the torsional stiffness was reduced by 8.8%(optimization target 10%).The redesigned optimized plate can reduce the axial stiffness specifically,and retained the torsional stiffness of the original steel plate.It meet the individual plate design with controllable stiffness.ConclusionsThe study showed the topology optimization can meet patient-specific treatment for distal radius fractures,such as individualization design and mechanical characteristics optimization of plate.It can effectively improve the treatment effects and reduce the risk of complications related to surgical treatment.