The Optimum Configuration Of Unilateral External Fixator For The Definitive Treatment Of Tibia Diaphyseal Fractures:a Finite Element Analysis And Clinical Study

Objective: External fixator is widely used in the treatment of tibiofibular fractures with open or poor soft tissue conditions.However,external fixator still have many complications,so there is lack of clinical practice in the definitive treatment.This study aims to establish and analyze the model of unilateral external fixator treatment tibial diaphyseal fractures,find out the optimum configuration of unilateral external fixator,and apply it to clinical practice to verify its efficacy,so as to provide reference for the unilateral external fixator definitive treatment of tibiofibular diaphyseal fractures.Methods: CT scan was performed on a 35-year-old healthy male volunteer to establish a finite element model of the tibia and fibula.The 3cm long bone segment of the middle tibiofibular shaft was removed and made into the tibial diaphyseal fractures model.Furthermore,9 kinds of unilateral external fixator model were further made to fix the tibial diaphyseal fractures model.A 600 N longitudinal load was applied to 9 groups of models,and the maximum displacement was observed and recorded.Based on its finite element model and clinical experience,the optimum configuration of unilateral external fixator for tibial diaphyseal fractures was determined.A total of 31 patients with tibial diaphyseal fractures with poor soft tissue condition who were admitted to the trauma emergency center of the Third Hospital of Hebei Medical University between 12.2017 and 08.2019 were enrolled and treated with the optimum configuration of unilateral external fixator obtained by finite element analysis.Early functional exercise was encouraged post-operation and regular follow-up was conducted.We using the Visual Analogue Scale(VAS)to assessed the pian that before surgery,3 days and one month post-operation.During the follow-up,LEFS lower limb function score and Johner-Wruh tibial diaphyseal fractures efficacy score were used to evaluate the function.Statistical analysis was performed using SPSS software.Results: The mean age of the 31 patients was 36.5±12.9 years(19-63years),and the mean length of hospital stay was 7.3±2.3 days(4-12 days).The mean follow-up time was 25.2±5.7 months(16-36 months).There were23 closed fractures and 8 Gustilo type I open fractures.The rate of pin track infection was 12.9%(4 cases),and the rate of reoperation was 3.2%(1 case).The patients walked without crutches post-operation,and the clinical healing time was 3.0±0.85 months(2-5 months).The average VAS score of the patients 3 days after surgery was 3.8±1.2,significantly lower than the preoperative score of 7.1±1.3,and 1.0±1.2 one month after surgery,which was again significantly lower than the score 3 days after surgery,and the difference was statistically significant.The LEFs scores of patients 3,6 and 12 months after surgery were 35.5±9.7,59.5±4.2 and 75.2±3.7,respectively,and the difference was statistically significant.According to the Johner-Wruh system,27 cases(87.1%)were excellent and 4 cases(12.9%)were good.Conclusions: Using unilateral external fixator with reasonable configuration definitive treatment of tibiofibular fractures,which is characterized by small trauma,reliable fixation,no need for second operation and early functional exercise.It is the ultimate safe and effective choice for the treatment of tibiofibular fractures.