title: Pelvic incidence: a predictive factor for three-dimensional acetabular orientation-a preliminary study.
abstract: Acetabular cup orientation (inclination and anteversion) is a fundamental topic in orthopaedics and depends on pelvis tilt (positional parameter) emphasising the notion of a safe range of pelvis tilt. The hypothesis was that pelvic incidence (morphologic parameter) could yield a more accurate and reliable assessment than pelvis tilt. The aim was to find out a predictive equation of acetabular 3D orientation parameters which were determined by pelvic incidence to include in the model. The second aim was to consider the asymmetry between the right and left acetabulae. Twelve pelvic anatomic specimens were measured with an electromagnetic Fastrak system (Polhemus Society) providing 3D position of anatomical landmarks to allow measurement of acetabular and pelvic parameters. Acetabulum and pelvis data were correlated by a Spearman matrix. A robust linear regression analysis provided prediction of acetabulum axes. The orientation of each acetabulum could be predicted by the incidence. The incidence is correlated with the morphology of acetabula. The asymmetry of the acetabular roof was correlated with pelvic incidence. This study allowed analysis of relationships of acetabular orientation and pelvic incidence. Pelvic incidence (morphologic parameter) could determine the safe range of pelvis tilt (positional parameter) for an individual and not a group.
authors.affiliation: Service de Neurologie Pédiatrique, CHU Timone Enfants, 13385 Marseille, France ; Département de Médecine Physique et de Réadaptation, CHU Caremeau, 30029 Nîmes, France ; Laboratoire d'Anatomie, UFR de Médecine Montpellier-Nîmes, 30907 Nîmes, France ; Service de Chirurgie Orthopédique Pédiatrique, CHU la Timone Enfants, 264 Rue Saint-Pierre, 13385 Marseille Cedex 05, France.
authors.forename: Christophe
authors.identifier: 0000-0001-8749-6341
authors.initials: C
authors.lastname: Boulay
authors.affiliation: Service de Chirurgie Orthopédique Pédiatrique, CHU la Timone Enfants, 264 Rue Saint-Pierre, 13385 Marseille Cedex 05, France.
authors.forename: Gérard
authors.initials: G
authors.lastname: Bollini
authors.affiliation: Service d'Orthopédie, Clinique Universitaires UCL. de Mont-Godinne, 5530 Yvoir, Belgium.
authors.forename: Jean
authors.initials: J
authors.lastname: Legaye
authors.affiliation: UMR 7179 CNRS, Mécanismes Adaptatifs: des Organismes aux Communautés, Pavillon d'Anatomie Comparée, Museum National Histoire Naturelle, 75005 Paris, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Tardieu
authors.affiliation: Laboratoire d'Anatomie, UFR de Médecine Montpellier-Nîmes, 30907 Nîmes, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Prat-Pradal
authors.affiliation: Service de Neurologie Pédiatrique, CHU Timone Enfants, 13385 Marseille, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Chabrol
authors.affiliation: Service de Chirurgie Orthopédique Pédiatrique, CHU la Timone Enfants, 264 Rue Saint-Pierre, 13385 Marseille Cedex 05, France.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Jouve
authors.affiliation: INSERM U 215, CHU Raymond Poincaré, 92380 Garches, France.
authors.forename: Ginette
authors.initials: G
authors.lastname: Duval-Beaupère
authors.affiliation: Département de Médecine Physique et de Réadaptation, CHU Caremeau, 30029 Nîmes, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Pélissier