Fig. 3

The cartilage-reproducing image reconstruction method of CT image at proximal radioulnar joint. a Determine the ANA junctions (white arrow) using an alteration of the circular curve of nonarticular portion. b Create a reforming axis (blue dash line) using perpendicular line from the midpoint of the straight line between both ANA junctions. c Translate the articular portion along this axis until a reformed border touches half the distance between the subchondral surfaces at the mid portion of radial notch. d Fill the area over ANA junctions until the uneven borders are on the same arch. ANA: articular-nonarticular