Research On Foot Multi-Body Model And Hallux Valgus Orthosis Design

Hallux Valgus is a lateral displacement of the hallux at the first metatarsophalangeal joint.Hallux valgus is a complex anatomical deformity,and it is very challenging to treat.Finite element model construction and biomechanical analysis make it possible to explore the formation of hallux valgus foot and the recovery of related structural functions.In this paper,a finite element model of moderate hallux valgus foot in load-bearing neutral position was established by collecting CT image data and using computer 3D imaging technology for 3D finite element modeling to verify the effectiveness of the model.The measurement method of the Angle between the first metatarsophalangeal joint Angle and the 1-2 metatarsophalangeal joint Angle was standardized,variables were controlled,and the changes of the above two angles were observed by changing the force in turn.The stress distribution of the first metatarsal bone and the proximal phalangeal bone were analyzed.The results are as follows: The model shows that a large stress concentration occurs in the first metatarsal bone,and the distribution trend is from the medial and lateral middle of the bone,gradually decreasing to the dorsal bottom of the bone body.The reference points of the axis of the first metatarsal bone,the second metatarsal bone and the proximal phalangeal bone of the hallunion used above are feasible in finite element analysis.The horizontal force acting on the middle lateral region of the distal phalangeal bone of the first hallux toe has a direct effect on the change of the Angle of the first metatarsophalangeal joint,but the effect is not linear.The force acting on the inner capsule of the metatarsophalangeal joint mainly affects the size of the 1-2 metatarsal Angle.Horizontal forces acting on the medial and lateral sides of the proximal metatarsal bone have little effect on either Angle.Based on the experimental conclusions and data,the product design of bunion orthosis was carried out.The reverse 3D printing technology based on parameterization was used to reduce the technical requirements of the operator and improve the modeling efficiency.The product was evaluated by testing the use efficiency of the program,verifying the deviation between orthotics and foot models,and verifying the pressure between the market product and the product in this study.