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Age- and gender-related differences in the geometric properties and biomechanical significance of intracortical porosity in the distal radius and tibia.
J Bone Miner Res 2010; 25(5):983-93JB

Abstract

Cortical bone contributes the majority of overall bone mass and bears the bulk of axial loads in the peripheral skeleton. Bone metabolic disorders often are manifested by cortical microstructural changes via osteonal remodeling and endocortical trabecularization. The goal of this study was to characterize intracortical porosity in a cross-sectional patient cohort using novel quantitative computational methods applied to high-resolution peripheral quantitative computed tomography (HR-pQCT) images of the distal radius and tibia. The distal radius and tibia of 151 subjects (57 male, 94 female; 47 +/- 16 years of age, range 20 to 78 years) were imaged using HR-pQCT. Intracortical porosity (Ct.Po) was calculated as the pore volume normalized by the sum of the pore and cortical bone volume. Micro-finite element analysis (microFE) was used to simulate 1% uniaxial compression for two scenarios per data set: (1) the original structure and (2) the structure with intracortical porosity artificially occluded. Differential biomechanical indices for stiffness (Delta K), modulus (Delta E), failure load (Delta F), and cortical load fraction (Delta Ct.LF) were calculated as the difference between original and occluded values. Regression analysis revealed that cortical porosity, as depicted by HR-pQCT, exhibited moderate but significant age-related dependence for both male and female cohorts (radius rho = 0.7; tibia rho = 0.5; p < .001). In contrast, standard cortical metrics (Ct.Th, Ct.Ar, and Ct.vBMD) were more weakly correlated or not significantly correlated with age in this population. Furthermore, differential microFE analysis revealed that the biomechanical deficit (Delta K) associated with cortical porosity was significantly higher for postmenopausal women than for premenopausal women (p < .001). Finally, porosity-related measures provided the only significant decade-wise discrimination in the radius for females in their fifties versus females in their sixties (p < .01). Several important conclusions can be drawn from these results. Age-related differences in cortical porosity, as detected by HR-pQCT, are more pronounced than differences in standard cortical metrics. The biomechanical significance of these structural differences increases with age for men and women and provides discriminatory information for menopause-related bone quality effects.

Authors+Show Affiliations

Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California-San Francisco, San Francisco, CA 94158, USA. andrew.burghardt@radiology.ucsf.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

19888900

Citation

Burghardt, Andrew J., et al. "Age- and Gender-related Differences in the Geometric Properties and Biomechanical Significance of Intracortical Porosity in the Distal Radius and Tibia." Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research, vol. 25, no. 5, 2010, pp. 983-93.
Burghardt AJ, Kazakia GJ, Ramachandran S, et al. Age- and gender-related differences in the geometric properties and biomechanical significance of intracortical porosity in the distal radius and tibia. J Bone Miner Res. 2010;25(5):983-93.
Burghardt, A. J., Kazakia, G. J., Ramachandran, S., Link, T. M., & Majumdar, S. (2010). Age- and gender-related differences in the geometric properties and biomechanical significance of intracortical porosity in the distal radius and tibia. Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research, 25(5), pp. 983-93. doi:10.1359/jbmr.091104.
Burghardt AJ, et al. Age- and Gender-related Differences in the Geometric Properties and Biomechanical Significance of Intracortical Porosity in the Distal Radius and Tibia. J Bone Miner Res. 2010;25(5):983-93. PubMed PMID: 19888900.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Age- and gender-related differences in the geometric properties and biomechanical significance of intracortical porosity in the distal radius and tibia. AU - Burghardt,Andrew J, AU - Kazakia,Galateia J, AU - Ramachandran,Sweta, AU - Link,Thomas M, AU - Majumdar,Sharmila, PY - 2009/11/6/entrez PY - 2009/11/6/pubmed PY - 2010/8/31/medline SP - 983 EP - 93 JF - Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research JO - J. Bone Miner. Res. VL - 25 IS - 5 N2 - Cortical bone contributes the majority of overall bone mass and bears the bulk of axial loads in the peripheral skeleton. Bone metabolic disorders often are manifested by cortical microstructural changes via osteonal remodeling and endocortical trabecularization. The goal of this study was to characterize intracortical porosity in a cross-sectional patient cohort using novel quantitative computational methods applied to high-resolution peripheral quantitative computed tomography (HR-pQCT) images of the distal radius and tibia. The distal radius and tibia of 151 subjects (57 male, 94 female; 47 +/- 16 years of age, range 20 to 78 years) were imaged using HR-pQCT. Intracortical porosity (Ct.Po) was calculated as the pore volume normalized by the sum of the pore and cortical bone volume. Micro-finite element analysis (microFE) was used to simulate 1% uniaxial compression for two scenarios per data set: (1) the original structure and (2) the structure with intracortical porosity artificially occluded. Differential biomechanical indices for stiffness (Delta K), modulus (Delta E), failure load (Delta F), and cortical load fraction (Delta Ct.LF) were calculated as the difference between original and occluded values. Regression analysis revealed that cortical porosity, as depicted by HR-pQCT, exhibited moderate but significant age-related dependence for both male and female cohorts (radius rho = 0.7; tibia rho = 0.5; p < .001). In contrast, standard cortical metrics (Ct.Th, Ct.Ar, and Ct.vBMD) were more weakly correlated or not significantly correlated with age in this population. Furthermore, differential microFE analysis revealed that the biomechanical deficit (Delta K) associated with cortical porosity was significantly higher for postmenopausal women than for premenopausal women (p < .001). Finally, porosity-related measures provided the only significant decade-wise discrimination in the radius for females in their fifties versus females in their sixties (p < .01). Several important conclusions can be drawn from these results. Age-related differences in cortical porosity, as detected by HR-pQCT, are more pronounced than differences in standard cortical metrics. The biomechanical significance of these structural differences increases with age for men and women and provides discriminatory information for menopause-related bone quality effects. SN - 1523-4681 UR - https://www.unboundmedicine.com/medline/citation/19888900/Age__and_gender_related_differences_in_the_geometric_properties_and_biomechanical_significance_of_intracortical_porosity_in_the_distal_radius_and_tibia_ L2 - https://doi.org/10.1359/jbmr.091104 DB - PRIME DP - Unbound Medicine ER -