Cortical and trabecular bone in the femoral neck both contribute to proximal femur failure load prediction.
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.


BACKGROUND
The relative contribution of femoral neck trabecular and cortical bone to proximal femur failure load is unclear.


OBJECTIVE
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.


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 degrees regions. The femora were loaded to failure.


RESULTS
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.


CONCLUSIONS
Both cortical and trabecular bone make significant contributions to failure load in ex vivo measures of bone strength.
Manske
S L
SL
UBC Department of Orthopaedics, Centre for Hip Health and Musculoskeletal Research, Vancouver Coastal Health Research Institute, 302-2647 Willow Street, Vancouver, BC V5Z3P1, Canada.
Liu-Ambrose
T
T
Cooper
D M L
DM
Kontulainen
S
S
Guy
P
P
Forster
B B
BB
McKay
H A
HA
D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density / Q000502:physiology*; D002102:Cadaver; D005260:Female; D005272:Femur Neck / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D006620:Hip Fractures / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed