Finite Element Analysis Of Stability Of Three Types Fixation Systems For Calcaneal Fractures Of Sanders Type ?

BACKGROUND: Minimally invasive treatment of calcaneal fractures was a hot topic at present.The new type of sinus approach with minimally invasive plate fixation of Sanders type ? of calcaneus fractures made great progress in the treatment of calcaneus fractures.As reported,the treatment had found the advantages of less trauma and few complications.Meanwhile,the results of finite element biomechanical analysis were consistent with those of clinical research.Some studies had reported that the minimally invasive fixation systems had early stability and good progresis in Sanders type ? calcaneal fractures.However,the data of long-term follow-up and finite element biomechanical analysis were still lacking.Finite element analysis of the minimally invasive fixation systems in Sanders type ? of calcaneus fractures would provide clinical basis for treating calcaneal fractures.METHODS: The CT data of the ankle were collected.And finite element model and finite element analysis were performed by Minics,Geomagic Studio,SolidWorks and ANASYS software.The availability of the finite element 3D model was confirmed by comparing the previous literature data,then Sanders type ? of calcaneal fractures were constructed.Three types ofinternal fixation devices were used to fix the Sanders type ? of calcaneal fractures.Researchers evaluated the stability of internal fixation devices in Sanders type ? of calcaneal fractures by the relative displacement of fracture line,internal fixation peak and peak of calcaneal with different internal fixation devices.RESULTS: Based on CT data,the three-dimensional finite element model of the ankle was established.The maximum stress in the lower surface of the humerus was 3.65 MPa when standing on one foot.The stress distribution was similar to the previous studies.These morphological data of the calcaneus were 70.31 mm in the length of calcaneus,21.41 mm in the anterior calcaneus,25.12 mm in the calcaneus and 35.53 mm in the posterior calcaneus,which were similar to the anatomical data of the normal calcaneus.Therefore,the availability of established models was demonstrated.In the finite element analysis,the locking,anatomical and minimally invasive devices maintained mechanical stability in the fixation of Sanders type ? of calcaneal fractures.The displacements of fracture were smaller than the corresponding anatomical and minimally invasive devices in Sanders type ?AB of calcaneus fractures.The maximum stress peak in the locking devices was smaller than which in anatomical device and less than the minimally invasive devices.The maximum stress of the calcaneus was similar in the three devices.There was no significant difference in the relative displacement of fracture in Sanders type ?AC of calcaneal fracture.The maximum stress in anatomical device was greater than that in locking device and the minimally invasive device,and the calcaneus stress peak was relatively close.In the Sanders type ?BC of calcaneus fracture,the relative displacement of fracture in locking device was slightly smaller than that in anatomical and minimally invasive devices,but the difference of relativedisplacement was not significant.The maximum stress in minimally invasive device was larger than that in anatomical device and locking device.The maximum stress of the calcaneus was no significant.CONCLUSION: The CT data could quickly establish the availability and mechanical distribution of three-dimensional finite element model.Three internal fixation devices could be used to fix the Sanders type ? of calcaneus fracture.The locking devices was obviously superior to anatomical and minimally invasive device in the Sanders type ?AB of calcaneal factures.There was no obvious difference in the stability of the three kinds of devices in Sanders type ?AC type and Sanders type ?BC of calcaneal factures.The reinforcement of partial stress concentration area of minimally invasive device was more favorable for its application.