Mechanical strength of the proximal femur as predicted from geometric and densitometric bone properties at the lower limb versus the distal radius.

This experimental study compares geometric and densitometric properties of cortical and trabecular bone at the lower limb and the distal radius with those at the femoral neck, and evaluates their ability to predict mechanical failure loads of the proximal femur. One hundred five cadavers were examined with peripheral quantitative computed tomography (LpQCT), with measurements being performed in situ at the distal radius (4%, 20%, 33%), at the distal and proximal tibia, at the tibial and femoral shaft, and at the distal femur. Ex situ measurements were obtained at the femoral neck and at the proximal femoral shaft. Pairs of femora were mechanically tested in a vertical loading and a side impact (fall) configuration. The total (cross-sectional) bone mineral content and trabecular density, but not the cortical properties, displayed a higher association between the femoral neck and the peripheral lower limb than between the neck and the distal radius. Approximately 50%-60% of the variability of femoral failure loads (and >80% of trochanteric side impact fractures) were predicted by in vitro measurements at the neck. Geometric cortical parameters and density contributed independently and significantly to femoral strength. Measurements at the peripheral skeleton explained, however, only 30%-45% of the variability of femoral failure, with no significant difference between the lower limb and the distal radius. At peripheral sites, a combination of geometric and densitometric variables was slightly superior to bone mineral content alone in predicting failure in vertical loading, but this was less evident for cervical side impact fractures. The results show that a stronger association of total bone mineral content and trabecular density between the femoral neck and the lower limb does not translate into improved prediction of femoral strength from measurements at the lower limb vs. those at the distal radius.

[1]  F. Eckstein,et al.  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 , 2000, Osteoporosis International.

[2]  H. Genant,et al.  Quantitative Bone Mineral Assessment at the Forearm: A Review , 1998, Osteoporosis International.

[3]  F. Eckstein,et al.  Precision and intersite correlation of bone densitometry at the radius, tibia and femur with peripheral quantitative CT , 1999, Skeletal Radiology.

[4]  R. Putz,et al.  Correlation of Femoral and Lumbar DXA and Calcaneal Ultrasound, Measured In Situ with Intact Soft Tissues, with the In Vitro Failure Loads of the Proximal Femur , 1998, Osteoporosis International.

[5]  Wilson C. Hayes,et al.  Basic Orthopaedic Biomechanics , 1995 .

[6]  J. Ferretti Peripheral Quantitative Computed Tomography for Evaluating Structural and Mechanical Properties of Small Bone , 1999 .

[7]  M. Anliker,et al.  Bone loss in premenopausal and postmenopausal women. A cross-sectional and longitudinal study using quantitative computed tomography. , 1984, The Journal of bone and joint surgery. American volume.

[8]  T A Einhorn,et al.  Fractures Attributable to Osteoporosis: Report from the National Osteoporosis Foundation , 1997, Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research.

[9]  S. Majumdar,et al.  Noninvasive assessment of bone mineral and structure: State of the art , 1996, Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research.

[10]  W C Hayes,et al.  Age-related reductions in the strength of the femur tested in a fall-loading configuration. , 1995, The Journal of bone and joint surgery. American volume.

[11]  W. C. Hayes,et al.  Ultrasound and densitometry of the calcaneus correlate with the failure loads of cadaveric femurs , 1995, Calcified Tissue International.

[12]  M. Bouxsein,et al.  Prediction of the strength of the elderly proximal femur by bone mineral density and quantitative ultrasound measurements of the heel and tibia. , 1999, Bone.

[13]  R I Price,et al.  Formalin fixation effects on vertebral bone density and failure mechanics: an in-vitro study of human and sheep vertebrae. , 1994, Clinical biomechanics.

[14]  R. Epstein,et al.  Hip fractures in the elderly. How to reduce morbidity and mortality. , 1988, Postgraduate medicine.

[15]  C. Reiners,et al.  Clinical evaluation of a high-resolution new peripheral quantitative computerized tomography (pQCT) scanner for the bone densitometry at the lower limbs. , 1998, Physics in medicine and biology.

[16]  L. Claes,et al.  Prediction of fracture load at different skeletal sites by geometric properties of the cortical shell , 1996, Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research.

[17]  P. Kannus,et al.  Peripheral Quantitative Computed Tomography in Human Long Bones: Evaluation of In Vitro and In Vivo Precision , 1998, Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research.

[18]  F. Eckstein,et al.  Effect of Fixation, Soft-Tissues, and Scan Projection on Bone Mineral Measurements with Dual Energy X-ray Absorptiometry (DXA) , 2001, Calcified Tissue International.

[19]  H. Genant,et al.  Quantitative computed tomography at the axial and peripheral skeleton , 1997, European Radiology.

[20]  L. Melton,et al.  Medical Expenditures for the Treatment of Osteoporotic Fractures in the United States in 1995: Report from the National Osteoporosis Foundation , 1997, Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research.

[21]  D. Gazit,et al.  Osteoporosis as the sole presentation of bone marrow mastocytosis , 1990, Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research.

[22]  M. Hahn,et al.  Heterogeneity of the skeleton: Comparison of the trabecular microarchitecture of the spine, the iliac crest, the femur, and the calcaneus , 1996, Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research.

[23]  H K Genant,et al.  Assessment of bone mineral at appendicular sites in females with fractures of the proximal femur. , 1998, Bone.

[24]  H. Takahashi,et al.  Peripheral Quantitative Computed Tomography of the Femoral Neck in 60 Japanese Women , 1999, Calcified Tissue International.