title: Correlation of pelvic incidence with radiographical parameters for acetabular retroversion: a retrospective radiological study.
abstract: BACKGROUND
  Pelvic incidence (PI) has been linked to several degenerative processes within the spinopelvic system. Acetabular retroversion is a recognised risk factor for osteoarthritis of the hip. We therefore hypothesised that these two factors might be part of a specific anatomical variant associated with degenerative changes. This study was performed to clarify this issue.
  
  
  METHODS
  The pelvic incidence was measured on 589 computertomographical data sets acquired between 2008 and 2010. For 220 patients a 2D rendering in an antero-posterior view of the CT data set was performed to evaluate the parameters of acetabular retroversion. Those included the prominence of the ischial spine sign (PRISS), the cross-over sign (COS) and the posterior wall sign (PWS). Between 477 and 478 hips were evaluated depending on the parameter of retroversion.
  
  
  RESULTS
  The mean pelvic incidence was significantly lower in hips positive for the PRISS and the PWS. However, there were no significant differences between hips positive or negative for the COS.
  
  
  CONCLUSIONS
  As hypothesised, the lower PI values in PWS and PRISS positive hips suggest a link between PI and retroversion of the acetabulum. Whether this is of any clinical relevance remains, however, unknown.
  
  
  CONCLUSIONS
  Acetabular retroversion is linked to PI. In hips where the prominence of the ischial spine sign and/or the posterior wall sign was present, the mean pelvic incidence value was lower.
authors.affiliation: Department of Surgery, Division of Trauma Surgery, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. simon.tiziani@uzh.ch.
authors.forename: Simon
authors.initials: S
authors.lastname: Tiziani
authors.affiliation: Department of Surgery, Division of Trauma Surgery, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. lucienne.gautier@balgrist.ch.
authors.forename: Lucienne
authors.initials: L
authors.lastname: Gautier
authors.affiliation: Department of Surgery, Division of Trauma Surgery, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. jan.farei-campagna@uzh.ch.
authors.forename: Jan
authors.initials: J
authors.lastname: Farei-Campagna
authors.affiliation: Department of Surgery, Division of Trauma Surgery, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. georg.osterhoff@usz.ch.
authors.forename: Georg
authors.initials: G
authors.lastname: Osterhoff
authors.affiliation: Department of Surgery, Division of Trauma Surgery, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. thorsten.jentzsch@usz.ch.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Jentzsch
authors.affiliation: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. thidanlinh.nguyen@usz.ch.
authors.forename: Thi Dan Linh
authors.initials: TD
authors.lastname: Nguyen-Kim
authors.affiliation: Department of Surgery, Division of Trauma Surgery, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. clement.werner@usz.ch.
authors.forename: Clément M L
authors.initials: CM
authors.lastname: Werner
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D060751:Bone Retroversion / Q000000981:diagnostic imaging*; D005260:Female; D006615:Hip / Q000000981:diagnostic imaging*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D013131:Spine / Q000000981:diagnostic imaging*; D055815:Young Adult