title: Cancellous bone changes in hip osteoarthritis: a short-term longitudinal study using fractal signature analysis.
abstract: OBJECTIVE
  To quantify changes to the trabecular structure in the femoral heads of patients with hip osteoarthritis (OA).
  
  
  METHODS
  Patients with OA (n=14; F=7), mean (standard deviation age) 50.6 (10.1) years, had macroradiographs at approximately x4 magnification at baseline and 18 months later using a standardized protocol. Following digitization, computerized measurement was obtained of minimum hip joint space width and fractal signature analysis (FSA) measured longitudinal changes separately in the principal compressive (vertical) and horizontal trabeculae at the region of interest within the centre of the head.
  
  
  RESULTS
  The patient group had mean annual rate of joint space narrowing of 0.14+/-0.36 mm/yr. FSA detected no significant changes in horizontal trabeculae, whereas the larger principal compressive (vertical) trabeculae (0.96 mm to 1.02 mm) increased significantly in thickness and the fine to medium trabeculae (0.18 mm to 0.54 mm) decreased significantly in number.
  
  
  CONCLUSIONS
  The increased thickness of the larger trabeculae within the compressive structural element of the femoral head is a response to the increase in stress associated with an overall loss of trabeculae in this region, suggesting the presence of an osteoporosis within the femoral head in OA patients.
authors.affiliation: Department of Applied Clinical Anatomy, King's College London, School of Biomedical Sciences, Guy's Hospital Campus, London, UK.
authors.forename: C D
authors.initials: CD
authors.lastname: Papaloucas
authors.forename: R J
authors.initials: RJ
authors.lastname: Ward
authors.forename: C J
authors.initials: CJ
authors.lastname: Tonkin
authors.forename: C
authors.initials: C
authors.lastname: Buckland-Wright
mesh_terms: D005260:Female; D005270:Femur Head / Q000000981:diagnostic imaging*; D017709:Fractals; D006621:Hip Joint / Q000000981:diagnostic imaging; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging*; D011859:Radiography