152,832 research outputs found
Quantitative Ultrasound of Cortical Bone in the Femoral Neck Predicts Femur Strength: Results of a Pilot Study
No full textArticle first published online: 15 JAN 2013 Pour consulter la version éditeur DOI: 10.1002/jbmr.1742A significant risk of femoral neck (FN) fracture exists for men and women with an areal bone mineral density (aBMD) higher than the osteoporotic range, as measured with dual-energy X-ray absorptiometry (DXA). Separately measuring the cortical and trabecular FN compartments and combining the results would likely be a critical aspect of enhancing the diagnostic capabilities of a new technique. Because the cortical shell determines a large part of FN strength a novel quantitative ultrasound (QUS) technique that probes the FN cortical compartment was implemented, aimed at testing the sensitivity of the method to variations of FN cortical properties and FN strength. Nine femurs (women, mean age 83 years) were subjected to QUS to measure the through transmission time-of-flight (TOF) at the FN and mechanical tests to assess strength. Quantitative computed tomography (QCT) scans were performed to enable analysis of the dependence of TOF on bone parameters. DXA was also performed for reference. An ultrasound wave propagating circumferentially in the cortical shell, which TOF was not influenced by the properties of the trabecular compartment Q3, was measured in all specimens. Averaged TOF for nine FN measurement positions/orientations was significantly correlated to strength (R² = 0.79) and FN cortical QCT variables: total BMD (R² = 0.54); regional BMD in the inferoanterior (R² = 0.90) and superoanterior (R² = 0.57) quadrants; and moment of inertia (R² = 0.71). The results of this study demonstrate that QUS can perform a targeted measurement of the FN cortical compartment. Because the method involves mechanical guided waves, the QUS variable is related to the geometric and material properties of the cortical shell (cortical thickness, tissue elasticity, and porosity). This work opens the way to a multimodal QUS assessment of the proximal femur, combining our approach targeting the cortical shell with the existing modality sensitive to the trabecular compartment. In vivo feasibility of our approach has to be confirmed with experimental data in patients
The Warwick Hip Trauma Evaluation – an abridged protocol for the WHiTE Study : a multiple embedded randomised controlled trial cohort study
No full textFractures of the proximal femur are one of the greatest challenges facing the medical community, constituting a heavy socioeconomic burden worldwide. The National Hip Fracture Audit currently provides a framework for service evaluation. This evaluation is based upon the assessment of process rather than assessment of patient-centred outcome and therefore it fails to provide meaningful data regarding the clinical effectiveness of treatments. This study aims to capture data from the cohort of patients who present with a fracture of the proximal femur at a single United Kingdom Major Trauma Centre. Patient-centred outcomes will be recorded and provide a baseline cohort within which to test the clinical effectiveness of experimental interventions
Adjusting bone mass for differences in projected bone area and other confounding variables: an allometric perspective.
No full textThe traditional method of assessing bone mineral density (BMD; given by bone mineral content [BMC] divided by projected bone area [Ap], BMD = BMC/Ap) has come under strong criticism by various authors. Their criticism being that the projected bone "area" (Ap) will systematically underestimate the skeletal bone "volume" of taller subjects. To reduce the confounding effects of bone size, an alternative ratio has been proposed called bone mineral apparent density [BMAD = BMC/(Ap)3/2]. However, bone size is not the only confounding variable associated with BMC. Others include age, sex, body size, and maturation. To assess the dimensional relationship between BMC and projected bone area, independent of other confounding variables, we proposed and fitted a proportional allometric model to the BMC data of the L2-L4 vertebrae from a previously published study. The projected bone area exponents were greater than unity for both boys (1.43) and girls (1.02), but only the boy's fitted exponent was not different from that predicted by geometric similarity (1.5). Based on these exponents, it is not clear whether bone mass acquisition increases in proportion to the projected bone area (Ap) or an estimate of projected bone volume (Ap)3/2. However, by adopting the proposed methods, the analysis will automatically adjust BMC for differences in projected bone size and other confounding variables for the particular population being studied. Hence, the necessity to speculate as to the theoretical value of the exponent of Ap, although interesting, becomes redundant
PERAN FORUM PENGUSAHA MUDA NAHDHIYYIN (F-PMNI) DALAM RECOVERY PEREKONOMIAN KABUPATEN BONE PADA ERA NEW NORMAL
No full textOne of the communities or associations of youth entrepreneurs in Bone is the Nahdhiyyin Indonesia Youth Entrepreneurs Forum (F-PMNI). The presence of F-PMNI is also expected to be able to play a role in economic recovery in Bone in the new normal era. This study aims to provide a description and description of the role played by youth nahdhiyyin entrepreneurs in Bone in economic recovery and becoming more responsive to changes in the business climate during the new normal. This study used a type of field research with a descriptive qualitative approach. The results of research related to the role of F-PMNI in the economic recovery of Bone district in the new normal era, namely Providing education for business actors, Providing capital assistance for business development, As innovators in their contribution to economic development, entrepreneurs looking for sources of innovation, paying close attention to changes -changes that occur, calculate opportunities, and plan innovations to be carried out, Act as a Risk Taker, and the presence of F-PMNI is also expected to be able to become a liaison between the community or business actors with the government so that synergy and good partners can be established, so that the economic recovery able to walk well. Salah satu komunitas atau lembaga perkumpulan pengusaha muda yang ada di Kabupaten Bone, yaitu Forum Pengusaha Muda Nahdhiyyin Indonesia (F-PMNI). Kehadiran F-PMNI juga diharapkan mampu berperan dalam recovery perekonomian di Kabupaten Bone pada era new normal. Penelitian ini bertujuan untuk memberikan deskripsi dan gambaran terkait peran yang dilakukan oleh para pengusaha muda nahdhiyyin di Kabupaten Bone dalam recovery perekonomian dan menjadi lebih responsif terhadap perubahan iklim bisnis pada masa new normal. Penelitian ini menggunakan jenis penelitian lapangan dengan pendekatan kualitatif deskripstif. Adapun hasil penelitian terkait peran F-PMNI dalam recovery perekonomian kabupaten Bone pada era new normal, yaitu Memberikan edukasi bagi para pelaku usaha, Memberikan bantuan permodalan untuk pengambangan usaha, Sebagai inovator dalam kontribusinya atas pembangunan ekonomi, pengusaha mencari sumber inovasi, memperhatikan dengan seksama perubahan-perubahan yang terjadi, melakukan kalkulasi peluang, serta merencanakan inovasi yang akan dilakukan, Berperan sebagai Risk Taker, dan Kehadiran F-PMNI juga diharapkan mampu menjadi penghubung masyarakat atau para pelaku usaha dengan pemerintah agar mampu terjalin sinergitas dan mitra yang baik, sehingga recovery perekonomian mampu berjalan dengan baik
Neural networks for analysis of trabecular bone in osteoarthritis
No full textThis study investigated the correlation of age in male and female specimens with physico-mechanical properties of trabecular bone including compressive strength, bone volume fraction, structural model index, trabecular thickness factor, level of inter-connectivity and pore morphology. An artificial neural network was designed to analyse 35 available samples in order to account for complex inter-dependencies of the key parameters in multi-dimensional space. Trained by using Levenberg-Marquardt back propagation algorithm, the network achieved regression factor of 0·96 by optimisation and showed that age correlates strongly with the physical properties of the bone affected by severe osteoarthritis. In addition, the compressive strength was found to be the most important factor for predicting the bone aging. Within the limitations of the input data set, the model developed provides a reliable predictive tool to tissue engineering applications
Bone fractures after menopause
No full textEvery year 30% of individuals above age 65 fall, and falls are the principal cause of bone fractures. To reduce fracture incidence requires both prevention of falls and maintenance of bone strength.PubMed searches were performed, for studies of the epidemiology of fractures, bone physiology, endocrine effects, osteoporosis measurement, genetics, prevention and effectiveness. Topic summaries were presented to the Workshop Group and omissions or disagreements were resolved by discussion.Ageing reduces bone strength in post-menopausal women because estrogen deficiency causes accelerated bone resorption. Bone mineral density (BMD) decreased more than 2.5 standard deviation below the mean of healthy young adults defines osteoporosis, a condition associated with an increased risk of fractures. Risk factors such as age and previous fracture are combined with BMD for a more accurate prediction of fracture risk. The most widely used assessment tool is FRAX (TM) which combines clinical risk factors and femoral neck BMD. General preventive measures include physical exercise to reduce the risk of falling and vitamin D to facilitate calcium absorption. Pharmacological interventions consist mainly in the administration of inhibitors of bone resorption. Randomized controlled trials show treatment improves BMD, and may reduce the relative fracture risk by about 50% for vertebral, 20-25% for non-vertebral and up to 40% for hip fractures although the absolute risk reductions are much lower.Although diagnosis of osteoporosis is an important step, the threshold for treatment to prevent fractures depends on additional clinical risk factors. None of the presently available treatment options provide complete fracture prevention.</p
Notochordal inclusions in the vertebral bone marrow
No full textNontumoral notochordal inclusions in vertebral bone marrow give rise to MRI-detectable lesion without osteolysis, and their detection may cause concern or overtreatment. These lesions likely arise from dislocation of notochordal cells from the nucleus pulposus early in life, followed by growth in a permissive bone marrow microenvironment. We present a case of nontumoral notochordal inclusions in vertebral bone marrow, giving rise to an MRI detectable lesion without osteolysis. MRI detection of such lesions may cause concern or overtreatment. Quite distinct from chordomas, these lesions likely arise from dislocation of notochordal cells from the nucleus pulposus early in life, followed by growth in a permissive bone marrow microenvironment
A comparison of cortical and trabecular bone from C57 Black 6 mice using Raman spectroscopy
No full textPeer reviewe
An experimental and computational investigation of bone cement residual stresses
No full textHip arthroplasty is a common orthopaedic procedure with considerable success in alleviating hip joint pain and disability. To transfer loads from the prosthesis to the contiguous bone, self-curing polymethyl methacrylate, often referred to as bone cement, is routinely used. Residual stresses due to shrinkage of the bone cement during and after polymerisation have been implicated in the formation of cement mantle cracks before any functional loading.
Contemporary cemented hip arthroplasties involve mixing the bone cement under vacuum and applying bone cement pressurisation in situ. However vacuum-mixed bone cement has been linked with increased cement shrinkage and theoretically linked with greater residual stress. In this thesis, experimental work was performed to investigate the effect of vacuum mixing and pressurisation with respect to bone cement residual stress. Also, two commercial brands of bone cement were compared against each other. Results revealed that vacuum mixing did not appreciably alter the residual stress levels compared with cement mixed under atmospheric conditions. Likewise, negligible residual stress difference was measured between CMW® 1 Gentamicin and SmartSet® HV Gentamicin bone cements. However, pressurisation of the curing bone cement mass had a significant effect on the residual stress magnitudes.
Finite element analysis was implemented to quantify the bone cement residual stresses for the experimental construct. Differential scanning calorimetry and dilatometry experimentation was performed to quantify the bone cement’s exotherm and linear coefficient of thermal expansion properties respectively. Both the transient thermal and residual stress predictions were directly comparable with the experimental measurements. Utilising the same finite element methodology, the transient thermal and residual stresses were predicted for a representative in vivo scenario. The representative in vivo stresses for the rehabilitation activity of walking was also predicted. Predictions revealed the residual stresses were significant and should be included to establish the cement mantle stress magnitude and distribution for the early portion of the artificial hip replacement lifetime
A QTL for osteoporosis detected in an F2 population derived from White Leghorn chicken lines divergently selected for bone index
No full textOsteoporosis, resulting from progressive loss of structural bone during the period of egg-laying in hens, is associated with an increased susceptibility to bone breakage. To study the genetic basis of bone strength, an F(2) cross was produced from lines of hens that had been divergently selected for bone index from a commercial pedigreed White Leghorn population. Quantitative trait loci (QTL) affecting the bone index and component traits of the index (tibiotarsal and humeral strength and keel radiographic density) were mapped using phenotypic data from 372 F(2) individuals in 32 F(1) families. Genotypes for 136 microsatellite markers in 27 linkage groups covering approximately 80% of the genome were analysed for association with phenotypes using within-family regression analyses. There was one significant QTL on chromosome 1 for bone index and the component traits of tibiotarsal and humeral breaking strength. Additive effects for tibiotarsal breaking strength represented 34% of the trait standard deviation and 7.6% of the phenotypic variance of the trait. These QTL for bone quality in poultry are directly relevant to commercial populations
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