Summary
We examined the contributions of femoral neck cortical and trabecular bone to proximal femur failure load. We found that trabecular
bone mineral density explained a significant proportion of variance in failure load after accounting for total bone size and
cortical bone mineral content or cortical area.
Introduction
The relative contribution of femoral neck trabecular and cortical bone to proximal femur failure load is unclear.
Objectives
Our primary objective was to determine whether trabecular bone mineral density (TbBMD) contributes to proximal femur failure
load after accounting for total bone size and cortical bone content. Our secondary objective was to describe regional differences
in the relationship among cortical bone, trabecular bone, and failure load within a cross-section of the femoral neck.
Materials and methods
We imaged 36 human cadaveric proximal femora using quantitative computed tomography (QCT). We report total bone area (ToA),
cortical area (CoA), cortical bone mineral content (CoBMC), and TbBMD measured in the femoral neck cross-section and eight
45° regions. The femora were loaded to failure.
Results and observations
Trabecular bone mineral density explained a significant proportion of variance in failure load after accounting for ToA and
then either CoBMC or CoA respectively. CoBMC contributed significantly to failure load in all regions of the femoral neck
except the posterior region. TbBMD contributed significantly to failure load in all regions of the femoral neck except the
inferoanterior, superoposterior, and the posterior regions.
Conclusion
Both cortical and trabecular bone make significant contributions to failure load in ex vivo measures of bone strength.
Keywords Bone strength - Cortical bone - Femoral neck - Proximal femur - QCT - Trabecular bone