Fig. 4
From: Calculation of pediatric femoral fracture rotation from direct roentgenograms
In this example fracture edges are clearly seen. Midline axes of proximal and distal fragments are drawn. The intersection point of proximal fracture line and proximal midline axis is determined. Vertical distance of this point to the fracture edge is h. This distance is transfered to the distal fragment. Note that each h line is parallel to the corresponding midline axis. The corresponding point on the distal fracture line is determined. Its horizontal distance to the distal midline axis is d. α = sin−1(d/r), α = sin−1(7/20), α = 20.5°