Modeling of unstable pelvic fractures for 20 ° sagittally rotated pelvic displacement.

Early and accurate assessment of unstable pelvic fractures decreases mortality and morbidity by improving the outcomes of closed reduction surgery. In some circumstances (such as in developing countries or in acute trauma), accurate computed tomography (CT) 3D reconstructions are difficult to obtain and plain radiography must be relied upon for surgical planning. Therefore, a simulation model of pelvic displacement was evaluated as a basis for improving the assessment of pelvic fracture displacement from plain radiography images. The simulated model was based on a modified anteroposterior (AP) view of the pelvis constructed using anatomical data. Plain radiography imaging data of sagittal 20 ° hemipelvic rotation, similar to that observed in trauma, was obtained from the simulated model and were compared with normal pelvic rings from 10 cadaveric specimens (actual model). For each data set, the anterior superior iliac spine and ipsilateral pubic symphysis were measured on both sides. There was no significant difference between pelvic sides in the simulated and actual models (P = 0.870). Furthermore, no significant difference was found between the rotational degree of each pelvis based on calculated or simulated degrees and the 20 ° rotational angle (P = 0.322). A simulation model based on plain radiography of pelvic displacement could contribute to the optimal surgical management of unstable pelvic fractures without relying on CT.