Preoperative Evaluation for Pelvic Discontinuity Using a New Reformatted Computed Tomography Scan Protocol

The identification of suspected pelvic discontinuity is important for preoperative planning in revision hip arthroplasty. Computed tomography (CT) of the pelvis with reconstructions in the axial, sagittal, and coronal planes has been previously described for the identification of pelvic discontinuity but fails to show some discontinuities. The purpose of this study was to determine whether reformatted 45° oblique CT scans of the pelvis, similar in projection to Judet views on plain films, provide advantages in detecting pelvic discontinuity preoperatively over standard reconstruction CT scans. We describe a new technique of reformatting conventional CT scans to present 45° oblique views of the pelvis.

Using an institutional joint registry, we retrospectively identified 22 patients who had intraoperative findings of pelvic discontinuity and also had a preoperative CT scan of the pelvis. The criterion for diagnosis of pelvic discontinuity was a continuous visible fracture line involving the entire width of the anterior and posterior columns.

In this study, standard reconstruction CT scans were 73% sensitive in identifying discontinuity based on these parameters and the addition of reformatted 45° oblique CT scans increased sensitivity to 91%.

Unique reconstructive techniques in revision hip arthroplasty can be used, and the operative plan may be modified if pelvic discontinuity is identified preoperatively. CT scans of the pelvis with reconstructions at 45° iliac oblique and obturator oblique views in patients with suspected pelvic discontinuity provide a high level of sensitivity when the diagnosis cannot be firmly established from plain films.