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“Stress fracture”

Paola Chivers, Timo Rantalainen, Fleur McIntyre, Beth Hands, Benjamin Weeks, Belinda Beck, Nimphius Sophia, Nicolas Hart, Aris Siafarikas
BACKGROUND: Australian adolescents with low motor competence (LMC) have higher fracture rates and poorer bone health compared to European normative data, but currently no normative data exists for Australians. AIMS: To examine whether there were bone health differences in Australian adolescents with LMC or Developmental Coordination Disorder (DCD) when compared to typically developing age-matched Australian adolescents. METHODS AND PROCEDURES: Australian adolescents aged 12-18 years with LMC/DCD (n = 39; male = 27; female = 12) and an Australian comparison sample (n = 188; boys = 101; girls = 87) undertook radial and tibial peripheral Quantitative Computed Tomography (pQCT) scans...
August 14, 2018: Research in Developmental Disabilities
Tomoki Yasui, Eiji Kamio, Hideto Matsuyama
Tough inorganic/organic composite network gels consisting of a partially developed silica-particle network and a large amount of an ionic liquid, named micro-double-network (μ-DN) ion gel, are fabricated via two methods. One is a one-pot/one-step process conducted using a simultaneous network formation via sol-gel reaction of tetraethyl orthosilicate and free radical polymerization of N,N-dimethylacrylamide in an ionic liquid. When the network formation rates of the inorganic and organic networks are almost the same, the μ-DN structure is formed...
August 17, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Mitsuru Saito, Keishi Marumo
PURPOSE OF REVIEW: Homocystinuria is a congenital metabolic disorder in which cystathionine β-synthase deficiency results in a prominent increase in homocysteine (serum levels > 100 μM), causing mental retardation, atherosclerotic cerebral infarction, and osteoporosis accompanied by fragility fractures. Encountering a case with excessive homocysteinemia such as that seen in hereditary homocystinuria is unlikely during usual medical examinations. However, in individuals who have vitamin B or folate deficiency, serum homocysteine concentrations are known to increase...
August 17, 2018: Current Osteoporosis Reports
Claude Schwartz
BACKGROUND: Osteopenia of the front half of the distal femur is a well-known problem after total knee arthroplasty (TKA) with secondary issues after years, especially when must be addressed fractures or revisions for loosening. Stress shielding has been recognized as a cause in different biomechanical studies of the bone. QUESTION/PURPOSES: It was logical to look for a solution by changing the design to minimize stress shielding behind the femoral shield. PATIENTS AND METHODS: It was proved that radiological measure of bone density was reliable although not so early and accurate as densitometry...
August 16, 2018: European Journal of Orthopaedic Surgery & Traumatology: Orthopédie Traumatologie
Satish Mishra, Rosa Maria Badani Prado, Thomas E Lacy, Santanu Kundu
Gels are increasingly being used in many applications, and it is important to understand how these gels fail subjected to mechanical deformation. Here, we investigate the failure behavior of a thermoplastic elastomer gel (TPEG) consisting of poly(styrene)-poly(isoprene)-poly(styrene) in mineral oil, in tensile mode, under constant stress, and in fracture tests, where the fracture initiates from a predefined crack. In these gels, the poly(styrene) endblocks associate to form spherical aggregates, as captured using SAXS...
August 16, 2018: Soft Matter
Jun Zhou, Zhaoxian Zheng, Menglin Zhou, Jing Zheng
The internal fixation using metal bone plate is one of common method for the clinical treatment of fracture, it plays a role in fixation, protection and supporting of the fractured bone segments, but it also suffers high failure rates in clinical practice. This article reviewed the commonly used methods of failure analysis of bone plate, and described the research results of the failure analysis of bone plate in detail. The fatigue fracture of bone plate caused by stress concentration is the common fracture pattern...
July 30, 2018: Zhongguo Yi Liao Qi Xie za Zhi, Chinese Journal of Medical Instrumentation
Biao Kong, Enyuan Wang, Zenghua Li
High temperature causes thermal damage to rock; the macrofracture and microfracture of rock can be produced under the action of temperature treatment. Under the influence of high temperature, the surrounding rock of deep underground engineering will suffer instability damage and cause serious harm to the people. In order to use the electromagnetic radiation (EMR) technology (a non-contact geophysical method) for evaluating the thermal stability of rock in underground thermal engineering applications, we established the EMR testing experimental system of rock under the action of a continuous heat source...
August 15, 2018: Environmental Science and Pollution Research International
A Rajeev
The incidence of insufficiency fractures is approximately 1% in rheumatoid arthritis patients. The predisposing factors are chronic inflammation, skeletal deformities, biomechanical stresses and osteoporosis. The medications used in the treatment of rheumatoid arthritis such as Glucocorticosteroids and Methotrexate also contribute to the development of osteoporosis and insufficiency fractures. A 68-year old lady who was suffering from rheumatoid arthritis and on long term Methotrexate was seen in the outpatient clinic with recurrent episodes of heel pain...
July 2018: Malaysian Orthopaedic Journal
Elizabeth M Leimer, Laura M Tanenbaum, Dana L Nettles, Richard D Bell, Mark E Easley, Lori A Setton, Samuel B Adams
BACKGROUND: Post-traumatic osteoarthritis (PTOA) is a frequent complication in patients with a previous traumatic joint injury, and the pathophysiology is not well understood. The goal of this study was to characterize the biochemical signature of amino acids, peptides, and amino acid metabolites in ankle synovial fluid following intra-articular fracture. METHODS: Synovial fluid from both the injured and contralateral ankles of 19 patients with an intra-articular ankle fracture was obtained and analyzed via metabolic profiling...
August 15, 2018: Foot & Ankle International
Shareen H Elshiyab, Noor Nawafleh, Laurence Walsh, Roy George
AIM: The aim of the present study was to investigate fracture resistance of implant-supported zirconia-based crowns (monolayer vs bilayer) cemented to hybrid abutments. METHODS: Monolayer and bilayer zirconia crowns were constructed and cemented to zirconia hybrid abutments. Crowns were divided into two subgroups: (a) untreated control group; and (b) experimental group, which underwent thermal-cycling mechanical loading in a chewing simulator. Up to 1.2 million stress cycles with simultaneous thermocycling (5 and 55°C) were applied...
August 13, 2018: Journal of Investigative and Clinical Dentistry
Ronald H Heisser, Vishal P Patil, Norbert Stoop, Emmanuel Villermaux, Jörn Dunkel
Fracture fundamentally limits the structural stability of macroscopic and microscopic matter, from beams and bones to microtubules and nanotubes. Despite substantial recent experimental and theoretical progress, fracture control continues to present profound practical and theoretical challenges. While bending-induced fracture of elongated rod-like objects has been intensely studied, the effects of twist and quench dynamics have yet to be explored systematically. Here, we show how twist and quench protocols may be used to control such fracture processes, by revisiting Feynman's observation that dry spaghetti typically breaks into three or more pieces when exposed to large pure bending stresses...
August 13, 2018: Proceedings of the National Academy of Sciences of the United States of America
Martin Frank, Dorothee Marx, Vedran Nedelkovski, Julia-Theresa Fischer, Dieter H Pahr, Philipp J Thurner
Trabecular bone is located inside flat bones as well as in the epi- and metaphysis of long bones and plays a key role with respect to load transfer. Disorders, such as osteoporosis, weaken the structural integrity and may also cause changes in the mechanical properties of individual trabeculae, such as Young's modulus. Knowledge of mechanical tissue properties are necessary to assess risk of bone fracture with finite element analysis (FEA). However, such parameters are most often obtained from experiments on air-dried specimens which do not reflect the physiological conditions...
August 1, 2018: Journal of the Mechanical Behavior of Biomedical Materials
Kiara Serafini Dapieve, Luí S Felipe Guilardi, Tais Silvestri, Marília Pivetta Rippe, Gabriel Kalil Rocha Pereira, Luiz Felipe Valandro
This study aims to evaluate the flexural fatigue strength and survival estimates of an Y-TZP monolithic ceramic after grinding and aging. Ceramic discs (1.2 mm thickness × 15.0 mm diameter - ISO, 6872, 2015) of zirconia (Zirlux FC2 - Ardent; Ivoclar Vivadent) were made and randomly allocated into 6 groups (n = 10), according to grinding and aging factors: Ctrl - as-sintered; Ctrl Sto - as-sintered and dry stored at room temperature for 2 years; Ctrl Aut Sto - as-sintered, submitted to autoclaved aging (134 °C, 2 bar, 20 h) and then dry stored for 2 years; and similar conditions for ground samples (Ground; Ground Sto; Ground Aut Sto)...
July 31, 2018: Journal of the Mechanical Behavior of Biomedical Materials
Viacheslav Sorkin, Yong-Wei Zhang
Using density functional tight-binding theory, we investigated the elastic properties and deformation and failure behaviors of pristine and defective carbon-phosphide (CP) monolayers subjected to uniform uniaxial tensile strain along armchair (AC) and zigzag (ZZ) directions. Two variants of carbon phosphide (α-CP and β-CP) were studied and two types of carbon and phosphorous vacancies (single and double) were considered. It was found that carbon monovacancies have the lowest formation energy, while phosphorous divacancies have the highest one in both CP allotropes...
August 13, 2018: Nanotechnology
Xiaozhong Chen
To facilitate the creation, modification, and optimization of patient-specific plates for distal femur fractures, a novel approach was proposed for the rapid and convenient design of patient-specific plates for patients' fractured femurs using feature parameterization. First, several femur parameter values were obtained for a specific patient and used to construct a restored surface model of the fractured femur. Next, combined with the particular femur anatomy and the fracture, a parameterized plate with a suitable shape was created automatically based on the parameter maps between the femur and plate...
August 13, 2018: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of Engineering in Medicine
Sergey Strafun, Ievgen Levadnyi, Vasily Makarov, Jan Awrejcewicz
Radial head fractures are becoming a major public health problem and are an increasingly important target for both clinical and mechanical researchers. In this work, comparative biomechanical analyses of the stress-strain state of a healthy elbow joint and elbow joints with radial head compression from 2 to 5 mm due to injury are performed. Three-dimensional models of the elbow joint with cartilage surfaces and ligaments were constructed based on the results of computed tomography. This study is focused on an elbow joint range of motion ranging from 0° to 120° flexion...
2018: Journal of Medical and Biological Engineering
Ryan C Hurley, Eric B Herbold, Darren C Pagan
Three-dimensional X-ray diffraction (3DXRD), a method for quantifying the position, orientation and elastic strain of large ensembles of single crystals, has recently emerged as an important tool for studying the mechanical response of granular materials during compaction. Applications have demonstrated the utility of 3DXRD and X-ray computed tomography (XRCT) for assessing strains, particle stresses and orientations, inter-particle contacts and forces, particle fracture mechanics, and porosity evolution in situ ...
August 1, 2018: Journal of Applied Crystallography
Francesco Ascione, Christopher M Kilian, Mitzi S Laughlin, Giulia Bugelli, Peter Domos, Lionel Neyton, Arnaud Godeneche, T Bradley Edwards, Gilles Walch
BACKGROUND: Scapular stress fractures after reverse shoulder arthroplasty (RSA) are a potentially serious complication with modern lateralized and onlay implants. The aim of this study was to report the scapular spine stress fracture rate after RSA with an onlay, 145° humeral stem, analyzing potential fracture risk factors and clinical outcomes in a large cohort of patients. METHODS: A consecutive series of 485 RSAs were implanted with the Aequalis Ascend Flex stem...
August 8, 2018: Journal of Shoulder and Elbow Surgery
Takeshi Utsunomiya, Goro Motomura, Satoshi Ikemura, Yusuke Kubo, Kazuhiko Sonoda, Hiroyuki Hatanaka, Shoji Baba, Koichiro Kawano, Takuaki Yamamoto, Yasuharu Nakashima
Stress distribution remains unclear in early-stage osteonecrosis of the femoral head (ONFH). To clarify this issue, we generated patient-specific finite element models (FEMs) from 51 patients with ONFH. Patients' hips were classified into three groups: ONFH without a sclerotic boundary (Stage 1, n = 6), ONFH with a sclerotic boundary (Stage 2, n = 10), and ONFH with both a sclerotic boundary and <2 mm collapse (Stage 3, n = 35). Four hips without ONFH were used as controls. Stress distribution in each FEM was compared with magnetic resonance imaging (MRI) and computed tomography (CT) results...
August 11, 2018: Journal of Orthopaedic Research: Official Publication of the Orthopaedic Research Society
Yu Kuroiwa, Takahiro Niikura, Sang Yang Lee, Keisuke Oe, Takashi Iwakura, Tomoaki Fukui, Tomoyuki Matsumoto, Takehiko Matsushita, Kotaro Nishida, Ryosuke Kuroda
PURPOSE: This study investigated whether Escherichia coli-derived bone morphogenetic protein (BMP)-2 (E-BMP-2) adsorbed onto β-tricalcium phosphate (β-TCP) granules can induce bone regeneration in critical-size femoral segmental defects in rabbits. METHODS: Bone defects 20 mm in size and stabilized with an external fixator were created in the femur of New Zealand white rabbits, which were divided into BMP-2 and control groups. E-BMP-2-loaded β-TCP granules were implanted into defects of the BMP-2 group, whereas defects in the controls were implanted with β-TCP granules alone...
August 10, 2018: International Orthopaedics
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