Morphology of the radial head: a reverse engineering based evaluation using three-dimensional anatomical data of radial bone

The proximal part of the radius has a complex shape and dimension that cannot be precisely determined by standard roentgenogram for real three-dimensional anatomical shape which is important for prosthesis design. This study presents a method by which computer tomography (CT ) images are combined with the reverse engineering technique to obtain and analyse the threedimensional inner and outer geometry of the proximal radius. The three-dimensional models were reconstructed from CT images obtained from 40 radial bones and approximated with two- and threedimensional fitting algorithms based on reverse engineering methods. The mean total length of the radius was 240.0 mm [standard deviation (SD)=17.3]. The radial head in this study is more likely to be circular with an average diameter of 20.5 mm (SD=1.9). The outer diameter of the radial neck averages 14.7 mm (SD=1.0). The thickness of the radial head averages 12.9 mm (SD=1.4). The intramedullary canal diameter of the radial neck averages 7.4 mm (SD=1.4). The depth of the fossa at the articular surface averages 1.5 mm (SD=0.4).