Sinus Tarsal Plate In The Treatment Of Talar Neck Fractures:a Finite Element Analysis

Background:With the rising number of traffic accidents and falling from high places in today’s society,talar neck fracture has become a focus of clinicians.At present,there are conservative treatments and surgical treatments.Most surgeons recommend the use of surgery for treatment.Open reduction and internal fixation for talar neck fracture has gradually become the first choice.In clinical work,there are many choices of internal fixation for the surgical treatment of talar neck fracture,including Kirschner wire fixation and screw fixation,but the occurrence of follow-up complications and the prognosis of patients are still a major problem.When this part of the bone is injured,the lateral talar neck will be accompanied by comminuted fracture,which can not be supported by Kirschner wire or screw alone.Therefore,we designed a new type of tarsal sinus plate,which can play a good role in supporting and fixing the talus of this part of the comminuted fracture.Purpose:Using the finite element three-dimensional analysis software on the computer,the three-dimensional finite element model of the ankle joint is established,and verifying the validity of the model.Then,on the basis of the normal ankle model,the finite element models of four internal fixation methods were established,including sinus tarsal plate combined with antero-posterior screw,antero-posterior parallel dual screws,sinus tarsal plate combined with postero-anterior screw,and postero-anterior parallel dual screws.The biomechanical characteristics of tarsal sinus plate and dual screw fixation were analyzed and compared,in order to provide a theoretical basis for further research and development of tarsal sinus plate and better clinical treatment of talar neck fractures.Methods:1.A 25-year-old healthy man was selected to perform CT scan of the ankle joint,and then importing the data into Mimics 19.0 software to generate a three-dimensional model of the normal ankle joint.Then the Geomagic Studio 2017 software and Solidworks 2017 software were introduced into the finite element analysis software Workbench 17.0 after processing,to divide the finite element mesh and add ligaments and other ancillary structures.Setting up a normal finite element model of ankle joint and verifying its effectiveness.2.Four kinds of internal fixation models of talar neck fracture were constructed by finite element analysis software,including sinus tarsal plate combined with antero-posterior screw,antero-posterior parallel dual screws,sinus tarsal plate combined with postero-anterior screw,and postero-anterior parallel dual screws.The stress load was applied to the four models,and the biomechanical characteristics of different internal fixation methods were compared,so as to provide further theoretical basis for the research and development of tarsal sinus plate.Results:The talus stress and internal fixation stress of dual screw fixation model were less than those of tarsal sinus plate fixation model,but there was no significant difference in talus displacement on X,Y and Z axis among them.The results showed that the maximum talus stress of tarsal sinus plate fixation model was 9.8 MPa,and that of dual screw fixation model was 4.7 MPa.The maximum stress values of tarsal sinus plate fixation model and dual screw fixation model were 53.3 MPa and 30.1 MPa,respectively.In these four models,the displacement of talar fracture was less than 1 mm on X,Y and Z axis,and there was no significant statistical difference.Conclusions:Compared with dual screw fixation in the treatment of talus neck fracture,tarsal sinus plate fixation has no obvious biomechanical advantage,but when comminuted fracture occurs in the lateral talus,it can play a better supporting and fixing role,so it can be used in clinic and the details should be combined with the clinic according to the patient’s condition.