Comparison of extra-articular radiographic parameters of distal radius fractures on plain radiographs and CT scans

The aim of this study was to compare extra-articular radiographic parameters of distal radial fractures measured on plain radiographs and CT scans. Two researchers independently measured four extra-articular radiographic parameters (dorsal tilt, carpal alignment, radial inclination and ulnar variance) on both radiographs and CT scans in 85 patients. Inter-observer reliability for both techniques was assessed, along with the agreement between CT scans and radiographs using the intraclass correlation coefficient and Bland-Altman plots. The results showed that dorsal tilt, carpal alignment, radial inclination and ulnar variance can be measured reliably on both radiographs and CT scans. At a patient level, carpal alignment, radial inclination and ulnar variance CT scan measurements are an acceptable alternative to plain radiograph measurements in the vast majority of patients. In contrast, dorsal tilt CT scan measurements are not comparable with radiographs in 40% of the cases. Therefore, caution should be taken in measuring dorsal tilt on CT scans.