“Stress fracture”

Introduction: As a result of increasing longevity, we are seeing more elderly patients with complex medical co-morbidities who sustain hip fractures requiring surgical management. The aim of this study is to understand and analyze the effect of preoperative medical comorbidities and associated low physiological reserve status on functional rehabilitation outcomes following surgical management of hip fractures. Materials and methods: This study conducted a retrospective analysis of 73 patients who fulfilled the inclusion criteria ...

Case summary: Osteogenesis imperfecta (OI) is an inherited disorder related to the synthesis of type 1 collagen. Clinical signs of pain from the fracture of fragile bones are common. A 3-month-old male Chinchilla cat was presented for lameness and pain from a right femoral fracture. After surgical repair using intramedullary pins, and since repeated fractures occurred and there is little information about genes causing OI in cats, various examinations were performed to discriminate other diseases that could cause the pathological fracture...

Due to their excellent mechanical and biocompatibility properties, titanium-based implants are successfully used as biomedical devices. However, when new bone formation fails for different reasons, impaired fracture healing becomes a clinical problem and affects the patient's quality of life. We aimed to design a new bioactive surface of titanium implants with a synergetic PEG biopolymer-based composition for gradual delivery of growth factors (FGF2, VEGF, and BMP4) during bone healing. The optimal architecture of non-cytotoxic polymeric coatings deposited by dip coating under controlled parameters was assessed both in cultured cells and in a rat tibial defect model (100% viability)...

A finite element (FE) model of an 11-month-old child's femur was developed to evaluate fracture risk in short-distance feet-first falls and bed falls. Pediatric material properties were applied to the FE model. Femur loading was derived from previously conducted fall experiments using a child surrogate where fall conditions (e.g., fall height, impact surface) were varied. Fracture thresholds based on principal stress and strain were used to examine potential for fracture. Peak stress/strain were significantly greater for feet-first falls from greater heights and onto harder impact surfaces...

With the development of industrial lasers and novel glass processing techniques, which offer high speed, quality and precision, this becomes an attractive alternative to conventional methods, such as mechanical scribing and cleaving, diamond saw and waterjet cutting, commonly used in the industry. However, the emerging techniques lack thorough validation with respect to well-established methods. To this end, we present a detailed comparison of different glass cutting methods, taking into account surface quality, side-wall roughness, residual stresses and flexural strength...

We aimed to determine factors related to tooth fracture experience in Korean adolescents. This study used data from the 14th Korea Youth Risk Behavior Survey in 2018, a cross-sectional web-based survey of health-risk behaviors among a representative sample of Korean middle- and high-school students aged 12-17 years. A total of 60,040 participants were selected using a complex sampling design of the survey from 400 middle schools and 400 high schools. They answered a self-administered questionnaire survey in classrooms...

Willam's test is a quick numerical benchmark in tension-shear regime, which can be used to verify inelastic (quasi-brittle) material models at the point level. Its sequence consists of two separate steps: uniaxial tension accompanied with contraction-until the tensile strength is attained; and next for softening (cracking) of the material-tension in two directions together with shear. A rotation of axes of principal strains and principal stresses is provoked in the second stage. That kind of process occurs during the analysis of real concrete structures, so a correct response of the material model at the point level is needed...

This paper presents double shear tests performed to investigate factors influencing the bond behavior between basalt fiber-reinforced polymer (BFRP), glass fiber-reinforced polymer (GFRP) laminate, and concrete blocks. In detail, thirty-six twin concrete blocks strengthened with the aforementioned FRP types were tested to evaluate the influence of FRP length, width, and thickness, and their bonding behavior. The 2D-DIC (digital image correlation) technique and several strain gauges bonded along the laminate were used to measure the strain distributions of the FRP-to-concrete interface...

The present work investigates the microstructural, thermo-mechanical, and electrical properties of a promising, but still not thoroughly studied, biobased polymer, i.e., poly(decylene furanoate) (PDeF), and its performance when multi-walled carbon nanotubes (CNTs) are added. After sample preparation by solution mixing and film casting, the microstructural investigation evidences that the fracture surface becomes smoother and more homogeneous with a small fraction of CNTs, and that the production process is suitable to achieve good disentanglement and dispersion of CNTs within the matrix, although some aggregates are still observable...

Field experience shows that extending shut-in periods are conducive to increasing tight oil production after fracturing operations. Understanding the regularity of pressure decay is helpful to establish an appropriate shut-in time. However, the characteristics and influencing factors of pressure decay are unclear. This paper studies the porosity, permeability, mineral composition, and pore structure of samples in six different blocks. The pressure decay regularity is tested according to an independently designed indoor shut-in experimental device, and the oil distribution of experimental samples is monitored using nuclear magnetic resonance technology...

OBJECTIVE: To establish a new mechanical model of distal humerus in children with epiphysial cartilage, stimulate supracondylar humerus fracture and perform three dimensional finite elements, and study effect of pins numbers, pin tract, outlet height and pin configurations on stability of fixation. METHODS: Three dimensional computed tomography (CT) data of 6-year-old boy with distal humerus was downloaded from picture archiving and communications systems software (PACS), the data of picture was imported into Simpleware and SolidWorks 2016 software to establish distal humerus fracture in children contained ossific nucleus of the capitellum (ONC) and distal cartilage...

A large number of post mortem human subjects was used to investigate the relation between the micro-structure of rib cortical bone and the mechanical properties using Fractal Dimension. Uniaxial tensile tests were performed on coupons of rib cortical bone. Tensile strength, yield stress, Young's Modulus, maximum strain, and work to fracture were determined for each coupon. Fractal dimension was computed using CT images and Digital Image Correlation procedures. A highly significant effect of fractal dimension in the mechanical properties was found...

OBJECTIVES: Residual hip dysplasia is the most common underlying condition leading to secondary osteoarthritis (OA) of the hip. Subchondral bone alterations in OA secondary to hip dysplasia (HD-OA) are poorly investigated. The aim of the present study was to analyse the microarchitecture, bone remodelling and pathological alterations of subchondral bone in femoral heads from patients with HD-OA. METHODS: Subchondral bone specimens were extracted from both weight-bearing and non-weight-bearing regions of femoral heads from 20 patients with HD-OA and 20 patients with osteoporotic femoral neck fracture, during hip replacement surgery...

The modern wood converting processes consists of several stages and material drying belongs to the most influencing future performances of products. The procedure of drying wood is usually realized between subsequent sawing operations, affecting significantly cutting conditions and general properties of material. An alternative methodology for determination of mechanical properties (fracture toughness and shear yield stress) based on cutting process analysis is presented here. Two wood species (pine and beech) representing soft and hard woods were investigated with respect to four diverse drying methods used in industry...

PURPOSE: In this research, low modulus carbon fiber (CF)-reinforced polyetheretherketone composite plates (CF-PEEK plates) were compared with traditional metal plates using finite element analysis to establish a reference for clinical application. MATERIAL AND METHODS: Plates of stainless steel, titanium alloy (Ti6Al4V), or CF-PEEK with different carbon fiber reinforcement ratios (CF30, CF50, and CF60) were used to fix the tibial shaft comminuted fracture. The maximum stress, the maximum displacement of fracture and the stress shielding of cortex bone were analyzed...

The aim of this study was to compare the radiological and clinical outcomes of the same make of modular and monoblock tapered fluted stems in patients with failure of internal fixation following osteoporotic intertrochanteric fracture. This retrospective, comparative study included patients older than 65 years who underwent hemiarthroplasty with a modular or monoblock distally fixed fluted stem and had failed treatment with proximal femoral nailing between 2012 and 2017, with at least a 2-year follow-up period...

Both human immunodeficiency virus (HIV) infection and antiretroviral therapy are related to an increased risk of fracture. As a result of the developments in HIV treatment in recent years, life expectancy in HIV-infected patients has increased. Therefore, HIV-related musculoskeletal problems such as osteoporosis and avascular necrosis are more common currently. There are complex mechanisms in HIV-related osteoporosis. The loss of bone mineral density is particularly distinctive in the first months of the therapy...

We report for the first time a case of atypical unilateral sacroiliitis secondary to mechanical stress injury. Unilateral sacroiliitis can be caused by a variety of etiologies. The first diagnosis to rule out is infection since it requires urgent treatment to avoid its serious consequences. Spondyloarthritis can be manifested by unilateral sacroiliitis in its early stage. Sacral fractures should always be looked for on the imaging modalities performed. In our case, no signs of infection or systemic disease were found...

It is a difficult task to describe what constitutes a 'healthy' shellfish (e.g., crustacean, bivalve). Visible defects such as discolouration, missing limbs or spines, fouling, lesions, and exoskeletal fractures can be indicative of underlying issues, senescence, or a 'stressed' animal. The absence of such symptoms is not evidence of a disease-free or a stress-free state. Now, more than ever, aquatic invertebrates must cope with acute and chronic environmental perturbations, such as, heatwaves and cold shocks, xenobiotic contaminants, intoxication events, and promiscuous pathogens expanding their host and geographic ranges...

The high water content of hydrogels makes them important as synthetic biomaterials, and tuning the mechanical properties of hydrogels to match those of natural tissues without changing chemistry is usually difficult. In this study, we have developed a series of hydrogels with varied stiffness, strength, and toughness based on a combination of poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS), a strong acidic polyelectrolyte, and poly- N -(carboxymethyl)- N , N -dimethyl-2-(methacryloyloxy) ethanaminium) (PCDME), a polyzwitterion with a weak acidic moiety...