Rotational displacement on the sagittal plane in unstable pelvic fractures: a clinical case study

Abstract

Objective To investigate the clinical significance and distribution of different rotational displacements on the sagittal plane in unstable pelvic fractures radiologically. Methods We retrospectively reviewed 82 patients with unilateral pelvic fracture who had been treated at our department from June 2005 to June 2015. They were 48 men and 34 women, with an average age of 43±18 years. By Tile classification, there were 48 cases of type B and 34 cases of type C. Their rotational displacements on the sagittal plane of the pelvic ring were determined on the anteroposterior X-ray films of the pelvis by measuring the changed distances from the top of iliac crest to the lowest point of ischial tuberosity and to the pubic tubercle. The data were recorded for analysis of different displacements and their clinical significance. Results Of all the 82 patients, based on the preoperative radiographic evidence, 36 (43.9%) showed sagittal plane rotational displacement. Of them, 28 (77.8%) showed supination displacement and 8 (22.2%) pronation displacement. The preoperative CT three-dimensional reconstruction confirmed the findings from the X-ray films. Twenty-one of the 48 cases of Tile type B (43.8%) and 15 of the 34 cases of Tile type C (44.1%) showed sagittal plane rotational displacement. The success rate of closed reduction was, respectively, 66.7% (24/36) in the 36 cases with sagittal plane rotational displacement, 62.5% (5/8) in those with pronation displacement and 67.9% (19/28) in those with supination displacement, all significantly lower than the total success rate of closed reduction in this cohort (84.1%). Conclusions The sagittal plane rotational (pronation and supination) displacement of pelvic fracture can be determined by measuring special points and lines on the anteroposterior radiographs of the pelvis. The supination displacement on the sagittal plane is more common. The unstable pelvic fracture with sagittal plane rotational displacement is more difficult to reduce. Key words: Pelvis; Fractures, bone; Closed reduction; X-ray; Rotation