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Correlation of the cross-over ratio of the cross-over sign on conventional pelvic radiographs with computed tomography retroversion measurements

Werner, Clément ; Copeland, Carol ; Stromberg, Jeff ; Ruckstuhl, Thomas

In: Skeletal Radiology, 2010, vol. 39, no. 7, p. 655-660

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    Titre
    • Correlation of the cross-over ratio of the cross-over sign on conventional pelvic radiographs with computed tomography retroversion measurements
    Auteur
    • Werner, Clément. Department of Orthopaedics, Uniklinik Balgrist, University of Zurich, Zurich, Switzerland
    • Copeland, Carol. R Adams Cowley Shock Trauma Center, University of Maryland Medical Systems, Baltimore, MD, USA
    • Stromberg, Jeff. R Adams Cowley Shock Trauma Center, University of Maryland Medical Systems, Baltimore, MD, USA
    • Ruckstuhl, Thomas. Department of Orthopaedics, Uniklinik Balgrist, University of Zurich, Zurich, Switzerland
    Type de document
    • Postprint
    Identifiant OAI-PMH
    • oai:doc.rero.ch:317089
    Summary
    Objective: To find a correlation between the cross-over ratio of the cross-over sign on conventional anteroposterior (AP) pelvic radiographs and retroversion measurements (‘roof-edge angle' and ‘equatorial-edge angle) on computed tomography (CT) scans. This would facilitate the interpretation of the cross-over sign regarding the amount of acetabular retroversion. Materials and methods: Correctly projected AP pelvic radiographs (2,925 hips) were examined for the presence of the cross-over sign (COS), and the overlap ratio of the COS was measured. On CT scans of the same patients the ‘roof-edge angle' (RE angle) and the ‘equatorial-edge angle' (EE angle) were also calculated. Results: A statistically significant but only weak relationship could be found between the overlap ratio of the COS and the ‘roof-edge angle' (P < 0.0001; correlation coefficient −0.486) and between this ratio and the ‘equatorial-edge angle' (P < 0.0001; correlation coefficient −0.395). Conclusion: A relationship between the overlap ratio and orientation measurements on CT scans could be found, but it was less strong than expected