Osteoporosis International

, Volume 11, Issue 4, pp 361–367

In Situ Femoral Dual-Energy X-ray Absorptiometry Related to Ash Weight, Bone Size and Density, and its Relationship with Mechanical Failure Loads of the Proximal Femur

Authors

  • E.-M. Lochmüller
    • I. Frauenklinik des Klinikums der Ludwig-Maximilians-Universität München, Munich
  • P. Miller
    • Institut für Physiologie, Physiologische Chemie und Tieremährung der Ludwig-Maximilians-Universität München, Munich,
  • D. Bürklein
    • I. Frauenklinik des Klinikums der Ludwig-Maximilians-Universität München, Munich
  • U. Wehr
    • Institut für Physiologie, Physiologische Chemie und Tieremährung der Ludwig-Maximilians-Universität München, Munich,
  • W. Rambeck
    • Institut für Physiologie, Physiologische Chemie und Tieremährung der Ludwig-Maximilians-Universität München, Munich,
  • F. Eckstein
    • Musculoskeletal Research Group, Institute of Anatomy, Ludwig-Maximilians-Universität München, Munich, Germany
Original Article

DOI: 10.1007/s001980070126

Cite this article as:
Lochmüller, E., Miller, P., Bürklein, D. et al. Osteoporos Int (2000) 11: 361. doi:10.1007/s001980070126

Abstract:

The objective of this study was to directly compare in situ femoral dual-energy X-ray absorptiometry (DXA) and in vitro chemical analysis (ash weight and calcium) with mechanical failure loads of the proximal femur, and to determine the influence of bone size (volume) and density on mechanical failure and DXA-derived areal bone mineral density (BMD, in g/cm2). We performed femoral DXA in 52 fixed cadavers (age 82.1 ± 9.7 years; 30 male, 22 female) with intact skin and soft tissues. The femora were then excised, mechanically loaded to failure in a stance phase configuration, their volume measured with a water displacement method (proximal neck to lesser trochanter), and the ash weight and calcium content of this region determined by chemical analysis. The correlation coefficient between the bone mineral content (measured in situ with DXA) and the ash weight was r= 0.87 (standard error of the estimate = 16%), the ash weight allowing for a better prediction of femoral failure loads (r= 0.78; p<0.01) than DXA (r= 0.67; p<0.01). The femoral volume (r= 0.61; p<0.01), but not the volumetric bone density (r= 0.26), was significantly associated with the failure load. The femoral bone volume had a significant impact (r= 0.35; p< 0.01) on the areal BMD (DXA), and only 63% of the variability of bone volume could be predicted (based on the basis of body height, weight and femoral projectional bone area. The results suggest that accuracy errors of femoral DXA limit the prediction of mechanical failure loads, and that the influence of bone size on areal BMD cannot be fully corrected by accounting for body height, weight and projected femoral area.

Key words:Ash weight – Bone density – Bone size – DXA – Mechanical failure – Proximal femur

Copyright information

© International Osteoporosis Foundation and National Osteoporosis Foundation 2000