Background The acetabular teardrop is often used to guide acetabular component placement in total hip arthroplasty （THA）.Placing the lower acetabular component aspect at the same level as the lower teardrop edge was...Background The acetabular teardrop is often used to guide acetabular component placement in total hip arthroplasty （THA）.Placing the lower acetabular component aspect at the same level as the lower teardrop edge was assumed to restore the hip center of rotation.Here we radiographically analyzed the relationship between cup center and normal contralateral acetabulum center height on unilateral THA using this placement method.Methods A total of 106 unilateral THA cases with normal contralateral acetabula were reviewed and the vertical and horizontal distances in relation to the lower acetabular teardrop edge from both hip joint centers,cup inclination,and anteversion were measured radiographically.The paired t-test was used to compare left and right hip center heights.Scatter plots and Pearson＇s correlation coefficients were used to evaluate differences in hip center heights,cup anteversion,inclination angles,and medialized cup center distance compared to the contralateral hip joint.Results Cup center height was significantly greater （P ＜0.01） than contralateral hip joint center height （93.4％ in the 0-5 mm range,6.6％ ＞5 mm）.There was a weak correlation between hip center height difference and inclination （r=0.376,P ＜0.01） and between difference and anteversion （r=0.310,P ＜0.01） but no correlation between difference and outer cup diameter （r=0.184,P=0.058） or difference and medialized cup center distance （r＝-0.098,P=0.318）.Conclusions Although this method did not exactly replicate anatomic hip center height,the clinical significance of cup center height and anatomic hip center height differences is negligible.This acetabular component placement method has high simplicity,reliability,and stability.展开更多
Firstly, in view of the respective defects of existing self-centering devices for vehicle suspension height, the design scheme of the proposed mechanical self-centering device for suspension height is described. Takin...Firstly, in view of the respective defects of existing self-centering devices for vehicle suspension height, the design scheme of the proposed mechanical self-centering device for suspension height is described. Taking the rear suspension of a certain light bus as a research example, the structures and parameters of the novel device are designed and ascertained. Then, the road excitation models, the performance evaluation indexes and the half-vehicle model are built, the simulation outputs of time and frequency domain are obtained with the road excitations of random and pulse by using MATLAB/Simulink software. So the main characteristics of the self-centering suspension are presented preliminarily. Finally, a multi-objective parameter design optimization model for the self-centering device is built by weighted sum approach, and optimal solution is obtained by adopting complex approach. The relevant choosing-type parameters for self-centering device components are deduced by using discrete variable optimal method, and the optimal results are verified and analyzed. So the performance potentials of the self-centering device are exerted fully in condition of ensuring overall suspension performances.展开更多
目的:使用CT联合Mimics软件测量全髋关节置换术(total hip arthroplasty,THA)后股骨偏心距(femoral offset,FO)、旋转中心高度(rotation center height,RCH)与双下肢长度差(lower leg length discrepancy,LLD),并探讨THA后FO、RCH与LLD...目的:使用CT联合Mimics软件测量全髋关节置换术(total hip arthroplasty,THA)后股骨偏心距(femoral offset,FO)、旋转中心高度(rotation center height,RCH)与双下肢长度差(lower leg length discrepancy,LLD),并探讨THA后FO、RCH与LLD的关系。方法:回顾性分析2020年10月至2022年6月符合标准的40例行单侧THA的患者,其中男21例,女19例;年龄30~81(58.90±14.13)岁;身体质量指数(body mass index,BMI)为17.3~31.5(25.3±3.4)kg·m^(-2);左侧18例,右侧22例。诊断为股骨头坏死30例(FicatⅣ期),髋关节骨性关节炎2例(TünnisⅢ期),发育性髋关节脱位合并终末期骨关节炎2例(CroweⅢ期),股骨颈骨折6例(GardenⅣ期)。术前、术后拍摄骨盆CT三维重建,经Mimics软件处理后建立三维重建模型,在模型上对FO、RCH、LLD进行测量。结果:术后双侧FO差值与LLD呈正相关性(r=0.744,P<0.001);将FO重建组与偏心距未重建组进行卡方检验得出:FO重建组下肢等长率高于FO未重建组(χ^(2)=6.320,P=0.012)。术后双侧RCH差值与LLD呈负相关性(r=-0.877,P<0.001);双侧FO差值及双侧RCH差值与术后LLD之间存在线性关系,且满足线性回归方程:术后LLD=0.038x-0.099y+0.257(x为术后双侧FO差值;y为术后双侧RCH差值;单位为cm),F=77.993,R2=0.808,P=0.009。结论:THA术后LLD随着FO的增大而增大,随着RCH增大而减小;重建FO更易获得下肢等长效果。THA术后双侧FO差值及双侧RCH差值与LLD之间存在线性关系,回归方程可为判断LLD提供一种理论参考。展开更多
文摘Background The acetabular teardrop is often used to guide acetabular component placement in total hip arthroplasty （THA）.Placing the lower acetabular component aspect at the same level as the lower teardrop edge was assumed to restore the hip center of rotation.Here we radiographically analyzed the relationship between cup center and normal contralateral acetabulum center height on unilateral THA using this placement method.Methods A total of 106 unilateral THA cases with normal contralateral acetabula were reviewed and the vertical and horizontal distances in relation to the lower acetabular teardrop edge from both hip joint centers,cup inclination,and anteversion were measured radiographically.The paired t-test was used to compare left and right hip center heights.Scatter plots and Pearson＇s correlation coefficients were used to evaluate differences in hip center heights,cup anteversion,inclination angles,and medialized cup center distance compared to the contralateral hip joint.Results Cup center height was significantly greater （P ＜0.01） than contralateral hip joint center height （93.4％ in the 0-5 mm range,6.6％ ＞5 mm）.There was a weak correlation between hip center height difference and inclination （r=0.376,P ＜0.01） and between difference and anteversion （r=0.310,P ＜0.01） but no correlation between difference and outer cup diameter （r=0.184,P=0.058） or difference and medialized cup center distance （r＝-0.098,P=0.318）.Conclusions Although this method did not exactly replicate anatomic hip center height,the clinical significance of cup center height and anatomic hip center height differences is negligible.This acetabular component placement method has high simplicity,reliability,and stability.
基金supported by Youth Technological Phosphor Project of Shanghai City (No.04QMX1474).
文摘Firstly, in view of the respective defects of existing self-centering devices for vehicle suspension height, the design scheme of the proposed mechanical self-centering device for suspension height is described. Taking the rear suspension of a certain light bus as a research example, the structures and parameters of the novel device are designed and ascertained. Then, the road excitation models, the performance evaluation indexes and the half-vehicle model are built, the simulation outputs of time and frequency domain are obtained with the road excitations of random and pulse by using MATLAB/Simulink software. So the main characteristics of the self-centering suspension are presented preliminarily. Finally, a multi-objective parameter design optimization model for the self-centering device is built by weighted sum approach, and optimal solution is obtained by adopting complex approach. The relevant choosing-type parameters for self-centering device components are deduced by using discrete variable optimal method, and the optimal results are verified and analyzed. So the performance potentials of the self-centering device are exerted fully in condition of ensuring overall suspension performances.
文摘目的:使用CT联合Mimics软件测量全髋关节置换术(total hip arthroplasty,THA)后股骨偏心距(femoral offset,FO)、旋转中心高度(rotation center height,RCH)与双下肢长度差(lower leg length discrepancy,LLD),并探讨THA后FO、RCH与LLD的关系。方法:回顾性分析2020年10月至2022年6月符合标准的40例行单侧THA的患者,其中男21例,女19例;年龄30~81(58.90±14.13)岁;身体质量指数(body mass index,BMI)为17.3~31.5(25.3±3.4)kg·m^(-2);左侧18例,右侧22例。诊断为股骨头坏死30例(FicatⅣ期),髋关节骨性关节炎2例(TünnisⅢ期),发育性髋关节脱位合并终末期骨关节炎2例(CroweⅢ期),股骨颈骨折6例(GardenⅣ期)。术前、术后拍摄骨盆CT三维重建,经Mimics软件处理后建立三维重建模型,在模型上对FO、RCH、LLD进行测量。结果:术后双侧FO差值与LLD呈正相关性(r=0.744,P<0.001);将FO重建组与偏心距未重建组进行卡方检验得出:FO重建组下肢等长率高于FO未重建组(χ^(2)=6.320,P=0.012)。术后双侧RCH差值与LLD呈负相关性(r=-0.877,P<0.001);双侧FO差值及双侧RCH差值与术后LLD之间存在线性关系,且满足线性回归方程:术后LLD=0.038x-0.099y+0.257(x为术后双侧FO差值;y为术后双侧RCH差值;单位为cm),F=77.993,R2=0.808,P=0.009。结论:THA术后LLD随着FO的增大而增大,随着RCH增大而减小;重建FO更易获得下肢等长效果。THA术后双侧FO差值及双侧RCH差值与LLD之间存在线性关系,回归方程可为判断LLD提供一种理论参考。
