Fig. 5

Method for measuring the flexion angle of the knee. (A) - (B) represents measurements of knee flexion angles in images from different time frames using the same measurement method. Two circles are made at the level of the median of the tibia and femur respectively. The edges of the circles intersect the cortex of the anterior and posterior margins of the bone and the center of the other circle. The long axes of the tibia and femur are the lines joining the centers of the two circles. The angle between the long axes of the tibia and femur is the knee flexion angle. (A) Angle measurements with the subject in the extended position; (B) knee flexed at 60°