| 1.Background and ObjectiveGait cycle refers to the normal walking or running,the same side of the foot from the heel to the front foot off the ground-the air swing until the heel again to the ground.The transverse bow of the forefoot supports the normal standing and walking of human beings,participates in the construction of the function of the sole,and plays a key role in the gait cycle of the whole action.The results show that according to gait system,there are some rules for the normal plantar foot pressure,which decreases from the inner(first metatarsal head)to the fifth metatarsal head.The change of the distribution of foot pressure is a signal of the change of the foot structure,which will break the whole foot biomechanical state and affect the whole gait cycle and even the normal walking process.The common diseases in the foot ankle clinic are hallux valgus combined with metatarsal pain and metastatic metatarsal pain after the operation of thumb valgus.The main pathological manifestations are the formation of corpus callosum and the pain under the metatarsal head.Because of the genetic hallux valgus deformity,the transverse arch of the forefoot collapsed or the acquired medical factors caused the arch structure change,which increased the load of the front foot and the foot pressure was concentrated under the local metatarsal head.In recent years,because of the large traditional open operation,complex process and long recovery period,the minimally invasive treatment of thumb valgus is widely accepted.This operation mainly includes five steps,i It is normal again,thus correcting the deformity.Therefore,when the deformity of thumb valgus is corrected by manual reconstruction after the micro bit osteotomy,the shortening and displacement distance of the distal metatarsal should be controlled as far as possible according to the length of the first metatarsal bone.There is no quantitative index research on the displacement distance in the current study.In order to meet the clinical needs,when we strengthen the displacement research of minimally invasive osteotomy end in the gait cycle,determine the specific quantitative relationship,and realize scientific,standardized and accurate medical treatment.2.MethodA volunteer patient with thumb valgus combined with plantar pain was selected to construct a finite element model before and after the operation of thumb valgus with minimally invasive treatment of thumb valgus by using the finite element three-dimensional software such as MIMIS,rapidform xor364 and ABAQUS.Two volunteers with hallux valgus were selected,one of them was the patients with thumb valgus and metatarsal pain,and the plantar pain was cured after operation.The dynamic test of plantar pressure before and after operation was carried out by using the six dimensional force measuring platform acquisition and analysis system of Elli.The data after gait test were compared with the finite element model constructed to verify the validity of the finite element model;the results showed that the model was effective;the results showed that the model was effective;the results showed that the model was effective;the results showed that the model was effective;the results showed that the model was effective The operation steps of minimally invasive treatment of thumb valgus were simulated in the pre operation finite element model.The distal end of the first metatarsal head after osteotomy was corrected from inside to outside,from top to bottom,and the displacement unit was defined as 2mm,and the final displacement distance was Omm,2mm,4mm and 6mm.The stress data of the amputated end and each metatarsal head during the gait cycle were collected and analyzed.The quantitative relationship between the vertical displacement and horizontal displacement and the stress changes of the first and second metatarsal heads was determined.The relationship between the pressure change of the first and second metatarsal head in the gait cycle and the occurrence of the postoperative metastatic metatarsal pain was analyzed,and the accurate displacement quantitative index was obtained.3.ResultIn this study,the simulation finite element model of bone cartilage and soft tissue of the whole foot of thumb valgus and metatarsal pain was established.At the same time,the stress,strain model and dynamic process support phase of the whole foot after the operation of thumb valgus were simulated.The finite element model of the end stage of the support phase of the abduction of thumb with metatarsal pain includes 80 independent models,namely tarsal,metatarsal,phalangeal,articular cartilage and tendon ligament.There are 610861 units and 173618 nodes in the end stage of the support phase of the sup.The results of the finite element model analysis based on the end of dynamic simulation of thumb valgus and plantar pain show that there is a linear correlation between the displacement of the distal end of the first metatarsal osteotomy and the lateral metatarsal head:when the horizontal displacement is fixed,the vertical displacement increases,but the distal end of the osteotomy(the lower pressure of the first metatarsal head)increases gradually,but the pressure under the second metatarsal head decreases accordingly Light.The results show that when the horizontal displacement is fixed at 0mm,the change of vertical displacement is the most correlated with the change of distal section(pressure under the first metatarsal head),R value is 0.873;the change of pressure under the second metatarsal head is moderately negative,R value is-0.650;when the horizontal displacement is 2mm-6mm,the change of vertical displacement is related to the pressure change of the first metatarsal head.R The results showed that the values were 0.912,0.987 and 0.799 in turn;when the horizontal displacement was between 4mm and 6mm,the change of vertical displacement was highly correlated with the pressure change of the second metatarsal head,and the R value was-0.811 and-0.699(when the horizontal displacement was 2mm,the lower pressure of the second metatarsal head had no obvious correlation with the vertical displacement).In the same case,when the vertical displacement changes dynamically(0-6mm),the dynamic increase of horizontal displacement is significantly related to the pressure relationship under the first metatarsal head,and the pressure of the corresponding position of the second metatarsal head decreases in turn;in the end of the supporting phase,when the vertical displacement is fixed to 4mm,the increase of horizontal displacement is the highest in order with the pressure change of the distal end of the osteotomy(under the first metatarsal head),The highest R value was 0.981 and-0.890.When the vertical displacement is certain,the other data(0mm and 4mm)have obvious correlation with the increase of horizontal displacement.The R value is 0.826 and 0.930 respectively with the lower stress of the first metatarsal bone,which is negatively correlated with the stress under the second metatarsal head,and the specific R values are-0.581 and-0.512.When the vertical displacement is 4mm,the stress under the first metatarsal head increases with the increase of horizontal displacement.On the contrary,the pressure under the second metatarsal head decreases,and both of them have a high correlation with the horizontal displacement,R values are 0.981 and-0.890;meanwhile,the pressure x of the distal end of the osteotomy(under the first metatarsal head)is the highest with the corresponding pressure y of the second metatarsal head,and the R value is the highest-0.830,the quantitative relation equation is y=-0.4528x+0.4159;when the horizontal displacement is 4mm,the vertical displacement increases,the pressure x of the distal end of the osteotomy(under the first metatarsal head)is negative,the R value is-0.894,and the quantitative relationship is y=-0.6504x+0.5232.4.ConclusionIn gait cycle,the displacement of the osteotomy end of thumb with minimally invasive treatment with traditional Chinese and Western medicine has a linear relationship with the occurrence of metatarsal pain.When the displacement of the distal end of the first metatarsal bone is 4mm and 4mm,the deformity of thumb valgus can be corrected,and the incidence of metatarsal pain is significantly reduced. |
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