Sex-related variations in cortical and trabecular bone of the femoral neck in an elderly Chinese population

Sagittal support rather than medial cortical support matters in geriatric intertrochanteric fracture: A finite element analysis study

Hip fracture, increasing exponentially with age, is osteoporosis's most severe clinical consequence. Intertrochanteric fracture, one of the main types of hip fracture, is associated with higher mortality and morbidity. The current research hotspots lay in improving the treatment effect and optimizing the secondary stability after intertrochanteric fracture surgery. Cortex buttress reduction is a widely accepted method for treating intertrochanteric fracture by allowing the head-neck fragment to slide and rigidly contact the femoral shaft's cortex. Medial cortical support is considered a more effective option in treating young patients. However, osteo-degenerations features, including bone weakness and cortical thickness thinning, affect the performance of cortex support in geriatric intertrochanteric fracture treatment. Literature focusing on the age-specific difference in cortex performance in the fractured hip is scarce. We hypothesized that this osteo-19 degenerative feature affects the performance of cortex support in treating intertrochanteric fractures between the young and the elderly. We established twenty models for the old and the young with intertrochanteric fractures and performed static and dynamic simulations under one-legged stance and walking cycle conditions. The von Mises stress and displacement on the femur, proximal femoral nail anti-rotation (PFNA) implant, fracture plane, and the cutting volume of cancellous bone of the femur were compared. It was observed that defects in the anterior and posterior cortical bone walls significantly increase the stress on the PFNA implant, the displacement of the fracture surface, and cause a greater volume of cancellous bone to be resected. We concluded that ensuring the integrity and alignment of the anterior and posterior cortical bones is essential for elderly patients, and sagittal support is recommended. This finding suggests that the treatment method for intertrochanteric fracture may differ, considering the patient's age difference.

To Evaluate the Value of Vertebral Body Cortical Thickness in Predicting Osteoporosis by Opportunistic CT

BACKGROUND

In vertebrae, the amount of cortical bone has been estimated at 30-60%, but 45-75% of axial load on a vertebral body is borne by cortical bone (1).

RATIONALE AND OBJECTIVES

The purpose of this study is to investigate the accuracy, sensitivity, specificity, positive predictive value and negative predictive value of vertebral body cortical thickness in predicting osteoporosis (OP) by analyzing the relationship between vertebral body cortical thickness and bone mineral density (BMD) in different age and gender groups. The optimal diagnostic cut-off value of vertebral body cortical thickness in predicting OP was analyzed.

MATERIALS AND METHODS

The data of 150 patients (50-89 years old) who underwent chest or abdominal Quantitative computed tomography (QCT) scan (obtained in one scan) in our hospital from July 2021 to July 2022 were retrospectively analyzed. The average volume bone mineral density (vBMD) of L1-L2 vertebral bodies was obtained and grouped according to BMD, age, and gender. According to BMD, the patients were divided into three groups: osteoporosis, osteopenia and normal. According to age, the patients were divided into three groups: 50-59 years, 60-69 years and ≥70 years. The axial images of T11, T12 and L1 were reconstructed with 1.25 mm slice thickness by AW4.7 workstation provided by General Electric Co (GE) Company. The images were imported into the computed tomography (CT) Spine Bone Quantification System software for spine analysis, and the vertebral body cortical thickness values were obtained. CT Spine Bone Quantification System is a software for quantitative analysis and separation of cortical bone and cancellous bone.

RESULTS

A total of 150 patients were enrolled in this study, including 49 patients in the osteoporosis group, 51 patients in the osteopenia group, and 50 patients in the normal group. The cortical thickness values of T11, T12 and L1 were positively correlated with BMD, and the correlation coefficient was 0.750 at T11. According to the receiver operating characteristic (ROC) curve analysis of T11, T12, L1 cortical thickness value and BMD, OP was diagnosed when T11 < 2.75 mm, T12 < 3.06 mm, and L1 < 2.67 mm. The sensitivity was 83.67%, 87.76%, 75.51%, respectively. The specificity was 79.21%, 71.29% and 90.10%, respectively, and the difference was statistically significant.

CONCLUSION

Vertebral body cortical thickness is correlated with BMD and age. According to the cut-off value of different vertebral bodies, OP can be predicted when T11 < 2.75 mm or T12 < 3.06 mm or L1 < 2.67 mm.

General and local predictors of mandibular cortical bone morphology in adult females and males: the seventh survey of the Tromsø Study

OBJECTIVES

To analyze factors predicting mandibular cortical width (MCW) and mandibular cortical index (MCI) in adult females and males.

MATERIAL AND METHODS

Data on 427 females and 335 males aged 40-84 from The Tromsø study: Tromsø7 were used. T-score, age, menopausal status (for females), remaining teeth, and periodontal status were analyzed in linear and logistic regression analyses as predictors of MCW and MCI, respectively.

RESULTS

T-score, age, and the number of remaining teeth significantly predicted MCW in females but not males. Standardized β coefficients were 0.286, -0.231, and 0.131, respectively. The linear regression model explained 24% of MCW variation in females. MCI in females was significantly predicted by T-score, age, and remaining teeth with the Wald values of 9.65, 6.17, and 5.83, respectively. The logistic regression model explained 16.3-23% of the variation in MCI in females. In males, T-score was the only significant predictor of the eroded cortex, and the logistic model explained only 4.3-5.8% of the variation in MCI.

CONCLUSIONS

The T-score demonstrated a stronger relationship with MCW and MCI than other factors in females, which supports the usefulness of those indices for osteoporosis screening. Conversely, the T-score exhibited no association with MCW and remained the only significant predictor of MCI in males, yet to a lesser extent than in females.

CLINICAL RELEVANCE

Understanding factors affecting mandibular cortical morphology is essential for further investigations of MCW and MCI usefulness for osteoporosis screening in females and males.

Site-Specific Differences in Bone Mineral Density of Proximal Femur Correlate with the Type of Hip Fracture

The aim of this study was to investigate whether site-specific differences in bone mineral density (BMD) of proximal femur correlate with the type of hip fracture using quantitative computed tomography. Femoral neck (FN) fractures were classified as nondisplaced or displaced subtypes. Intertrochanteric (IT) fractures were classified as A1, A2, or A3. The severe hip fractures were identified as displaced FN fractures or unstable IT fractures (A2 and A3). In total, 404 FN fractures (89 nondisplaced and 317 displaced) and 189 IT fractures (76 A1, 90 A2, and 23 A3) were enrolled. Areal BMD (aBMD) and volumetric BMD (vBMD) were measured in the regions of total hip (TH), trochanter (TR), FN, and IT of the contralateral unfractured femur. IT fractures exhibited lower BMD than FN fractures (all p ≤ 0.01). However, unstable IT fractures had higher BMD compared with stable ones (p < 0.01). After adjusting for covariates, higher BMD in TH and IT were associated with IT A2 (A1 vs. A2: odds ratios (ORs) from 1.47 to 1.69, all p < 0.01). Low bone measurements were risk factors for stable IT fractures (IT A1 vs. FN fracture subtypes: ORs from 0.40 to 0.65, all p < 0.01). There are substantial site-specific differences in BMD between IT fractures A1 and displaced FN fractures. Higher bone density was associated with unstable IT fracture when compared with stable ones. The understanding of biomechanics of various fracture types could help to improve the clinical management of these patients.

Intrinsic Cortical Property Analysis of the Medial Column of Proximal Humerus

OBJECTIVE

Adequate mechanical support of the medial column is paramount to maintain fracture reduction in locking plating of proximal humerus fractures. However, intrinsic cortical properties of the medial column are rarely discussed. The purpose of the study is to describe regional variation of cortex in the medial column.

METHODS

A total of 147 healthy participants were eligible for enrollment between December 2016 and December 2018. Subjects were divided into three groups: group A (20-39 years), group B (40-59 years), and group C (>60 years). For each individual, a color 3D thickness map for proximal humerus was created by cortical bone mapping (CBM) technique after bilateral shoulders were imaged by computed tomography. Measurement Indices including the cortical thickness (CTh), cortical mass surface density (CM) and the endocortical trabecular density (ECTD) were determined, after six regions of interest (ROI) were defined in metaphyseal region. Regional parameter variations were analyzed by one-way ANOVA.

RESULTS

The CTh, CM and ECTD values were approximately equivalent between genders in the proximal part of the medial column across all ages (P > 0.05).The greatest difference between sexes was found in CTh and CM values of middle and distal part (P < 0.05). The CTh and CM within medial column were negatively associated with age (P < 0.05). The proximal cortical bone of the medial column was thicker and more dense, compared to the lateral column (P < 0.05). Significant regional variation was found in all measured parameters in group A, but not in groups B and C.

CONCLUSION

Our finding proved that regional differences in the distribution of cortical bone in the medial column The attenuation of cortical bone heterogeneity in the medial column was found after the age of 40 years.

Structural Factors Associated With Femoral Neck Fractures and its Prediction in Chinese Males

We have recently proposed a new approach to evaluate 2D femoral neck (FN) structure, named the Minimal Model (MM), that comprised FN areal bone mineral density (FNaBMD) and FNWidth and 2 new internal structural measures; (1) the standard deviation of normalized mineral mass projection profile distribution (FNSigma), and (2) the displacement between center-of-mineral mass and geometric center of mineral mass projection profile (FNDelta). The contralateral hip of 67 FN fracture Chinese male patients had a QCT scan shortly after fracture and was compared to 156 community participants without hip fracture. The QCT scans were analyzed using Mindways software to enable DXA-equivalent 2D images to be obtained; MM variables were calculated from these images. In FN fracture and nonfracture participants, the 4 MM variables as well as age, weight and height were compared. Compared to nonfracture, fracture participants were older, weighed less and were taller. After adjustment for these differences FN fracture participants compared to nonfracture had mean ± SD lower FNaBMD 0.54 ± 0.11 vs 0.70 ± 0.11 g/cm² (p < 0.001); larger FNSigma 1.05 ± 0.11 vs 0.98 ± 0.10 cm (p < 0.001); larger FNDelta 0.43 ± 0.09 vs 0.33 ± 0.09 cm (p < 0.001), however FNWidth did not differ 2.96 ± 0.35 vs 2.92 ± 0.34 cm. All variables except FNaBMD and FNWidth were correlated; however logistic regression identified increased age and height, reduced FNaBMD and increased FNSigma as independent contributors to differentiating participants with FN fracture from nonfracture. Area under ROC analysis identified significant improvement in discrimination with addition of FNSigma to the base model of Age and FNaBMD (C statistic 0.88 and 0.91, p = 0.019). These analyses identified important internal structural information available from 2D DXA imaging that contributes to discrimination of FN fracture in addition to low bone mass. This analytical approach may contribute to improved clinical FN fracture prediction, extending value of widely available DXA technology.

Morphometric Evaluation of Detailed Asymmetry for the Proximal Humerus in Korean Population

Computer-assisted orthopedic surgery and patient-specific instruments are widely used in orthopedic fields that utilize contralateral side bone data as a template to restore the affected side bone. The essential precondition for these techniques is that the left and right bone features are similar. Although proximal humerus fracture accounts for 4% to 8% of all fractures, the bilateral asymmetry of the proximal humerus is not fully understood. The aim of this study is to investigate anthropometric differences of the bilateral proximal humerus. One hundred one pairs of Korean humerus CT data from 51 females and 50 males were selected for this research. To investigate bilateral shape differences, we divided the proximal humerus into three regions and the proximal humerus further into five sections in each region. The distance from the centroid to the cortical outline at every 10 degrees was measured in each section. Differences were detected in all regions of the left and right proximal humerus; however, males had a larger number of significant differences than females. Large bilateral differences were measured in the greater tubercle. Nevertheless, using contralateral data as a template for repairing an affected proximal humerus might be possible.

Lack of periosteal apposition in the head and neck of femur after menopause in Chinese women with high risk for hip fractures - A cross-sectional study with QCT

In elderly subjects and in particular in those with osteoporosis the evidence on age related volume changes of the hip is still very limited. Even less is known about bone changes of the femoral head. The aim of this study is to explore associations of bone size of the femoral head and neck with age in postmenopausal women with very high risk of hip fracture and to investigate associations of femoral head and neck bone mineral density. MIAF (medical image analysis framework)-Femur was used for the analysis of CT datasets from 319 females with acute hip fractures age 50 to 98. Integral BMD and volume of the head and neck were assessed. The femoral head was divided into four quadrants to address differential vBMD and volume responses of its superior, inferior, posterior and anterior parts. Areal BMD (aBMD) of femoral neck was also obtained. In this population of postmenopausal women we did not observe age-related changes in bone volume of the femoral head or neck between ages 50 and 98 years. Integral vBMD in the head in the 90-98 year group was 48.0 mg/cm³ lower than that in 50-59 year group, which accounts for nearly 30% decrease in vBMD with 40 years increase. Age-related vBMD changes in the head quadrants were similar to that in total. With age, the trend line correlation coefficients for vBMD in quadrants were relatively small, but significant (p < 0.001) for all. The femoral head integral vBMD correlates well with neck vBMD and FN aBMD. FN aBMD explained 45% of head integral vBMD variance (p < 0.0001). Elderly women had relative preservation of femoral head and neck bone volume from 50 yrs. over four decades but markedly lower integral vBMD of proximal femur. The findings of our study call in question about the concept of bone expansion with aging even in elderly age.

Age-related fatty infiltration of lumbar paraspinal muscles: a normative reference database study in 516 Chinese females

Background

Fatty infiltration, as a result of aging, is an essential biomarker of muscle degeneration. This research aimed to investigate the age-dependent change of fatty degeneration in the paraspinal muscles of healthy Chinese women. This study also explores the effect of body size on fatty infiltration of paraspinal muscles.

Methods

Cross-sectional area of paraspinal muscles (CSA_muscle) and intermuscular adipose tissue (CSA_IMAT) were measured at the L3 mid-vertebral level of 516 healthy females, who underwent abdomen quantitative computed tomography (QCT) scans. Subsequently, IMAT% [CSA_IMAT / (CSA_IMAT + CSA_muscle)] were calculated. The relationship between basic information and measurements was evaluated using Spearman correlations. Comparisons of QCT results among different BMI subgroups in different age groups were analyzed with the Kruskal-Wallis H test and LSD, post-hoc correction. Age-related changes were calculated after the adjustment of height and weight.

Results

The mean CSA_IMAT of 20-29 years group (n=69) and 70-79 years group (n=25) were 3.00 cm² and 11.06 cm², respectively. While the mean CSA_muscle of 20-29 years group was 38.46 cm² and 70-79 years group was 30.86 cm². The mean IMAT% difference between 20-29 years group and 70-79 years group was -18.55%. Strong, positive non-linear associations were observed between ageing and CSA_IMAT, along with IMAT% (r=0.656, P<0.01; r=0.714, P<0.01). However, CSA_muscle was shown to decrease with age in a weak, negative linear fashion (r=-0.265, P<0.01). Positive relationships between BMI and CSA_IMAT, CSA_muscle, along with IMAT%, were found. Significant differences were observed between obesity and normal BMI subgroup for all variables in three age groups. CSA_IMAT showed a larger age-related difference compared to CSA_muscle.

Conclusions

Fatty infiltration in paraspinal muscles increased with age and BMI, while muscle loss may be associated with aging. The present study provided standardized reference data for the fatty degeneration of paraspinal muscles across the adult lifespan of Chinese females, which will play a critical role in future studies.

CTXA hip: the effect of partial volume correction on volumetric bone mineral density data for cortical and trabecular bone

This study compares the results of computed tomography X-ray absorptiometry (CTXA) hip volumetric BMD (vBMD) analyses of cortical and trabecular bone with and without partial volume correction. For cortical bone in some circumstances, corrected cortical volumes were negative and corrected vBMD was very high. For trabecular bone, the correction effects are smaller. CTXA volumetric data should be interpreted with caution.

PURPOSE

Previous studies have reported concerns about the reliability of CTXA hip cortical vBMD measurements generated using partial volume (PV) correction (the "default" analysis, with cortical PV correction). To date, no studies have examined the results of the alternative ("new") analysis (with trabecular PV correction). This study presents in vivo and phantom data comparing the corrected and uncorrected data for cortical and trabecular bone respectively.

METHODS

We used the commercial QCTPro CTXA software to analyze CT scans of 129 elderly Chinese men and women and an anthropomorphic European Proximal Femur phantom (EPFP) and accessed data for two alternative scan analyses using the database dump utility. The CTXA software gives the user two methods of performing the PV correction: (1) a default analysis in which only cortical bone results are corrected; (2) a new analysis in which only trabecular bone results are corrected. Both methods are based on a numerical recalculation of vBMD values without any change in volume of interest (VOI) placement.

RESULT

In vivo, the results of the two analyses for integral bone were the same while cortical and trabecular results were different. PV correction of cortical bone led to a decrease of cortical volume for all four VOIs: total hip (TH), femoral neck (FN), trochanter (TR), and intertrochanter (IT) volumes were reduced on average by 7.8 cm³, 0.9 cm³, 2.5 cm³, and 4.3 cm³ respectively. For TR, where cortex was thinnest, average corrected cortical volume was negative (- 0.4± 1.3 cm³). Corrected cortical vBMD values were much larger than uncorrected ones for TH, FN, and IT. Scatter plots of corrected cortical vBMD against cortical bone thickness showed that elevated results correlated with thinner cortices. When trabecular bone was corrected for the PV effect, trabecular volumes of TH, FN, TR, and IT were reduced on average by 7.9 cm³, 0.8 cm³, 2.6 cm³, and 4.4 cm³ respectively, while vBMD measurements were increased correspondingly. The trabecular volume and vBMD measurements of the two datasets both had highly positive correlations. For the EPFP, the PV-corrected FN data deviated from the nominal phantom value, but was closer for the TR and IT VOIs. Both corrected and uncorrected data overestimated trabecular vBMD, with the corrected results showing greater deviation from nominal values.

CONCLUSION

The default and new CTXA analyses for volumetric data generate different results, both for cortical and trabecular bone. For cortical bone, the uncorrected results are subject to partial volume effects but the correction method of the default analysis overcorrects the effect leading to in part unreasonable results for cortical bone volume and BMD. For trabecular bone, the correction effects are smaller. CTXA volumetric data should be interpreted with caution.

The spatial differences in bone mineral density and hip structure between low-energy femoral neck and trochanteric fractures in elderly Chinese using quantitative computed tomography

The purpose of this study was to investigate the differences in bone mineral density (BMD) and hip structure between femoral neck and trochanteric fractures in elderly Chinese individuals using quantitative computed tomography (QCT). A total of 625 Chinese patients (mean age 75.8 years) who sustained low-energy hip fractures (female: 293 femoral neck, 175 trochanteric; male: 82 femoral neck, 75 trochanteric) were recruited. Each patient underwent a hip QCT scan. The areal BMD (aBMD) of the contralateral normal hip was obtained using a computed tomography X-ray absorptiometry module. Using the bone investigation toolkit (BIT) module, the femoral neck was divided into four quadrants: supero-anterior (SA), infero-anterior (IA), infero-posterior (IP), and supero-posterior (SP). Estimated cortical thickness, cortical BMD, and trabecular BMD were measured in each quadrant. Using the hip structure analysis (HSA) function, several parameters were calculated. Stratified by sex, covariance analyses were applied to compare the femoral neck fractures group with trochanteric fractures group after adjustments for age, height, and weight. In women, trochanteric fractures exhibited lower trabecular BMD and estimated cortical thickness at three quadrants of the femoral neck (IA: P = 0.02, P < 0.01; IP: P < 0.01, P = 0.01; SP: P = 0.01, P < 0.01), and lower aBMD at the trochanter area (P < 0.01); femoral neck fractures exhibited lower cortical BMD and estimated cortical thickness at the SA quadrant (P = 0.04, P = 0.01). Differences in HSA parameters were not statistically significant. Among all parameters, the most valuable ones to discrimination of hip fracture type are estimated cortical thickness of the SA quadrant of femoral neck and the aBMD of the trochanter area. In men, only lower cortical BMD at the SP quadrant and aBMD at the trochanter were found in the trochanteric fractures (P = 0.02, P < 0.01). QCT outcomes indicate that spatial differences are helpful to explore the pathogenesis of different type of hip fractures. In women, trochanteric fractures are related to severer osteoporosis, whereas cortical fragility in the SA region of the femoral neck predominates in cases of femoral neck fractures. In men, trochanteric fractures are related to more bone loss of trochanter.

Regional characteristics of cortical bone quality in the proximal humerus of postmenopausal women: a preliminary study

BACKGROUND

Proximal humeral fractures represent the third most common fragility fracture treated in osteoporotic populations, after hip and distal radial fractures. The purpose of this study was to characterize the spatial variability in cortical geometry in the proximal humerus in postmenopausal women.

METHODS

The proximal humeri in 43 healthy postmenopausal women were imaged by computed tomography. Cortical bone mapping was applied to create color 3-dimensional thickness maps for each proximal humerus. Cortical parameters, including the cortical thickness (CTh), cortical mass surface density (CM), and endocortical trabecular density, were measured over the humeral head and metaphyseal region after 15 regions of interest (ROIs) were defined.

RESULTS

In the humeral head region, significant differences in CTh and CM values were detected between the anterior, lateral, and posterior walls (P < .05). The highest CTh and CM were found in the anterior wall in each plane (P < .05). Regarding the endocortical trabecular density, no significant findings were noted in the 3 planes (P > .05). In the metaphyseal region, the cortical structure in the medial column had higher CTh and CM values in ROI 10 compared with the lateral column (P < .05). The highest CTh and CM values of compact bone were seen in ROI 10 of the medial column (ROIs 10-12) (P < .05).

CONCLUSION

Our results showed significant regional variation of cortical bone in the humeral head region in postmenopausal women. Similar conditions were seen in the medial column in the metaphyseal region. This finding provides discriminatory information for stronger fixation of implants.

QCT of the femur: Comparison between QCTPro CTXA and MIAF Femur

QCT is commonly employed in research studies and clinical trials to measure BMD at the proximal femur. In this study we compared two analysis software options, QCTPro CTXA and MIAF-Femur, using CT scans of the semi-anthropometric European Proximal Femur Phantom (EPFP) and in vivo data from 130 Chinese elderly men and women aged 60-80 years. Integral (Int), cortical (Cort) and trabecular (Trab) vBMD, volume, and BMC of the neck (FN), trochanter (TR), inter-trochanter (IT), and total hip (TH) VOIs were compared. Accuracy was determined in the 5 mm wide central portion of the femoral neck of the EPFP. Nominal values were: cross-sectional area (CSA) 4.9 cm², cortical thickness (C.Th) 2 mm, CortBMD 723 mg/cm³ and TrabBMD 100 mg/cm³. In MIAF the so-called peeled trabecular VOI was analyzed, which excludes subcortical bone to avoid partial volume artefacts at the endocortical border that artificially increase TrabBMD. For CTXA uncorrected, so called raw cortical values were used for the analysis. QCTPro and MIAF phantom results were: CSA 5.9 cm² versus 5.1 cm²; C.Th 1.68 mm versus 1.92 mm; CortBMD 578 mg/cm³ versus 569 mg/cm³; and TrabBMD 154 mg/cm³ versus 104 mg/cm³. In vivo correlations (R²) of integral and trabecular bone parameters ranged from 0.63 to 0.96. Bland-Altman analysis for TH and FN TrabBMD showed that lower mean values were associated with higher differences, which means that TrabBMD differences between MIAF and CTXA are larger for osteoporotic than for normal patients, which can be largely explained by the inclusion of subcortical BMD in the trabecular VOI analyzed by CTXA in combination with fixed thresholds used to separate cortical from trabecular bone compartments. Correlations between CTXA corrected CortBMD and MIAF were negative, whereas raw data correlated positively with MIAF measurements for all VOIs questioning the validity of the CTXA corrections. The EPFP results demonstrated higher MIAF accuracy of cortical thickness and TrabBMD. Integral and trabecular bone parameters were highly correlated between CTXA and MIAF. Partial volume artefacts at the endocortical border artificially increased trabecular BMD by CTXA, especially for osteoporosis patients. With respect to volumetric cortical measurements with CTXA, the use raw data is recommended, because corrected data cause a negative correlation with MIAF CortBMD.

Differences in femoral neck structure between elderly Caucasian and Chinese populations: a cross-sectional study of Perth-Beijing cohorts

Structural skeletal differences of the femoral neck of older Beijing-Chinese and Perth-Caucasian women were compared; adjusting for frame size-related differences, Beijing-Chinese have lower periosteal width; however, indices of internal bone distribution suggest that Beijing-Chinese may exhibit increased resistance to fracture that may relate to the reduced hip fracture incidence.

INTRODUCTION

Ethnic differences in skeletal structure may relate to differences in hip fracture risk in Chinese and Caucasian populations. 2D mass, size, and structural biomechanics were compared in the two populations.

METHODS

Quantitative computed tomography-derived geometric variables were compared in age-matched community-derived female populations, 196 Beijing-Chinese 76.5 ± 4.8 (mean ± SD) years and 237 Perth-Caucasians 77.1 ± 5.0 years. These included scanned area (A), periosteal width (W), bone mineral content (BMC), aBMD, bone cross-sectional area (bCSA), section modulus (Z) and buckling ratio (BR). Assumption-free measures included sigma (σ), related to the distribution of bone in the scanned image previously identified as a predictor of hip fracture, and delta (δ), the center-of-mass displacement from the geometric center.

RESULTS

Compared to Beijing-Chinese, Perth-Caucasians were heavier (Beijing-Chinese 58.7 ± 11.8; Perth-Caucasians 66.1 ± 11.0 kg), taller (154.9 ± 16.7 vs 158.9 ± 6.0 cm), and had higher BMC, A, and W. After adjustment for frame size, BMC was not significantly different but W remained higher in Perth-Caucasians. Differences in variables aBMD, Z, BR, and σ favored higher resistance to failure with Beijing-Chinese before and after adjustment for frame size. δ was similar in both populations; bCSA was higher in Beijing-Chinese before adjustment for frame size but not after.

CONCLUSIONS

Bone mass differences in two populations were related to frame size differences. However, femoral neck width remained smaller in Beijing-Chinese suggesting effects of local genetic and environmental factors. In Beijing-Chinese participants compared to Perth-Caucasians, internal bone distribution suggests increased resistance to deformation if exposed to same force that may, in-part, relate to reduced incidence of hip fracture in Beijing-Chinese.