title: Is the acetabulum retroverted in slipped capital femoral epiphysis?
abstract: BACKGROUND
  Recent biplanar radiographic studies have demonstrated acetabular retroversion and increased superolateral femoral head coverage in hips with slipped capital femoral epiphysis (SCFE), seemingly divergent from earlier CT-based studies suggesting normal acetabular version.
  
  
  OBJECTIVE
  We therefore asked: Are there differences in (1) acetabular version at the superior ¼ of the acetabular dome (AV(sup)), (2) acetabular version at the center of the femoral head (AV(cen)), and (3) superolateral femoral head coverage (lateral center-edge angle [LCEA]) among affected SCFE hips, unaffected hips, and normal controls?
  
  
  METHODS
  We identified 32 patients with SCFE who underwent CT between 2007 and 2012. Twenty-three met our inclusion criteria. Seventy-six age- and sex-matched normal patients comprised the control group. Pelvic rotation, tilt, and inclination were corrected on each CT. AV(sup), AV(cen), and LCEA were measured.
  
  
  RESULTS
  The mean AV(sup) of the affected hips (-1.71°) demonstrated retroversion compared to the unaffected hips and the control group; the mean AV(sup) of the unaffected hips was similar to that of the normal controls. Mean AVcen was similar among the three groups. The LCEA was higher in affected and unaffected SCFE hips than in the control group (34.3° versus 34.5° versus 28.9°, respectively), but we found no difference between affected and unaffected hips.
  
  
  CONCLUSIONS
  Our data suggest an association of superior acetabular retroversion and increased superolateral femoral head coverage in SCFE. Whether this represents a primary abnormal morphology or a secondary pathologic response remains unclear. Further studies investigating the role of acetabular morphology in SCFE and its implications for development of symptomatic femoroacetabular impingement are warranted.
authors.affiliation: Department of Orthopedic Surgery, Rady Children's Hospital and Health Center, San Diego, CA 92123, USA.
authors.forename: Shafagh
authors.initials: S
authors.lastname: Monazzam
authors.forename: Venkatadass
authors.initials: V
authors.lastname: Krishnamoorthy
authors.forename: Bernd
authors.initials: B
authors.lastname: Bittersohl
authors.forename: James D
authors.initials: JD
authors.lastname: Bomar
authors.forename: Harish S
authors.initials: HS
authors.lastname: Hosalkar
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000503:physiopathology*; D000293:Adolescent; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D060751:Bone Retroversion / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D016022:Case-Control Studies; D002648:Child; D005260:Female; D057925:Femoracetabular Impingement / Q000209:etiology / Q000503:physiopathology; D005270:Femur Head / Q000000981:diagnostic imaging / Q000503:physiopathology; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D011379:Prognosis; D016059:Range of Motion, Articular; D060048:Slipped Capital Femoral Epiphyses / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D014057:Tomography, X-Ray Computed