3D-DXA: Assessing the Femoral Shape, the Trabecular Macrostructure and the Cortex in 3D from DXA images

DXA-based 3D finite element models predict hip fractures better than areal BMD in elderly women

Bone strength is a major contributor to fracture risk. Areal bone mineral density (aBMD) obtained from dual-energy X-ray absorptiometry (DXA) is used as a surrogate for bone strength in fracture risk prediction. 3D finite element (FE) models predict bone strength better than aBMD but need 3D computed tomography and are not automated. We have earlier developed a method to automatically reconstruct the 3D hip anatomy from a 2D hip DXA image, followed by subject-specific FE-based prediction of proximal femoral strength. In this study, we evaluate the method's ability to predict incident hip fractures in a population-based cohort of women (OSTPRE). We used a sub-cohort including 46 cases with a hip fracture (<10 years from DXA scan) and 2 healthy controls to each hip fracture case, matched by age, height, and body mass index. We automatically reconstructed the 3D hip anatomy and predicted proximal femoral strength using FE analysis for all the subjects of the sub-cohort. The FE-predicted proximal femoral strength was a significantly better predictor of incident hip fractures than aBMD (difference in area under the receiver operating characteristics curve, ΔAUROC = 0.10). This is the first time that 3D FE models obtained from a 2D hip DXA scan outperform aBMD in predicting incident hip fractures in a population-based prospectively followed cohort of women. Our approach provided an improved fracture risk prediction in a clinically feasible manner (only one single DXA image is needed) and without additional costs compared to the current clinical approach.

Bone evaluation and relationship between body composition and bone mass in anorexia nervosa followed up by a multidisciplinary team

PURPOSE

Anorexia nervosa is a psychiatric disorder characterized by self-imposed fasting and significant weight loss, leading to nutrient deficiencies that disrupt bone metabolism. This cross-sectional observational study aimed to characterize the bone health of women with anorexia nervosa using dual-energy X-ray absorptiometry (DXA), trabecular bone score (TBS), and 3D shaper analysis.

METHODS

The study involved 12 women diagnosed with anorexia nervosa monitored by a multidisciplinary team and 11 control subjects. Both groups underwent blood sampling and assessments with DXA, TBS, and 3D shaper analysis.

RESULTS

The results indicated that areal bone mineral density (aBMD) and Z-scores at the total hip and femoral neck were significantly lower in the anorexia group compared to controls (p < 0.05). Additionally, the fat mass index was reduced in women with anorexia (p < 0.05). Appendicular lean mass index (ALMI) was similar between the two groups. 3D shaper analysis revealed that surface BMD (sBMD), volumetric BMD (vBMD), integral vBMD, and trabecular vBMD were generally lower in the anorexia group. Associations were found between proximal femur 3D parameters and total hip and femoral neck aBMD. Moreover, significant correlations were observed between total cortical vBMD, total cortical sBMD, integral vBMD, and TBS. ALMI was associated with total cortical thickness and showed a trend toward association with femoral neck Z-score.

CONCLUSION

In addition to previous studies indicating bone impairment in AN using DXA and TBS, the present study suggests that the 3D Shaper is also capable of detecting bone loss in this disorder. Therefore, the data encourage the further studies to assess the role of the 3D Shaper in prediction of fracture.

Long-Term Changes in Parameters of Bone Quality in Kidney Transplant Recipients Treated with Denosumab

Kidney transplant recipients (KTRs) have an elevated fracture risk. While dual-energy X-ray absorptiometry (DXA) is commonly used to assess areal bone mineral density (aBMD), it does not capture all aspects of bone quality. We investigated the long-term effects on bone DXA-derived indices of bone quality in KTRs treated with denosumab and untreated with denosumab. This is a retrospective study, including KTRs treated with denosumab and untreated age and sex-matched KTR controls. DXA-derived parameters, including trabecular bone score (TBS) and 3D-DXA parameters, were measured at the lumbar spine and femur at baseline and after four years. Hierarchical linear models were used to assess the between-group effect of treatment over time, also adjusting for site-specific aBMDs. We enrolled 23 KTRs treated with denosumab and 23 KTR denosumab-untreated KTRs. Significant between-group differences over time in favor of the denosumab group were observed for TBS (0.843, 95%CI 0.439; 1.248,p < 0.001), trabecular volumetric BMD at the total hip (Tb.vBMD TH) (13.492, 95%CI 1.707; 25.278, p = 0.003), cortical volumetric BMD at the femoral neck (Ct.vBMD FN) (28.766, 95%CI 8.373; 49.158, p = 0.008), cortical surface BMD at the total hip (c.sBMD TH) (10.507, 95%CI 4.140; 16.873,p = 0.002), cortical surface at the femoral neck (c.sBMD FN) (8.795, 95%CI 2.818; 14.771, p = 0.006), and cortical thickness at the total hip (Ct.th.TH) (0.075, 95%CI 0.020; 0.130, p = 0.010). After adjusting for BMD, the differences on TBS and Ct.vBMD FN and c.sBMD FN remained significant. Denosumab treatment in KTRs was associated with better outcomes in terms of bone quality and geometry parameters, independent of changes in aBMD.

Use of 3D-DXA in the assessment of bone structure among patients with chronic kidney disease

Introduction

Patients in later stages of chronic kidney disease (CKD) have a 2- to 14-fold increase in fracture risk. Bone mineral density (BMD) assessment is limited due to the inability to measure trabecular and cortical bone characteristics and the interference of aortic calcifications.

Study objective

This study aimed to assess the trabecular bone score (TBS) and three-dimensional dual-energy X-ray absorptiometry (3D-DXA) in participants across all CKD stages.

Patients and methods

In total, 64 CKD patients (consisting of 28 female participants and 36 male participants, with an average age of 69.5 years) were included. There were 9, 12, 8, 9, 11, and 15 participants in stages G1, G2, G3a, G3b, G4, and G5 of CKD, respectively. BMD at the lumbar spine (LS) and proximal femur, as well as the LS TBS, were analyzed. The proximal femur parameters such as cortical and trabecular volumetric (v)BMD, cortical thickness (CTh), and surface (s)BMD at the total hip (TH) and femoral neck (FN) were analyzed using 3D-Shaper software.

Results

Comparison between the earlier stages (G1-G3a) and the later CKD stages (G3b-G5) showed significant differences in carboxy terminal collagen crosslinks (CTx) (386 vs.1053 ng/L), TH areal bone mineral density (aBMD; 0.991 vs. 0.859 g/cm2), cortical TH vBMD (831 vs. 795 mg/cm3), FN (837 vs. 788 mg/cm3), TH cortical sBMD (170 mg/cm2), and TH Cth (2.03 vs. 1.92 mm; all p < 0.05). Cross-sectional comparisons between each CKD stage showed a gradual decrease in the LS BMD, TH cortical vBMD, sBMD (FN and TH), and TH Cth. Strong positive associations between the glomerular filtration rate (GFR) and cortical parameters (FN/TH vBMD and TH Cth) were observed (p < 0.01).

Conclusion

In conclusion, advanced stages of CKD (G3b-G5) were associated with lower cortical bone parameters. The majority of the cortical parameters were correlated with the GFR, demonstrating a direct relationship between the kidney function and bone structure.

Modification of bone architecture following sleeve gastrectomy: a five-year follow-up

Bariatric surgery induces a decrease in areal BMD (aBMD), but the long-term effect on trabecular and cortical volumetric BMD (vBMD) has not been well assessed. The main aim of this 5-yr longitudinal study was to investigate the changes following sleeve gastrectomy (SG) in aBMD, bone turnover markers, and trabecular and cortical vBMD. Forty-five patients with obesity were assessed before and 1, 2, and 5 yr after SG. Trabecular and cortical vBMD, cortical thickness, and structural parameters were assessed by 3D-Shaper software at the hip. Values of bone turnover markers peaked after 1 yr and decreased after 2 and 5 yr, but without returning to baseline values. aBMD decreased mostly at the femoral neck (-9.7%) and total hip (-10.7%) over the 5 yr, with the greatest loss occurring at 1 yr (-5.9% and -6.3%, respectively). A similar profile of decrease was observed for integral hip vBMD with significant decreases of 6.6%, 7.7%, and 10.7% after 1, 2, and 5 yr, mainly due to a reduction in the trabecular (10.5%, 12.0%, and 17.2%, respectively) rather than cortical (1.4%, 1.9%, and 2.9%, respectively) component. A modest decrease in mean cortical thickness (2.5%, 2.8%, and 3.9%, respectively) and an alteration in the structural parameters were concomitantly observed. Older age and greater body weight loss were the factors most associated with an increased loss of aBMD and vBMD. In conclusion, the study demonstrates that SG induces not only an alteration in bone turnover and aBMD, but also a reduction in vBMD at the hip, predominantly due to trabecular component deterioration as determined by 3D-Shaper software. The maintenance of bone deterioration for at least 5 yr-ie, after 4 yr of relative body weight stabilization or minimal weight regain-suggests the need for a therapeutic approach to preserve bone health in patients who undergo SG.

Bone Structural Parameters as Measured by 3-Dimensional Dual-Energy X-Ray Absorptiometry Are Superior in Black Women and Demonstrate Unique Associations With Prior Fracture Versus White Women

OBJECTIVE

Black patients fracture less often than White patients at any given bone mineral density (BMD). This may be related to superior bone structure; however, bone structure is challenging to measure in clinical practice. Advances in 3-dimensional (3D) modeling have allowed for the measurement of trabecular and cortical parameters from dual-energy x-ray absorptiometry (DXA). This technology, known as 3D-DXA, may provide a way to assess hitherto unexplained differences in bone structure between Black and White patients.

METHODS

This is a secondary analysis of 775 women (368 Black and 407 White) previously recruited from an osteoporosis clinic. All women had undergone DXA and vertebral fracture assessment, and 3D-DXA was run retrospectively on the proximal femur BMD scan. Participants were classified as having a prior fracture if there was a fracture on vertebral fracture assessment or a self-reported history of fragility fracture.

RESULTS

Black women had generally superior 3D-DXA parameters, with the largest differences in cortical thickness of the femoral neck (FN) and buckling ratio of the FN. There were substantial differences in associations between fracture and 3D-DXA parameters in Black women compared with White women. After adjusting for age, glucocorticoids, and areal BMD T-score, cortical thickness of the FN was significantly associated with prior fracture (odds ratio, 1.4 per standard deviation decline; 95% CI, 1.0-1.9; P = .04) in Black women but not White women.

CONCLUSION

3D-DXA parameters were superior in Black women than in White women, and cortical thickness of the FN was associated with fractures only in Black women. 3D-DXA may improve fracture risk assessment in Black patients.

Characterization of bone disease in cystic fibrosis

With the increased life expectancy of people with cystic fibrosis (CF), clinical attention has focused on prevention and treatment of non-pulmonary comorbidities. CF-related bone disease (CFBD) is a common complication and leads to increased fracture rates. Dual energy X-ray absorptiometry (DXA) is the recommended and gold standard technique to identify and monitor bone health. However, DXA has limitations because of its two-dimensional nature. Complementary tools to DXA are available, such as trabecular bone score (TBS) and vertebral fracture assessment (VFA). Quantitative computed tomography (QCT), magnetic resonance imaging (MRI) and quantitative ultrasound (QUS) may also be useful.

Updated practice guideline for dual-energy X-ray absorptiometry (DXA)

The introduction of dual-energy X-ray absorptiometry (DXA) technology in the 1980s revolutionized the diagnosis, management and monitoring of osteoporosis, providing a clinical tool which is now available worldwide. However, DXA measurements are influenced by many technical factors, including the quality control procedures for the instrument, positioning of the patient, and approach to analysis. Reporting of DXA results may be confounded by factors such as selection of reference ranges for T-scores and Z-scores, as well as inadequate knowledge of current standards for interpretation. These points are addressed at length in many international guidelines but are not always easily assimilated by practising clinicians and technicians. Our aim in this report is to identify key elements pertaining to the use of DXA in clinical practice, considering both technical and clinical aspects. Here, we discuss technical aspects of DXA procedures, approaches to interpretation and integration into clinical practice, and the use of non-bone mineral density measurements, such as a vertebral fracture assessment, in clinical risk assessment.

Advanced 3D-DXA insights into bone density changes in hyperparathyroidism

Objectives

Primary hyperparathyroidism (PHPT) is a disorder marked by chronic parathyroid hormone hypersecretion, which affects bone turnover and remodelling processes. With a loss of bone density and an increase in bone porosity, the cortical compartment is most severely impacted. The study's goal is to assess PHPT's effects on the volumetric bone mineral density (vBMD) of the femur's trabecular compartment as well as the vBMD and thickness of the cortical bone.

Methods

This is a retrospective case-control study, valuating age, biochemical doses, anthropometric measurements, and bone measurements. Between 2011 and 2016, 74 Caucasian Italian women and men with PHPT were sought out. Biochemical analyses were added to bone mineral density (BMD) values found in the lumbar spine and femoral neck. Proximal femur parameters such as cortical and trabecular volumetric (v) BMD, cortical thickness (CTh) and surface (s) BMD were analyzed by 3D-DXA software (3D-SHAPER Medical, Spain).

Results

The findings showed a negative correlation between PHPT patients and controls, which was equally affecting the cortical and trabecular compartments. This correlation was especially evident in the areal BMD (aBMD) and vBMD measurements. Nonetheless, no appreciable correlation was found between the cortical level and the thickness of the cortical bone.

Conclusions

Parathormone (PHT) levels had an adverse effect on the cortical, trabecular volumetric density in this investigation, as was expected. Cortical thickness, however, is unaffected significantly. The literature and these findings are consistent.

Intraoperative physician assessment during total hip arthroplasty correlates with DXA parameters

PURPOSE

Orthopedic surgeons can assess bone status intraoperatively and recommend skeletal health evaluation for patients with poor bone quality. Intraoperative physician assessment (IPA) at the time of total knee arthroplasty correlates with preoperative DXA-measured bone mineral density (BMD). This study evaluated IPA during total hip arthroplasty (THA) as a quantitative measure of bone status based on tactile assessment.

METHODS

This retrospective analysis identified 60 patients (64 hips) undergoing primary THA who had IPA recorded in the operative report and a DXA within 2 years before surgery. Intraoperatively, two surgeons assessed bone quality on a 5-point scale (1 = excellent; 5 = poor). IPA score was compared to DXA BMD and T-score, 3D Shaper measurements, WHO classification, FRAX scores, radiographic Dorr classification, and cortical index.

RESULTS

There was a strong correlation between the IPA score and lowest T-score, WHO classification, and FRAX major and hip fracture scores (r =  ± 0.485-0.622, all p < 0.001). There was a moderate correlation between IPA score and total hip BMD and 3D Shaper measurements, including trabecular volumetric BMD, cortical surface BMD, and cortical thickness (r =  ± 0.326-0.386, all p < 0.01). All patients with below-average IPA scores had osteopenia or osteoporosis by DXA.

CONCLUSION

IPA during THA is a simple, valuable tool for quantifying bone status based on tactile feedback. This information can be used to identify patients with poor bone quality that may benefit from skeletal status evaluation and treatment and provide intraoperative guidance for implant selection. Orthopedic surgeons can assess bone health at the time of surgery. Intraoperative physician assessment (IPA) is a bone quality score based on surgeons' tactile assessment that correlates strongly with the lowest T-score, WHO classification, and FRAX fracture risk. IPA can guide surgical decision-making and future bone health treatment.

Age- and Sex-Related Volumetric Density Differences in Trabecular and Cortical Bone of the Proximal Femur in Healthy Population

BACKGROUND

There are age- and sex-related increases in the prevalence of osteoporosis. Bone densitometry based on dual energy X-ray absorptiometry (DXA) is the gold standard for the assessment of bone mineral density (BMD). Three-dimensional (3D) analysis of the proximal femur (3D-DXA) allows discrimination between cortical and trabecular compartments, and it has shown a good correlation with computed tomography. We aimed to assess age- and sex-related volumetric density differences in trabecular and cortical bone using 3D-DXA and determine the reference intervals for integral volumetric (v)BMD within the Argentine population.

METHODS

Healthy female and male adult subjects (N=1,354) from Argentina were included. Hip BMD was measured using DXA, and 3D analysis was performed using 3D-Shaper software. The integral vBMD, cortical surface BMD, and trabecular vBMD (trab vBMD) were measured.

RESULTS

The study population included 73.9% women (N=1,001) and 26.13% men (N=353). We found a significant decrease in integral vBMD between 20 and 90 years in both sexes (women, -23.1%; men, -16.6%). Bone loss indicated in the integral vBMD results was mainly due to a decrease in trabecular bone in both sexes (women, -33.4%; men, -27.7%). The age-related loss of cortical bone density was less and was limited to the female population, without no age-related differences in men. Moreover, 3D-DXA allowed us to propose reference intervals for integral vBMD.

CONCLUSIONS

We found age- and sex-related bone loss between 20 and 90 years in an Argentine cohort via integral vBMD measurements using 3D-DXA, mainly due to decreases in trabecular bone in both sexes. The age-related loss of cortical bone density was less and was limited to the female population.

Bone loss after bariatric surgery is observed mainly in the hip trabecular compartment and after hypoabsorptive techniques

We evaluated the impact of bariatric surgery on bone mineral density (BMD) and microarchitecture over one year using dual-energy X-ray absorptiometry (DXA), the trabecular bone score (TBS), and 3D-DXA to assess changes after different surgical techniques. This prospective, single-center study of 153 patients with severe obesity contrasts the effects on bone health of sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), and duodenal switch/single anastomosis duodeno-ileostomy with sleeve gastrectomy (DS/SADIS). To our knowledge, this is the first study to evaluate patients undergoing DS/SADIS and to incorporate 3D-DXA analysis in the assessment of bone loss. Patients were 81 % female with a mean age of 50 ± 9 years. Fifty-four per cent underwent SG; 16 %, RYGB; and 30 %, DS/SADIS. Our findings revealed a significant decrease in areal BMD at the LS (-3.49 ± 5.44 %), FN (-5.24 ± 5.86 %), and TH (-8.06 ± 5.14 %) one year after bariatric surgery. Bone microarchitecture at the LS assessed by TBS was degraded in 30 % of patients. Proximal femur 3D-DXA analysis showed that surgery-induced bone loss predominantly affects the trabecular compartment (Trabecular volumetric (v) BMD: -8.00 ± 6.57 %) rather than the cortical compartment (Cortical vBMD: -1.37 ± 2.79 %). These results suggest hypoabsorptive and mixed techniques (DS/SADIS and RYGB) were associated with greater BMD loss and deterioration of microarchitecture than restrictive techniques (SG). The primary determinants of bone density and impairment of microarchitecture were the extent of weight loss and the type of surgical procedure. Despite overall bone loss, Z-score assessments indicated that post-surgical bone status remained within or above the average ranges compared to a healthy population, except for TH following DS/SADIS. In conclusion, our research shows differences in the impact of bariatric surgery techniques on bone density and microarchitecture, emphasizing the need for careful postoperative monitoring of bone health, particularly in patients undergoing hypoabsorptive and mixed procedures.

Association between CKD-MBD and hip-bone microstructures in dialysis patients

Background

The longitudinal changes in hip-bone microstructures and estimated bone strength in dialysis patients, and the impact of chronic kidney disease-mineral and bone disorder (CKD-MBD) biomarkers on these changes, remain insufficiently explored.

Methods

This retrospective study examined changes in cortical and trabecular bone compartments and estimated bone-strength indices, obtained by using 3D-SHAPER software, in the hip regions of 276 dialysis patients over up to 2.5 years. We used multivariate mixed models to investigate the associations between time-dependent CKD-MBD biomarkers and bone health metrics.

Results

There was a significant decrease in areal bone mineral density (aBMD), integral volumetric BMD (vBMD), trabecular vBMD, cortical thickness and cortical surface BMD (sBMD). Similar deteriorations were found in estimated bone-strength indices [cross-sectional area (CSA), cross-sectional moment of inertia (CSMI), section modulus (SM) and buckling ratio]. Neither serum calcium nor phosphate levels were significantly associated with changes in three-dimensional parameters or estimated bone-strength indices. In contrast, serum alkaline phosphatase levels showed a significant inverse correlation with aBMD and CSA. The intact-parathyroid hormone (i-PTH) was significantly inversely correlated with aBMD, integral vBMD, trabecular vBMD, cortical thickness, cortical vBMD, CSA, CSMI and SM. When applying the KDIGO criteria as a sensitivity analysis, the higher PTH group had significant negative associations with aBMD, integral vBMD, cortical vBMD, cortical thickness and cortical sBMD. Notably, the lower PTH group showed a positive significant correlation with integral vBMD and trabecular vBMD.

Conclusions

Elevated PTH, not low PTH, was associated with deterioration of hip-bone microstructures. Better management of PTH levels may play a crucial role in the hip-bone microstructure in dialysis patients.

Effects of Abaloparatide on Bone Mineral Density in Proximal Femoral Regions Corresponding to Arthroplasty Gruen Zones: A Study of Postmenopausal Women with Osteoporosis

BACKGROUND

Low hip bone mineral density (BMD) in patients who undergo total hip arthroplasty (THA) increases the risk of periprosthetic fractures, implant instability, and other complications. Recently, emphasis has been placed on bone health optimization: treating low BMD prior to a planned orthopaedic implant procedure in an effort to normalize BMD and reduce the potential risk of future complications. Abaloparatide is a U.S. Food and Drug Administration-approved osteoanabolic agent for men and postmenopausal women with osteoporosis and a candidate drug for bone health optimization that, in addition to benefits at the spine, increases hip BMD and reduces nonvertebral fracture risk. We hypothesized that abaloparatide would improve BMD in proximal femoral regions surrounding a virtual THA stem.

METHODS

This post hoc analysis obtained dual x-ray absorptiometry (DXA) hip scans from 500 randomly selected postmenopausal women with osteoporosis from the Phase-3 Abaloparatide Comparator Trial in Vertebral Endpoints (ACTIVE, NCT01343004) study after 0, 6, and 18 months of abaloparatide (250 patients) or placebo (250 patients). Hip DXA scans underwent 3-dimensional (3D) modeling via 3D-Shaper, followed by virtual resection of the proximal femur and simulated placement of a tapered, flat-wedge hip stem that guided delineation of the Gruen zones that were fully (zones 1 and 7) or largely (zones 2 and 6) captured in the scanning region. Integral, cortical, and trabecular volumetric BMD, cortical thickness, and cortical surface BMD (the product of cortical volumetric BMD and cortical thickness) were determined for each zone.

RESULTS

Compared with placebo, the abaloparatide group showed greater increases in integral volumetric BMD in all zones at months 6 and 18; cortical surface BMD in zones 1, 6, and 7 at month 6; cortical thickness, cortical volumetric BMD, and cortical surface BMD in all zones at month 18; and trabecular volumetric BMD in zones 1 and 7 at months 6 and 18.

CONCLUSIONS

Abaloparatide increases BMD in proximal femoral regions that interact with and support femoral stems, suggesting that abaloparatide may have value for preoperative or potentially perioperative bone health optimization in patients with osteoporosis undergoing THA.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Effects of differences in dose and frequency of teriparatide on bone structure in Proximal Femur. - Analysis by DXA-based 3D-modeling (3D-SHAPER Software) -TRIPLE-BONE study (The effects of TeRIParatide preparation on bone mineraL density increase and BONE structure)

Trends toward more favorable improvement of the cortical bone parameters by once-weekly (56.5 μg once a week) and twice-weekly teriparatide (28.2 μg twice a week), and that of the trabecular bone parameters by once-daily (1/D) teriparatide (20 μg/day once a day) were shown.

PURPOSE

To examine the effects of differences in the amount of teriparatide (TPTD) per administration and its dosing frequency on the bone structure in the proximal femur by dual-energy X-ray absorptiometry (DXA)-based 3D-modeling (3D-SHAPER software).

METHODS

This was a multicenter retrospective study. Patients aged 50 years or older with primary osteoporosis who continuously received once-/twice-weekly (1・2/W, n = 60) or 1/D TPTD (n = 14) administration for at least one year were included in the study. Measurement regions included the femoral neck (FN), trochanter (TR), femoral shaft (FS), and total proximal hip (TH). Concurrently, the bone mineral density (BMD) and Trabecular Bone Score (TBS) were measured.

RESULTS

The cross-sectional area, cross-sectional moment of inertia, and section modulus in the FS were significantly improved in the 1・2/W TPTD group, as compared to the 1/D TPTD group. However, significant improvement of the cortical thickness and buckling ratio in the FN was observed in the 1/D TPTD group, as compared to the 1・2/W TPTD group. Trabecular BMD values in the FS and TH were significantly increased in the 1/D TPTD group, as compared to the 1・2/W TPTD group, while the cortical BMD values in the TR, FS, and TH were significantly increased in the 1・2/W TPTD group, as compared to the 1/D TPTD group.

CONCLUSION

Trends toward more favorable improvement of the cortical bone by 1・2/W TPTD and that of the trabecular bones by 1/D TPTD were observed.

3D-modeling from hip DXA shows improved bone structure with romosozumab followed by denosumab or alendronate

Romosozumab treatment in women with postmenopausal osteoporosis increases bone formation while decreasing bone resorption, resulting in large BMD gains to reduce fracture risk within 1 yr. DXA-based 3D modeling of the hip was used to assess estimated changes in cortical and trabecular bone parameters and map the distribution of 3D changes in bone parameters over time in patients from 2 randomized controlled clinical trials: FRAME (romosozumab vs placebo followed by denosumab) and ARCH (romosozumab vs alendronate followed by alendronate). For each study, data from a subset of ~200 women per treatment group who had TH DXA scans at baseline and months 12 and 24 and had provided consent for future research were analyzed post hoc. 3D-SHAPER software v2.11 (3D-SHAPER Medical) was used to generate patient-specific 3D models from TH DXA scans. Percentage changes from baseline to months 12 and 24 in areal BMD (aBMD), integral volumetric BMD (vBMD), cortical thickness, cortical vBMD, cortical surface BMD (sBMD), and trabecular vBMD were evaluated. Data from 377 women from FRAME (placebo, 190; romosozumab, 187) and 368 women from ARCH (alendronate, 185; romosozumab, 183) with evaluable 3D assessments at baseline and months 12 and 24 were analyzed. At month 12, treatment with romosozumab vs placebo in FRAME and romosozumab vs alendronate in ARCH resulted in greater increases in aBMD, integral vBMD, cortical thickness, cortical vBMD, cortical sBMD, and trabecular vBMD (P < .05 for all). At month 24, cumulative gains in all parameters were greater in the romosozumab-to-denosumab vs placebo-to-denosumab sequence and romosozumab-to-alendronate vs alendronate-to-alendronate sequence (P < .05 for all). 3D-SHAPER analysis provides a novel technique for estimating changes in cortical and trabecular parameters from standard hip DXA images. These data add to the accumulating evidence that romosozumab improves hip bone density and structure, thereby contributing to the antifracture efficacy of the drug.

A statistical shape analysis for the assessment of the main geometrical features of the distal femoral medullary canal

Statistical Shape Models (SSMs) are widely used in orthopedics to extract the main shape features from bone regions (e.g., femur). This study aims to develop an SSM of the femoral medullary canal, investigate its anatomical variability, and assess variations depending on canal length. The canals were isolated from 72 CT femur scans, through a threshold-based segmentation. A region of interest (ROI) was selected; sixteen segments were extracted from the ROI, ranging from 25% of the full length down to the most distal segment. An SSM was developed to identify the main modes of variation for each segment. The number of Principal Components (PCs) needed to explain at least 90% of the shape variance were three/four based on the length of the canal segment. The study examined the relationship between the identified PCs and geometric parameters like length, radius of curvature, ellipticity, mean diameter, and conicity, reporting range and percentage variation of these parameters for each segment. The SSMs provide insights into the anatomical variability of the femoral canal, emphasizing the importance of considering different segments to capture shape variations at various canal length. These findings can contribute for the design of personalized orthopedic implants involving the distal femur.

3D-DXA Based Finite Element Modelling for Femur Strength Prediction: Evaluation Against QCT

Osteoporosis is characterised by the loss of bone density resulting in an increased risk of fragility fractures. The clinical gold standard for diagnosing osteoporosis is based on the areal bone mineral density (aBMD) used as a surrogate for bone strength, in combination with clinical risk factors. Finite element (FE) analyses based on quantitative computed tomography (QCT) have been shown to estimate bone strength better than aBMD. However, their application in the osteoporosis clinics is limited due to exposure of patients to increased X-rays radiation dose. Statistical modelling methods (3D-DXA) enabling the estimation of 3D femur shape and volumetric bone density from dual energy X-ray absorptiometry (DXA) scan have been shown to improve osteoporosis management. The current study used 3D-DXA based FE analyses to estimate femur strength from the routine clinical DXA scans and compared its results against 151 QCT based FE analyses, in a clinical cohort of 157 subjects. The linear regression between the femur strength predicted by QCT-FE and 3D-DXA-FE models correlated highly (coefficient of determination R2 = 0.86) with a root mean square error (RMSE) of 397 N. In conclusion, the current study presented a 3D-DXA-FE modelling tool providing accurate femur strength estimates noninvasively, compared to QCT-FE models.

Primary Hyperparathyroidism: Assessment of the Effects of Parathyroidectomy Using Dual X-Ray Absorptiometry, Trabecular Bone Score, and Dual X-Ray Absorptiometry-Based Three-Dimensional Modeling

OBJECTIVE

This study aimed to evaluate the bone microstructure to determine whether curative surgery of primary hyperparathyroidism produces changes in bone mineral density (BMD), trabecular bone score (TBS), and three-dimensional (3D) dual x-ray absorptiometry (DXA) parameters and whether these changes are comparable.

METHODS

We retrospectively studied 85 patients (60 women and 25 men, 60.4 ± 12.5 years) diagnosed with primary hyperparathyroidism and undergoing parathyroidectomy. Mean percent changes in BMD (lumbar spine [LS], femoral neck [FN], total hip [TH], and 1/3 radius), TBS and 3D-DXA parameters (trabecular volumetric BMD (vBMD), cortical vBMD, integral vBMD, cortical surface density (sBMD), and cortical thickness at TH) after surgery (12, 24, and/or 36 months) were calculated and compared, and we sought the determinants of these changes.

RESULTS

After parathyroidectomy, BMD presented statistically significant mean increases in LS, FN, and TH during the first 3 years after surgery (P < .001), accompanied by an improvement in all 3D-DXA parameters, but there were no significant changes in 1/3 radius BMD or TBS. Cortical sBMD, trabecular vBMD, and integral vBMD reached mean increases of similar magnitude to those of FN and TH BMD. Age and preoperative serum levels of parathyroid hormone and carboxy-terminal telopeptide of type 1 collagen were significantly associated with percent changes after surgery.

CONCLUSION

We found a benefit of parathyroidectomy for bone, with significant percent increases in LS, FN, and TH BMD up to the third year after surgery, and a qualitative benefit for the hip in both its trabecular and cortical compartments and bone strength.

Use of noninvasive imaging to identify causes of skeletal fragility in adults with diabetes: a review

Diabetes, a disease marked by consistent high blood glucose levels, is associated with various complications such as neuropathy, nephropathy, retinopathy, and cardiovascular disease. Notably, skeletal fragility has emerged as a significant complication in both type 1 (T1D) and type 2 (T2D) diabetic patients. This review examines noninvasive imaging studies that evaluate skeletal outcomes in adults with T1D and T2D, emphasizing distinct skeletal phenotypes linked with each condition and pinpointing gaps in understanding bone health in diabetes. Although traditional DXA-BMD does not fully capture the increased fracture risk in diabetes, recent techniques such as quantitative computed tomography, peripheral quantitative computed tomography, high-resolution quantitative computed tomography, and MRI provide insights into 3D bone density, microstructure, and strength. Notably, existing studies present heterogeneous results possibly due to variations in design, outcome measures, and potential misclassification between T1D and T2D. Thus, the true nature of diabetic skeletal fragility is yet to be fully understood. As T1D and T2D are diverse conditions with heterogeneous subtypes, future research should delve deeper into skeletal fragility by diabetic phenotypes and focus on longitudinal studies in larger, diverse cohorts to elucidate the complex influence of T1D and T2D on bone health and fracture outcomes.

Areal bone mineral density, trabecular bone score and 3D-DXA analysis of proximal femur in psoriatic disease

Objectives

To evaluate bone mineral density (BMD) and bone quality, with assessment of the cortical and trabecular compartments, in patients with psoriasis (PsO) alone or with psoriatic arthritis (PsA).

Methods

Patients with PsA and patients with PsO alone were evaluated and compared to control subjects matched for age, sex and body mass index category. Areal BMD (aBMD) was determined for the lumbar spine, femoral neck, total hip and total body using dual-energy X-ray absorptiometry (DXA). Bone quality was evaluated by using trabecular bone score (TBS) at the lumbar spine, and by 3D DXA-based analysis (3D Shaper) for the proximal femur.

Results

One hundred ninety-six subjects including 52 patients with PsA and 52 patients with PsO and their respective paired controls were analyzed. Patients with PsA had comparable aBMD, TBS and 3D DXA analysis parameters compared to their paired controls. After adjustment for confounders, patients with PsO alone were characterized by a higher aBMD at the left femur and higher cortical 3D DXA derived parameters (total hip cortical surface BMD and total hip cortical thickness) than their paired controls. TBS was decreased in PsO compared to their controls.

Conclusion

Patients with PsA had normal bone mass and bone quality parameters. Patients with PsO were characterized by higher femoral neck bone density by DXA and cortical parameters by 3D DXA-based analysis, supporting no increased risk for hip fracture. Conversely, bone texture by TBS assessment was decreased in patients with PsO, which may be associated with impaired vertebral bone resistance.

Alteration of Volumetric Bone Mineral Density Parameters in Men with Spinal Cord Injury

Spinal cord injury (SCI) induces severe losses of trabecular and cortical volumetric bone mineral density (vBMD), which cannot be discriminated with conventional dual-energy X-ray absorptiometry (DXA) analysis. The objectives were to: (i) determine the effects of SCI on areal BMD (aBMD) and vBMD determined by advanced 3D-DXA-based methods at various femoral regions and (ii) model the profiles of 3D-DXA-derived parameters with the time since injury. Eighty adult males with SCI and 25 age-matched able-bodied (AB) controls were enrolled in this study. Trabecular and cortical vBMD, cortical thickness and derived strength parameters were assessed by 3D-SHAPER® software at various femoral subregions. Individuals with SCI had significantly lower integral vBMD, trabecular vBMD, cortical vBMD, cortical thickness and derived bone strength parameters (p < 0.001 for all) in total proximal femur compared with AB controls. These alterations were approximately to the same degree for all three femoral subregions, and the difference between the two groups tended to be greater for cortical vBMD than trabecular vBMD. There were minor differences according to the lesion level (paraplegics vs tetraplegics) for all 3D-DXA-derived parameters. For total proximal femur, the decreasing bone parameters tended to reach a new steady state after 5.1 years for integral vBMD, 7.4 years for trabecular vBMD and 9.2 years for cortical vBMD following SCI. At proximal femur, lower vBMD (integral, cortical and trabecular) and cortical thickness resulted in low estimated bone strength in individuals with SCI. It remains to be demonstrated whether these new parameters are more closely associated with fragility fracture than aBMD.

3D Finite Element Models Reconstructed From 2D Dual-Energy X-Ray Absorptiometry (DXA) Images Improve Hip Fracture Prediction Compared to Areal BMD in Osteoporotic Fractures in Men (MrOS) Sweden Cohort

Bone strength is an important contributor to fracture risk. Areal bone mineral density (aBMD) derived from dual-energy X-ray absorptiometry (DXA) is used as a surrogate for bone strength in fracture risk prediction tools. 3D finite element (FE) models predict bone strength better than aBMD, but their clinical use is limited by the need for 3D computed tomography and lack of automation. We have earlier developed a method to reconstruct the 3D hip anatomy from a 2D DXA image, followed by subject-specific FE-based prediction of proximal femoral strength. In the current study, we aim to evaluate the method's ability to predict incident hip fractures in a population-based cohort (Osteoporotic Fractures in Men [MrOS] Sweden). We defined two subcohorts: (i) hip fracture cases and controls cohort: 120 men with a hip fracture (<10 years from baseline) and two controls to each hip fracture case, matched by age, height, and body mass index; and (ii) fallers cohort: 86 men who had fallen the year before their hip DXA scan was acquired, 15 of which sustained a hip fracture during the following 10 years. For each participant, we reconstructed the 3D hip anatomy and predicted proximal femoral strength in 10 sideways fall configurations using FE analysis. The FE-predicted proximal femoral strength was a better predictor of incident hip fractures than aBMD for both hip fracture cases and controls (difference in area under the receiver operating characteristics curve, ΔAUROC = 0.06) and fallers (ΔAUROC = 0.22) cohorts. This is the first time that FE models outperformed aBMD in predicting incident hip fractures in a population-based prospectively followed cohort based on 3D FE models obtained from a 2D DXA scan. Our approach has potential to notably improve the accuracy of fracture risk predictions in a clinically feasible manner (only one single DXA image is needed) and without additional costs compared to the current clinical approach. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Long-Term Effect of Denosumab on Bone Disease in Patients with CKD

BACKGROUND

The effect of long-term denosumab therapy and of denosumab discontinuation on the cortical bone of the hip regions in dialysis patients has not been studied.

METHODS

This retrospective study investigated the cortical and trabecular compartments and estimated strength indices of the hip region, obtained using 3D-SHAPER software, after a maximum of 5 years of denosumab therapy in 124 dialysis patients. A Wilcoxon signed-rank test was used to identify the differences in each parameter before and after denosumab initiation. Similarly, we investigated the changes in these parameters after denosumab discontinuation in 11 dialysis patients.

RESULTS

Integral and trabecular volumetric bone mineral densities (BMD) were significantly lower at the start of denosumab therapy than those in 1 year before denosumab initiation. After starting denosumab, areal BMD (median change +7.7% [interquartile range (IQR), +4.6 to +10.6]), cortical volumetric BMD (median change +3.4% [IQR, +1.0 to +4.7]), cortical surface BMD (median change +7.1% [IQR, +3.4 to +9.4]), and cortical thickness (median change +3.2% [IQR, +1.8 to +4.9]) showed a significantly higher trend for 3.5 years, which then stabilized at a higher value compared with baseline. A similar trend in the trabecular volumetric BMD (median change +9.8% [IQR, +3.8 to +15.7]) was observed over 2.5 years, with a higher value maintained thereafter. The whole area of the hip region improved after denosumab therapy. Similar trajectories were also found in the estimated strength indices. Conversely, at 1 year after denosumab discontinuation, these 3D parameters and estimated strength indices tended to largely worsen. The lateral aspect of the greater trochanter was the most pronounced location showing volumetric BMD loss.

CONCLUSIONS

The BMD of both cortical and trabecular components in the hip region was significantly higher after starting denosumab therapy. However, these measurements exhibited a trend of declining substantially after the discontinuation of denosumab.

Femur 3D-DXA Assessment in Female Football Players, Swimmers, and Sedentary Controls

Cortical and trabecular volumetric bone mineral density (vBMD), cortical thickness and surface BMD (sBMD, density-to-thickness ratio) were analyzed in the proximal femur of elite female football players and artistic swimmers using three-dimensional dual-energy X-ray absorptiometry (3D-DXA) software and compared to sedentary controls. Football players had significantly higher (p<0.05) vBMD (mg/cm³) in the trabecular (263±44) and cortical femur (886±69) than artistic swimmers (224±43 and 844±89) and sedentary controls (215±51 and 841±85). Football players had also higher (p<0.05) cortical thickness (2.12±0.19 mm) and sBMD (188±22 mg/cm²) compared to artistic swimmers (1.85±0.15 and 156±21) and sedentary controls (1.87±0.16 and 158±23). Artistic swimmers did not show significant differences in any parameter analyzed for 3D-DXA when compared to sedentary controls. The 3D-DXA modeling revealed statistical differences in cortical thickness and vBMD between female athletes engaged in weight-bearing (football) and non-weight bearing (swimming) sports and did not show differences between the non-weight bearing sport and the sedentary controls. 3D-DXA modeling could provide insight into bone remodeling in the sports field, allowing evaluation of femoral trabecular and cortical strength from standard DXA scans.

Application of statistical shape modeling to the human hip joint: a scoping review

OBJECTIVE

The objective of this scoping review was to identify all examples of the application of statistical shape models to the human hip joint, with a focus on applications, population, methodology, and validation.

INTRODUCTION

Clinical radiographs are the most common imaging tool for management of hip conditions, but it is unclear whether radiographs can adequately diagnose or predict outcomes of 3D deformity. Statistical shape modeling, a method of describing the variation of a population of shapes using a small number of variables, has been identified as a useful tool to associate 2D images with 3D anatomy. This could allow clinicians and researchers to validate clinical radiographic measures of hip deformity, develop new ones, or predict 3D morphology directly from radiographs. In identifying all previous examples of statistical shape modeling applied to the human hip joint, this review determined the prevalence, strengths, and weaknesses, and identified gaps in the literature.

INCLUSION CRITERIA

Participants included any human population. The concept included development or application of statistical shape models based on discrete landmarks and principal component analysis. The context included sources that exclusively modeled the hip joint. Only peer-reviewed original research journal articles were eligible for inclusion.

METHODS

We searched MEDLINE, Embase, Cochrane CENTRAL, IEEE Xplore, Web of Science Core Collection, OCLC PapersFirst, OCLC Proceedings, Networked Digital Library of Theses and Dissertations, ProQuest Dissertations and Theses Global, and Google Scholar for sources published in English between 1992 and 2021. Two reviewers screened sources against the inclusion criteria independently and in duplicate. Data were extracted by 2 reviewers using a REDCap form designed to answer the review study questions, and are presented in narrative, tabular, and graphical form.

RESULTS

A total of 104 sources were considered eligible based on the inclusion criteria. From these, 122 unique statistical shape models of the human hip were identified based on 86 unique training populations. Models were most often applied as one-off research tools to describe shape in certain populations or to predict outcomes. The demographics of training populations were skewed toward older patients in high-income countries. A mean age between 60 and 79 years was reported in 29 training populations (34%), more than reported in all other age groups combined, and 73 training populations (85%) were reported or inferred to be from Europe and the Americas. Only 4 studies created models in a pediatric population, although 15 articles considered shape variation over time in some way. There were approximately equal numbers of 2D and 3D models. A variety of methods for labeling the training set was observed. Most articles presented some form of validation such as reporting a model's compactness (n = 71), but in-depth validation was rare.

CONCLUSIONS

Despite the high volume of literature concerning statistical shape models of the human hip, there remains a need for further research in key areas. We identified the lack of models in pediatric populations and low- and middle-income countries as a notable limitation to be addressed in future research.

The accuracy of statistical shape models in predicting bone shape: A systematic review

BACKGROUND

This systematic review aims to ascertain how accurately 3D models can be predicted from two-dimensional (2D) imaging utilising statistical shape modelling.

METHODS

A systematic search of published literature was conducted in September 2022. All papers which assessed the accuracy of 3D models predicted from 2D imaging utilising statistical shape models and which validated the models against the ground truth were eligible.

RESULTS

2127 papers were screened and a total of 34 studies were included for final data extraction. The best overall achievable accuracy was 0.45 mm (root mean square error) and 0.16 mm (average error).

CONCLUSION

Statistical shape modelling can predict detailed 3D anatomical models from minimal 2D imaging. Future studies should report the intended application domain of the model, the level of accuracy required, the underlying demographics of subjects, and the method in which accuracy was calculated, with root mean square error recommended if appropriate.

Geometry and bone mineral density determinants of femoral neck strength changes following exercise

Physical exercise induces spatially heterogeneous adaptation in bone. However, it remains unclear where the changes in BMD and geometry have the greatest impact on femoral neck strength. The aim of this study was to determine the principal BMD-and-geometry changes induced by exercise that have the greatest effect on femoral neck strength. Pre- and post-exercise 3D-DXA images of the proximal femur were collected of male participants from the LIFTMOR-M exercise intervention trial. Meshes with element-by-element correspondence were generated by morphing a template mesh to each bone to calculate changes in BMD and geometry. Finite element (FE) models predicted femoral neck strength changes under single-leg stance and sideways fall load. Partial least squares regression (PLSR) models were developed with BMD-only, geometry-only, and BMD-and-geometry changes to determine the principal modes that explained the greatest variation in neck strength changes. The PLSR models explained over 90% of the strength variation with 3 PLS components using BMD-only (R² > 0.92, RMSE < 0.06 N) and 8 PLS components with geometry-only (R² > 0.93, RMSE < 0.06 N). Changes in the superior neck and distal cortex were most important during single-leg stance while the superior neck, medial head, and lateral trochanter were most important during a sideways fall. Local changes in femoral neck and head geometry could differentiate the exercise groups from the control group. Exercise interventions may target BMD changes in the superior neck, inferior neck, and greater trochanter for improved femoral neck strength in single-leg stance and sideways fall.

2D-3D reconstruction of the proximal femur from DXA scans: Evaluation of the 3D-Shaper software

Introduction: Osteoporosis is currently diagnosed based on areal bone mineral density (aBMD) computed from 2D DXA scans. However, aBMD is a limited surrogate for femoral strength since it does not account for 3D bone geometry and density distribution. QCT scans combined with finite element (FE) analysis can deliver improved femoral strength predictions. However, non-negligible radiation dose and high costs prevent a systematic usage of this technique for screening purposes. As an alternative, the 3D-Shaper software (3D-Shaper Medical, Spain) reconstructs the 3D shape and density distribution of the femur from 2D DXA scans. This approach could deliver a more accurate estimation of femoral strength than aBMD by using FE analysis on the reconstructed 3D DXA. Methods: Here we present the first independent evaluation of the software, using a dataset of 77 ex vivo femora. We extend a prior evaluation by including the density distribution differences, the spatial correlation of density values and an FE analysis. Yet, cortical thickness is left out of this evaluation, since the cortex is not resolved in our FE models. Results: We found an average surface distance of 1.16 mm between 3D DXA and QCT images, which shows a good reconstruction of the bone geometry. Although BMD values obtained from 3D DXA and QCT correlated well (r ² = 0.92), the 3D DXA BMD were systematically lower. The average BMD difference amounted to 64 mg/cm³, more than one-third of the 3D DXA BMD. Furthermore, the low correlation (r ² = 0.48) between density values of both images indicates a limited reconstruction of the 3D density distribution. FE results were in good agreement between QCT and 3D DXA images, with a high coefficient of determination (r ² = 0.88). However, this correlation was not statistically different from a direct prediction by aBMD. Moreover, we found differences in the fracture patterns between the two image types. QCT-based FE analysis resulted mostly in femoral neck fractures and 3D DXA-based FE in subcapital or pertrochanteric fractures. Discussion: In conclusion, 3D-Shaper generates an altered BMD distribution compared to QCT but, after careful density calibration, shows an interesting potential for deriving a standardized femoral strength from a DXA scan.

Lumbar Bone Mineral Density Estimation From Chest X-Ray Images: Anatomy-Aware Attentive Multi-ROI Modeling

Osteoporosis is a common chronic metabolic bone disease often under-diagnosed and under-treated due to the limited access to bone mineral density (BMD) examinations, e.g., via Dual-energy X-ray Absorptiometry (DXA). This paper proposes a method to predict BMD from Chest X-ray (CXR), one of the most commonly accessible and low-cost medical imaging examinations. The proposed method first automatically detects Regions of Interest (ROIs) of local CXR bone structures. Then a multi-ROI deep model with transformer encoder is developed to exploit both local and global information in the chest X-ray image for accurate BMD estimation. The proposed method is evaluated on 13719 CXR patient cases with ground truth BMD measured by the gold standard DXA. The model predicted BMD has a strong correlation with the ground truth (Pearson correlation coefficient 0.894 on lumbar 1). When applied in osteoporosis screening, it achieves a high classification performance (average AUC of 0.968). As the first effort of using CXR scans to predict the BMD, the proposed algorithm holds strong potential to promote early osteoporosis screening and public health.

DXA-derived advanced hip analysis and the trabecular bone score in end-stage kidney disease secondary to type 1 diabetes

OBJECTIVE

Patients with end-stage kidney disease (ESKD) caused by type 1 diabetes mellitus (T1DM) have a heightened fracture risk. Bone mineral density (BMD) may predict fracture less accurately in ESKD than in patients with chronic kidney disease (CKD) stages 1-3b or the general population. Alternate, readily available imaging modalities are needed to improve ESKD fracture risk assessment. This study aimed to assess dual-energy X-ray absorptiometry (DXA)-derived BMD, the trabecular bone score (TBS) and advanced hip analysis parameters in patients with ESKD due to T1DM and to compare their results with those of patients with ESKD from other causes.

METHODS

We compared the DXA-derived TBS, hip cortical thickness (CT) and femoral neck (FN) buckling ratio (BR), an index of FN stability, of patients with T1DM and ESKD undergoing simultaneous pancreas kidney transplantation, patients with ESKD from other causes receiving kidney transplants and population reference ranges.

RESULTS

Of 227 patients with ESKD, 28% had T1DM and 65% were male. Compared with other ESKD patients, patients with T1DM were younger (42 ± 7.7 vs 51 ± 13.8 years), had shorter dialysis duration (24.4 ± 21 vs 42.6 ± 40 months), had higher HbA1c (7.9 ± 1.57% vs 5.4 ± 0.95%) and had lower BMI (25 ± 6 vs 27 ± 5 kg/m2). They had lower spine, hip and UD radius BMD Z-scores (all P ≤ 0.001), TBS (1.33 ± 0.12 vs 1.36 ± 0.12; P = 0.05), CT at the FN (P = 0.03), calcar (P = 0.006) and shaft (P < 0.001) and higher BR (10.1±7.1 vs 7.7±4; P = 0.006). All ESKD parameters were lower than population-based reference ranges (P < 0.001). Adjusting for age, sex, dialysis vintage and weight, prevalent vertebral fractures in patients with T1DM and ESKD were associated with higher BR (odds ratio (OR): 3.27 (95% CI: 1.19-8.92), P = 0.002) and lower FN CT (OR: 3.70 (95% CI: 1.13-12.50)).

CONCLUSION

Patients with ESKD and T1DM have reduced TBS, reduced CT and increased BR compared with other ESKD patients. Prospective study of these parameters is warranted to determine their utility in fracture risk prediction and management.

SIGNIFICANCE STATEMENT

Patients with ESKD and T1DM have an elevated fracture risk due to decreased bone strength. As an adjunct to BMD, evaluating dual-energy X-ray absorptiometry parameters that incorporate structural change may have greater value in patients with ESKD and T1DM than in the general population. In this study, patients with ESKD due to T1DM had lower BMD, lower trabecular bone scores, more severe loss of CT and higher BR than other patients with ESKD and people from the general population. Both lower CT and higher BR were associated with prevalent vertebral fractures in patients with T1DM and ESKD. Changes to these parameters should be evaluated for incident fracture prediction.

High-Intensity Exercise and Geometric Indices of Hip Bone Strength in Postmenopausal Women on or off Bone Medication: The MEDEX-OP Randomised Controlled Trial

To compare the effects of high-intensity resistance and impact training (HiRIT) to low-intensity, Pilates-based exercise (LiPBE) on proximal femur geometry and explore the influence of antiresorptive medication on those effects. Postmenopausal women with low bone mass, on or off antiresorptive bone medications were randomly allocated, stratified on medication intake, to eight months of twice-weekly, supervised HiRIT (Onero™) or LiPBE (Buff Bones®). 3D hip software was used to analyse proximal femur DXA scans. Outcomes included femoral neck (FN) and total hip (TH), volumetric (e.g. vBMC, vBMD) and geometric (e.g. cortical thickness, cross-sectional area [CSA], section modulus [Z]) indices of bone strength. Data were analysed using analysis of variance. Scans of 102 women were examined: LiPBE, 43; HiRIT, 37; LiPBE-med, 11; HiRIT-med, 11. HiRIT improved TH trabecular vBMC and vBMD (3.1 ± 1.1% versus - 1.2 ± 1.2%, p = 0.008; and 1.5 ± 1.0% versus - 1.6 ± 1.2%, p = 0.042, respectively) and FN and TH total vBMC (2.0 ± 0.8% versus - 0.2 ± 0.7%, p = 0.032; and 0.7 ± 0.4% versus - 0.8 ± 0.6%, p = 0.032, respectively), compared to losses in LiPBE. HiRIT also increased Z while LiPBE did not (p = 0.035). The combination of HiRIT and medication achieved greater improvements in FN total and trabecular vBMD, total BMC, CSA and Z than HiRIT alone. HiRIT improved geometric parameters of proximal femur strength, while LiPBE exercise was largely ineffective. Medication may enhance some HiRIT effects. Findings suggest reduced hip fracture risk in response to HiRIT.Trial registration number ACTRN12617001511325.

Abaloparatide Effects on Cortical Volumetric BMD and Estimated Strength Indices of Hip Subregions by 3D-DXA in Women With Postmenopausal Osteoporosis

In ACTIVE, abaloparatide increased areal BMD (aBMD) of the hip and femoral neck vs teriparatide and placebo in women with osteoporosis. Previously, 3D-processing of dual X-ray absorptiometry (DXA) scans of a subgroup of ACTIVE subjects showed similar increases in trabecular volumetric BMD (Tb.vBMD) and greater increases in cortical vBMD (Ct.vBMD) of the total hip with abaloparatide vs teriparatide. The current analyses from this subgroup describe 2D- and 3D-DXA data for hip subregions. Randomly selected subjects from ACTIVE (n = 250/treatment group) who received 18 mo of placebo, abaloparatide 80 µg, or open-label teriparatide 20 µg by daily subcutaneous injection underwent hip DXA at baseline, and mo 6 and 18 of treatment. Areal BMD of the femoral neck, trochanter, and femoral shaft was determined using standard 2D-DXA and 3D-SHAPER software to retrospectively evaluate changes from baseline in volumetric parameters of these 3 hip subregions, including trabecular and cortical segmentation. Changes in biomechanical parameters cross-sectional moment of inertia (CSMI), section modulus (Z), and buckling ratio were also evaluated. Femoral neck, trochanter, and shaft aBMD increased in the abaloparatide and teriparatide groups at mo 6 and 18 vs placebo, with greater increases for abaloparatide vs teriparatide at the femoral neck at mo 6 and the shaft at mo 6 and 18. All 3 subregions showed similar significant increases in Tb.vBMD with abaloparatide and teriparatide vs placebo, whereas Ct.vBMD of all 3 subregions showed greater increases after 18 mo of abaloparatide vs teriparatide. Biomechanical parameters improved in all subregions with abaloparatide and teriparatide vs placebo, with greater improvements in CSMI and Z of the femoral neck and lower shaft after 6 and 18 mo of abaloparatide vs teriparatide. Differential femoral neck and shaft Ct.vBMD responses may explain the greater increases in CSMI and Z of those subregions with abaloparatide vs teriparatide.

Proximal Femur Responses to Sequential Therapy with Abaloparatide Followed by Alendronate in Postmenopausal Women with Osteoporosis by 3D Modeling of Hip DXA

Previous subgroup analyses from the ACTIVE trial in women with postmenopausal osteoporosis (NCT01343004) using three‐dimensional (3D)‐processing of dual X‐ray absorptiometry (DXA) scans indicated greater increases in total hip cortical volumetric bone mineral density (Ct.vBMD) and estimated indices of hip strength following 18 months of abaloparatide (ABL) versus placebo or teriparatide. The current post hoc analyses describe hip 3D‐DXA data for ACTIVExtend (NCT01657162), in which 18 months of ABL followed by 24 months of alendronate (ABL/ALN) increased hip and spine areal BMD (aBMD) and reduced fracture risk versus placebo (PBO) followed by ALN (PBO/ALN). In an ACTIVExtend subgroup (ABL/ALN, n = 204; PBO/ALN, n = 202), hip DXA scans retrospectively underwent 3D modeling via 3D‐Shaper software. Changes from baseline in cortical and trabecular compartments were calculated for total hip and hip subregions (femoral neck, trochanter, and shaft). Estimated strength indices comprising cross‐sectional moment of inertia, section modulus, and buckling ratio were calculated for each hip subregion. Correlations between bone turnover marker levels at the time of alendronate initiation and subsequent BMD gains with alendronate were also investigated within each group. Total hip trabecular and cortical 3D‐DXA parameters increased from baseline in both groups (all p < 0.001), with greater average increases for ABL/ALN versus PBO/ALN (trabecular vBMD: 10.87% versus 4.3%; cortical thickness: 2.32% versus 1.14%; Ct.vBMD: 3.41% versus 1.86%; cortical surface BMD: 5.82% versus 3.0%; all p < 0.001). Strength indices in the ABL/ALN group improved in all subregions versus baseline (all p < 0.0001) and versus PBO/ALN (all p < 0.02). In the ABL/ALN group, collagen type I N‐terminal propeptide (P1NP) levels at the time of alendronate initiation correlated with subsequent percent changes in all 3D‐DXA parameters with 24 months of alendronate therapy. In conclusion, sequential ABL/ALN or PBO/ALN treatment improves trabecular and cortical 3D‐DXA parameters at the hip, as well as strength indices of hip subregions, with greater increases with ABL/ALN versus PBO/ALN. © 2022 Radius Health, Inc. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Do patients with type 2 diabetes have impaired hip bone microstructure? A study using 3D modeling of hip dual-energy X-ray absorptiometry

AIM

Patients with type 2 diabetes (T2DM) have more risk of bone fractures. However, areal bone mineral density (aBMD) by conventional dual-energy x-ray absorptiometry (DXA) is not useful for identifying this risk. This study aims to evaluate 3D-DXA parameters determining the cortical and trabecular compartments in patients with T2DM compared to non-diabetic subjects and to identify their determinants.

MATERIALS AND METHODS

Case-control study in 111 T2DM patients (65.4 ± 7.6 years old) and 134 non-diabetic controls (64.7 ± 8.6-year-old). DXA, 3D-DXA modelling via 3D-Shaper software and trabecular bone score (TBS) were used to obtain aBMD, cortical and trabecular parameters, and lumbar spine microarchitecture, respectively. In addition, biochemical markers as 25-hydroxyvitamin d, type I procollagen N-terminal propeptide (P1NP), C-terminal telopeptide of type I collagen (CTX), and glycated haemoglobin (HbA1c) were analysed.

RESULTS

Mean-adjusted values showed higher aBMD (5.4%-7.7%, ES: 0.33-0.53) and 3D-DXA parameters (4.1%-10.3%, ES: 0.42-0.68) in the T2DM group compared with the control group. However, TBS was lower in the T2DM group compared to the control group (-14.7%, ES: 1.18). In addition, sex (β = 0.272 to 0.316) and body mass index (BMI) (β = 0.236 to 0.455) were the most consistent and positive predictors of aBMD (p ≤ 0.01). BMI and P1NP were negative predictors of TBS (β = -0.530 and -0.254, respectively, p ≤ 0.01), while CTX was a positive one (β = 0.226, p=0.02). Finally, BMI was consistently the strongest positive predictor of 3D-DXA parameters (β = 0.240 to 0.442, p<0.05).

CONCLUSION

Patients with T2DM present higher bone mass measured both by conventional DXA and 3D-DXA, suggesting that 3D-DXA technology is not capable of identifying alterations in bone structure in this population. Moreover, BMI was the most consistent determinant in all bone outcomes.

Statistical Shape and Appearance Models: Development Towards Improved Osteoporosis Care

PURPOSE OF REVIEW

Statistical models of shape and appearance have increased their popularity since the 1990s and are today highly prevalent in the field of medical image analysis. In this article, we review the recent literature about how statistical models have been applied in the context of osteoporosis and fracture risk estimation.

RECENT FINDINGS

Recent developments have increased their ability to accurately segment bones, as well as to perform 3D reconstruction and classify bone anatomies, all features of high interest in the field of osteoporosis and fragility fractures diagnosis, prevention, and treatment. An increasing number of studies used statistical models to estimate fracture risk in retrospective case-control cohorts, which is a promising step towards future clinical application. All the reviewed application areas made considerable steps forward in the past 5-6 years. Heterogeneities in validation hinder a thorough comparison between the different methods and represent one of the future challenges to be addressed to reach clinical implementation.

Vertebral Fractures Occur Despite Control of Acromegaly and Are Predicted by Cortical Volumetric Bone Mineral Density

CONTEXT

Recent studies suggest that cortical bone could also play a role in vertebral fracture (VF) development in acromegaly.

OBJECTIVE

Evaluate the occurrence of VFs and their relationship to dual energy x-ray absorptiometry-derived bone parameters.

METHODS

A single-center 2-year prospective study of acromegaly patients was conducted. Each subject had L1-4 spine, femoral neck and total hip (TH) areal BMD measured using DXA, and trabecular bone score (TBS) measurement performed. 3D Shaper™ was used to assess proximal femur trabecular and cortical volumetric (v)BMD, cortical surface (s)BMD, and cortical thickness (Cth). VF assessment was performed using the lateral spine imaging IVA™ mode with a Hologic Horizon® densitometer using a semiquantitative approach. Study outcomes were assessed at 2 time points: baseline and month 24.

RESULTS

70 acromegaly patients (34 M/36F; average 55.1 years) were studied, including 26 with active disease. In 13 patients, 9 with controlled disease, VF was observed. A decrease in TBS, sBMD, neck trabecular vBMD, TH, and neck cortical vBMD in VF compared with non-VF subjects was observed (P < .05). Multivariate analysis of fracture prediction showed TH cortical vBMD as the best fracture prediction parameter with area under the curve of 0.774. TBS was negatively associated with fasting plasma glucose and glycated hemoglobin (HBA1c) at each time point during the follow-up.

CONCLUSION

From the total number of 13 VF subjects, 9 were in the controlled disease group. The most sensitive and specific predictor of incident VF was TH cortical vBMD, suggesting that cortical bone is involved in fracture development.

Predictive ability of novel volumetric and geometric indices derived from dual-energy X-ray absorptiometric images of the proximal femur for hip fracture compared with conventional areal bone mineral density: the Japanese Population-based Osteoporosis (JPOS) Cohort Study

Areal BMD (aBMD) from DXA is not a sufficiently accurate predictor of fracture. Novel volumetric BMD derived from 3D modeling of the hip from DXA images significantly improved the predictive ability for hip fracture relative to aBMD at the femoral neck, but not aBMD at the total hip.

INTRODUCTION

To clarify whether volumetric and geometric indices derived from novel three-dimensional (3D) modeling of the hip using dual-energy X-ray absorptiometric (DXA) images improve hip fracture prediction relative to areal bone mineral density (aBMD).

METHODS

We examined 1331 women who had completed the baseline survey and at least one follow-up survey over 20 years (age 40-79 years at baseline). Each survey included aBMD measurement at the hip by DXA. Volumetric and geometric indices of the hip at baseline and the 10-year follow-up were estimated from DXA images using a 3D modeling algorithm. Incident hip fractures during the 20-year follow-up period were identified through self-report. Cox proportional hazards regression models allowing for repeated measurements of predictors and outcomes were constructed, and their predictive ability for hip fracture was evaluated using areas under receiver operating characteristic curves (AUCs) and net reclassification improvement (NRI) over aBMD at the femoral neck (FN) and total hip (TH) as references.

RESULTS

During a median follow-up of 19.8 years, 68 incident hip fractures were identified (2.22/1000 person-years). A significantly larger AUC of trabecular volumetric BMD (vBMD) at the total hip (AUC = 0.741), femoral neck (AUC = 0.748), and intertrochanter (AUC = 0.738) and significant NRI (0.177, 0.149, and 0.195, respectively) were observed compared with FN-aBMD (AUC = 0.701), but not TH-aBMD.

CONCLUSIONS

vBMD obtained from 3D modeling using routinely obtained hip DXA images significantly improved hip fracture risk prediction over conventional FN-aBMD, but not TH-aBMD.

TRIAL REGISTRATION

The Japanese Population-Based Osteoporosis (JPOS) Cohort Study was retrospectively registered as UMIN000032869 in the UMIN Clinical Trials Registry on July 1, 2018.

Volumetric BMD by 3D-DXA and Trabecular Bone Score in Adults With Down Syndrome

Adults with Down syndrome (DS) have lower bone mineral density (BMD) than the general population. The objective of our study was to describe bone mineral status in DS population through volumetric BMD (vBMD) and trabecular bone score (TBS). Retrospective study of 297 subjects recruited from the Adult DS Outpatient Clinic of a tertiary care hospital in Spain, who underwent a bone densitometry for clinical purposes between January 2010 and June 2015. vBMD determination and TBS analysis on conventional DXA (Hologic QDR 4500) densitometer were performed in this cohort. The mean (±SD) age of our population was 34.3 (±10.9) years; 51% were women. Trabecular vBMD at total hip and femoral neck was lower in males than in females (191.7 ± 48.4 mg/cm³ vs 206.9 ± 46.7 mg/cm³, p = 0.007, and 250.5 ± 70.1 mg/cm³ vs 275.7 ± 66.2 mg/cm³, p = 0.002, respectively). Trabecular and cortical vBMD decreased with age, but age decline in trabecular vBMD was more pronounced in males. Likewise, lumbar TBS declined with age being normal in 63%, low in 29% and very low in 8% of subjects with DS, without differences between sexes. TBS showed a positive correlation (r = 0.37; p < 0.001, Kappa index= 0.275) with conventional DXA lumbar Z-score. vBMD at the hip showed lower values in DS subjects than in the general population, especially in males. Moreover, TBS was also lower at lumbar spine. Therefore, both assessments could be used as complementary tools to areal BMD (Z-score) to assess bone status in DS subjects.

Modification of bone mineral density, bone geometry and volumetric BMD in young women with obesity

BACKGROUND

Most obese women with low-trauma fractures present normal areal bone mineral density (aBMD), suggesting that other bone parameters are more determinant for fracture risk in these patients.

OBJECTIVES

(i) Determine the effects of obesity in young women on areal bone mineral density (aBMD), bone geometry, strength, and volumetric BMD determined by advanced DXA-based methods; (ii) model the profiles of bone parameters for each population with age; and (iii) determine the factors related to body composition (i.e. lean tissue mass and fat mass) potentially implicated in the "bone adaptation" in the femoral region.

SUBJECTS AND METHODS

Two hundred and twenty adolescent and young women from 18 to 35 years old were enrolled in this study: 128 patients with obesity and 92 age-matched (±6 months) normal-weight controls. aBMD was determined with DXA, whereas hip geometry and strength parameters were assessed by hip structural analysis (HSA) and volumetric BMD by 3D-SHAPER® software.

RESULTS

Compared with controls, subjects with obesity presented significantly higher aBMD at all bone sites, but the difference was greater at hip compared with lumbar spine or radius. Bone size estimates (i.e. cortical thickness), as well as strength estimates (i.e. cross-sectional area) were higher at all femoral subregions including femoral neck, intertrochanteric region and femoral shaft in young women with obesity. In whole proximal femur and all femoral compartments, vBMD was also higher in subjects with obesity, but the difference between groups was greater for cortical vBMD compared with trabecular vBMD. When hip bone parameters were modelled for each group from individual values, maximal values were reached between 20 and 26 years in both groups but, whatever the age, subjects with obesity presented higher values than controls. In both groups, lean body mass (LBM) was the parameter most positively associated with the greatest number of bone parameters studied.

CONCLUSION

Our study confirmed that young women with obesity presented higher aBMD, better hip geometry and greater strength compared with normal-weight controls. Additionally, cortical and trabecular compartments measured by 3D-SHAPER® were favourably and concomitantly modified. However, it remains to be demonstrated whether the evaluation of these new parameters would provide better prediction of fracture risk in this population than aBMD.

Bone Analysis Using Trabecular Bone Score and Dual-Energy X-Ray Absorptiometry-Based 3-Dimensional Modeling in Postmenopausal Women With Primary Hyperparathyroidism

OBJECTIVE

Predominance of bone loss in cortical sites with relative preservation of trabecular bone, even in postmenopausal women, has been described in primary hyperparathyroidism (PHPT). The aim of this study was to evaluate bone microarchitectural differences using dual-energy x-ray absorptiometry (DXA), trabecular bone score (TBS), and DXA-based 3-dimensional (3D) modeling (3D-DXA) between postmenopausal women diagnosed with PHPT (PM-PHPT) and healthy postmenopausal controls.

METHODS

This retrospective study included 44 women with PM-PHPT (9 of whom had fractures) and 48 healthy women matched by age, body mass index, and years since menopause treated at Hospital Universitario Fundación Jiménez Díaz between 2008 and 2017. The bone mineral density (BMD) of the lumbar spine (LS), femoral neck, total hip (TH), and 1/3 radius was assessed using DXA, and trabecular volumetric BMD (vBMD), cortical vBMD, integral vBMD, cortical thickness, and cortical surface BMD at TH were assessed using a 3D-DXA software and TBS at LS.

RESULTS

The mean adjusted BMD values at LS, the femoral neck, and TH; TBS at LS; and TH 3D-DXA parameters (trabecular vBMD, integral vBMD, cortical thickness, and cortical surface BMD) were significantly reduced in women with PM-PHPT compared with those in the controls. However, differences in mean cortical vBMD were not statistically significant (P = .078). There were no significant differences in mean BMD, TBS, or the 3D-DXA parameters between patients with fractures and those without fractures. The 25-hydroxyvitamin D level appeared to be associated with TBS but not with DXA and 3D-DXA measurements.

CONCLUSION

PM-PHPT has significant involvement of the trabecular and cortical compartments of the bone, as determined by DXA, TBS, and 3D-DXA.

Characterization of Structural Bone Properties through Portable Single-Sided NMR Devices: State of the Art and Future Perspectives

Nuclear Magnetic Resonance (NMR) is a well-suited methodology to study bone composition and structural properties. This is because the NMR parameters, such as the T2 relaxation time, are sensitive to the chemical and physical environment of the 1H nuclei. Although magnetic resonance imaging (MRI) allows bone structure assessment in vivo, its cost limits the suitability of conventional MRI for routine bone screening. With difficulty accessing clinically suitable exams, the diagnosis of bone diseases, such as osteoporosis, and the associated fracture risk estimation is based on the assessment of bone mineral density (BMD), obtained by the dual-energy X-ray absorptiometry (DXA). However, integrating the information about the structure of the bone with the bone mineral density has been shown to improve fracture risk estimation related to osteoporosis. Portable NMR, based on low-field single-sided NMR devices, is a promising and appealing approach to assess NMR properties of biological tissues with the aim of medical applications. Since these scanners detect the signal from a sensitive volume external to the magnet, they can be used to perform NMR measurement without the need to fit a sample inside a bore of a magnet, allowing, in principle, in vivo application. Techniques based on NMR single-sided devices have the potential to provide a high impact on the clinical routine because of low purchasing and running costs and low maintenance of such scanners. In this review, the development of new methodologies to investigate structural properties of trabecular bone exploiting single-sided NMR devices is reviewed, and current limitations and future perspectives are discussed.

3D analysis of bone mineral density in a cohort: age- and sex-related differences

Women have lower areal BMD (g/cm²) than men; however, the women have smaller-size bones. Our study showed that women ≤ 59 years have a hip volumetric BMD by DXA 3D similar to that of men of the same age. This makes us think about the importance of taking into account bone size at the time of analyzing the sex-related differences in bone mass.

PURPOSE

Women have lower areal BMD (g/cm²) than men; however, these studies do not take into account that women have smaller-size bones. Recently, three-dimensional (3D) modeling methods were proposed to analyze volumetric BMD (vBMD). We want to determine the values of vBMD at the hip by DXA-based 3D modeling in a cohort of people in order to know the age- and sex-related differences.

METHODS

A total of 2647 people of both sexes (65% women) were recruited from a large cohort (Camargo cohort, Santander, Spain). 3D-SHAPER® software (version 2.8, Galgo Medical, Barcelona, Spain) was used to derive 3D analysis from the hip DXA scans at baseline RESULTS: The differences were less pronounced for vBMD (cortical sBMD 9.3%, trabecular vBMD 6.4%, integral vBMD 2.2%) compared to aBMD (FN aBMD 11.4% and TH aBMD 13.3%). After stratifying by age (≤ 59 years, 60-69 years, 70-79 years, and ≥ 80 years), we observed in ≤ 59 years that aBMD was lower in women compared to men, at FN (0.758 [0.114] g/cm² vs. 0.833 [0.117] g/cm²; p = 1.4 × 10^-20) and TH (0.878 [0.117] g/cm² vs. 0.990 [0.119] g/cm²; p = 4.1 × 10^-40). Nevertheless, no statistically significant difference was observed for integral vBMD (331 [58] mg/cm³ in women and 326 [51] mg/cm³ in men; p = 0.19) and trabecular vBMD (190 [41] mg/cm³ in women and 195 [39] mg/cm³ in men; p = 0.20).

CONCLUSION

Our results make us think about the importance of taking into account bone size at the time of analyzing the sex-related differences in bone mass.

Patients with end-stage kidney disease have markedly abnormal cortical hip parameters by dual-energy X-ray absorptiometry

BACKGROUND

Patients with end-stage kidney disease (ESKD) have higher fracture rates and post-fracture mortality than the general population, but bone mineral density by dual-energy X-ray absorptiometry (DXA) is less predictive of fracture in this patient group. Bone biopsy and high-resolution imaging indicate that cortical thickness (CT) is reduced and cortical porosity is increased in ESKD. The aim of this study was to assess cortical parameters using DXA in patients with ESKD. It was hypothesized that these parameters would show deterioration and be associated with fracture.

METHODS

Using advanced hip analysis, normal age-related ranges were determined from 752 female and 861 male femur scans and were compared with scans of 226 patients with ESKD at the time of transplantation.

RESULTS

Compared with controls, female patients had lower mean±SD CT (mms) at the femoral neck (FN) (2.59 ± 1.42 versus 5.23 ± 1.85), calcar (3.46 ± 1.07 versus 5.09 ± 1.30) and shaft (4.42 ± 1.21 versus 7.44 ± 2.07; P < 0.001 for each), and buckling ratios were higher (8.21 ± 4.6 versus 3.63 ± 1.42; P < 0.001), indicating greater FN instability. All findings were similar for men. Prevalent fracture was documented in 28.8% of patients; 12.4% vertebral only, 8.4% non-vertebral only and 8% vertebral plus non-vertebral. In adjusted models, each 1 SD reduction in FN CT and increase in the buckling ratio was associated with a respective 1.73 (1.22-2.46)- and 1.82 (1.49-2.86)-fold increase in the risk of prevalent vertebral fracture.

CONCLUSIONS

In patients with ESKD, DXA-derived cortical parameters are markedly abnormal compared with age- and sex-matched controls. These parameters should be assessed for incident fracture prediction and targeting treatment.

In Silico Clinical Trials in the Orthopedic Device Industry: From Fantasy to Reality?

The orthopedic device industry relies heavily on clinical evaluation to confirm the safety, performance, and clinical benefits of its implants. Limited sample size often prevents these studies from capturing the full spectrum of patient variability and real-life implant use. The device industry is accustomed to simulating benchtop tests with numerical methods and recent developments now enable virtual "in silico clinical trials" (ISCT). In this article, we describe how the advancement of computer modeling has naturally led to ISCT; outline the potential benefits of ISCT to patients, healthcare systems, manufacturers, and regulators; and identify how hurdles associated with ISCT may be overcome. In particular, we highlight a process for defining the relevant patient risks to address with ISCT, the utility of a versatile software pipeline, the necessity to ensure model credibility, and the goal of limiting regulatory uncertainty. By complementing-not replacing-traditional clinical trials with computational evidence, ISCT provides a viable technical and regulatory strategy for characterizing the full spectrum of patients, clinical conditions, and configurations that are embodied in contemporary orthopedic implant systems.

Feasibility, safety and effectiveness of a pilot 16-week home-based, impact exercise intervention in postmenopausal women with low bone mineral density

The feasibility and efficacy of home-based, impact exercise are unclear. This pilot impact exercise intervention was feasible and safe, and improved bone health and physical function in postmenopausal women with low bone density. Appropriately designed randomised controlled trials are now required to determine whether such interventions can reduce fracture risk.

INTRODUCTION

The feasibility and efficacy of impact exercise in postmenopausal women with low bone mineral density (BMD) are unclear. We aimed to determine adherence, safety and changes in BMD, bone microarchitecture and physical function following a pilot home-based, impact exercise intervention in postmenopausal women with low BMD.

METHODS

Fifty community-dwelling postmenopausal women with BMD T-scores < - 1.0 participated in 16 weeks of home-based impact exercise progressively increasing to 50 multi-directional unilateral hops on each leg daily. Bone density and structure were assessed by lumbar spine and hip dual-energy X-ray absorptiometry (DXA), 3D modelling (3D-SHAPER) of hip DXA scans and distal tibial high-resolution peripheral quantitative computed tomography scans. Physical performance was assessed by repeated chair stand time and stair climb time.

RESULTS

Forty-four women (mean ± SD age 64.5 ± 7.5 years) completed the intervention, with adherence of 85.3 ± 17.3%. Reasons for withdrawal were related soreness (n = 2), unrelated injury (n = 1) and loss of interest (n = 3). Femoral neck areal BMD increased by 1.13 ± 3.76% (p = 0.048). Trabecular volumetric BMD (vBMD) increased at the total hip (2.27 ± 7.03%; p = 0.038) and femoral neck increased (3.20 ± 5.39%; p < 0.001). Distal tibia total vBMD increased by 0.32 ± 0.88% (p = 0.032) and cortical cross-sectional area increased by 0.55 ± 1.54% (p = 0.034). Chair stand and stair climb time improved by 2.34 ± 1.88 s (p < 0.001) and 0.27 ± 0.49 s (p < 0.001), respectively.

CONCLUSION

A 16-week home-based, impact exercise was feasible and may be effective in improving femoral neck areal BMD, total hip and distal tibial vBMD and physical function in postmenopausal women. Appropriately designed randomised controlled trials are now required to determine whether such interventions can reduce fracture risk in older populations.

A pilot study comparing daily teriparatide with monthly cycles of teriparatide and raloxifene

This 6-month pilot study in osteoporotic postmenopausal women evaluated cyclic TPD/RLX compared to daily subcutaneous TPD with the concept of optimizing bone formation. Compared to daily subcutaneous TPD, cyclic therapy showed comparable increase in spine BMD and favorable effects on total proximal femur BMD and cortical thickness.

PURPOSE

There is no cure for osteoporosis; better medications or different approaches with current agents are needed. We hypothesized that monthly cycles of teriparatide (TPD) followed by raloxifene (RLX) might promote ongoing bone formation. Additionally, as TPD might initially adversely affect hip BMD, such effects may be mitigated by a cyclic approach. Therefore, this 6-month pilot study evaluated the effect of cyclic TPD/RLX compared to daily subcutaneous TPD on bone markers, BMD, trabecular bone score (TBS), and hip parameters assessed by 3D modeling.

METHODS

Postmenopausal osteoporotic women (n=26) were randomized to open-label TPD 20 daily or alternating monthly cycles of TPD followed by monthly RLX 60 mg daily. BMD was measured at the lumbar spine (LS), femur, and radius by DXA. To further assess LS BMD, QCT and opportunistic CT (L1 Hounsfield units [HU]) were performed. LS TBS and hip cortical and trabecular parameters were assessed using DXA. Baseline group comparisons were performed by unpaired T-test with change over time evaluated by repeated measures ANOVA.

RESULTS

Participant mean age, BMI, and lowest T-score were 67.0 years, 26.0 kg/m², and -2.7; no between-group differences in serum chemistries, 25(OH)D, or BMD were observed. LS-BMD increased (p<0.001) with TPD or TPD/RLX as measured by DXA (4.8%/5.2%), QCT (13%/9.4%), or HU (15.6%/10.2%) with no between-group difference. TPD/RLX produced beneficial between-group differences in total proximal femur BMD (1.5%, p<0.05) and cortical thickness (1.6%, p<0.05).

CONCLUSION

Compared with daily TPD, cyclic TPD/RLX comparably increased spine BMD and might have favorable effects on proximal femur BMD and cortical thickness.