CT Based Characterization of Volar Surface of Distal Radius: Can an Ideal Volar Plate for Fixation of Distal Radial Fractures be Designed?

Abstract

Background: Literature has limited evidence concerning the morphology of volar surface of distal radius. A mismatch between the plate-contour and contour of the actual volar bony surface can result in malreduction. The purpose of this study is to analyze the normal curvature morphology of volar surface of distal radius and related parameters that can help in designing of the volar plates for fixation of distal radial fractures. Methods: We retrospectively analyzed CT scans of uninjured healthy distal radii performed during a one year period (2018-2019). The mediolateral extent of the pronator quadratus line, the mediolateral curve of the pronator quadratus line, the mediolateral surface angle between intermediate column and radial column of distal radius, the curvatures and locations of their vertices for radial and intermediate columns were measured. Results: A total of 84 CT-based studies were analyzed. The mediolateral extent of the pronator quadratus line, the mediolateral curve of the pronator quadratus line, and the mediolateral surface angle between intermediate column and radial column of the distal radius were 24.27 mm, 144.8 degrees and 163.1 degrees, respectively. The mean volar curvatures of the radial and intermediate columns were 156.5 and 151.4 degrees, respectively and distances of their vertices from the pronator-quadratus line were 10.96 mm and 14.13 mm, respectively. Conclusions: Considerable variations occur in curvature morphology of distal radial volar surface. A best fit rather than an anatomical fit can be considered during implant selection owing to these variations. Besides volar curvature of radial and ulnar columns, location of their vertices, mediolateral angulation and surface curvature between these columns at the level of watershed line should also be considered in plate selection. A combination of a few serial increments of the described parameters in the designs of volar fixation plates would be helpful for surgeons in the best implant selection.