Evaluating the utility of post-reduction imaging for simple hip joint dislocations: Is computed tomography always necessary?

Introduction: Following closed reduction of hip dislocations, computed tomography (CT) is considered standard of care to identify occult fractures or intra-articular loose bodies that may be missed on X-ray. The purpose of this study was to evaluate the sensitivity of post-reduction X-rays and the usefulness of subsequent post-reduction CT imaging. Methods: All patients presenting to our hospital system for traumatic hip dislocations from 2013 to 2022 were retrospectively reviewed. Participants were included if they had a simple dislocation of a native hip, underwent closed reduction, and received post-reduction X-ray and CT imaging. A sensitivity analysis was performed for the detection of associated fractures and intraarticular loose bodies by post-reduction X-ray, using CT as a reference standard. Results: Thirty-five subjects with a mean age of 26 years were included. Post-reduction CT revealed 6 fractures and 3 loose bodies, whereas post-reduction X-ray identified 3/6 (50%) fractures and 3/3 (100%) loose bodies. Four cases received operative management, all of which were identified by X-ray. Post-reduction X-ray had a sensitivity of 67% for identifying pathology that was subsequently found on CT, and a sensitivity of 100% for identifying pathology requiring surgery. Of the 13 cases with pre-reduction CT scans, none had new findings identified on post-reduction CT. Conclusions: Post-reduction X-rays are effective in the evaluation of acute pathology associated with closed reduction of traumatic hip dislocations, especially for cases requiring operative management. Our findings suggest that if a fracture or loose body was not identified on post-reduction X-ray, a post-reduction CT added no value in surgical decision-making and was not necessary.