title: Acetabular retroversion in developmental dysplasia of the hip.
abstract: BACKGROUND
  Patients with developmental dysplasia of the hip are prone to the development of degenerative changes in the affected hip. The aim of this study was to evaluate the prevalence, morphological features, and clinical relevance of acetabular retroversion in these patients.
  
  
  METHODS
  We investigated the version and morphological features of the acetabulum using pelvic radiographs and computed tomography images of ninety-six hips in fifty-nine patients with developmental dysplasia of the hip. A diagnosis of acetabular retroversion was based on the presence of a positive cross-over sign on the pelvic radiograph. Using computed tomography images, we determined the acetabular anteversion angle at various levels in the axial plane. The acetabular sector angle served as an indicator of acetabular coverage of the femoral head. We evaluated the association between acetabular version and the patient's age at the onset of pain. Fifty normal hips were examined as controls.
  
  
  RESULTS
  We observed acetabular retroversion in 18% (seventeen) of the ninety-six hips in the patients with developmental dysplasia of the hip. The mean acetabular anteversion angle in the hips with acetabular retroversion was significantly smaller, at all levels, than that in the hips with acetabular anteversion; this tendency was more evident at proximal levels. There was significantly less posterior and posterosuperior coverage in the hips with acetabular retroversion than in those with acetabular anteversion, but superior acetabular coverage did not differ between the groups. Multivariate analysis showed that the onset of pain occurred at a significantly earlier age in patients with acetabular retroversion (27.9 years) than in those with acetabular anteversion (40.5 years), regardless of the severity of the dysplasia (p = 0.003).
  
  
  CONCLUSIONS
  In patients with developmental dysplasia of the hip, acetabular retroversion results from relatively deficient coverage by the posterior portion of the acetabulum. Developmental dysplasia with acetabular retroversion is associated with an earlier onset of pain than is developmental dysplasia with anteversion, suggesting a correlation between deficiency of the posterior acetabular wall and the earlier onset of pain.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. m-fujii@ortho.med.kyushu-u.ac.jp
authors.forename: Masanori
authors.initials: M
authors.lastname: Fujii
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Nakashima
authors.forename: Takuaki
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Taro
authors.initials: T
authors.lastname: Mawatari
authors.forename: Goro
authors.initials: G
authors.lastname: Motomura
authors.forename: Akinobu
authors.initials: A
authors.lastname: Matsushita
authors.forename: Shuichi
authors.initials: S
authors.lastname: Matsuda
authors.forename: Seiya
authors.initials: S
authors.lastname: Jingushi
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Iwamoto
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging*; D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D018856:Cystitis, Interstitial; D005260:Female; D006618:Hip Dislocation, Congenital / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010384:Pelvic Bones / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D055815:Young Adult