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Impact microindentation (IMI) is a novel technique for assessing bone material strength index (BMSi) in vivo, by measuring the depth of a micron-sized, spherical tip into cortical bone that is then indexed to the depth of the tip into a reference material. The aim of this study was to define the reference intervals for men and women by evaluating healthy adults from the United States of America, Europe and Australia. Participants included community-based volunteers and participants drawn from clinical and population-based studies. BMSi was measured on the tibial diaphysis using an OsteoProbe in 479 healthy adults (197 male and 282 female, ages 25 to 98 years) across seven research centres, between 2011 and 2018. Associations between BMSi, age, sex and areal bone mineral density (BMD) were examined following an a posteriori method. Unitless BMSi values ranged from 48 to 101. The mean (± standard deviation) BMSi for men was 84.4 ± 6.9 and for women, 79.0 ± 9.1. Healthy reference intervals for BMSi were identified as 71.0 to 97.9 for men and 59.8 to 95.2 for women. This study provides healthy reference data that can be used to calculate T- and Z-scores for BMSi and assist in determining the utility of BMSi in fracture prediction. These data will be useful for positioning individuals within the population and for identifying those with BMSi at the extremes of the population.

UNLABELLED: We tested whether cortical porosity of the proximal femur measured using StrAx1.0 software provides additional information to areal bone mineral density (aBMD) or Fracture Risk Assessment Tool (FRAX) in differentiating women with and without fracture. Porosity was associated with fracture independent of aBMD and FRAX and identified additional women with fractures than by osteoporosis or FRAX thresholds. INTRODUCTION: Neither aBMD nor the FRAX captures cortical porosity, a major determinant of bone strength. We therefore tested whether combining porosity with aBMD or FRAX improves identification of women with fractures. METHODS: We quantified femoral neck (FN) aBMD using dual-energy X-ray absorptiometry, FRAX score, and femoral subtrochanteric cortical porosity using StrAx1.0 software in 211 postmenopausal women aged 54-94 years with nonvertebral fractures and 232 controls in Tromsø, Norway. Odds ratios (ORs) were calculated using logistic regression analysis. RESULTS: Women with fractures had lower FN aBMD, higher FRAX score, and higher cortical porosity than controls (all p < 0.001). Each standard deviation higher porosity was associated with fracture independent of FN aBMD (OR 1.39; 95% confidence interval 1.11-1.74) and FRAX score (OR 1.58; 1.27-1.97) in all women combined. Porosity was also associated with fracture independent of FRAX score in subgroups with normal FN aBMD (OR 1.88; 1.21-2.94), osteopenia (OR 1.40; 1.06-1.85), but not significantly in those with osteoporosis (OR 1.48; 0.68-3.23). Of the 211 fracture cases, only 18 women (9%) were identified using FN aBMD T-score < -2.5, 45 women (21%) using FRAX threshold >20%, whereas porosity >80th percentile identified 61 women (29%). Porosity identified 26% additional women with fractures than identified by the osteoporosis threshold and 21% additional women with fractures than by this FRAX threshold. CONCLUSIONS: Cortical porosity is a risk factor for fracture independent of aBMD and FRAX and im

UNLABELLED: Guidelines concerning the definition of failure of therapies used to reduce the risk of fracture are provided. INTRODUCTION: This study aims to provide guidelines concerning the definition of failure of therapies used to reduce the risk of fracture. METHODS: A working group of the Committee of Scientific Advisors of the International Osteoporosis Foundation was convened to define outcome variables that may assist clinicians in decision making. RESULTS: In the face of limited evidence, failure of treatment may be inferred when two or more incident fractures have occurred during treatment, when serial measurements of bone remodelling markers are not suppressed by anti-resorptive therapy and where bone mineral density continues to decrease. CONCLUSION: The provision of pragmatic criteria to define failure to respond to treatment provides an unmet clinical need and may stimulate research into an important issue.

Summary: Changes in bone mineral density and bone strength following treatment with zoledronic acid (ZOL) were measured by quantitative computed analysis (QCT) or dual-energy X-ray absorptiometry (DXA). ZOL treatment increased spine and hip BMD vs placebo, assessed by QCT and DXA. Changes in trabecular bone resulted in increased bone strength. Introduction: To investigate bone mineral density (BMD) changes in trabecular and cortical bone, estimated by quantitative computed analysis (QCT) or dual-energy X-ray absorptiometry (DXA), and whether zoledronic acid 5 mg (ZOL) affects bone strength. Methods: In 233 women from a randomized, controlled trial of once-yearly ZOL, lumbar spine, total hip, femoral neck, and trochanter were assessed by DXA and QCT (baseline, Month 36). Mean percentage changes from baseline and between-treatment differences (ZOL vs placebo, t-test) were evaluated. Results: Mean between-treatment differences for lumbar spine BMD were significant by DXA (7.0%, p<0.01) and QCT (5.7%, p<0.0001). Between-treatment differences were significant for trabecular spine (p=0.0017) [non-parametric test], trabecular trochanter (10.7%, p<0.0001), total hip (10.8%, p<0.0001), and compressive strength indices at femoral neck (8.6%, p=0.0001), and trochanter (14.1%, p<0.0001). Conclusions: Once-yearly ZOL increased hip and spine BMD vs placebo, assessed by QCT vs DXA. Changes in trabecular bone resulted in increased indices of compressive strength. © International Osteoporosis Foundation and National Osteoporosis Foundation 2009.

Summary: Changes in bone mineral density and bone strength following treatment with zoledronic acid (ZOL) were measured by quantitative computed analysis (QCT) or dual-energy X-ray absorptiometry (DXA). ZOL treatment increased spine and hip BMD vs placebo, assessed by QCT and DXA. Changes in trabecular bone resulted in increased bone strength. Introduction: To investigate bone mineral density (BMD) changes in trabecular and cortical bone, estimated by quantitative computed analysis (QCT) or dual-energy X-ray absorptiometry (DXA), and whether zoledronic acid 5 mg (ZOL) affects bone strength. Methods: In 233 women from a randomized, controlled trial of once-yearly ZOL, lumbar spine, total hip, femoral neck, and trochanter were assessed by DXA and QCT (baseline, Month 36). Mean percentage changes from baseline and between-treatment differences (ZOL vs placebo, t-test) were evaluated. Results: Mean between-treatment differences for lumbar spine BMD were significant by DXA (7.0%, p<0.01) and QCT (5.7%, p<0.0001). Between-treatment differences were significant for trabecular spine (p=0.0017) [non-parametric test], trabecular trochanter (10.7%, p<0.0001), total hip (10.8%, p<0.0001), and compressive strength indices at femoral neck (8.6%, p=0.0001), and trochanter (14.1%, p<0.0001). Conclusions: Once-yearly ZOL increased hip and spine BMD vs placebo, assessed by QCT vs DXA. Changes in trabecular bone resulted in increased indices of compressive strength. © International Osteoporosis Foundation and National Osteoporosis Foundation 2009.

This paper describes the reconstruction of the remodelling cycle in normal iliac crest cortical bone from static and dynamic variables after double labelling with tetracycline in 10 young normal individuals.The average duration of the resorptive period was 27 days during which the average rate of resorption was 4.7-mu-m/day. The final resorption depth was 76-mu-m. The diameter of osteoclast containing cutting cones was significantly smaller (P < 0.05) than cutting cones containing mononclear cells, indicating an initial osteoclastic resorption phase preceeding a mononuclear resorption phase. The average mineralization lag-time was 8 days and the formative period 89 days. Osteoid thickness during this period averaged 5.8-mu-m. The seam thickness varied with the underlying uncompleted wall thickness, i.e., during the course of the formative period, with matrix deposition initially exceeding, later equalling and finally lower than the rate of mineralization. The mineral appositional rate (MAR) was 1.2-mu-m/day and the adjusted mineral oppositional rate (Aj.AR)0.9-mu-m/day. Both MAR and Aj.AR decreased during the formative period. A completed wall thickness of 62-mu-m left a Haversian canal with a diameter of 29-mu-m. After a quiescent period of 438 days the osteon (or parts of it) was reactivated. The average activation frequency was 0.93 per year.

This paper describes the reconstruction of the remodelling cycle in normal iliac crest cortical bone from static and dynamic variables after double labelling with tetracycline in 10 young normal individuals.The average duration of the resorptive period was 27 days during which the average rate of resorption was 4.7-mu-m/day. The final resorption depth was 76-mu-m. The diameter of osteoclast containing cutting cones was significantly smaller (P < 0.05) than cutting cones containing mononclear cells, indicating an initial osteoclastic resorption phase preceeding a mononuclear resorption phase. The average mineralization lag-time was 8 days and the formative period 89 days. Osteoid thickness during this period averaged 5.8-mu-m. The seam thickness varied with the underlying uncompleted wall thickness, i.e., during the course of the formative period, with matrix deposition initially exceeding, later equalling and finally lower than the rate of mineralization. The mineral appositional rate (MAR) was 1.2-mu-m/day and the adjusted mineral oppositional rate (Aj.AR)0.9-mu-m/day. Both MAR and Aj.AR decreased during the formative period. A completed wall thickness of 62-mu-m left a Haversian canal with a diameter of 29-mu-m. After a quiescent period of 438 days the osteon (or parts of it) was reactivated. The average activation frequency was 0.93 per year.