Interpretation of Post-operative Distal Humerus Radiographs After Internal Fixation: Prediction of Later Loss of Fixation

PURPOSE

Stable fixation of distal humerus fracture fragments is necessary for adequate healing and maintenance of reduction. The purpose of this study was to measure the reliability and accuracy of interpretation of postoperative radiographs to predict which implants will loosen or break after operative treatment of bicolumnar distal humerus fractures. We also addressed agreement among surgeons regarding which fracture fixation will loosen or break and the influence of years in independent practice, location of practice, and so forth.

METHODS

A total of 232 orthopedic residents and surgeons from around the world evaluated 24 anteroposterior and lateral radiographs of distal humerus fractures on a Web-based platform to predict which implants would loosen or break. Agreement among observers was measured using the multi-rater kappa measure.

RESULTS

The sensitivity of prediction of failure of fixation of distal humerus fracture on radiographs was 63%, specificity was 53%, positive predictive value was 36%, the negative predictive value was 78%, and accuracy was 56%. There was fair interobserver agreement (κ = 0.27) regarding predictions of failure of fixation of distal humerus fracture on radiographs. Interobserver variability did not change when assessed for the various subgroups.

CONCLUSIONS

When experienced and skilled surgeons perform fixation of type C distal humerus fracture, the immediate postoperative radiograph is not predictive of fixation failure. Reoperation based on the probability of failure might not be advisable.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic III.

Mechanistic investigation of a flame retardant coating made by layer-by-layer assembly

A flame retardant coating based on poly(allylamine) (PAH) and montmorillonite (MMT), deposited on polyamide 6 (PA6) sheets, is investigated. PA6-(PAH-MMT) at 40 bilayers was tested in a cone calorimeter and interrupted at different characteristic times. A possible mechanism of action of PA6 in the presence of layer-by-layer coating is proposed.

Tuning the conditions for the deposition of nanocrystalline diamond by hot filament chemical vapour deposition

Although large focus has been placed into the deposition of nanocrystalline and ultra-nanocrystalline diamond films, most of this research uses microwave plasma assisted CVD systems. However, the growth conditions used in microwave systems cannot be directly used in hot-filament CVD systems. This paper, aims to enlarge the knowledge of the diamond film depositing process. H2/CH4/Ar gas mixtures have been used to deposit micro, nano and ultra-nanocrystalline diamond films by hot-filament CVD systems. Additionally, the distance between the filaments array and the substrate was varied, in order to observe its effect and consequently the effect of a lower substrate temperature in the nucleation density and deposition. All the samples were characterized for microstructure and quality, using scanning electron microscopy and Raman spectroscopy.

Nanocrystalline diamond coatings for mechanical seals applications

A mechanical seal is a type of seal used in rotating equipment, such as pumps and compressors. It consists of a mechanism that assists the connection of the rotating shaft to the housings of the equipments, preventing leakage or avoiding contamination. A common cause of failure of these devices is end face wear out, thus the use of a hard, smooth and wear resistant coating such as nanocrystalline diamond would be of great importance to improve their working performance and increase their lifetime. In this paper, different diamond coatings were deposited by the HFCVD process, using different deposition conditions. Additionally, the as-grown films were characterized for, quality, morphology and microstructure using scanning electron microscopy (SEM) and Raman spectroscopy. The topography and the roughness of the films were characterized by atomic force microscopy (AFM).

Peculiar reduction of graphene oxide into graphene after diffusion in exponentially growing polyelectrolyte multilayers

In the present work, in situ reduction of graphene oxide (GO) into graphene was preformed, after diffusion in exponentially growing polyelectrolyte multilayers, using sodium citrate as the reducing agent. First, the graphene oxide was obtained by treating a commercial grade of Expanded Graphite (EG). Based on XRD and Raman spectroscopy results, a complete exfoliation of graphene nanopellets down to one layer was achieved during the oxidation process. Secondly, the diffusion of GO was carried out in an exponentially growing polyelectrolyte multilayer film made from poly(diallyldimethylammonium chloride) as the polycation and from poly(acrylic acid) as the polyanion. Electrical conductivity of the GO based films was measured during the reduction process as a function of time. The conductivity reached values of the order of 10(-4) S cm(-1), whereas the pristine polyelectrolyte multilayer was highly insulating (∼10(-8) S cm(-1)). The conductivity also reached a maximal value after about 24 h of reduction and decreased for longer reduction duration. Some tentative explanations for this peculiar finding will be given.

Comparative study of nanocrystalline diamond deposition on WC-Ni and WC-Co substrates

Tungsten carbide alloys possess a large number of applications, due to its high hardness, high resistance to heat and to wear, which makes it ideal to be used in wear parts of machinery or on surfaces liable to corrosion, abrasion or high temperatures. For practical applications, it is alloyed with cobalt (Co) or nickel (Ni) in order to improve its properties. The increasing demand of broadening the operation limits of some components, impose the need to improve its life time. Coating these parts with hard and smooth diamond thin film may improve the wear performance and decrease their roughness and friction coefficient. In this work, a comparative study of nanodiamond films deposit onto WC-Co and WC-Ni, by means of a hot-filament Chemical Vapour Deposition (HFCVD) system, is presented. The study was accomplished by varying the CH4/H2/Ar gas ratio of the deposition process. The substrate temperature was kept low (< 700 degrees C) to minimize the thermal stress in the coating-substrate system. The microstructure of the deposited diamond film was characterized using Scanning Electron Microscopy (SEM), Raman spectroscopy and X-ray diffraction spectroscopy. Roughness of the working surfaces were also accessed prior and after the depositions.

Investigation of the stiffness and yield behaviour of melt-intercalated poly(methyl methacrylate)/organoclay nanocomposites: characterisation and modelling

The elastic modulus and yield stress behaviour of a melt intercalated Poly(methylmethacrylate)/ organoclay (PMMA/C30B and PMMA/C20A) were studied using uniaxial tensile tests at different temperatures and different strain rate. The stress-strain response was obtained for different loading rates and different test temperature. Both the stiffness and the yield stress were then clearly identified as function of strain rate and temperature. Our experimental results show that the yield stress and modulus of both PMMA/C20A and PMMA/C30B organoclay nanocomposites are very sensitive to clay concentration, strain rate and temperature. A micromechanically-based composite approach was used to predict the yield stress of both PMMA/C20A and PMMA/C30B organoclay nanocomposites. The results obtained from the model are in good agreement with our experimental results. As expected, the activation enthalpy of cooperative model increased slightly while the activation volume decreases slightly with the clay concentration.

Hybrid layers deposited by an atmospheric pressure plasma process for corrosion protection of galvanized steel

Finding alternative treatments to reproduce anticorrosion properties of chromated coatings is challenging since both physical barrier and self-healing effects are needed. Siloxane based treatments are known to be a promising way to achieve physical barrier coatings, mainly plasma polymerized hexamethyldisiloxane (ppHMDSO). In addition, it is known that cerium-based coatings can also provide corrosion protection of metals by means of self-healing effect. In this frame, innovative nanoAlCeO3/ppHMDSO layers have thus been deposited and studied. These combinations allow to afford a good physical barrier effect and active properties. Liquid siloxane and cerium-based particles mixture is atomized and introduced as precursors into a carrier gas. Gas mixture is then injected into an atmospheric pressure dielectric barrier discharge (DBD) where plasma polymerization of the siloxane precursor occurs. The influence of cerium concentration on the coating properties is investigated: coating structure and topography have been studied by scanning electron microscopy (SEM) and interferometry, and corrosion resistance of these different coatings is compared by electrochemistry techniques: polarization curves and electrochemical impedance spectroscopy (EIS). Potential self-healing property afforded by cerium in the layer was studied by associating EIS measurements and nanoscratch controlled damaging. Among the different combinations investigated, mixing of plasma polymerized HMDSO and AICeO3 nanoparticles seems to give promising results with a good physical barrier and interesting electroactive properties. Indeed, corrosion currents measured on such coatings are almost as low as those measured with the chromated film. Combination of nanoscratch damaging of layers with EIS experiments to investigate self-healing also allow to measure the active protection property of such layers.

Towards optimization of time modulated chemical vapour deposition for nanostructured diamond films on Ti6Al4V

In this paper, we report the use of the TMCVD technique for the optimisation of deposited diamond films onto Ti6Al4V substrates. A number of samples were made varying the experimental parameters. The specimen surfaces were characterised using micro Raman spectra and SEM analyses. Results show that very different surface finish (from micro to nanostructures) and film characteristics can be obtained from the experimental parameters used. The quality of deposited diamond is very dependant on the experimental settings and process. It was found that lower residual stresses are developed using the TMCVD technique than with conventional CVD but depend on the structural diamond growth during the process. The quality of the deposited film was evaluated as a function of diamond to amorphous carbon ratio but showed no direct relation with the surface finish since it characterises the quality of the deposited diamond but not the quality of the film surface.

Use of functionalized nanosilica to improve thermo-mechanical properties of epoxy adhesive joint bonding aluminium substrates

The present work is concerned with the improvement of thermal properties and mechanical strength of adhesive joints consisting of an epoxy adhesive layer bonding aluminium substrates by grafted nanosilica. Epoxy resin/silica nanocomposites were prepared by using functionalized silica. Silica was functionalized by amine group (SiO2-NH2). It was identified by Raman and Fourier Transform Infrared (FTIR). Effects of silica on viscoelastic properties for epoxy resin and its assemblies with aluminium substrates were studied by Dynamical Mechanical Analysis (DMA). Particles distribution was characterized by Scanning Electron Microscope (SEM). Our experimental results showed that functionalized silica presents a better distribution in the matrix than the pure silica. Our results also showed that grafting of functionalized silica improves the glass transition temperature (Tg) and the ultimate strength of aluminium/epoxy/aluminium assembly.

Game-based training in young elite handball players

This study compared the effect of high-intensity interval training (HIT) versus specific game-based handball training (HBT) on handball performance parameters. Thirty-two highly-trained adolescents (15.5+/-0.9 y) were assigned to either HIT (n=17) or HBT (n=15) groups, that performed either HIT or HBT twice per week for 10 weeks. The HIT consisted of 12-24 x 15 s runs at 95% of the speed reached at the end of the 30-15 Intermittent Fitness Test (V(IFT)) interspersed with 15 s passive recovery, while the HBT consisted of small-sided handball games performed over a similar time period. Before and after training, performance was assessed with a counter movement jump (CMJ), 10 m sprint time (10 m), best (RSAbest) and mean (RSAmean) times on a repeated sprint ability (RSA) test, the V(IFT) and the intermittent endurance index (iEI). After training, RSAbest (-3.5+/-2.7%), RSAmean (-3.9+/-2.2%) and V(IFT) (+6.3+/-5.2%) were improved (P<0.05), but there was no difference between groups. In conclusion, both HIT and HBT were found to be effective training modes for adolescent handball players. However, HBT should be considered as the preferred training method due to its higher game-based specificity.

Secondary ion and laser ablation mass spectrometry for the quantitative characterization of styrene-butadiene copolymers

Styrene-butadiene copolymers were analyzed by static secondary ion mass spectrometry (S-SIMS) and laser ablation Fourier transform ion cyclotron resonance mass spectrometry (LA-FTICRMS) to obtain quantitative information based on specific ions. Silver deposition was performed on polystyrene, butadiene rubber and styrene-butadiene rubber. Under these experimental conditions, new secondary ions were detected, in particular silver-cationized butadiene [M(butadiene) - Ag](+) and styrene [M(styrene) - Ag](+) monomers. In contrast, LA-FTICRMS experiments did not require pretreatment. At high laser power density, UV photons (193, 266 and 355 nm) allowed the detection of styrene and butadiene monomers at m/z 104 and 54, respectively. The use of the observed ions by SIMS or LA-FTICRMS ensures that quantitative information on the relative distribution of each monomer is obtained. However, the silver coating thickness in the SIMS experiment seems to have an important influence on the quantitative information obtained. For LA-FTICRMS experiments, the best results are obtained at a wavelength of 355 nm.

Elevated alpha-fetoprotein and a normal fetal sonogram: association with placental abnormalities

This report documents the outcome of 25 pregnancies with elevated serum alpha-fetoprotein levels on two separate samplings despite normal anatomic appearance of the fetus on a detailed "consultative" sonographic examination. Six of these also had elevated amniotic fluid alpha-fetoprotein. All fetuses in this series were anatomically normal at time of delivery; one aborted fetus was triploid. Of the 25 pregnancies, 16 had sonographically demonstrable placental hemorrhage, eight retroplacental and eight subchorionic. One had hydropic changes in the placenta associated with triploidy. Of the subgroup of six pregnancies in which both serum and amniotic fluid values were elevated, one had a retroplacental hemorrhage, one had a subchorionic hemorrhage, and one had diffuse hydropic changes in the placenta. A control group of 112 patients with normal alpha-fetoprotein levels yielded four with small (less than 2 cm3) subchorionic hemorrhage. The occurrence rate of placental hemorrhage in women with elevated alpha-fetoprotein and normal fetus was 64%, whereas the control group of patients with normal alpha-fetoprotein had a 3.6% occurrence rate of placental hemorrhage. Sonographically detectable placental abnormalities may be associated with elevated alpha-fetoprotein in serum and/or amniotic fluid samples. Such abnormalities may occur because of fetomaternal admixture associated with placental hemorrhage and/or intraamniotic bleeding resulting from subchorionic hemorrhage.