title: Three-dimensional magnetic resonance imaging analysis of hip morphology in the assessment of femoral acetabular impingement.
abstract: OBJECTIVE
  To determine a possible association between femoral-acetabular impingement (FAI) volume and the development of labral tear using a three-dimensional (3D) model reconstruction of the acetabulum and the femoral head.
  
  
  METHODS
  Magnetic resonance arthrography images of the hip in 42 patients with pain and suspected labral tear were acquired using a 1.5T MRI machine. Using 3D analysis software, outlines of the acetabular cup and femoral head were drawn and 3D reconstruction obtained. To control for differences in patient size, ratios of acetabulum : femoral head volume (AFV) and acetabulum : femoral head surface area (AFA) were used for analysis. The association between volume of acetabulum : femoral head and FAI was investigated using ANOVA analysis.
  
  
  RESULTS
  There were 19 men and 23 women with a mean age of 39 years (range 18-78 years). The average AFV was 0.64 (range 0.37-1.05, SD 0.16) and AFA was 0.73 (range 0.36-1.26, SD 0.23). Herniation pit was significantly associated with a small AFV.
  
  
  CONCLUSIONS
  Femoral neck herniation pits are associated with a low AFV. Gross volume and surface area ratios do not appear to correlate with labral tears or cartilage loss. This technique will enable more advanced analysis of morphological variations associated with FAI.
authors.affiliation: Department of Radiology, Mater Misericordiae Hospital, Dublin, Ireland.
authors.forename: E C
authors.initials: EC
authors.lastname: Kavanagh
authors.forename: P
authors.initials: P
authors.lastname: Read
authors.forename: F
authors.initials: F
authors.lastname: Carty
authors.forename: A C
authors.initials: AC
authors.lastname: Zoga
authors.forename: J
authors.initials: J
authors.lastname: Parvizi
authors.forename: W B
authors.initials: WB
authors.lastname: Morrison
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001175:Arthrography / Q000379:methods*; D005260:Female; D057925:Femoracetabular Impingement / Q000175:diagnosis*; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D055815:Young Adult