Correlation of Malrotation Deformity in Distal Radius Fractures With Radiographic Analysis: Cadaveric Study

PurposeThe radiographic parameters commonly used for evaluating distal radius fractures are radial length, palmar tilt, radial inclination, and articular congruity. Rotation of the distal fragment is not routinely evaluated after distal radius fractures. The purpose of this study was to define the appearance of distal fragment malrotation on conventional radiographs and to correlate varying degrees of malrotation with the corresponding radiographic findings.MethodsSix distal radiuses from embalmed cadavers were cut and stabilized in 10°, 20°, and 30° of pronated malrotation. Posteroanterior, lateral, and oblique (45° pronated view) radiographs were taken and radiographic measurements were made of radial length, palmar tilt, radial inclination, and rotation.ResultsWith malrotation, the visible cortical width of the distal fragment mismatched the visible cortical width of the proximal fragment. This was most evident on the oblique view (p < .05) and measured 2.2 mm for 10° of rotation (standard deviation [SD] 0.6), 3.4 mm for 20° of rotation (SD 0.8), and 5.3 mm for 30° of rotation (SD 2.2).ConclusionsThe radiographic parameter of rotation should be considered when evaluating distal radius fracture reduction. Malrotation is best seen on a 45° oblique pronated radiographic view as a mismatch of the cortical width of the distal fragment compared with the cortical width of the proximal fragment. In the absence of radial shortening, a 5.3-mm mismatch is associated with 30° of malrotation and is the upper limit of acceptability.