title: Bone shape, structure, and density as determinants of osteoporotic hip fracture: a pilot study investigating the combination of risk factors.
abstract: OBJECTIVE
  This article compares and combines methods for examining the external shape and the internal structure of the proximal femur with bone mineral density (BMD) to provide a classifier for hip fracture.
  
  
  METHODS
  Fifty standard pelvic radiographs were available from age-matched fracture and control groups of postmenopausal women. Femoral shape was measured using an active shape model, the trabecular structure by means of a Fourier transform.
  
  
  RESULTS
  Both the shape and various structure measures were independent of BMD (P=0.16 and >0.50, respectively). Calculating the area under the receiver operator characteristic (ROC) curve (Az), each of shape (Az=0.81), the best structure measure (Az=0.79-0.93), and BMD (Az=0.79), could partially classify the fracture and control groups. However, the combination achieved almost perfect separation (Az=0.99).
  
  
  CONCLUSIONS
  This pilot study shows how bone shape and structure can complement BMD measurements for investigations of fracture risk.
authors.affiliation: Department of Orthopaedics, University of Aberdeen, Aberdeen, Scotland, U.K. j.gregory@abdn.ac.uk
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Gregory
authors.forename: Alison
authors.initials: A
authors.lastname: Stewart
authors.forename: Peter E
authors.initials: PE
authors.lastname: Undrill
authors.forename: David M
authors.initials: DM
authors.lastname: Reid
authors.forename: Richard M
authors.initials: RM
authors.lastname: Aspden
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D015519:Bone Density / Q000502:physiology*; D016002:Discriminant Analysis; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging* / Q000502:physiology*; D005583:Fourier Analysis; D006620:Hip Fractures / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D015663:Osteoporosis, Postmenopausal / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D010865:Pilot Projects; D012372:ROC Curve