Vertebral strength prediction under anterior compressive force using a finite element model for osteoporosis assessment

Vertebral fractures are one of the most common clinical manifestations with the major adverse consequences of osteoporosis as they usually occur under non-traumatic loading conditions. Height loss, back pain and func-tional disability are the most encountered consequences of vertebral fractures with repetitive fracture experience more likely occurring within a year after the first fracture. Early diagnosis of osteoporosis is therefore important for vertebral fracture prevention as drug treatments are more effective before perforation of the trabeculae (Mc Donnell et al. 2007). Bone mineral density (BMD) measured by dual energy X-ray absorptiometry (DXA) is the most clinically used method to diagnose osteopo-rosis. However this technique can only predict 40–70% of vertebral fractures as it only measures areal BMD which does not account for three dimensional (3D) geometry and BMD distribution (Sornay-Rendu et al. 2005). The combination of patient-specific 3D geometry and 3D BMD distribution is necessary to predict vertebral strength. Finite element models (FEM) derived from quantitative computed tomography (qCT) images are used to predict failure strength of vertebral bodies (Crawford et al. 2003; Imai et al. 2006; Buckley et al. 2007). Most of these models were validated under axial compressive forces to the vertebral body while vertebral fractures are more associated with eccentric compres-sion (Lunt et al. 2003). The purpose of this study was to compare the performance of the aBMD from DXA and qCT-based FEM in predicting experimen-tal vertebral strength. The experimental set up allowed for anterior compression testing on isolated vertebral bodies to ensure repeatable loading condition simulat-ing an anterior wedge-shape fracture

Vertebral strength prediction from Bi-Planar dual energy x-ray absorptiometry under anterior compressive force using a finite element model: An in vitro study

Finite element models (FEM) derived from qCT-scans were developed as a clinical tool to evaluate vertebral strength. However, the high dose, time and cost of qCT-scanner are limitations for routine osteoporotic diagnosis. A new approach considers using bi-planar dual energy (BP2E) X-rays absorptiometry to build vertebral FEM using synchronized sagittal and frontal plane radiographs. The purpose of this study was to compare the performance of the areal bone mineral density (aBMD) measured from DXA, qCT-based FEM and BP2E-based FEM in predicting experimental vertebral strength. Twenty eight vertebrae from eleven lumbar spine segments were imaged with qCT, DXA and BP2E X-rays before destructively tested in anterior compression. FEM were built based on qCT and BP2E images for each vertebra. Subject-specific FEM were built based on 1) the BP2E images using 3D reconstruction and volumetric BMD distribution estimation and 2) the qCT scans using slice by slice segmentation and voxel based calibration. Linear regression analysis was performed to find the best predictor for experimental vertebral strength (Fexpe); aBMD, modeled vertebral strength and vertebral stiffness. Areal BMD was moderately correlated with Fexpe (R2 = 0.74). FEM calculations of vertebral strength were highly to strongly correlated with Fexpe (R2 = 0.84, p < 0.001 for BP2E model and R2 = 0.95, p < 0.001 for qCT model). The results of this study suggest that aBMD accounted for only 74% of Fexpe variability while FE models accounted for at least 84%. For anterior compressive loading on isolated vertebral bodies, simplistic loading condition aimed to replicate anterior wedge fractures, both FEM were good predictors of Fexpe. Therefore FEM based on BP2E X-rays absorptiometry could be a good alternative to replace qCT-based models in the prediction of vertebral strength. However future work should investigate the performance of the BP2E-based model in vivo in discriminating patients with and without vertebral fracture in a prospective study.The authors would like to thank S. Persohn and M. Jeyasankar for contributing to mechanical testing. The authors would also thank Anabela Darbon, advanced research engineer at EOS Imaging, for EOS® dual energy acquisition and calibration. This work was supported by the Banque Publique d’Investissement through the dexEOS project part of the FUI14. The funding agencies had no role in the design and conduct of the study, in the collection, management, analysis and interpretation of the data, or in the preparation, review, or approval of the manuscript

FRAX (R): Prediction of Major Osteoporotic Fractures in Women from the General Population: The OPUS Study

Purposes: The aim of this study was to analyse how well FRAXH predicts the risk of major osteoporotic and vertebral fractures over 6 years in postmenopausal women from general population. Patients and methods: The OPUS study was conducted in European women aged above 55 years, recruited in 5 centers from random population samples and followed over 6 years. The population for this study consisted of 1748 women (mean age 74.2 years) with information on incident fractures. 742 (43.1%) had a prevalent fracture; 769 (44%) and 155 (8.9%) of them received an antiosteoporotic treatment before and during the study respectively. We compared FRAXH performance with and without bone mineral density (BMD) using receiver operator characteristic (ROC) c-statistical analysis with ORs and areas under receiver operating characteristics curves (AUCs) and net reclassification improvement (NRI). Results: 85 (4.9%) patients had incident major fractures over 6 years. FRAXH with and without BMD predicted these fractures with an AUC of 0.66 and 0.62 respectively. The AUC were 0.60, 0.66, 0.69 for history of low trauma fracture alone, age and femoral neck (FN) BMD and combination of the 3 clinical risk factors, respectively. FRAXH with and without BMD predicted incident radiographic vertebral fracture (n = 65) with an AUC of 0.67 and 0.65 respectively. NRI analysis showed a significant improvement in risk assignment when BMD is added to FRAXH. Conclusions: This study shows that FRAXH with BMD and to a lesser extent also without FN BMD predict major osteoporotic and vertebral fractures in the general population

Macro architecture osseuse et prédiction du risque fracturaire vertébral chez les patients ostéoporotiques

LE KREMLIN-B.- PARIS 11-BU Méd (940432101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Les hyperdensités osseuses de l’adulte

International audienceLors de la mesure de densité minérale osseuse (DMO) par dual-energy X-ray absorptiometry (DXA), il n’est pas rare de retrouver des valeurs augmentées témoignant d’une hyperdensité osseuse. La définition de l’hyperdensité osseuse n’est pas consensuelle (T-scores et/ou Z-scores ≥ +2,5 ou +4 selon les auteurs). Une grande variété de pathologies est associée avec une hyperdensité osseuse avec une classification habituellement selon le caractère localisé ou généralisé ou encore selon le caractère acquis ou constitutionnel de cette hyperdensité osseuse. Une interprétation attentive du compte rendu et des images de DMO permet dans plus de la moitié des cas de retrouver une étiologie artéfactuelle (arthrose rachidienne, calcifications vasculaires, syndesmophytose…) ou localisée (métastases condensantes, localisation pagétique…). Les causes d’hyperdensité osseuse diffuses et acquises sont nombreuses et variées (fluorose, ostéosclérose diffuse liée à l’ostéodystrophie rénale, hémopathies, hépatite C…) et nécessitent parfois des investigations cliniques et paracliniques supplémentaires pour parvenir à un diagnostic (imagerie, tryptase sérique, sérologie hépatite C…). Enfin, il existe de nombreuses maladies génétiques entraînant une hyperdensité osseuse. Les principales sont les ostéopétroses et les maladies liées à une mutation du gène SOST (sclérostéose et maladie de van Buchem) ou du corécepteur de Wnt, LDL-R-Related Protein 5 (LRP5)

High bone mass in adults

International audienceA finding of high bone mineral density (BMD) from routine dual-energy X-ray absorptiometry (DXA) screening is not uncommon. No consensus exists about the definition of high BMD, and T-score and/or Z-score cutoffs of ≥+2.5 or ≥+4 have been suggested. The many disorders that can result in high BMD are usually classified based on whether the BMD changes are focal vs. generalized or acquired vs. constitutional. In over half the cases, careful interpretation of the DXA report and images identifies the cause as an artefact (e.g., degenerative spinal disease, vascular calcifications, or syndesmophytes) or focal lesion (e.g., sclerotic bone metastasis or Paget's disease). Generalized acquired high BMD may be secondary to a diverse range of disorders such as fluorosis, diffuse bone sclerosis related to renal osteodystrophy, hematological diseases, and hepatitis C. Identification of the cause may require additional investigations such as imaging studies, serum tryptase assay, or serological tests for the hepatitis C virus. Finally, high BMD is a feature of many genetic diseases, most notably osteopetrosis and the disorders caused by mutations in the sclerostin gene SOST (sclerosing bone dysplasia and van Buchem disease) or in the LRP5 gene encoding the low-density lipoprotein receptor-related protein 5 (which is the Wnt co-receptor)

FEMOROPLASTY USING AN INJECTABLE AND RESORBABLE CALCIUM PHOSPHATE BISPHOSPHONATE LOADED BONE SUBSTITUTE (CAP-BP) BY MINI-INVASIVE TECHNIQUE TO PREVENT CONTRA-LATERAL HIP FRACTURE IN THE ELDERLY: A CADAVERIC BIOMECHANICAL STUDY

1st IOF-ESCEO Pre-Clinical Symposium, Valencia, SPAIN, MAR 23-26, 201

Prospective assessment of bone texture parameters at the hand in rheumatoid arthritis

International audienceObjective: Fractal bone analysis (Hmean) is a texture parameter ă reflecting bone microarchitecture. The BMA device (D3ATM Medical ă Systems, Orleans, France) is a high-resolution X-ray device that allows ă assessment of bone texture analysis. We aimed to measure Hmean in ă rheumatoid arthritis patients at the second and third metacarpal bones, ă at baseline and after 1 year of follow-up, and to assess the ă relationship of Hmean and rheumatoid arthritis disease parameters. ă Methods: Patients with rheumatoid arthritis according to ACR criteria ă were included. They were assessed over 1 year, in the context of a ă prospective study conducted in Maastricht. For this substudy, activity ă of the disease was assessed by erythrocyte sedimentation rate, ă C-reactive protein and Disease Activity Score 28 performed at each ă visit. Radiographic bone damage was assessed using hand and feet ă radiographs at baseline and on a 1-year basis. The bone texture ă parameters were evaluated on the second and third metacarpal heads of ă the left hand using BMA device. ă Results: One hundred and sixty-five rheumatoid arthritis patients were ă included in this study. At baseline, Hmean was negatively correlated ă with age [r= 0.22 (13= 0.013)] and erythrocyte sedimentation rate ă [r= 0.16 (13= 0.039)]. No significant correlation was found between ă Hmean and Disease Activity Score, disease activity Visual Analog Scale, ă daily corticosteroid dose and C-reactive protein. There was a ă significant increase in Hmean of second and third metacarpal bones over ă 1 year (1.6% and 1.3%, P< 0.01) except in patients with local second ă and third metacarpal bones erosion. ă Conclusion: The bone texture parameter Hmean is influenced by age, ă inflammation and local erosions in rheumatoid arthritis. (C) 2013 ă Societe francaise de rhumatologie. Published by Elsevier Masson SAS. All ă rights reserved

Bone mineral density and bone remodeling markers in chronic low back pain patients with active discopathy: A case-control exploratory study.

OBJECTIVE:We aimed to compare bone mineral density (BMD) and bone remodeling markers in chronic low back pain (cLBP) patients with and without active discopathy (Modic 1 changes). DESIGN:We conducted a single center case-control exploratory study. For 18 months, all patients referred to a tertiary care physical medicine and rehabilitation department in France were consecutively screened. Patients fulfilling the inclusion criteria were prospectively enrolled. Cases were defined as cLBP patients with lumbar active discopathy detected on MRI and controls as cLBP patients without active discopathy. Bone mineral density (BMD) at the spine, femoral neck and total femur was assessed by dual-energy X-ray absorptiometry, and bone remodeling markers were assessed in fasting serum samples. Overall, 37 cLBP patients (13 cases and 24 controls) fulfilled inclusion criteria and were included. RESULTS:The median age was 42.0 years (Q1-Q3: 36.0-51.0) and mean (SD) LBP duration 72.3 (57.4) months. We found that BMD and levels of bone remodeling markers in cLBP patients did not differ with and without active discopathy. CONCLUSION:Our results do not support the association between active discopathy and systemic bone fragility