The Study Of DXA Bone Strength Measurement Based On 3D Printed Human Proximal Femur Model

Objective The three-dimensional(3D)printed human proximal femoral model can reproduce the complex three-dimensional spatial structure of the proximal femur,and the series of parameters of macroscopic structural which obtained from DXA(Dual-energy X-ray absorptiometry)HSA(hip strength analysis)measurement,can reflect bone strength of proximal femur to some extent.In this study,DXA measurements and mechanical destruction experiments were performed on in vitro rabbit femurs and plaster 3D printed rabbit femur models.On the basis of understanding the degree of conformity between the mechanical strength of 3D printed rabbit bone model and the mechanical strength of the in vitro rabbit femur,the 3D printed human proximal femur model was used to simulate the subjects' femurs for DXA HSA measurements and mechanical destruction experiments,in order to provide an objective basis for the feasibility of the human bone model as an in vitro model for DXA HSA quality control measurements and understand how well the human femur mechanical strength can be simulated by the bone strength measurements.Methods(1)Using plaster as raw material,according to CT scan data of 5 New Zealand rabbits,10 3D printed rabbit femur models were made.The 3D printed rabbit femur models and the in vitro rabbit femur were subjected to DXA HSA measurements and mechanical disruption experiments.(2)According to 6 subjects' hips CT scan data,13 3D printed human proximal femur models were made,5 of these 3D printed Models of human Proximal Femur were based on the same subject's CT scan data,for reproducibility testing of the 3D printed models;the remaining 8 different human bone models were used for DXA HSA precision testing.(3)DXA HSA measurements and mechanical destruction experiments were performed on 8 different proximal femur models,correlations were calculated between corresponding subjects' DXA HSA parameters and human proximal femur models' DXA HSA parameters,also compared two sets of parameters.Results(1)There is a positive correlation between the DXA HSA parameters of the rabbit femur [CSA,CSMI,SM] and the bone strength results(maximum load)of the destruction experiment(r= 0.723 ~ 0.882,P<0.05);There was a positive correlation between the DXA HSA parameters(CSA,CSMI,SM)and the bone strength results(maximum load)of the destruction experiment in the rabbit bone model(r= 0.829 to 0.856,P<0.05).(2)The CV% values of DXA HSA parameters and partial destruction experimental bone strength related results of 5 human bone models of the same subject were less than 5%;The 3D printing of the proximal femur model "bone mineral density" and bone strength related parameters with RMS-CV% of 1.88% ~ 2.94%.The least significant change was 0.052 ~ 0.082.(3)The result of DXA HSA measurements showed that there was a high correlation between proximal femoral HSA parameters and proximal femur HSA parameters(r= 0.719 ~ 0.914,P<0.05).The results of the human femur model mechanical test were positively correlated with the DXA HSA parameter results(r= 0.767 ~ 0.831,P<0.05).Conclusions(1)The rabbit femoral model made by 3D printing technology can reflect the true bone strength of rabbit bone.(2)The DXA HSA measurement precision of the human proximal femur models is similar to the subjects' DXA HSA measurement precision,and the DXA HSA parameters of the 3D printed human proximal femur models had a good correlation with the subjects',demonstrated the 3D printed human proximal femur model has the feasibility of being a measurement quality control model needed for clinical DXA HSA measurement and analysis.(3)The 3D printed human proximal femur model can simulate the level of the subject proximal femur bone strength measurement.