title: Iliac crest histomorphometry and skeletal heterogeneity in men.
abstract: OBJECTIVE
  The cortical characteristics of the iliac crest in male have rarely been investigated with quantitative histomorphometry. Also it is still unknown how cortical microarchitecture may vary between the iliac crest and fractures related sites at the proximal femur. We studied the microarchitecture of both external and internal cortices within the iliac crest, and compared the results with femoral neck and subtrochanteric femoral shaft sites.
  
  
  METHODS
  Undecalcified histological sections of the iliac crest were obtained bicortically from cadavers (n= 20, aged 18-82 years, males). They were cut (7 μm) and stained using modified Masson-Goldner stain. Histomorphometric parameters of cortical bone were analysed with low (× 50) and high (× 100) magnification, after identifying cortical bone boundaries using our previously validated method. Within cortical bone area, only complete osteons with typical concentric lamellae and cement line were selected and measured.
  
  
  RESULTS
  At the iliac crest, the mean cortical width of external cortex was higher than at the internal cortex (p < 0.001). Also, osteon structural parameters, e.g. mean osteonal perimeter, were higher in the external cortex (p < 0.05). In both external and internal cortices, pore number per cortical bone area was higher in young subjects (≤ 50 years) (p < 0.05) while mean pore perimeter was higher in the old subjects (> 50 years) (p < 0.05). Several cortical parameters (e.g. osteon area per cortical bone area, pore number per cortical area) were the lowest in the femoral neck (p < 0.05). The maximal osteonal diameter and mean wall width were the highest in the external cortex of the iliac crest (p < 0.05), and the mean cortical width, osteon number per cortical area were the highest in the subtrochanteric femoral shaft (p < 0.05). Some osteonal structural parameters (e.g. min osteonal diameter) were significantly positively correlated (0.29 ≤ R2≤ 0.45, p < 0.05) between the external iliac crest and the femoral neck.
  
  
  CONCLUSIONS
  This study reveals heterogeneity in cortical microarchitecture between the external and internal iliac crest cortices, as well as between the iliac crest, the femoral neck and the subtrochanteric femoral shaft. Standard iliac crest biopsy does not reflect accurately cortical microarchitecture of other skeletal sites.
authors.affiliation: Kuopio Musculoskeletal Research Unit (KMRU), Institute of Clinical Medicine, University of Eastern Finland, POB 1627, FIN-70211 Kuopio, Finland; Department of Applied Physics, University of Eastern Finland, POB 1627, FIN-70211 Kuopio, Finland.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Tong
authors.affiliation: Kuopio Musculoskeletal Research Unit (KMRU), Institute of Clinical Medicine, University of Eastern Finland, POB 1627, FIN-70211 Kuopio, Finland; Department of Applied Physics, University of Eastern Finland, POB 1627, FIN-70211 Kuopio, Finland.
authors.forename: Inari S
authors.initials: IS
authors.lastname: Burton
authors.affiliation: Department of Applied Physics, University of Eastern Finland, POB 1627, FIN-70211 Kuopio, Finland; Diagnostic Imaging Centre, Kuopio University Hospital, POB 100, FIN-70029 KYS, Kuopio, Finland.
authors.forename: Jukka S
authors.initials: JS
authors.lastname: Jurvelin
authors.affiliation: Department of Biomedical Engineering, Department of Orthopaedics, Lund University, POB 118, SE-221 00 Lund, Sweden.
authors.forename: Hanna
authors.initials: H
authors.lastname: Isaksson
authors.affiliation: Kuopio Musculoskeletal Research Unit (KMRU), Institute of Clinical Medicine, University of Eastern Finland, POB 1627, FIN-70211 Kuopio, Finland; Department of Orthopaedics, Traumatology, and Hand Surgery, Kuopio University Hospital, POB 100, FIN-70029 KYS, Kuopio, Finland.
authors.forename: Heikki
authors.initials: H
authors.lastname: Kröger
keywords: Bone histomorphometry; Cortical bone; Femoral neck; Iliac crest; Subtrochanteric femoral shaft