Multi-body System Modeling Of Hallux Valgus Foot And Optimal Design Of Orthoses

Hallux valgus is a complex anatomical deformity that can be difficult to treat.The number of bones in the foot is 52,which is a quarter of the total number of bones in the human body.The hallux valgus sick foot model presents the characteristics of complex coupling relationship and unsteady mechanical properties of multi-tissue motion cycle.The early treatment of hallux valgus can effectively reduce the pain of patients,and the hallux valgus orthosis can effectively correct the angle of the phalange,compensate for part of the muscle function,and insist on wearing it to achieve the orthopedic effect.However,the current hallux valgus orthosis has the problems of bulky and complex appearance,far-fetched orthopedic principle,and unscientific design of human-machine contact surface,which leads to patients subjectively not being satisfied with the appearance of the orthosis,and it is easy to produce pain,redness and swelling when wearing.Chapter 3: Obtaining foot data of a volunteer with moderate hallux valgus through CT thin-slice scanning,and jointly modeling Mimics,Geomagic,SW,and Ansys software to establish a foot heterogeneous multibody system model including foot bones,ligaments,soft tissues and skin for finite element simulation.Chapter 4 is based on the principle of three-point force orthopedics to simulate the profit and loss compensation combination force of the orthosis,first determine the initial force range of the distal phalange,the top of the proximal metatarsal and the base of the proximal metatarsal,and then divide the position of the orthopedic force,use orthogonal optimization analysis to improve the screening efficiency of the scheme,and record the hallux valgus angle(HVA),intermetatarsal angle(IMA),deformation of the first metatarsal and proximal phalange,Von-mise and other effect force data of each scheme.The best orthopedic option is determined by protocol comparison.Chapter 5 introduces the design of human-machine contact surfaces,which directly determines the comfort of the orthosis.Traditional orthoses believe that the best orthopedic surface is the shape of the human body,so directly use the surface scanning method to obtain the contact surface shape in reverse,this study establishes a body pressure mapping function,which can determine the contour of the human-machine contact surface by quantifying the pressure and deformation data.Then combine the design elements of the orthosis in combination with the CMF elements to customize an orthosis.Chapter 6 combines surface electromyography and VAS visual evaluation scale to evaluate the subjective and objective customized effect of orthoses.The results showed that the slope of the extensor pollicis breve MPF-t in the modified group was smaller than that in the control group,and the fluctuation of i EMG in the modified group was generally smaller than that in the control group,and the peak fatigue was smaller,reflecting better comfort.The research results of this project will provide theoretical research support and basic technical support for the research and development of foot orthotic devices including hallux valgus orthosis.