Anatomical And Finite Element Analysis Of The Lateral Ankle Ligaments Reconstruction Within Biomechanical Insertion

Objective: The anatomy,alignment,and position of Anterior talofiligament(ATFL)and Calcaneofibular ligament(CFL)will be explored through necropathic studies at anatomic level,through which Anterior talofiligament(ATFL)and Calcaneofibular ligament(CFL)ligament will be anatomically explored.Combined with THE THREE-DIMENSIONAL finite element analysis of ATFL and CFL,the optimal location of the fibular tract in clinical anatomic reconstruction of the lateral malleolus ligament was determined.Material and Method: 1.Fresh frozen cadaver study: anatomical observation was performed on 12 fresh frozen ankle specimens of lower limbs.(1)Palpated the position of the Inferior tip of fibula(IT)and Anterior tubrcle of fibula(AT)on the epidermis,and recorded the distance between the above two bone markers of each specimen.(2)Dissection revealed IT and AT,and measured whether the distance was consistent with epidermal palpation,and further observed Fibular obscure tubercle(FOT).(3)The joint capsule around the lateral side of the ankle joint and the fibula longus tendon and brevis tendon were cut and palpated for the following bone markers: IT,AT and FOT.The IT-AT distance was measured and compared with previous measurements.ATFL and CFL were dissected completely,and the relationship between ATFL and CFL fibula insertion center,ATFL and CFL interchange point and fibula bone markers were observed.(4)After cutting ATFL and CFL,the above bone markers were measured again.Each group of data was measured twice and averaged for further research.2.Computer simulation and finite element analysis Using normal ankle joint Magnetic Resonance Imaging MRI and Computed Tomography,The DICOM format(medical digital imaging and communication)MRI,CT image data import MIMICS17.0 software(Materialise,Leuven,Belgium).MIMICS was used to construct 3d models of bone,cartilage and ligament,including normal control model,model of reconstruction of lateral malleolar ligament with CFL fibula tunnel at ATFL fibula insertion,model of CFL fibula tunnel with fibula tunnel5 mm down the lower edge,model of CFL fibula tunnel with fibula tip.Abaqus 6.14(Dassault Systemes Simulia)was used to complete the THREE-DIMENSIONAL finite element model,and the finite element analysis was performed after the model verification.The drawer test and varus stress test before clinical examination were simulated in the model,and the talus anterior displacement and talus oblique Angle of ATFL and CFL reconstruction models were observed under different positions of fibula passage.Result:1.Bone markers: Bone markers of IT and AT could be identified by palpation in all cadvers,but FOT could not be identified by palpation in epidermis,and the presence of FOT could be found by anatomy in 70% of the specimens.ATFL ligament: of the 12 specimens,2 were double bundles of ATFL ligament and 10 were single bundles.The mean length and width of the ATFL ligaments were 17.11±2.45 mm and 7.76±2.95 mm respectively.In FOT specimens where FOT could be found,the center of ATFL fibula insertion was about3.53±1.03 mm on average from FOT.The average distance from the fibular insertion center of ATFL to the IT point was 15.10±2.34 mm.CFL ligaments: All the 12 specimens were single bundles,with an average length of 23.94±3.15 mm and an average width of 4.96±2.68 mm.CFL fibular insertion center was 4.93±2.32 mm from FOT point on average;CFL fibular insertion center was 8.35±1.91 mm away from IT point on average.The average distance between THE intersection of ATFL and CFL is about 12.37±2.26 mm from IT point.The IT-AT distance is about 30.92±2.98 mm.The distance from the intersection of the fibular insertion of the ATFL and CFL ligaments to IT and the IT-AT ratio were about 40% in all 12 specimens.2.The front drawer test was simulated in each finite element model(50N traction was added to the calcaneus).The CFL ligament and ATFL ligament had the same fibula insertion,and the CFL fibula insertion was moved down 5mm.Compared with the CFL model,the fibula insertion was closer to the normal contrast model.In the varus stress test simulated in each model(adding internal rotation moment 1.5N·mm along the longitudinal axis),the CFL ligament and ATFL ligament took the same fibula insertion,and the CFL fibula insertion was moved down 5mm.In the two models,the talus inclination Angle was 2.177° and 2.234°,respectively.Compared with the CFL model,the fibula insertion was closer to the normal contrast model.Conclusions:In chapter 1,the reference ratio of relevant anatomical structures was obtained through anatomical analysis: the ratio of the distance from the intersection of ATFL and CFL fibular insertion to IT and the distance from AT-IT was about 40%.In the second chapter,through the three-dimensional finite element analysis,it is concluded that the CFL and ATFL common fibular insertion model of the three reconstruction models of the lateral ankle ligament is more similar to the anatomy and stress distribution characteristics of the human ankle joint.Finally,combined with the results of anatomical study and finite element analysis,IT is concluded that the it-AT distance can be palpated extradermal during minimally invasive reconstruction of the lateral ankle ligament,and the fibula tunnel can be made AT the lower edge of 40% of the length of the FIbula AT IT.