title: Underdevelopment of trabecular bone microarchitecture in the distal femur of nonambulatory children with cerebral palsy becomes more pronounced with distance from the growth plate.
abstract: CONCLUSIONS
  We found that the underdeveloped trabecular bone microarchitecture in the distal femur of children with cerebral palsy (CP) who are unable to ambulate independently becomes more pronounced with increased distance from the growth plate. This suggests that the degree of underdevelopment in trabecular bone in children with CP is greater than previously understood.
  
  
  BACKGROUND
  Children with CP who are unable to ambulate independently have severely underdeveloped trabecular bone microarchitecture in the distal femur. The aim of the study was to determine if the level of underdevelopment in trabecular bone microarchitecture is consistent across the distal femur in children with CP.
  
  
  METHODS
  Children with quadriplegic CP and typically developing children were studied (n=12/group, 5-14 years). Apparent bone volume to total volume (appBV/TV), trabecular number (appTb.N), trabecular thickness (appTb.Th), and trabecular separation (appTb.Sp) were estimated in each of 20 magnetic resonance images collected above the growth plate in the distal femur.
  
  
  RESULTS
  For the total region, appBV/TV, appTb.N, and appTb.Th were lower (30, 21, and 12%, respectively) and appTb.Sp was higher (52%) (all p≤0.001) in children with CP than in controls. Distance from the growth plate was inversely related to appBV/TV and appTb.N and was positively related to appTb.Sp at the same distance in children with CP and controls (all p<0.01). However, the relationships were stronger (r2=0.87 to 0.92 versus 0.36 to 0.65) and the slopes were steeper in children with CP (all p<0.01). Furthermore, the steepness of the slopes in children with CP was positively related to appBV/TV, appTb.N, appTb.Th, and appTb.Sp for the total region (r2=0.37 to 0.75, p<0.05).
  
  
  CONCLUSIONS
  The underdeveloped trabecular bone microarchitecture in the metaphysis of the distal femur in children with CP becomes more pronounced with greater distance from the growth plate. This pattern is most profound in children with the least developed trabecular bone microarchitecture.
authors.affiliation: Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, 19716, USA, modlesky@udel.edu.
authors.forename: C M
authors.initials: CM
authors.lastname: Modlesky
authors.forename: D G
authors.initials: DG
authors.lastname: Whitney
authors.forename: H
authors.initials: H
authors.lastname: Singh
authors.forename: M F
authors.initials: MF
authors.lastname: Barbe
authors.forename: J T
authors.initials: JT
authors.lastname: Kirby
authors.forename: F
authors.initials: F
authors.lastname: Miller
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002547:Cerebral Palsy / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005269:Femur / Q000473:pathology*; D006132:Growth Plate; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D051346:Mobility Limitation