背景:准确描述股骨近端形态特征对髋关节假体设计和假体置入十分关键。目的:基于逆向工程技术,对股骨近端形态参数描述股骨近端形态时产生的误差(简称股骨近端形态参数误差)进行有效分析。方法:基于Mimics软件、Imageware软件,对1例25岁女性健侧髋关节的股骨近端形态参数进行测量、逆向建模,并利用Imageware中差异分析命令进行相关的曲线-点云及曲面-点云差异的计算与分析。结果与结论:该例股骨基于股骨近端形态参数逆向建模后模型与人体股骨点云的整体差异为(1.29±0.99)mm,其中外壁的匹配误差占70.43%,髓腔占21.46%,股骨头占8.11%。股骨近端形态参数误差存在于以下方面:股骨头并不是标准球形;股骨干5个平面皮质骨内、外壁交线简单地认为是圆,或者认为是长短轴方向不变的椭圆;忽视小转子的几何特征的测量。提出以下改进意见:应在测量长短轴长度的同时,补充测量长短轴与正位片平面的夹角;增加小转子几何特征的测量。
BACKGROUND:Accurately describing the proximal femur morphology is very critical to the design and implantation of prosthesis.OBJECTIVE:Based on reverse engineering,this paper tried to analyze the error generated when the proximal femoral morphological parameters describe the morphology of the proximal femur(Proximal femoral morphological parameters Error),classify the areas generating proximal femoral morphological parameters error,and give suggestions for improvement.METHODS:Mimics and Imageware were used to measure the morphological parameters of a 25-year-old female's healthy hip to establish a model based on the parameters reversely.The commands "Curve-Cloud Difference" and "Surface to Cloud Difference" were used to analyze the proximal femoral morphological parameters error.RESULTS AND CONCLUSION:The overall proximal femoral morphological parameters error of this female femoral was(1.29±0.99) mm.Among the error,the out surface of the femoral shaft's matching error accounted for 70.43%,medullary cavity accounted for 21.46%,and the femoral head only accounted for 8.11%.The proximal femoral morphological parameters error existed in the following areas:the femoral head was not standard sphere;the intersecting curves between the five planes near the small rotor and the cortical bone surface was not simply circle or ellipse with same axis directions;the measurement of the small rotor's geometrical characteristics was also neglected.Improvements are as follows:researchers should measure both the length of the axes and the angle between the axes and the anteroposterior plane;researchers should also take more attention in measuring the geometrical characteristics of the rotor.