Imaging diagnosis of radial head fractures-evaluation of plain radiography vs. CT scans

Background Radial head fractures represent a common pathology that can cause permanent disability, especially if not treated correctly. Plain radiographs as well as computed tomography (CT) scans represent important diagnostic measures. The specific differences between these two imaging modalities with regard to diagnosis of radial head fractures have not been evaluated to date. Objective This study aimed to compare estimations of fracture classification, percentage of articular fracture involvement, and fragment sizes through plain radiography with CT scan evaluations. Methods A total of 52 consecutive cases of isolated radial head fractures with plain radiographs and CT scans were evaluated retrospectively. Two observers analyzed the fracture classification according to Mason, the percentage of articular fracture involvement, and the size of the largest fracture fragment by means of CT. Three trauma surgeons estimated these parameters through blinded plain radiographs. Intra- and inter-observer reliability were evaluated. Results The CT scan evaluations showed high intra- and inter-observer reliability without significant differences between the two observers. X-ray estimations of fracture classifications showed only fair agreements. Moreover, the estimations of articular fracture involvement and fragment sizes differed significantly from the CT scan evaluations. While the fragment size tended to be underrated, the articular involvement tended to be overrated. Conclusion This study shows that plain radiographs often provide unreliable information regarding classification, articular involvement, and fragment sizes of radial head fractures. When in doubt, an additional CT scan should be carried out to assess the injury in greater detail.