Comparison of acetabular and femoral morphologies on hip, pelvic, and lumbar radiographs

Purpose To evaluate the reliability of the parameters for acetabular/femoral pathomorphologies in L-spine and hip radiographs compared to pelvic radiographs. Methods A retrospective review of L-spine, hip, and pelvic radiographs from 101 patients was performed. Three radiologists independently measured five parameters (acetabular roof angle of Tonnis [Tonnis angle], center-edge-angle of Wiberg [CEA], femoral head extrusion index [FHEI], cross-over sign, pistol-grip deformity) in each radiograph. Results No significant differences were identified (p ≥ 0.07) except Tonnis angles and FHEIs from the L-spine radiographs. Inter-radiograph/inter-reader ICCs were excellent or good. Conclusion Pathomorphology-related measurements in L-spine radiographs can also be used as alternatives to those in pelvic or hip radiographs. If L-spine radiographs are already available, additional pelvic or hip radiographs may be unnecessary, thus reducing patients' overall radiation exposure.