Mechanical Performance And Finite Element Analysis Of External Fixator For Adjustable Pressure Department Of Orthopedics

External fixation is one of the main options for the treatment of open fractures.It has advantages of firm fixation,less trauma and postoperative micromotion adjustment.Clinical trials show that a certain stress stimulus after fracture is beneficial to fracture healing,but the timing and magnitude of stress are not yet clear.Therefore,studying the performance of external fixator from the point of view of mechanics is of theoretical significance for the clinical application of this stent.In this paper,a new type of adjustable external fixator is chosen as the research object,and two aspects are studied from experiment and finite element analysis.First,the mechanical properties of the four groups of compression,three point bending,cantilever bending and torsion were carried out to the adjustable pressure fixed arm and the external fixator respectively.Secondly,the structure and contact relationship of the adjustable pressure fixed arm are studied.The force process and the transfer and distribution relationship of the adjustable pressure fixed arm in the compression test are analyzed,and the corresponding mechanical model is established.At the same time,the main force components of the external fixator under the compression condition are adjustable pressure fixed arms,so the model is also applicable to the external fixator’s compression process.Third,the three-dimensional model of the external fixator was established,and the simulation of the two test conditions of three point bending and torsion was introduced into the finite element software,which was basically in agreement with the test.The validity of the model was verified.Fourth,the threedimensional model of the external fixator and the human tibiofibula model was assembled to get the stenting tibia and fibula model,and the effects of three variables,such as different pressure,diameter of fixed needle and distance of bone seams,on the daily use of the scaffold were studied.Under a certain pressure,the total deformation,the maximum stress,the needle stress and the fracture stress all increase with the increase of pressure.Under the condition of different fixed needle diameter,the maximum stress position of different models is different.When the maximum stress appears on the fixed needle,it is easy to cause the fixed needle to loose,so it should be avoided.Finally,the results showed that the total deformation and the maximum stress of the needle bone increased with the increase of the distance between the sutures.Therefore,in the treatment of fractures,proper bone gap distance should be controlled to help patients recover better.