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“Stress fracture”

Haley M McKissack, Jun Kit He, Tyler P Montgomery, John T Wilson, Aaradhana J Jha, Leonardo V Moraes, Ashish Shah
Metatarsal stress fractures are common injuries of the foot and can be a source of chronic pain without appropriate management. Conservative management is first line, but surgery may be indicated in athletes, cases of nonunion, and fractures of the fifth metatarsal. We report a case of a 34-year-old female who presented to clinic for intractable pain of the left foot secondary to a stress fracture of the left second metatarsal, which had been previously treated with injectable acrylic bone cement. Calcium sulfate hydroxyapatite cement has a multitude of applications in orthopedic surgery, but to our knowledge no studies have documented its use in the treatment of metatarsal stress fractures...
October 9, 2018: Curēus
Christopher A Iobst, Darvin Bunhor, David L Skaggs, Steven L Frick
Fractures of the supercondylar humerus are the most common elbow fracture in pediatrics. Management of this injury would be aided if surgeons could reliably test fracture stability intraoperatively after pinning. A transverse supracondylar humerus fracture model was created using 3 adult cadaver upper-extremity specimens with an intact soft tissue envelope. Using the lateral entry technique, three 2.0 mm pins were then drilled using lateral entry technique to create an "A" pinning. Pins were checked in anteroposterior and lateral views with the C-arm to confirm accurate placement in both planes...
December 2018: Techniques in Orthopaedics: TIO
Xipeng Wang, Kiyokazu Fukui, Ayumi Kaneuji, Kenichi Hirosaki, Hiroyasu Miyakawa, Norio Kawahara
PURPOSE: Although studies suggest that subchondral insufficiency fracture of the femoral head may cause rapidly progressive osteoarthritis of the hip, the mechanism of that relationship remains unclear. Our biomechanical study aimed to provide more data in this area by quantifying pressure distribution on the femoral head for normal and inverted hips and by determining the effects of labral inversion on pressure distribution across the joint, focusing on types of fracture under load. METHODS: We tested mid-sized fourth-generation composite femurs at 15° of adduction, and applied 1 mm/min of axial compressive force to the femoral heads until failure...
December 11, 2018: International Orthopaedics
Hao Wang, Masanori Kohyama, Shingo Tanaka, KaiJin Wang, Ying Chen
A first-principles computational tensile test (FPCTT) is a powerful tool
 to investigate intrinsic strength and failure processes of grain
 boundaries (GBs), according to atomic and
 electronic behaviors based on density-functional theory, while
 careful interpretation is required in comparison with experiments,
 because of ideal conditions used in FPCTTs. We
 observed serious effects of a bulk-region size in FPCTTs of
 the {001} Σ5 GB in Al.
 For a GB supercell with enough thick bulk regions, the energy-strain curve shows spontaneous failure with catastrophic energy release just after the maximum stress point, which we name Type-A failure...
December 11, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
David Scott, Jonas Johansson, Lachlan B McMillan, Peter R Ebeling, Anna Nordstrom, Peter Nordstrom
BACKGROUND: Lower skeletal muscle density, indicating greater infiltration of adipose tissue into muscles, is associated with higher fracture risk in older adults. We aimed to determine whether mid-calf muscle density is associated with falls risk and bone health in community-dwelling older adults. METHODS: 2214 community-dwelling men and women who participated in the Healthy Ageing Initiative (Sweden) study at age 70 were included in this analysis. Mid-calf muscle density (mg/cm3 ) at the proximal tibia, and volumetric bone mineral density (vBMD) and architecture at the distal and proximal tibia and radius, were assessed by peripheral quantitative computed tomography...
December 8, 2018: Bone
Romina H Aspera-Werz, Sabrina Ehnert, Daniel Heid, Sheng Zhu, Tao Chen, Bianca Braun, Vrinda Sreekumar, Christian Arnscheidt, Andreas K Nussler
Cigarette smoking has been identified as a major risk factor for osteoporosis decades ago. Several studies have shown a direct relationship between cigarette smoking, decreased bone mineral density, and impaired fracture healing. However, the mechanisms behind impaired fracture healing and cigarette smoking are yet to be elucidated. Migration and osteogenesis of mesenchymal stem/stromal cells (MSCs) into the fracture site play a vital role in the process of fracture healing. In human nicotine, the most pharmacologically active and major addictive component present in tobacco gets rapidly metabolized to the more stable cotinine...
2018: Oxidative Medicine and Cellular Longevity
Herzl Chai, Xiaohong Wang, Jirun Sun
OBJECTIVE: Millimeter-scale ("miniature") specimens enable in-situ evaluation of mechanical properties of engineering materials at reduced cost. Here three such specimens for measuring fracture toughness (KC ) are developed and implemented to new dental materials. The latter include concurrent methacrylate-based and new ether-based resin composites designed to reduce polymerization stress and enhance service life in restored teeth. METHODS: Fracture toughness of four experimental and one commercial dental resin composites are evaluated using three-point bending (3PB), wedge double-cantilever-beam (WDCD) and edge chipping miniature test specimens...
December 7, 2018: Dental Materials: Official Publication of the Academy of Dental Materials
Abhay Datarkar, Shikha Tayal, Abhishek Thote, Manlio Galie
The mandibular parasymphysis and body regions are highly dynamic areas. They are constantly subjected to both occlusal and muscular forces. Fractures at this transition zone of the parasymphysis and body region thus represent a special pattern that creates a dilemma for the surgeons - whether to use one miniplate fixation or two miniplates as per Champy's guidelines. Mental nerve paresthesia is a very common complication due to dissection and stretching of the mental nerve in this region. Hence, an in-vitro research study of a novel twin fork design of miniplate is performed, which evaluates the biomechanical behavior using computerized finite element analysis...
November 12, 2018: Journal of Cranio-maxillo-facial Surgery
Antonio Barquet, Peter V Giannoudis, Andrés Gelink
INTRODUCTION: Femoral neck fractures (FNF) after internal fixation of trochanteric fractures (AIFTF) with the implant in situ (WIIS) are uncommon. Publications of FNFAIFTFWIIS are rare. The purpose of this systematic review of the literature is to report on the frequency, risk factors, mechanisms, clinical presentation, diagnostic and therapeutic modalities, outcomes and the eventual prevention of this complication. MATERIALS AND METHODS: A comprehensive review of the literature was undertaken using the PRISMA guidelines with no language restriction...
December 2018: Injury
Stine B Bruun, Irene Petersen, Nickolaj R Kristensen, Deirdre Cronin-Fenton, Alma B Pedersen
Background and purpose - Selective serotonin reuptake inhibitors (SSRIs) are often used in the elderly and are associated with adverse effects. Therefore, it is important to ascertain the prevalence of SSRI use in fragile and surgery-treated hip fracture patients. Methods - This population-based prevalence study included Danish hip fracture patients aged ≥ 65 years operated in 2006-2016 (n = 68,607) and matched individuals from the background population (n = 343,020). Using Poisson regression, prevalence risk ratios (PRRs) with 95% confidence intervals (CIs) were estimated to compare hip fracture patients with the general population, and to estimate the association between hip fracture patient characteristics and SSRI prescriptions...
December 10, 2018: Acta Orthopaedica
Selvalakshmi Rathinavelu, Crissy Guidry-Elizondo, Jameela Banu
Diabetes is a common disease affecting majority of populations worldwide. Since 1980, there has been an increase in the number of people diagnosed as prediabetic and diabetic. Diabetes is characterized by high levels of circulating glucose and leads to most microvascular and macrovascular complications such as retinopathy, nephropathy, neuropathy, stroke, and myocardial infarction. Bone marrow vascular disruption and increased adiposity are also linked to various complications in type II diabetes mellitus. In addition to these complications, type 2 diabetic patients also have fragile bones caused by faulty mineralization mainly due to increased adiposity among diabetic patients that affects both osteoblast and osteoclast functions...
2018: Journal of Diabetes Research
Zhonglue Hu, Chandrasekhar Meduri, Jerzy Blawzdziewicz, Golden Kumar
Lithography-free nanomanufacturing by elongation and fracture of glass forming metallic liquid is presented. The viscous metallic liquid confined in a cavity is laterally downsized to nanoscale by stretching. The extent of size-reduction can be controlled by tuning the active volume of liquid and the viscous and capillary stresses. Very high aspect-ratio metal nanostructures can be fabricated without using lithography or expensive molds. A systematic study is performed using glass forming Pt-Cu-Ni-P alloy to understand the effects of viscosity, surface tension, pulling velocity, and cavity size on the evolution of cylindrical liquid column under tension...
November 26, 2018: Nanotechnology
Jorge A Padilla, Afshin A Anoushiravani, James E Feng, Ran Schwarzkopf, James Slover, Scott Marwin
BACKGROUND: Short-stem (SS) hip prostheses for total hip arthroplasty (THA) have gained popularity as surgeons strive to reproduce physiological stress distributions at the proximal femur. Additionally, as THA indications continue to target younger populations, preservation of femoral bone stock for potential revision surgeries is particularly appealing. However, little is known regarding the short-term complications of each variety of short stem during the learning curve period. The purpose of this study is to evaluate the short-term complications among the THA recipients with the use of a novel SS hip prosthesis...
December 6, 2018: European Journal of Orthopaedic Surgery & Traumatology: Orthopédie Traumatologie
Othmar J Wess, Juergen Mayer
Shock wave lithotripsy is the only non-invasive stone therapy and in clinical use since 1980. In spite of decades with millions of patients treated, the mechanism of fragmentation is still under debate. Detailed knowledge of the fragmentation process is required for improvements regarding safety and efficiency. The purpose of this paper is to gain a deeper insight into the mechanism of fragmentation by drawing attention to basic physical laws of inertia and momentum transfer. Many fragmentation experiments are based on the overall efficiency of multiple shock waves in crushing kidney stones or artificial model stones utilizing small baskets or latex pouches...
December 6, 2018: Urolithiasis
Tomofumi Sawada, Verena Wagner, Christine Schille, Sebastian Spintzyk, Ernst Schweizer, Jürgen Geis-Gerstorfer
OBJECTIVE: The present study investigated the biaxial flexural strengths of bilayered ceria-stabilized zirconia/alumina nanocomposite (Ce-TZP/A) disks with various layering porcelains veneered using a slow-cooling protocol. METHODS: Five porcelain materials (VITA VM9, Cercon Ceram Kiss, and Vintage ZR with experimental coefficient of thermal expansions; CTEs of 8.45, 9.04, and 9.61ppm/°C) were veneered on Ce-TZP/A disks and slow-cooled after firing to fabricate bilayered specimens (core-to-porcelain thickness: 0...
December 3, 2018: Dental Materials: Official Publication of the Academy of Dental Materials
P Balcells, J M Peñalver-Matamoros, J Villaba-Modol, M Balaguer-Castro
We present the case of an 81-year-old woman who was followed up by the Rheumatology Service for osteoporosis and treated with bisphosphonates for more than five years. She reported a fracture of the distal third of the contralateral femur by a low energy mechanism, treated with retrograde intramedullary nailing the previous year. She presented a clinic of cruralgia and left gonalgia, without previous trauma. A scintigraphy and radiographs were performed to support the diagnosis of stress fracture of the distal third of the left femur and osteonecrosis of the left internal femoral condyle...
May 2018: Acta Ortopédica Mexicana
Matthew Jian-Qiao Peng, Hai-Yan Chen, XiangYang Ju, Yong Hu, Ashraf Ayoub, Balvinder Khambay, ZiQing Liu, Bo Bai
BACKGROUND: Little is known about how biomechanics govern the five fixtures such as DHS, MLS, DHS + LS, LP, and HA are accepted as common therapeutic techniques. AIMS AND OBJECTIVES: A series of numerical models for a femoral neck fracture of Pauwels-I will be constructed by innovative approach of finite element in order to determine the most optimized option in comparison with biomechanical performance. METHOD: Twenty sets of computer tomography scanned femora were imported onto Mimics to extract 3 D models; these specimens were transferred to Geomagic-Studio for a simulative osteotomy and kyrtograph; then, they underwent UG to fit simulative solid models; 5 sorts of fixture were then expressed by Pro-Engineer virtually...
December 5, 2018: Journal of Investigative Surgery: the Official Journal of the Academy of Surgical Research
Chao He, Yujuan Wu, Liming Peng, Ning Su, Xue Li, Kun Yang, Yongjie Liu, Shucheng Yuan, Renhui Tian
Cyclic deformation at low-stress amplitudes of a rare earth-containing magnesium alloy (Mg⁻Gd⁻Y⁻Zr) was investigated with emphasis on the responsible microstructural relationship between deformation mechanism and fatigue crack initiation. The results show that the microstructural deformation is extremely inhomogeneous at the low-stress amplitudes. Both deformation twinning and non-basal slip are barely observed, and basal slip is the predominant deformation to accommodate micro-plasticity. Fatigue crack initiation occurred at the basal slip bands, causing the morphology of facet on the fracture surface...
November 30, 2018: Materials
Anja Beckmann, Alexander Grißmer, Sandra Wolf, Johanna Recktenwald, Carola Meier
In the intact brain, astrocytes play an important role in a number of physiological functions like spatial buffering of potassium, maintenance of calcium homeostasis, neurotransmitter release, regulation of the cerebral blood flow, and many more. As pathophysiological events upon hypoxic-ischemic brain injury include excitotoxicity by glutamate release as well as oxidative stress, astrocytes and their gap junction-based syncytium are of major relevance for regulating the extent of resulting brain damage. The gap junction protein Connexin 43 (Cx43) contributes mainly to the astrocytic intercellular communication...
December 1, 2018: Neuroscience
Can Zhang, Hui Tang, Zhoutong He, Jinliang Song, Yantao Gao
Presented in this article are mechanical property and microstructural data for fluoride molten salt infiltrated graphite at high temperature. Four infiltration pressures (0 kPa, 450 kPa, 600 kPa, and 1000 kPa) and two kinds of graphite (IG-110 and NG-CT-10) were used during molten salt infiltration. After fluoride molten salt infiltration, compression testing and tension testing were performed at 700 °C to determine compressive strength, tensile strength, softening coefficient, stress-strain curve, and absorbed energy...
December 2018: Data in Brief
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