Biomechanical Study Of The Unilateral External Fixation For Tibial Fracture

Tibia is one of the most important skeletons in human lower limbs,which can bear the function of movement and load-bearing.Tibial fracture will cause great inconvenience to patients.The treatment of tibial fracture mainly includes internal fixation and external fixation,and doctors usually use clinical experience to formulate the operation plan.External fixation is commonly used in infectious fractures,open fractures,multi segment fractures and fractures that cannot be fixed by other methods due to severe comminuted fractures.When the treatment plan is not reasonable,it will lead to loosening,fracture,nail infection and other risks.In order to solve this problem,this paper combines reverse engineering,3D printing technology,experiment and numerical simulation to study the biomechanical properties of the external fixation system under static and dynamic conditions when unilateral external fixation is used to treat tibial shaft fractures.Reverse engineering and 3D printing technology were used to reconstruct the 1:1tibial fracture model of fracture patients.XTDIC three-dimensional full field deformation measurement system was used to measure the overall deformation of Orthofix unilateral external fixator.The results showed that when the position of Schanz nail on the clip was1,2,3,the distance from the lateral Schanz nail to the fracture end was 120 mm,and the distance from the external fixator to the tibia was 30 mm,it was the best scheme,and the stiffness of the external fixator was the largest,and the stiffness of the external fixator was the better.The position of Schanz nail on the clip,the distance from the lateral Schanz nail to the fracture end and the distance from the external fixator to the tibia all affect the deformation and stiffness of Schanz nail,and the distance from the external fixator to the tibia has the most significant effect.Objective to analyze the rehabilitation stage of patients with tibial fracture,and simulate the gait of patients in different rehabilitation stages for biomechanical research.The purpose of this study is to determine the stability of the external fixation system under gait condition by comparing the stress of Schanz nail and the stress of tibial nail in different stages of external fixation of tibial fracture.The maximum stress distribution of unilateral external fixator in the fixation of tibial shaft fracture and the maximum stress distribution of nail placement from large to small were: the neutral phase was the largest,and the ground phase was the smallest.The stress concentration area of the tibia was distributed around the hole of the screw placement;The stress concentration area of Schanz nail was around the interface between tibia and external fixator.The static analysis of tibial external fixation model showed that the fatigue life of external fixator increased with the increase of the number of Schanz nails when the same cyclic load was applied to the external fixator with different number of Schanz nails.With the increase of cyclic load,the fatigue life of Schanz nail decreases,and the fatigue failure is most likely to occur near the tibia.When the distance between tibia and external fixator increased,the stress of Schanz nail increased and the fatigue life of external fixator decreased.