Zoghi M, Hefzy M S, Fu K C, Jackson W T
Department of Mechanical Engineering, University of Toledo, Ohio.
Proc Inst Mech Eng H. 1992;206(3):147-57. doi: 10.1243/PIME_PROC_1992_206_282_02.
The objective of this paper is to present a method to describe the three-dimensional variations of the geometry of the three portions forming the distal part of the human femur: the medial and lateral femoral condyles and the intercondylar fossa. The contours of equally spaced sagittal slices were digitized on the distal femur to determine its surface topography. Data collection was performed using a digitizer system which utilizes low-frequency, magnetic field technology to determine the position and orientation of a magnetic field sensor in relation to a specified reference frame. The generalized reduced gradient optimization method was used to reconstruct the profile of each slice utilizing two primitives: straight-line segments and circular arcs. The profile of each slice within the medial femoral condyle was reconstructed using two circular arcs: posterior and distal. The profile of each slice within the lateral femoral condyle was reconstructed using three circular arcs: posterior, distal and anterior. Finally, the profile of each slice within the intercondylar fossa was reconstructed using two circular arcs: proximal-posterior and anterior, and a distal-posterior straight-line segment tangent to the proximal-posterior circular arc. Combining the data describing the profiles of the different slices forming the distal femur, the posterior portions of each of the medial and lateral femoral condyles were modelled using parts of spheres having an average radius of 20 mm. The anterior portion of the lateral condyle was approximated to a right cylinder having its circular base parallel to the sagittal plane with an average radius of 26 mm. The anterior portion of the intercondylar fossa was modelled using an oblique cylinder having its circular base parallel to the sagittal plane with an average radius of 22 mm. Furthermore, it is suggested that the distal portion of the lateral femoral condyle could be modelled using parts of two oblique cones while the distal portion of the medial femoral condyle could be modelled using a part of a single oblique cone, all cones having their circular bases parallel to the sagittal plane. It is also suggested that the posterior portion of the intercondylar fossa could be modelled using two oblique cones: a proximal cone having its base parallel to the sagittal plane and a distal cone having its base parallel to the frontal plane.
本文的目的是提出一种方法，用于描述构成人类股骨远端的三个部分的几何形状的三维变化：内侧和外侧股骨髁以及髁间窝。在股骨远端对等间距矢状切片的轮廓进行数字化处理，以确定其表面形貌。数据收集使用了一种数字化仪系统，该系统利用低频磁场技术来确定磁场传感器相对于指定参考框架的位置和方向。广义简约梯度优化方法被用于利用两种基元来重建每个切片的轮廓：直线段和圆弧。内侧股骨髁内每个切片的轮廓使用两个圆弧重建：后部和远端。外侧股骨髁内每个切片的轮廓使用三个圆弧重建：后部、远端和前部。最后，髁间窝内每个切片的轮廓使用两个圆弧重建：近端后部和前部，以及一条与近端后部圆弧相切的远端后部直线段。结合描述构成股骨远端的不同切片轮廓的数据，内侧和外侧股骨髁各自的后部使用平均半径为20毫米的球体部分进行建模。外侧髁的前部近似为一个右圆柱体，其圆形底面与矢状面平行，平均半径为26毫米。髁间窝的前部使用一个斜圆柱体建模，其圆形底面与矢状面平行，平均半径为22毫米。此外，建议外侧股骨髁的远端部分可以使用两个斜圆锥体的部分进行建模，而内侧股骨髁的远端部分可以使用单个斜圆锥体的部分进行建模，所有圆锥体的圆形底面都与矢状面平行。还建议髁间窝的后部可以使用两个斜圆锥体建模：一个基部与矢状面平行的近端圆锥体和一个基部与额状面平行的远端圆锥体。
