Effect of elbow position on radiographic measurements of radio-capitellar alignment

Figure 2 Method for radiocapitellar ratio measurement. (1): A line, perpendicular to the joint, was drawn at the center of the articular surface of the radial head (point 1); (2): The diameter of the capitellum (Ø capitellum) was measured; (3): The center of the capitellum was identified as the bisector of the capitellum’s diameter (point 2); (4): The minimal distance between the center points of the radial head and the capitellum was measured (D_RH); (5): The RCR was calculated: RCR (%) = D_RH/Ø_capitellum. RCR: Radiocapitellar ratio.