Angle Surface Research Articles

Effect of plasma modification on UV-curable ink-jet coating on medium-density fiberboard (MDF)

ABSTRACT The UV-curable inkjet coating system on the surface of wood-based substrates consists of the substrate, primer, printing layer, and topcoat layer. To enhance the compatibility at the interface between the UV-curable primer and the inkjet coating on the substrate surface, this study employed air plasma to modify the medium-density fiberboard substrate's primer surface under varying treatment power and speeds. By analyzing the changes in contact angle, chemical composition, and elemental composition of the substrate primer surface under different plasma treatment conditions, theoretical support was provided for the improvement of the bonding between the UV-curable primer and the printing layer. The results show that with a plasma treatment speed of 0.4 m/min and power of 700 W, the contact angle with water on the surface was 20°, and the whiteness value was 80.5 Wb. The C = C bonds on the primer surface break and combine with oxygen elements to form oxygen-containing functional groups or peroxides, increasing the surface polarity and activity of the primer. When the plasma treatment power was 750 W and the speed was 0.8 m/min, the relative concentration of oxygen elements on the UV-curable primer surface increased to 49%, while the carbon element content decreases by 29%.

A green bulk modification for imparting a green VIPS membrane with antifouling properties

BackgroundMembrane preparation and membrane modification processes have long involved the use of toxic solvents. The present work proposes to only use envrionmentally-friendly solvents for both the fabrication and the surface modification of hydrophobic microfiltration membranes. In addition, coating processes for membrane modification are essentially surface modification processes. However, spray-coating may be a suitable method for both surface and bulk modification. MethodsAfter dissolving poly(vinylidene fluoride) in dimethylsulfoxide, membranes were formed by the vapor-induced phase separation process, and then modified using an aqeous solution of an amphiphilic copolymer containing poly(ethylene glycol) methyl ether methacrylate units. Then, a variety of physicochemical techniques were employed to characterize the membrane structure and prove the effectiveness of the surface/bulk modification. Antifouling tests in static and dynamic conditions were conducted. Significant findingsIt is possible to reduce the water contact angle of the top surface of the membrane from 135° to 0° and that of the bottom surface from 126° to 0° within <10 s, indicating successful hydrophilization of the membrane on the one hand, and top-to-bottom modification, despite solely exposing the top surface to the spray, on the other hand. This conclusion was confirmed by deidcated surface chemistry analyses. Besides, the membranes maintained their original highly porous and symmetric structure with light effects on surface porosity and pore size following the spray-coating process. The drasting improvement of hydrophilicity resulted in effective mitigation of fibrinogen adsorption (reduced by 85 %) and Escherichia coli adhesion (reduced by 86 %). Fouling during cyclic filtration involving a bacterial suspension was also effectively reduced with a flux recovery ratio of 53 % (against 37 % for a commercial hydrophilic membrane) and an irreversible flux decline ratio of 47 % (against 63 % for a commercial hydrophilic membrane) in the conditions of the test.

Calculation method for static and seismic active earth pressure on counterweight retaining walls under translation based on two critical slip surfaces

The counterweight retaining wall with polyline wall back is a kind of gravity walls, which can be alternatively used in high embankments. To completely analyze active earth pressure on the polyline back under the wall translation mode, a comprehensive method is proposed based on two planar slip surfaces in the retained soil, an inclined slice method within the frame of limit equilibrium, and the pseudo-static approach. Meanwhile, the two critical slip surfaces include the global and local ones in the soils behind the whole wall and only the upper wall, respectively; and mobilized shear strength coefficients on interslice surfaces are introduced to fully consider the interslice shear forces. Some examples show that the proposed resultant forces on the whole wall are close to the experimental and numerical results generally within 10% error. The dip angle of backfill surface has a significant effect on the two slip surfaces, and the inclination of the lower back mostly influences the global slip surface. The unloading effect of the platform on the lower earth pressure becomes obvious as the upper wall lengthens under a constant height of the whole wall. The magnitude and profile of the seismic earth pressure on the polyline back are greatly influenced by the seismic coefficients.

Experimental and numerical studies on spray cooling of a downward-facing surface under partial coverage of multi-nozzle sprays

A new experimental study (aka SPAYCOR-S2) on multi-nozzle spray cooling of a downward-facing heater surface is conducted on the SPAYCOR facility at KTH, to provide data assessing the feasibility of spray cooling for in-vessel melt retention (IVR) in light water reactors. It is intended to investigate the potential for reducing the number of nozzles for spray cooling of an 80 mm × 120 mm surface, from the 2 × 3 nozzle array in the previous study (Bandaru, 2021) to a 2 × 2 nozzle array in the present study. Given the same heater surface, the pitch-to-diameter ratio is enlarged in a 2 × 2 nozzle array, resulting a partial coverage of the spray cones of four nozzles, in contrast with the 2 × 3 nozzle array where the heater surface was fully covered by six-nozzle spray. The tests focus on the cooling performance of such partial coverage of multi-nozzle spray and the effects of heater surface’s inclination angle. The experimental results reveal that the inclination angle of the heat surface has a negligible impact on cooling capacity, although it is slightly higher on the surface inclined at 90° than on the surfaces inclined at 45° or 60°. The maximum steady heat flux of the 2 × 2 nozzle array at its minimum spray flowrate is determined as 1.96 MW/m2. A numerical study on the spray cooling of the 2 × 2 nozzle array is also performed with models in OpenFOAM, which are extended from our previous development (Fang, 2023) by adding models for thin-film boiling and conjugate heat transfer in solid. For validation of the numerical study, the spray cooling of the heater surface inclined at various degrees is simulated, and the results are compared with those of experiment. The simulation generally shows good correspondence with experiments.

An investigation into the use of incoherent UV light to augment IR nanosecond pulsed laser texturing of CFRP composites for improved adhesion

The preparation of Carbon Fibre Reinforced Polymers (CFRP) surfaces for adhesive bonding has been widely reported. Such reports include laser texturing using both near-infrared (IR) lasers and ultraviolet (UV) lasers. In this report, we present, for the first time, findings showing that surface treatment of CFRP using incoherent UV light, at 254 nm wavelength, can increase the adhesive bonding strength of CFRP by 75 % compared to non-treated samples. It is also around 10 % stronger than NIR laser-textured samples. However, combination treatments, where the UV irradiation is conducted either before or after laser texturing did not give a significant benefit over the laser-textured samples. A germicidal 46 W 254 nm UV lamp was used for the UV light treatment, while an IR nanosecond pulsed fibre laser operating at 1064 nm was used for the laser texturing treatment. The material tested was an autoclave-cured T700 CFRP composite.The wettability of the treated CFRP surfaces and the adhesive bonding were quantitatively assessed. This study concludes that low-cost incoherent UV treatment effectively reduces the water contact angle of the CFRP surface and activates CFRP surfaces. All treatments led to bonding strengths at least 50% greater than for the untreated surfaces.The predominant failure mode for UV-treated samples was Cohesive Substrate Failure (CSF), indicating that the adhesion strength exceeded the interlaminar shear strength of the CFRP material. All samples treated with the laser (including combined treatment with UV) exhibited Light Fibre Tear Failure.

Optimizing Outcomes in Distal Tibial Deformity Correction: The Role of Supramalleolar Osteotomy with Computer-assisted Hexapod External Fixator.

Distal tibial deformities can significantly impact patients if left uncorrected, often leading to pain, alterations in gait, and the eventual development of post-traumatic arthritis. The criteria for surgical correction in these patients continues to be a subject of debate, while supramalleolar osteotomy (SMO) is an effective method for correcting distal tibial deformities. The purpose of this study was to evaluate and compare the clinical results of SMO using internal fixation or using computer-assisted hexapod external fixator in the treatment of distal tibial deformity. A retrospective study was conducted on 290 patients who underwent SMO between June 2015 and January 2023. Forty-four patients met the inclusion and exclusion criteria. Among the participants, 19 underwent SMO combined with a computer-assisted hexapod external fixator, while 25 received SMO with plate and screw internal fixation. The tibial anterior surface (TAS) angle, tibial lateral surface (TLS) angle, the tibiotalar (TT) angle and the talocrural (TC) angle were assessed on weight-bearing X-ray films. Functional assessments were performed according to the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score. The study followed patients for an average duration of 31.7 ± 15.3 months, with a range from 12 to 67 months. Successful bone union was achieved in all cases. For patients treated with the computer-assisted hexapod external fixator, significant improvements were observed: the mean deviation in sagittal plane deformity parameters decreased from 14.3 ± 10.4 degrees preoperatively to 2.8 ± 3.8 degrees postoperatively (p < 0.05). Similarly, coronal plane deformity parameters showed a reduction from 25.9 ± 22.5 degrees preoperatively to 5.9 ± 11.0 degrees postoperatively (p < 0.05). The AOFAS ankle-hindfoot score improved markedly from 66.0 ± 14.9 to 86.1 ± 11.7 points (p < 0.05). For patients undergoing internal fixation, the absolute difference in coronal plane parameters improved from 15.4 ± 12.6 degrees preoperatively to 3.7 ± 3.4 degrees postoperatively (p < 0.05). A significant enhancement in AOFAS ankle-hindfoot score was also noted, increasing from 68.3 ± 14.3 points to 79.4 ± 13.5 points (p < 0.05). There were no significant differences in gender, side, follow-up time, postoperative deviation of deformity, pre- or postoperative AOFAS between the two groups. In conclusion, comprehensive preoperative planning of SMO combined with either internal fixation or a hexapod external fixator for treating distal tibial deformities can achieve satisfactory outcomes. The utilization of a computer-assisted hexapod external fixator facilitates a gradual and precise correction process, which proved to be an effective and relatively safe method.

Durable photobioreactor antibiofouling coatings for microalgae cultivation by photoreactive poly(2,2,2-trifluoroethyl methacrylate)

To improve the durability of the photobioreactor antibiofouling surface for microalgal cultivation, a series of photoreactive poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) were successfully synthesized and used to modify ethylene-vinyl acetate (EVA) films by a surface coating and UV light grafting method. Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy analysis (XPS) and fluorescence microscopy results indicated that PTFEMA were fixed successfully onto the EVA film surface through a covalent bond. During the microalgal adhesion assay, the number of EVA-PTFEMA film-adhered microalgae was 41.4% lower than that of the EVA film. Moreover, the number of microalgae attached to the EVA-PTFEMA film decreased by 61.7% after cleaning, while that of EVA film decreased by only 49.1%. It was found that the contact angle of EVA-PTFEMA film surface increased, and remained stable when immersed in acid and alkali solution for up to 90 days. HIGHLIGHTS Durable photobioreactor antibiofouling surfaces for microalgal cultivation were prepared successfully. The contact angle of antibiofouling coating surface remained stable in acid and base environment for 90 days. The attached microalgae on antibiofouling surface decreased 41.4% than those of unmodified surface. The attached microalgae on antibiofouling surface could be cleaned by 61.7% through changing the flow velocity of microalgal suspension.

Easy Fabrication of Ultrafiltration Membrane via Polyethersulfone-Fumed Silica

This study investigated the effect of low-concentration fumed silica (FS) in polyethersulfone (PES) membranes. The PES/FS blend membrane was fabricated using a wet phase inversion technique as a flat sheet membrane. Scanning electron microscopy analysis revealed improved pore connectivity and rounder middle structures due to the addition of fumed silica. The experimental results indicated that the fabricated membranes fell within the ultrafiltration range, with pure water flux increasing as fumed silica concentration rose. The pure water flux improved by 64% compared to the native PES membrane. Furthermore, the blend membranes exhibited better selectivity, rejecting pepsin and lysozyme 11% and 19% more efficiently, respectively. Although the low concentration of fumed silica had minimal impact on the water contact angles of the membrane surface, all membranes demonstrated hydrophilicity. This cost-effective approach enhances permeability while maintaining separation characteristics, making it suitable for clean water applications.

Determining the angle of the frontal working surface of the soil-piercing head asymmetrical tip for static soil-piercing

Problem. From the analysis of the technical literature, it was established that among the trenchless technologies for laying underground engineering communications and service pipelines, the technology with the possibility of forming a horizontally directed communication cavity in the soil using soil-piercing installations of static action is the most common. Goal. This method consists in forcefully pressing a soil-piercing working body, which has the form of a conical-cylindrical projectile, into the soil. At the same time, the well is formed by radial extrusion of the soil around the formed well. However, the use of such equipment does not provide high accuracy, which limits its practical application within 20 m. It is not sufficient for modern requirements of creating transitions during the laying of communications. Methodology. One of the ways to improve the efficiency of laying underground networks is to extend this method over a longer distance by correcting the trajectory of the working body. This is achieved by using a soil-piercing head with an asymmetric tip. Due to this, in addition to the axial resistance of the soil, a transverse component force appears, which deflects the head during its advancement in the soil. The question of determining the angle of displacement of such a tip is important in terms of the process control. Results. In the paper, a calculated dependence is proposed for determining the rational value of the angle of inclination of an asymmetric tip working surface, which is a flat plane cut at the angle of a cylinder. An analysis of the dependence of the angle of the working surface inclination on the physical and mechanical properties of the soil is also given. Originality. It was determined that the maximum angle of inclination of the frontal surface is determined by the conditions of soil descent from it. Its maximum value, for example when working in loam, should not exceed 55o-67o for a tip made of steel. Practical value. The obtained calculated dependence can be useful for determining the angle of inclination of the flat frontal surface of the tip of the soil piercing working tool for controlled static soil piercing at the stage of designing networks and choosing an effective method for drilling a well under roads or other obstacles.

Effects of Wire-Wrapping Patterns and Low Temperature on Combustion of Propellant Embedded with Metal Wire

Incorporating silver wires into propellant has emerged as a highly effective strategy for enhancing propellant burning rates, a technique extensively deployed in the construction of numerous fielded sounding rockets and tactical missiles. Our research, employing a multi-faceted approach encompassing thermogravimetric-differential scanning calorimetry measurements (TG-DSC), combustion diagnoses, burning rate tests, and meticulous collection of condensed combustion products, sought to elucidate how variations in silver wire quantity and winding configuration impact the combustion properties of propellants. Our findings underscore the remarkable efficacy of double tightly twisted silver wire in significantly boosting propellant burning rates under ambient conditions. Moreover, at lower temperatures, the reduced gap between the propellant and silver wire further magnifies the influence of silver wire on burning rates. However, it is noteworthy that the relationship between burning speed and combustion efficiency is not deterministic. While a smaller cone angle of the burning surface contributes to heightened burning rates, it concurrently exacerbates the polymerization effect of vapor phase aluminum particles, consequently diminishing propellant combustion efficiency. Conversely, propellants configured with sparsely twinned silver wires exhibit notable enhancements in combustion efficiency, despite a less pronounced impact on the burning rate attributed to the larger cone angle of the burning surface. Remarkably, these trends persist at lower temperatures. Based on the principle of heat transfer balance, a theoretical model for the combustion of propellants with wire inserts is developed. The reliability of this theoretical model is validated through a comparison of calculated values with experimental data. Our research outcomes carry significant implications for guiding the application and advancement of the silver wire method in solid propellants for solid rocket motors, offering valuable insights to inform future research and development endeavors in this domain.

Analysis of Critical Instability Conditions for Solid-Phase Plugging of Natural Fractures during Temporary Plugging and Fracturing.

Hydraulic fracturing has become a key technology for the development of unconventional oil and gas resources, such as deep shale. Due to the development of natural fractures in deep shale reservoirs, the opening of natural fractures during the fracturing process can cause a significant loss of fracturing fluid, resulting in a reduction in the width of the main fracture and construction risks, such as sand plugging. It is important to improve the fracturing effect of deep shale reservoirs by plugging natural fractures with solid phases, reducing filtration, and improving the efficiency of the fracturing fluid. Ensuring the effectiveness of solid plugging is key to optimizing the fracturing design and improving the stimulation effect after fracturing. In this study, solid plugging technology is introduced into the filtration control process of natural fractures. By setting a plugging zone with a certain length and permeability inside the natural fracture, a stability prediction model for the plugging zone of natural fractures is established, and the instability conditions of the plugging zone are analyzed. The simulation results indicate that the instability of the plugging zone is related to permeability and there is a critical permeability. When the permeability of the plugging zone is greater than this value, expansion instability will occur, and when it is less than or equal to this value, shear slip instability may occur. The strength of shear slip instability is mainly determined by the length of the plugging zone, the friction angle of the natural fracture surface, the friction angle between the plugging particles, and the porosity of the plugging zone. The friction angle of natural fracture surfaces affects only the strength of slip instability, while the friction angle of plugging particles and porosity mainly affect the strength of shear instability. The research results provide a theoretical basis for the optimization of fracturing construction parameters in deep shale reservoirs.

The Three-Dimensional Relationship of the Axes of the Capitate and Third Metacarpal

We quantified the morphology and angulation of the third metacarpal (MC3) relative to the capitate using three-dimensional computed tomography data to inform surgical procedures such as total wrist arthroplasty and wrist arthrodesis. Specifically, we report the three-dimensional location of the intersections of the long axis of MC3 axis with the capitate cortical surface, the sagittal and coronal angles between the MC3 and capitate axes, and the MC3 shaft angle in the sagittal plane. We tested the hypothesis that these metrics did not differ between women and men. Three-dimensional bone models of the capitate and MC3 were analyzed in 130 subjects (61M and 69F). Long axes of the MC3 and capitate were computed. The intersection of the metacarpal long axis with the cortical surface of the capitate, the angle between the metacarpal-capitate axes, and metacarpal shaft angle were calculated and compared between men and women. The long axis of the MC3 intersected the capitate at two locations on the outer cortical surface of the capitate. The proximal intersection was located near the midportion of the capitate, whereas the distal intersection was typically located within the capitate-MC3 articulation. The angle between the axes of the capitate and MC3 in the sagittal plane was a mean of 15°, ranging from 5° to 23°. The mean sagittal MC3 shaft angle was 166° and ranged from 158° to 173°.There were only subtle differences in these metrics between the sexes. The long axis of the MC3 penetrates the dorsal surface of the capitate about its midportion, but there is notable variation in this location as well as in the angular relationships. Three-dimensional measurements of the relationships between the third metacarpal and the capitate may serve as an important reference for the placement of intramedullary wires, plates, devices, and prosthetics.

Enhancing transonic compressor rotor efficiency by flow analysis-driven blade section modification

Abstract Transonic axial compressors are widely used in aero-engines and gas turbines, and their efficiency has a significant influence on the equipment energy utilization rate and fuel cost. In this research, blade section modification based on flow analysis is carried out on the Rotor 67 for improving efficiency. First, the numerical calculation method used is verified with experimental data to ensure the accuracy of the simulation. Then, according to the analysis of simulated flow field and shock structure, the blade section shapes are altered to optimize the blade passage wide distribution for the sections from hub to mid-span. In addition, the blade surface angle is altered to reduce the supersonic flow expansion angle for decreasing shock strength. With these optimizations, the efficiency of modified transonic rotor increases by 0.9 percentage at the design point and 1.0 percentage at near stall point (N = 1.0), respectively. Slightly higher efficiency at off-design speeds (N = 0.9 and 0.8) are also obtained, with maintaining the stall margin.

Effects and Modification Mechanisms of Different Plasma Treatments on the Surface Wettability of Different Woods

Plasma treatment of wood surfaces has shown significant effects, but different excitation methods used for different species of wood generally result in varied characteristics of wood surfaces. Secondly, plasma modification greatly enhances the absorption of liquids by wood, but the relationship between liquid absorption and surface wettability is rarely studied. Limited detailed investigation of the modification effects and mechanisms has hindered the large-scale applications of plasma treatment in the wood industry. In this study, two typical plasmas, radio frequency (RF) plasma and gliding arc discharge (GAD) plasma, were employed to treat three species of wood: poplar, black walnut, and sapele. By focusing on changes in the contact angle of the wood surface, an exponential equation fitting method is used to determine the measurement time for contact angles. The research identified that factors contributing to the decrease in contact angle after plasma modification include not only the increase in surface energy but also liquid absorption. SEM and XPS analyses demonstrate that plasma etching accelerated liquid absorption by modifying the surface topography, while the increase in surface energy was due to the addition of oxygen-containing groups. High-valence C=O and O-C=O groups serve as indicators of plasma-induced surface chemical reactions. RF modification primarily features surface etching, whereas GAD significantly increases the active surface groups. Thus, different plasmas, due to their distinct excitation modes, produce diverse modification effects on wood. Considering the various physical and chemical properties of plasma-modified wood surfaces, recommendations for adhesive use on plasma-modified wood are provided.

Carotid web catheter angiography hemodynamic parameters

BackgroundCarotid web (CaW)-related contrast stagnation on digital subtraction angiography (DSA) may be a marker supporting the pathophysiological theory of stasis and thrombosis/embolization. We aim to assess the correlation between DSA...

A 3D Elastoplastic Constitutive Model Considering Progressive Damage Behavior for Thermoplastic Composites of T700/PEEK.

Due to their excellent mechanical properties, the carbon fiber-reinforced polymer composites (CFRPs) of thermoplastic resins are widely used, and an accurate constitutive model plays a pivotal role in structural design and service safety. A two-parameter three-dimensional (3D) plastic potential was obtained by considering both the deviatoric deformation and the dilatation deformation associated with hydrostatic stress. The Langmuir function was first adopted to model the plastic hardening behavior of composites. The two-parameter 3D plastic potential, connected to the Langmuir function of plastic hardening, was thus proposed to model the constitutive behavior of the CFRPs of thermoplastic resins. Also, T700/PEEK specimens with different off-axis angles were subjected to tensile loading to obtain the corresponding fracture surface angles of specimens and the load-displacement curves. The two unknown plastic parameters in the proposed 3D plastic potential were obtained by using the quasi-Newton algorithm programmed in MATLAB, and the unknown hardening parameters in the Langmuir function were determined by fitting the effective stress-plastic strain curve in different off-axis angles. Meanwhile, the user material subroutine VUMAT, following the proposed constitutive model, was developed in terms of the maximum stress criterion for fiber failure and the LaRC05 criterion for matrix failure to simulate the 3D elastoplastic damage behavior of T700/PEEK. Finally, comparisons between the experimental tests and the numerical analysis were made, and a fairly good agreement was found, which validated the correctness of the proposed constitutive model in this work.

Numerical simulation of plume–surface interaction and lunar dust dispersion during lunar landing using four engines

As the lander approaches the lunar surface, the engine plumes impinge on the lunar regolith and entrain lunar dust from the surface. This plume–surface interaction and the resulting dispersion of lunar dust form a multi-physics, multi-scale problem, which becomes even more complex under multi-engine conditions. This study employed the direct simulation Monte Carlo method to simulate the plume–surface interaction flow field of a four-engine lunar lander at various landing altitudes and lunar surface angles. Flow characteristics were analyzed, and the impact of the plume and backflow on the lander was assessed. Subsequently, lunar dust simulation was conducted using the plume field as a basis. The study determined the spatial distribution of particles with different diameters at various landing altitudes and surface angles, as well as their impact velocities on the lander. Furthermore, taking into account the variations in the lander's altitude and attitude, a dynamic simulation of lunar dust during the landing process was conducted. This process resulted in the dynamic distribution of lunar dust during landing, laying the groundwork for real-time simulation of lunar dust distribution and reliable visualization during landing simulations. These findings are valuable for assessing and mitigating the hazards posed by lunar dust.

Accuracy of patient-specific instrumentation for implant positioning in custom-made total ankle arthroplasty.

This retrospective radiological analysis aimed to assess the accuracy of implant positioning in patients with ankle arthritis undergoing custom-made total ankle arthroplasty (TAA) with patient-specific instrumentation (PSI) compared with preoperative planning. Patients who underwent custom-made TAA with PSI from January 2018 to March 2023 were retrospectively evaluated, focusing on the tibial anterior surface (TAS) angle, tibial lateral surface (TLS) angleand tibiotalar ratio (TTR). Additionally, data regarding the time from the preoperative computed tomography (CT) scan to surgery, associated proceduresand complications were recorded. No associated procedures were performed, and only one intraoperative complication, an iatrogenic lateral malleolar fracture, was recorded. In the coronal plane, custom-made TAA with PSI consistently achieved precise positioning of prosthetic components, even in cases with significant preoperative deformities or bone deficits. However, a statistically significant deviation from the planned values was observed in the sagittal plane (p = 0.007). A notable correlation was identified between the time elapsed from the preoperative CT scan to surgery and the deviation from the planned to the actual postoperative TAS angle (p < 0.001). This study underscores the efficacy of PSI systems in achieving precise positioning in the coronal plane, in accordance with preoperative planning. In contrast, sagittal plane positioning did not demonstrate the same level of accuracy, as evidenced by a statistically significant difference between the planned and postoperative TLS values. Nevertheless, all measurements remained within the recommended range according to the existing literature. Level IV.

Radiologic and Clinical Outcomes of the Dovetailed Notch Scarf Osteotomy for Correcting the First Metatarsal Pronation in Moderate to Severe Hallux Valgus Deformity: A Comparative Study.

The traditional scarf osteotomy (TSO) has limited ability to correct the first metatarsal pronation. A novel modification that we refer to as a "dovetailed notch scarf osteotomy" (DNSO) has been developed to enhance the ability to correct coronal plane pronation. The study aimed to observe and compare TSO to DNSO in the treatment of moderate to severe hallux valgus deformity. This retrospective study included 78 feet that had a TSO and 105 feet that had a DNSO. Minimum follow-up was 24 months. Weightbearing computed tomography (WBCT) and weightbearing anterior-posterior (AP) radiographs were taken preoperatively and at the last follow-up. We measured the intermetatarsal angle (IMA), hallux valgus angle, distal metatarsal articular surface angle on AP radiographs and first metatarsal coronal pronation angle (α angle), tibial sesamoid coronal grading, and first metatarsal length on WBCT. Clinical assessment was done using visual analog scale (VAS), American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scale, Foot and Ankle Ability Measure (FAAM), and the 36-Item Short Form Health Survey (SF-36). The occurrence of postoperative complications was also documented. The DNSO group exhibited a significantly higher correction amount of α angle and IMA (14.3 ± 9.9 and 10.3 ± 4.6 degrees) than the TSO group (8.6 ± 5.9 and 5.4 ± 5.9 degrees) during the final follow-up assessment (P < .05).The DNSO group (10.1 [8.0-12.0] degrees and 4.8 [3.9-5.6] degrees) demonstrated significantly smaller α angle and IMA compared with the TSO group (4.8 [3.9-5.6] degrees and 9.5 [7.5-11.5] degrees) at 24 months postsurgery (P < .05). The postoperative FAAM activities of daily living and SF-36 physical functioning scores were significantly higher in the DNSO group (97.2 ± 3.3 and 95.7 ± 4.4 points) compared with the TSO group (92.3 ± 3.3 and 87.7 ± 8.7 points) (P < .05). Additionally, hallux varus occurred in 1 case in the DNSO group, whereas 4 cases were observed in the TSO group. Two osteotomy methods can effectively correct moderate to severe hallux valgus deformity. Compared with the TSO, the DNSO has stronger correction ability. The most crucial aspect lies in its controllability when correcting first metatarsal pronation and addressing IMA. Level III, retrospective comparative study.

Distal forelimb radiographic bone morphology in Thoroughbred foals during the first 10 months post-partum. Part 1: Carpus.

The risk of carpal injury in racehorses may be related to the morphology, yet whether carpal morphologies are set from birth or change through growth remains unclear. To quantify carpal bone changes through growth. Twenty privately owned Thoroughbred foals born between January 2022 and May 2023 were radiographed bimonthly from birth to 10 months of age. Imprint training was used to take radiographs safely without chemical restraints. Fifteen individual and 11 relative angular carpal parameters were measured using ImageJ on dorsopalmar radiographs of the carpus at zero degrees of vertical and horizontal rotation. Associations with age (growth), sex and the differences between left and right limbs were analysed separately using a linear mixed effects model. Six individual carpal parameters changed with age (radial carpal joint [RCJ], Prx.dor. radial carpal [Cr], Prx.Cu, Dis.dor. third carpal [C3], Dis.pal.C3 and Dis.pal. intermediate carpal), and one was influenced by side, that is higher in the left carpus (Dis.pal.Cr). Seven relative parameters changed with age, and one relative parameter was influenced by side, that is higher in the left (Ra.met-RCJ). The proximo-dorsal bone surface angle of Cr and disto-dorsal bone surface angle of C3 became flatter over time, which may be associated with the re-direction of the load towards the sagittal carpal plane. Sex did not influence any of the carpal parameters, nor did the combined effect of age, side of the limb and sex. Specific individual and relative angular carpal parameters changed significantly over time and some differed between the left and right limb, whereas other parameters did not change. The steeper carpal bone angles achieved proximally with the parameters that did change may improve stability by redirecting the load more medially through the carpus and the proximal and distal bones.