Ability of ultrasound bone profile score (UBPS) to discriminate between fractured and not fractured osteoporotic women

Quantitative bone ultrasound at phalanges and calcaneus in osteoporotic postmenopausal women: influence of age and measurement site

Phalangeal and calcaneal quantitative ultrasound (QUS) measurements were tested in a postmenopausal osteoporotic population of a wide age range to assess their ability to identify subjects with vertebral fractures in a population of postmenopausal women with osteoporosis. A group of 127 osteoporotic women aged from 50 to 85 y, who had been postmenopausal for at least 5 y, were enrolled. All subjects underwent phalangeal and calcaneal QUS measurements, femoral neck and lumbar spine dual energy X-ray absorptiometry (DXA) measurements and lateral thoracic and lumbar spine radiography. Osteoporosis was defined on the basis of femoral neck or lumbar spine bone mineral density (BMD) T-score lower than -2.5 SD or of the presence of one or more vertebral atraumatic fractures, independently of BMD values. Fifty-two women had one or more vertebral fractures, while the remaining 75 had no evidence of previous fracture. Both QUS techniques were able to discriminate between fractured and nonfractured subjects in the whole group (p < 0.05). When patients aged <70 y (n = 43) and patients aged > or = 70 y (n = 84) were considered separately, phalangeal QUS and lumbar spine BMD were able to discriminate vertebral fractures in the younger group (p < 0.05), whereas calcaneal QUS was able to discriminate vertebral fractures in the older one (p < 0.05). The results of this study raise an issue of the optimal use of different QUS techniques and different skeletal sites in the management of osteoporosis in early or late postmenopausal life.

The vertebral fracture cascade in osteoporosis: a review of aetiopathogenesis

Once an initial vertebral fracture is sustained, the risk of subsequent vertebral fracture increases significantly. This phenomenon has been termed the "vertebral fracture cascade". Mechanisms underlying this fracture cascade are inadequately understood, creating uncertainty in the clinical environment regarding prevention of further fractures. The cascade cannot be explained by low bone mass alone, suggesting that factors independent of this parameter contribute to its aetiopathogenesis. This review explores physiologic properties that may help to explain the vertebral fracture cascade. Differences in bone properties, including bone mineral density and bone quality, between individuals with and those without osteoporotic vertebral fractures are discussed. Evidence suggests that non-bone parameters differ between individuals with and those without osteoporotic vertebral fractures. Spinal properties, including vertebral macroarchitecture, intervertebral disc integrity, spinal curvature and spinal loading are compared in these groups of individuals. Cross-sectional studies also indicate that neurophysiologic properties, particularly trunk control and balance, are affected by the presence of a vertebral fracture. This review provides a synthesis of the literature to highlight the multi-factorial aetiopathogenesis of the vertebral fracture cascade. With a more comprehensive understanding of the mechanisms underlying this clinical problem, more effective preventative strategies may be developed to offset the fracture cascade.

Calcaneus ultrasonometry and dual-energy X-ray absorptiometry for the evaluation of vertebral fracture risk

The aim of this retrospective, cross-sectional, controlled, non-population-based study was to evaluate the specificity and sensitivity of quantitative ultrasonometry (QUS) of the heel and of dual-energy X-ray absorptiometry (DXA) in the prediction of morphometric vertebral fracture in postmenopausal women and to establish whether the combination of the two devices could improve the capacity to identify the presence of vertebral fracture. Also, we tried to identify the best T-score threshold for high risk of vertebral fracture for both QUS and DXA, highlighting the discrepancies between the two methodologies and between the various sites examined with DXA. From 6,300 patients examined by DXA (total body, lumbar spine, total femur, femoral neck), QUS and DXA vertebral morphometry (MXA), we selected 764 postmenopausal women with nontraumatic vertebral fractures; 770 postmenopausal women with normal morphometry were chosen as a control group. Logistic regression analysis yielded odds ratios (ORs) for bone mineral density (BMD) measurements and QUS that were comparable: BMD-total body 4.16, BMD-lumbar spine 4.80, BMD-total femur 3.77, BMD-femoral neck 3.86, and QUS 4.41, without statistical differences even after correction for different confounding variables (menopausal years, weight, height, body mass index, and age). The ORs obtained from different combinations of QUS and DXA results did not show statistically significant differences compared to those from a single method alone. The sensitivity and specificity of all measurements were determined by area using the receiver operating characteristic curve; these were 0.94 for total body, 0.95 for lumbar spine, 0.86 for total femur, 0.89 for femoral neck, and 0.93 for QUS, without statistical difference. The areas under the curve obtained from the combination of QUS and DXA were higher but without statistical significance compared to QUS alone. In conclusion, both QUS and DXA were able to discriminate women with fracture from women without fracture and independently contributed to determining the association with fracture. The combination of QUS and BMD did not improve the diagnostic ability of either individual technique. We found different diagnostic thresholds for QUS and DXA.

Effect of trabecular orientation on mechanical resistance and ultrasound propagation in specimens of equine vertebrae

Osteoporosis involves alterations, not only in density, but also in the architectural organisation of the bone; in particular, trabecular orientation, following the skeletal load directions, lends a high degree of stiffness to the whole bone. We investigated the relationship between trabecular orientation, density, stiffness and ultrasound (US) propagation in two orthogonal directions (par. = parallel to, and ort. = orthogonal to the main orientation of the trabeculae) in cylindrical equine bone specimens (thoracic vertebrae) where a preferential orientation is present. A total of 15 cylinders were progressively decalcified with 0.2 mol/L ethylenediaminetetraacetic acid (EDTA). At different levels of decalcification, we measured the apparent density (g/cm(3)), bone mineral density or BMD (g/cm(2)), stiffness coefficient (MPa) and various US parameters. Before decalcification, stiffness values were the same in all directions. As the decalcification proceeded, the stiffness declined and, at low BMD values, it was significantly different in the two directions, being the highest in the par. one. Different behaviours of US parameters were observed in the two directions: SoS (speed of sound) was closely related to apparent density, BMD and stiffness in the par. direction (r = 0.88, 0.92 and 0.88, respectively, p < 0.0001). In the ort. direction, no significant association has been found between SoS and apparent density, BMD or stiffness. In the same experimental setup, US fast wave amplitude (FWA) was related to apparent density and BMD in the par. direction (r = 0.72 and 0.67, respectively, p < 0.0001) and in the ort. direction (r = 0.83 and r = 0.84 respectively, p < 0.0001). FWA was also correlated to stiffness in both directions (r = 0.61 par.; 0.81 ort., p < 0.0001). These results show that trabecular orientation strongly influences both mechanical properties of bone and US propagation. Furthermore, we found that US parameters can be predictors of mechanical properties of the bone independent of bone density.