Anatomical reliability of two fundamental radiological and clinical pelvic parameters: incidence and thickness

• Published in: European journal of orthopaedic surgery & traumatology 2005-08, Vol.15 (3), p.197-204
• Main Authors: Boulay, C., Tardieu, C., Hecquet, J., Benaim, C., Mitulescu, A., Marty, C., Prat-Pradal, D., Legaye, J., Duval-Beaupère, G., Pélissier, J.
• Format: Article
• Language: English
• Subjects: Pelvis
• ISSN: 1633-8065; 1432-1068
• DOI: 10.1007/s00590-005-0239-5

Reliability and reproducibility of two radiological pelvic parameters are tested: thickness (length of the segment defined by the middle of the upper endplate of the sacrum to the middle of the bi-coxo-femoral axis) and pelvic incidence (angle defined by the perpendicular line to the centre of the upper endplate of the sacrum and the thickness line). These two parameters provide a pelvis description and assess the relation between pelvis and spinal curves. The anatomical reliability of these radiological parameters was not achieved. The values of these two parameters from X-ray versus direct measurement on 12 anatomical specimens are compared. The direct measurement was performed by means of an electromagnetic Fastrak system (Polhemus society) providing 3D position of anatomical landmarks and allowing to measure the incidence and the thickness. These parameters were also measured from sagittal X-ray. Their values were compared. Incidence: the paired t-test and the variance ratio test were not statistically significant and a highly significant positive correlation existed between anatomical and radiological values (r=0.98; P