股骨远端关节面几何学特征在人工关节设计中的意义

Geometric characters of distal femu r and knee prosthesis design

目的从几何学角度分析正常国人股骨远端关节面特征,探讨与膝关节运动学的关系及其在人工膝关节假体设计中的意义。方法收集10具尸体膝关节标本进行解剖,通过内外上髁轴钻孔后进行MR检查,同时收集20例正常成人志愿者膝关节MR图像资料。以几何学最小二乘法分析正常志愿者及尸体膝关节标本的股骨远端关节面特征,同时测量尸体膝关节标本通过内外上髁的钻孔与股骨远端关节面之间的关系。结果矢状位关节面拟合后得到股骨内外髁远端及后髁关节面相切的两个圆弧,钻孔通过滑车部位后十字韧带止点附近。经统计学分析,内外侧后髁圆弧半径及关节面圆弧半径之间比较差异无显著性意义(P>0.05);远端外髁关节面半径大于远端内髁(P<0.01),但内侧远端关节面弧度远远大于外侧(P<0.01);内髁远端曲面半径与内侧后髁曲面半径之比为1.89,外髁远端曲面半径与外侧后髁曲面半径之比为2.01,二者之间接近倍数关系。相关性检验显示内侧髁远端关节面半径与内侧后髁关节面半径有明显相关(r=0.814,P<0.01),外侧髁远端关节面半径与外侧后髁关节面半径有明显相关(r=0.740,P<0.01)。通过内外上髁轴的钻孔孔道近似于股骨远端后髁关节面的固定轴心。结论矢状位股骨髁内外侧关节面可被两个相切的圆弧所代表,其圆心近似于内外上髁轴,可看作膝关?

Objective To characterize the geometry of the d istal femur in normal Chinese people,and explore its correlation with kin ematics as well as prosthesis design of the knee joint.Methods The distal femurs of 10cadaver knee joints and 20knee joints of normal adult volunte ers were analyzed with MRI on the sagittal and horizontal planes.For cadaver knee joints,anatomic study was conducted,and a hole was drilled on the distal femur at the connection on the femoral insertions of the collateral ligaments.Least square fitt ing was used to analyze the MRI pictures o n the sagittal plane.Results On the sagittal plane,bilateral dis tal condylar surfaces and posterior con dylar surfaces were fitted into two t angent circles,the hole passed thro ugh the insertion of posterior cruciate ligament (PCL).The radius and the radian of the medi al posterior condylar circle were not statistically diffe rent from that of the lateral posterior condylar circle(P>0.05).The radius of the lateral distal condylar circle was statistically larger than that of the medial distal condylar circle(P<0.01),whereas the radian of the medial dis tal condylar circle was statistically larger than that of the lateral distal condylar circle(P<0.01).The radius of the distal circle was 1.89and 2.01fold of those of the medial posterior circle and the late ral posterior circle respectively.Correlation between radius of media l distal condylar circle and that of medial posterior condylar circle was statistically significant (r=0.814,P<0.01).Correlation between radius of lateral distal condylar circle and that of lateral posterior condylar circle w as statistically significant (r=0.740,P<0.01).The hole passing through the epicon dylar axis was approxi-mate with the fixed flexion axis.Conclusion On the sagittal plane,bilateral posterior condylar curvatures are well fitted into two tangent circ les;their centers are close to epicondylar axis and approximate the fixed flexion axis of the knee.The hole passing through the epicondylar axis is also pass the insert of PCL;this means that PCL play an important role in flexion of the knee.The radius of t he distal circle was approximate two times larger than that of the posterior circle.Medial condylar is fla tter than lateral condylar;distal articular surface determines the major charac-teristics of the femoral condyles.