The Biomechanics Research And Establishment Of Finite Element Model Of Human Foot And Ankle

Background and purpose:With the develop of the society and the improved the notion of the health,there are increasing in morbidity of the ankle. in everyday life, The normal biomechanics of the ankle is related with the plantar pressure buffer, weight and walking. Ankle joint is key position for the contact between body and land.There are many activitises which need the help of the ankle joint including walking jumping,running and climbing.Therefor,the ankle joint is one of the easiest injuried joints.In clinic, the mechanics of the ankle is complex.All kinds of injury can destroy the balance of the mechanics of ankle joint lead to instability and arthritis.The abnormity of the ankle not only results to ache and impaired mobility but also affect normal function of the lower extremity, pelvis and spine.Hence,it is important for clinic to research these.It is long time for us to research the ankle.Many researchers think that it is important for the illness of ankle to search the normal biomechanics of the ankle.In generally,people research ankle by traditional experiment while with the development of computers, we can use three-dimensional modelling software by the computer for clinic research.The finite element model of ankle can quantize internal organization of ankle including stress,strain, dislocation and tension.Howeve these information cannot be measured in vivo easily which is necessary for clinical medicine and rehabilitation medicine.So, The finite element is obligato for the biomechanics.People concern about the normal biomechanics of the ankle for a long time. Although we have been abtained many research results.there are many problems needed to be resolved. This study based researches previously not only explores the percentage of average plantar force borne by the forefoot and hindfoot regions and the contact mechanics and pressure distribution of the tibiotalar joint in the period of support under different Achilles tensile loads but also explore the ways of effective construction the finite element model of the ankle in order to build foundation for ankle biomechanics.Our resreach includes the following three parts:Objective:To explor the percentage of average plantar force borne by the forefoot and hindfoot regions in the period of support under different Achilles tensile loads.Methods:six fresh frozen human below-knee specimens were used and were placed on the material testing machine.350N axial load was added using material testing machine making sure that the ankles were in neutral position at all time.Achilles tensile loads varied from Okg to80kg (ON、100N、200N、300N、400N、500N、600N、700N、800N)were applied by weights.we recorded the results of plantar pressure distribution between the forefoot and hindfoot with increasing Achilles tensile force by scales.The one was under the forefoot of the specimen, and the other under the rearfoot.Results: Increasing Achilles tensile force from0to80kg,the percentage of plantar force borne by the forefoot increased with Achilles tensile force, while that borne by the hindfoot decreased. As the force was increased on the Achilles tendon, the percentage of average plantar force borne by the forefoot and Achilles tensile force was linear. The similar results appeared in rearfoot (P=0.000,R2=0.996)Conclusions:The percentage of average plantar force borne by the forefoot and hindfoot regions in the period of support under different Achilles tensile loads is simulated by the fresh human specimens in vitro which can provide theory evidence for some diseases(diabetic foot ulcers,metatarsalgia, plantar fasciitis) caused due to Achilles tensile contractures.Objective:To explor the contact mechanics and pressure distribution of the tibiotalar joint in the period of support under different Achilles tensile loads.Methods:six fresh frozen human below-knee specimens with the implanted sensors were used and were placed on the material testing machine.350N axial load was added using material testing machine making sure that the ankles were in neutral position at all time. Achilles tensile loads varied from0kg to60kg (0N、100N、200N、300N、400N、500N、600N) were applied by weights.we recorded the results of the contact mechanics and pressure distribution of tibiotalar joint with increasing Achilles tensile force.Results:Increasing Achilles tensile force from0to60kg, the contact force and average pressure of tibiotalar joint increased with Achilles tensile force, while contact area increased slow and peak stress varied little.Conclusions:the contact mechanics and pressure distribution of the tibiotalar joint in the period of support under different Achilles tensile loads is simulated by the fresh human specimens in vitro which can strengthen the understand of the biomechanics of the ankle and provide theory evidence for the care of ankle and function rehabilitation after surgery.Objective:To establish a three-dimensional finite element model of huaman ankle with intact bones and ligaments structure to provide a digital platform for ankle joint biomechanics research.Methods:Right foot of a normal young man was scanned by CT. Mimics software was used to reconstruct the3D structure of bones and external soft tissue, after processing by FreeForm importing to ANSYS, the three-dimensional finite element model ankle model was developed and meshed. Meanwhile, an articular cartilage, ligaments, crural interosse-ousmembrane were simulated in the model according to literature reviews.Results:A three-dimensional finite element model model of normal human right ankle joint including bones and soft tissue were established. Conclusion:The finite element model ankle model is established with complete structures, which can be the basic of the biomechanics research of human ankle.