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The second name of the ninth author, X.E. Guo, was incorrectly coded as part of his surname. The publisher apologises for the inconvenience caused.

This is a cross-sectional study to assess differences in bone quality in young Asian and Caucasian (n = 30/group) men between 25 and 35 years. We found that Asians had smaller bones, thicker and denser cortices, and more plate-like trabeculae, but stiffness did not differ between groups., Introduction: We conducted a cross-sectional study to assess differences in bone quality in young Asian and Caucasian (n = 30/group) men between 25 and 35 years., Methods: We measured bone mineral density (BMD) at the spine, total hip (TH), femoral neck (FN), and forearm by dual energy X-ray absorptiometry (DXA), and bone geometry, density, microarchitecture, and mechanical competence at the radius and tibia by high-resolution peripheral quantitative computed tomography (HR-pQCT) with application of individual trabecula segmentation (ITS) and trabecular and whole bone finite element analysis (FEA). We measured load-to-strength ratio to account for differences in bone size and height, respectively. We used Wilcoxon rank sum and generalized linear models adjusted for height, weight, and their interaction for comparisons., Results: Asians were 3.9 % shorter and weighed 6.5 % less than Caucasians. In adjusted models: by DXA, there were no significant race-based differences in areal BMD; by HR-pQCT, at the radius, Asians had smaller total and trabecular area (p = 0.003 for both), and denser (p = 0.01) and thicker (p = 0.04) cortices at the radius; by ITS, at the radius Asians, had more plate-like than rod-like trabeculae (PR ratio p = 0.01), greater plate trabecular surface (p = 0.009) and longer rod length (p = 0.002). There were no significant race-based differences in FEA or the load-to-strength ratio., Conclusions: Asians had smaller bones, thicker and denser cortices, and more plate-like trabeculae, but biomechanical estimates of bone strength did not differ between groups. Studies are needed to determine whether these differences persist later in life.

Unlabelled: Bone strength is dependent on bone density and microstructure. High-resolution peripheral quantitative computed tomography (HR-pQCT) can measure microstructure but is somewhat limited due to its resolution. We compared a new HR-pQCT scanner to existing technology and found very good agreement for most parameters. This study will be important when interpreting results from different devices., Introduction: Recently, a second-generation HR-pQCT scanner (XCT2) has been developed with a higher nominal isotropic resolution (61 μm) compared to the first-generation device (XCT1, 82 μm). It is unclear how in vivo measurements from these two devices compare. In this study, we obtained and analyzed in vivo XCT1 and XCT2 measurements of bone microarchitecture and estimated strength., Methods: We scanned 51 adults (16 men and 35 women, age 44.8 ± 16.0) on both XCT2 and XCT1 on the same day. We first compared XCT1 and XCT2 measurements obtained using their respective standard patient protocols. In XCT1, microarchitecture parameters were derived, while XCT2 measurements were directly measured. We also compared XCT2-D with XCT1 by finding the overlapping regions of interest and using the standard patient protocol for XCT1., Results: We obtained excellent agreement between XCT1 and XCT2 for most of the volumetric bone mineral density (vBMD), trabecular and cortical measurements (All R (2) > 0.820) except for cortical porosity at the radius (R (2) = 0.638), trabecular number (R (2) = 0.694, 0.787) and trabecular thickness (R (2) = 0.569, 0.527) at both radius and tibia, respectively. XCT1 and XCT2-D measurements also had excellent agreement for most of the measurements (all R (2) > 0.870) except trabecular number (R (2) = 0.524, 0.706), trabecular thickness (R (2) = 0.758, 0.734) at both radius and tibia, respectively, and trabecular separation (R (2) = 0.656) at the radius., Conclusion: While some caution should be exercised for parameters that are more dependent on image resolution, results from our study indicate that second-generation scans can be compared to more widely available first-generation data and may be beneficial for multicenter and longitudinal studies using both scanner generations.

Unlabelled: We used quantitative computed tomography and finite element analysis to classify women with and without hip fracture. Highly accurate classifications were achieved indicating the potential for these methods to be used for subject-specific assessment of fracture risk., Introduction: Areal bone mineral density (aBMD) is the current clinical diagnostic standard for assessing fracture risk; however, many fractures occur in people not defined as osteoporotic by aBMD. Finite element (FE) analysis based on quantitative computed tomography (QCT) images takes into account both bone material and structural properties to provide subject-specific estimates of bone strength. Thus, our objective was to determine if FE estimates of bone strength could classify women with and without hip fracture., Methods: Twenty women with femoral neck fracture and 15 women with trochanteric fractures along with 35 age-matched controls were scanned with QCT at the hip. Since it is unknown how a specific subject will fall, FE analysis was used to estimate bone stiffness and bone failure load under loading configurations with femoral neck internal rotation angles ranging from -30° to 45° with 15° intervals. Support vector machine (SVM) models and a tenfold cross-validation scheme were used to classify the subjects with and without fracture., Results: High accuracy was achieved when using only FE analysis for classifying the women with and without fracture both when the fracture types were pooled (82.9 %) and when analyzed separately by femoral neck fracture (87.5 %) and trochanteric fracture (80.0 %). The accuracy was further increased when FE analysis was combined with volumetric BMD (pooled fractures accuracy, 91.4 %), Conclusions: While larger prospective studies are needed, these results demonstrate that FE analysis using multiple loading configurations together with SVM models can accurately classify individuals with previous hip fracture.

Unlabelled: High-resolution peripheral quantitative computed tomography (HR-pQCT) measurements of distal radius and tibia bone microarchitecture and finite element (FE) estimates of bone strength performed well at classifying postmenopausal women with and without previous fracture. The HR-pQCT measurements outperformed dual energy x-ray absorptiometry (DXA) at classifying forearm fractures and fractures at other skeletal sites., Introduction: Areal bone mineral density (aBMD) is the primary measurement used to assess osteoporosis and fracture risk; however, it does not take into account bone microarchitecture, which also contributes to bone strength. Thus, our objective was to determine if bone microarchitecture measured with HR-pQCT and FE estimates of bone strength could classify women with and without low-trauma fractures., Methods: We used HR-pQCT to assess bone microarchitecture at the distal radius and tibia in 44 postmenopausal women with a history of low-trauma fracture and 88 age-matched controls from the Calgary cohort of the Canadian Multicentre Osteoporosis Study (CaMos) study. We estimated bone strength using FE analysis and simulated distal radius aBMD from the HR-pQCT scans. Femoral neck (FN) and lumbar spine (LS) aBMD were measured with DXA. We used support vector machines (SVM) and a tenfold cross-validation to classify the fracture cases and controls and to determine accuracy., Results: The combination of HR-pQCT measures of microarchitecture and FE estimates of bone strength had the highest area under the receiver operating characteristic (ROC) curve of 0.82 when classifying forearm fractures compared to an area under the curve (AUC) of 0.71 from DXA-derived aBMD of the forearm and 0.63 from FN and spine DXA. For all fracture types, FE estimates of bone strength at the forearm alone resulted in an AUC of 0.69., Conclusion: Models based on HR-pQCT measurements of bone microarchitecture and estimates of bone strength performed better than DXA-derived aBMD at classifying women with and without prior fracture. In future, these models may improve prediction of individuals at risk of low-trauma fracture.

Unlabelled: We used high-resolution peripheral quantitative computed tomography (HR-pQCT) to monitor changes in bone microarchitecture and strength at the distal radius and tibia associated with 18 months of teriparatide therapy in postmenopausal women with osteoporosis. Despite treatment-associated declines in total and cortical BMD, trabecular thinning and reduced trabecular bone volume, bone strength did not change significantly from baseline., Introduction: Teriparatide is an established anabolic therapy for osteoporosis; however, treatment effects at the distal radius are unclear. Therefore, we aimed to monitor changes in bone microarchitecture and estimated strength at the distal radius and tibia in osteoporotic postmenopausal women., Methods: We used high-resolution peripheral quantitative computed tomography (Scanco Medical, Switzerland) to perform a standard three-dimensional morphological analysis of the distal radius and tibia in 11 osteoporotic postmenopausal women (mean age, 68.7 ± 12.7 years) at baseline, 6, 12, and 18 months after initiation of 20 μg/day of teriparatide. Ten of the women received bisphosphonate therapy prior to starting on teriparatide. In addition to the standard analysis, we quantified cortical bone mineral density (BMD), porosity, and thickness using an automated segmentation procedure and estimated bone strength (ultimate stress) using finite element analysis., Results: After 18 months, we observed a decrease in total BMD (p = 0.03) at the distal radius and a decrease in cortical BMD at the distal radius (p = 0.05) and tibia (p = 0.01). The declines in cortical BMD were associated with trends for increased cortical porosity at both sites. At the distal radius, 18 months of teriparatide treatment was also associated with trabecular thinning (p = 0.009) and reduced trabecular bone volume ratio (p = 0.08). We observed similar trends at the distal tibia. Despite these changes in bone quality, bone strength was maintained over the 18-month follow-up., Conclusions: The observed changes in cortical bone structure are consistent with the effects of parathyroid hormone on intracortical bone remodeling. Controlled trials involving larger sample sizes are required to confirm the effects of teriparatide therapy on trabecular and cortical microarchitecture in the peripheral skeleton.