A new finite element based parameter to predict bone fracture

Dual Energy X-Ray Absorptiometry (DXA) is currently the most widely adopted non-invasive clinical technique to assess bone mineral density and bone mineral content in human research and represents the primary tool for the diagnosis of osteoporosis. DXA measures areal bone mineral density, BMD, which does not account for the three-dimensional structure of the vertebrae and for the distribution of bone mass. The result is that longitudinal DXA can only predict about 70% of vertebral fractures. This study proposes a complementary tool, based on Finite Element (FE) models, to improve the DXA accuracy. Bone is simulated as elastic and inhomogeneous material, with stiffness distribution derived from DXA greyscale images of density. The numerical procedure simulates a compressive load on each vertebra to evaluate the local minimum principal strain values. From these values, both the local average and the maximum strains are computed over the cross sections and along the height of the analysed bone region, to provide a parameter, named Strain Index of Bone (SIB), which could be considered as a bone fragility index. The procedure is initially validated on 33 cylindrical trabecular bone samples obtained from porcine lumbar vertebrae, experimentally tested under static compressive loading. Comparing the experimental mechanical parameters with the SIB, we could find a higher correlation of the ultimate stress, \u3c3ULT, with the SIB values (R2adj = 0.63) than that observed with the conventional DXA-based clinical parameters, i.e. Bone Mineral Density, BMD (R2adj = 0.34) and Trabecular Bone Score, TBS (R2adj = -0.03). The paper finally presents a few case studies of numerical simulations carried out on human lumbar vertebrae. If our results are confirmed in prospective studies, SIB could be used-together with BMD and TBS-to improve the fracture risk assessment and support the clinical decision to assume specific drugs for metabolic bone diseases

trabecular bone score tbs and bone metabolism in patients affected with type 1 neurofibromatosis nf1

In patients with neurofibromatosis type 1 (NF1), decreased bone mineral density (BMD) and low levels of 25-hydroxy vitamin D3 (25OHD) have been reported. Recently, the trabecular bone score (TBS) measurement has been proposed as index of bone microarchitecture and fracture risk. In 74 NF1 patients (48 females, 26 males, age 41 ± 12), we measured TBS and investigated clinical stage, lifestyle, vitamin D, serum bone turnover markers, vertebral and femoral BMD. A homogenous cohort of 61 healthy subjects was used as control group. TBS was lower in NF1 patients (1.266 ± 0.113 vs. 1.346 ± 0.105) without differences between sexes. No correlations with 25OHD, low exercise, low calcium intake, reduced sun exposure, and number of skin neurofibromas were observed. As expected, hypovitaminosis D was common (98.6%), as well as BMD reduction in hip and spine sites: In NF1 patients, bone texture evaluated by TBS was low in both sexes without any correlation with clinical or metabolic parameters, suggesting a direct role of the fibromin mutation

The Bone Strain Index: An Innovative Dual X-ray Absorptiometry Bone Strength Index and Its Helpfulness in Clinical Medicine

Bone strain Index (BSI) is an innovative index of bone strength that provides information about skeletal resistance to loads not considered by existing indexes (Bone Mineral Density, BMD. Trabecular Bone Score, TBS. Hip Structural Analysis, HSA. Hip Axis Length, HAL), and, thus, improves the predictability of fragility fractures in osteoporotic patients. This improved predictability of fracture facilitates the possibility of timely intervention with appropriate therapies to reduce the risk of fracture. The development of the index was the result of combining clinical, radiographical and construction-engineering skills. In fact, from a physical point of view, primary and secondary osteoporosis, leading to bone fracture, are determined by an impairment of the physical properties of bone strength: density, internal structure, deformation and fatigue. Dual X-ray absorptiometry (DXA) is the gold standard for assessing bone properties, and it allows measurement of the BMD, which is reduced mainly in primary osteoporosis, the structural texture TBS, which can be particularly degraded in secondary osteoporosis, and the bone geometry (HSA, HAL). The authors recently conceived and developed a new bone deformation index named Bone Strain Index (BSI) that assesses the resistance of bone to loads. If the skeletal structure is equated to engineering construction, these three indexes are all considered to determine the load resistance of the construct. In particular, BSI allows clinicians to detect critical information that BMD and TBS cannot explain, and this information is essential for an accurate definition of a patient’s fracture risk. The literature demonstrates that both lumbar and femoral BSI discriminate fractured osteoporotic people, that they predict the first fragility fracture, and further fragility fractures, monitor anabolic treatment efficacy and detect patients affected by secondary osteoporosis. BSI is a new diagnostic tool that offers a unique perspective to clinical medicine to identify patients affected by primary and, specially, secondary osteoporosis. This literature review illustrates BSI’s state of the art and its ratio in clinical medicine

Role of Citrate in Pathophysiology and Medical Management of Bone Diseases

Citrate is an intermediate in the “Tricarboxylic Acid Cycle” and is used by all aerobic organisms to produce usable chemical energy. It is a derivative of citric acid, a weak organic acid which can be introduced with diet since it naturally exists in a variety of fruits and vegetables, and can be consumed as a dietary supplement. The close association between this compound and bone was pointed out for the first time by Dickens in 1941, who showed that approximately 90% of the citrate bulk of the human body resides in mineralised tissues. Since then, the number of published articles has increased exponentially, and considerable progress in understanding how citrate is involved in bone metabolism has been made. This review summarises current knowledge regarding the role of citrate in the pathophysiology and medical management of bone disorders

Improving adherence in osteoporosis: A new management algorithm for the patient with osteoporosis

Introduction: Bisphosphonates are the first-choice treatment for osteoporosis. They effectively increase bone mineral density, reduce markers of bone resorption, and lower the incidence of new fractures in patients with osteoporosis-related fracture. However, the efficacy observed in clinical trials may not be realized in a real-life setting, partly due to poor adherence to therapy, with a significant worsening of clinical outcomes. Several issues contribute to poor adherence to osteoporosis medication, including inconvenient dosing regimens and concerns about possible adverse events. Although strategies to improve adherence have been investigated, new approaches are required. Areas covered: We review available data and propose a new approach to improve adherence to osteoporosis therapy in clinical practice. We present the current evidence and personal experience from a group of Italian osteoporosis experts. Expert opinion: To improve adherence, we propose a multifaceted approach, which includes the Triad Model suggested by the World Health Organization, direct observed therapy and the use of drugs with longer administration intervals, e.g., zoledronic acid. The integration of these strategies may provide the basis for a marked increase in adherence to osteoporosis therapy, and improved clinical outcomes in a real-life scenario. © 2011 Informa UK, Ltd

Usefulness of DXA-based bone strain index in postmenopausal women with type 2 diabetes mellitus

Bone Strain Index (BSI) is a new dual-energy x-ray absorptiometry (DXA)-based index. We retrospectively evaluated data from 153 postmenopausal women with a history of type 2 diabetes mellitus (T2DM). Lumbar spine and femoral Bone Strain Index (BSI) were sensitive to skeletal impairment in postmenopausal women suffering from T2DM. Purpose Bone Strain Index (BSI) is a new dual-energy X-ray absorptiometry (DXA)-based measurement. We evaluated the performance of BSI in predicting the presence of fragility fractures in type 2 diabetes mellitus (T2DM) postmenopausal women. Methods We retrospectively evaluated data from a case-control study of 153 postmenopausal women with a history of at least 5 years of T2DM (age from 40 to 90 years). For each subject, we assessed the personal or familiar history of previous fragility fractures and menopause age, and we collected data about bone mineral density (BMD), BSI, and Trabecular Bone Score (TBS) measurements. Statistical analysis was performed having as outcome the history of fragility fractures. Results Out of a total of 153 subjects, n = 22 (14.4%) presented at least one major fragility fracture. A negative correlation was found between lumbar BSI and lumbar BMD (r = - 0.49, p < 0.001) and between total femur BSI and total femur BMD (r = - 0.49, p < 0.001). A negative correlation was found between femoral neck BSI and femoral neck BMD (r = - 0.22, p < 0.001). Most DXA-based variables were individually able to discriminate between fractured and non-fractured subjects (p < 0.05), and lumbar BSI was the index with the most relative difference between the two populations, followed by femoral BSI. Conclusion Lumbar spine and femoral BSI are sensitive to skeletal impairment in postmenopausal women suffering from T2DM. The use of BSI in conjunction with BMD and TBS can improve fracture risk assessment

Comparison of trabecular bone score and hip structural analysis with FRAX® in postmenopausal women with type 2 diabetes mellitus

Purpose: To evaluate (a) the performance in predicting the presence of bone fractures of trabecular bone score (TBS) and hip structural analysis (HSA) in type 2 diabetic postmenopausal women compared to a control group and (b) the fracture prediction ability of TBS versus Fracture Risk Calculator (FRAX®) as well as whether TBS can improve the fracture prediction ability of FRAX® in diabetic women. Methods: Eighty diabetic postmenopausal women were matched with 88 controls without major diseases for age and body mass index. The individual 10-year fracture risk was assessed by FRAX® tool for Europe–Italy; bone mineral density (BMD) at lumbar spine, femoral neck and total hip was evaluated through dual-energy X-ray absorptiometry; TBS measurements were taken using the same region of interest as the BMD measurements; HSA was performed at proximal femur with the HSA software. Results: Regarding variables of interest, the only significant difference between diabetic and control groups was observed for the value of TBS (median value: 1.215; IQR 1.138–1.285 in controls vs. 1.173; IQR 1.082–1.217 in diabetic; p = 0.002). The prevalence of fractures in diabetic women was almost tripled than in controls (13.8 vs. 3.4 %; p = 0.02). The receiver operator characteristic curve analysis showed that TBS alone (AUC = 0.71) had no significantly lower discriminative power for fracture prediction in diabetic women than FRAX major adjusted for TBS (AUC = 0.74; p = 0.65). Conclusion: In diabetic postmenopausal women TBS is an excellent tool in identifying fragility fractures