Positions of the centers of the AM tunnel within the measurement grid on the lateral view photograph of the lateral femoral condyle. We superimposed a measurement grid  onto the lateral view photograph, using the roof of the intercondylar notch as a reference line. Then, the grid was divided into 16 zones. We also defined the X-Y coordinate system on this grid. The cordinate of the center of the femoral attachment of the AM mid-substance fibers, (Xc, Yc), was defined as follows: Xc was defined as the distance between the center and the Y axis, and Yc was defined as the distance between the center and the X axis.