A Finite Element Study On The Effect Of Adductor Active Response On The Fracture Behavior Of Elderly Hip Fracture With Pixu(Spleen Deficiency Pattern)

Objective1.To analyze the causes of different hip fracture types by clinical retrospective study on the incidence of femoral neck fractures and intertrochanteric fractures in different age groups.Then to put forward the idea that the active contraction response of adductor group in lower extremity can change the idea of fracture type.Furthermore,the relationship between the theory and the theory of "spleen charges muscle" in Chinese medicine to be further analyzed.2.Through the finite element method,to prove that the change of the fall position caused by The active contraction of the single functional muscle group in the thigh is of great influence on the occurrence of different hip fractures which are with the imbalance of lower extremity muscle strength when pixu(spleen deficiency pattern)occurs,and provide experimental reference for the mechanism and prevention of hip fracture.Methods1.Clinical research:Collected the total of 268 patients with hip fracture whom were hospitalized in the first affiliated hospital of guangzhou university of traditional Chinese medicine(age > 50 years)from January 1st,2012 to December 30 th,2013,grouped by age groups(every 10 years is an age group).SPSS20.0 software was used to analyze the occurrence rate of fractures in patients with hip fracture of all ages and two different types of hip fractures,then the major fracture types were analyzed,patients with spleen qi deficiency were screened out(referred to the spleen qi deficiency diagnostic criteria)and their age distribution were analyzed.The agedistribution of patients with spleen qi deficiency was analyzed.Ultimately,based on the theory of "spleen charges muscle",put forward the idea that in the imbalance of lower extremity muscle strength,the changing of fall posture caused by the active contraction of adductor muscle group may be the result of different types of hip fracture when pixu(spleen deficiency pattern)occurs.2.Experimental study:(1)Collected the CT images of a normal male volunteer,and established a three-dimensional model of the hip bone through the software of Mimics19.0 and Geomagic studio 2013,then imported it to the Hypermesh 14.0 software for material assignment and parameter setting.(2)Based on the muscle model provided by the national key laboratory of automobile body advanced design and manufacturing of hunan university,the human muscle characteristic curve was added to establish the active adductor muscle model in the thigh.(3)The muscle finite element model was matched with the volunteers' hip bone model in the Hypermesh 14.0 software then simulated the contraction of adductor muscles caused the odduction of the femoral in the imbalance of lower extremity muscle strength.(4)A three-dimensional model of uninjured side proximal femoral was established by Mimics19.0 by using the CT image of the hip fracture of a qualified elderly patients with femoral neck fracture.Geomagic studio 2013 software was used to model smooth processing.In the Hypermesh 14.0 software,two different material assignment and parameter setting were performed,then set the boundary conditions and load,finally established the proximal femoral finite element model A.Simulated adductor contraction caused proximal femur,Hypermesh 14.0 set the adduction Angle to5 °,then model B was established without changing other model parameters.The two models were imported into LS-DYNA software for calculation to observe the fracture initiation site and fracture line trend of the two models,and the stress distribution of the model Von-Mises.Results1.The number of fractures in the five age groups between 50 and 100 years old was counted and tested the difference of fracture in different age groups by using Chi-square test.The test displayed Chi-square value was18.712(P=0.001<0.010).It showed that the difference of fracture between different age groups was statistically significant.Among them,the femoral neck fracture mainly occurred in the 70~80 age group,with 49 cases(37.4%),intertrochanteric fractures mainly occurred in the age of 80~90,with 63 cases(45.99%).The incidence of femoral neck fracture between 50~79 years is higher than that of intertrochanteric fractur;the incidence rate of intertrochanteric fracture between 80~100 years is higher than that of femoral neck fracture with the chi-square value 17.087(P<0.05).Along our spleen deficiency syndrome screening,in all 268 cases of hip fracture patients,the spleen deficiency syndrome was more common,with 201 cases and 75% overall detection rate.Meanwhile,the detection rate of spleen deficiency syndrome was positively correlated with age.Among them,there were 100 cases of spleen deficiency syndrome in 50 to 79 years of age,and the detection rate was 65%.In the 80-100 year age group,101 cases were diagnosed with spleen deficiency syndrome,and the detection rate was 89%,with the chi-square value was 19.560,P< 0.05.2.The muscle finite element model and the combined operation of the hip bone model of the volunteers successfully simulated the contraction of adductor muscles caused the odduction of the femoral.3.After calculation,the maximum stress distribution of model A and B is concentrated in the lower part of the neck of the femur,The upper part of the femoral tuberosity and the medial side of the femoral shaft.Under sustained load,the medial side of the femoral neck in model A first appeared stress failured,finally formed type Garden ? fractures.The tuberosity in model A first appeared stress failured,eventually formed A1.2 type fractures.Conclusions1.The muscle active response model has a good contractile characteristic,which can provide a certain experimental basis for the in-depth study of the influence of the functional muscle group on the hip fracture.2.The change of the fall position caused by the active contraction lead by the adductor muscle in the olderly may be the important reason for the different types of hip fracture after the fall of the elderly follow the pixu(spleen deficiency pattern).3.The elderly patients with pixu(spleen deficiency pattern)have weaker Lower limb strength and poorer balance,cause their muscle strength of each functional muscle group is obviously unbalanced.Thus,they have more trendency to fall down and cause hip fracture.These provide a new idea for the prevention and treatment of the elderly hip fracture.