Position Of Plate Research Articles

Biomechanics of PHILOS plates in Vancouver B1 periprosthetic femoral fracture.

Objective: To investigate the clinical efficacy of PHILOS plates in the treatment of Vancouver B1 periprosthetic femoral fracture (PFF) and to validate its biomechanical reliability via finite element analysis and mechanical testing on the Synbone femoral models. Methods: Ten males and eight females with Vancouver B1 PFF who underwent PHILOS plate fixation between September 2017 and January 2022 were selected. The average age was 72.61 ± 8.19years, with a range of 57-86years old. X-ray films were taken to assess the fracture healing situation around the femoral prosthesis as well as the position of the PHILOS plates and femoral prosthesis. Two different plates (the PHILOS plate and the Cable GTR plate) were used for fixation, and the differences in biomechanical stability of the two fixation methods were compared using finite element analysis and mechanical testing on the Synbone femoral models to validate the biomechanical dependability of the PHILOS plate. Results: All 18 cases were followed for at least 1year, as a result. The average period of follow-up was 17months, ranging from 12 to 36months. At the most recent follow-up, Harris scores for the hip joints of patients ranged from 82 to 89, with an average score of 86. The X-rays revealed that all fractures surrounding the femoral prosthesis had healed and that there was no looseness in the femoral prosthesis. None of the PHILOS license plates had expired. All patients were able to perform full-load walking, and pain and claudication in affected limbs were significantly reduced. Finite element analysis and mechanical testing of the Synbone femoral model revealed that the fixation effect of the PHILOS group was superior to that of the Cable group; consequently, PHILOS plates can be used to effectively fix fractures around the proximal femoral prosthesis. Conclusion: PHILOS plates are initially used in the treatment of Vancouver B1 PFF, which may be a good choice due to their simpler operation, lower medical costs, and satisfactory clinical efficacy.

The Effect of the Layout of a Rigid Splitter Plate on the Flow-Induced Vibration of a Downstream Cylinder Subjected to Wake Flow

In this study, the effect of additional positions of rigid splitter plates on the response characteristics of tandem cylinders at a Reynolds number of 150 and a fixed distance ratio of 5.0 was numerically investigated via the computational fluid dynamics (CFD) method. Four layouts for the cylinder–plate body, including a downstream cylinder (DC), a downstream cylinder–plate body with a wake side plate (DCP), a downstream plate–cylinder body with an incoming flow side plate (DPC), and a downstream plate–cylinder–plate body with a double-sided plate (DPCP), are considered. The results show that the splitter plate attached to the incoming flow side or the wake side can suppress the vibration of the downstream cylinder in a specific reduced velocity range (4.0 < Ur ≤ 10.0). Compared with the DC, the maximum response amplitude of the DPC and DCP in the lock-in region is reduced by 30.8% and 47.4%, and the lock-in bandwidth is also significantly narrower. The layer separation point of the upstream cylinder moves downstream upon adding splitter plates to both the incoming flow and wake sides, and the resulting splitter shear layer of the DPCP is completely parallel to the free flow, while the maximum response amplitude is reduced by 93.6%, which realizes the best effect of stream-induced vibration suppression.

Theoretical Analysis of the Influence of Bearing Plate Position on the Bearing Performance of Soil around the CEP Antipull Force Double Pile

With the development of large-scale projects such as high-rise buildings, deep-sea platforms, bridges, etc., these construction facilities are affected by many factors such as environment and geological conditions, which put forward higher requirements for pile-bearing capacity. Compared with the straight-hole grouted piles, the CEP (concrete expanded-plate) piles have an increased bearing plate, which has stronger resistance to pullout under the action of axial tension. The location of the bearing plate is the main factor affecting the bearing capacity of a CEP pile. This study simulates and analyzes CEP double piles on ANSYS software (Ansys R19.0 versions) under ideal conditions, designs five types of model piles with different bearing plate positions, and divides them into six groups for simulation. Finally, a complete model of the two-pile system is established. It is obtained that when the bearing plate is in the same position, the longer the pile length above the bearing plate, the greater the ultimate bearing capacity of the CEP double piles; when the bearing plates of a double pile are at different positions, the antipull-force-bearing capacity of the double pile mainly depends on the pile with a smaller pile length above the bearing plate, and determines the calculation mode of a CEP double-pile antipull-force-bearing capacity at different bearing plate positions, so as to provide a theoretical basis for the design and application of CEP pile foundations in large building structures in the future.

Evaluation of a head rest prototype for rotational corrections in three degrees of freedom.

Cranial stereotactic irradiations require accurate reproduction of the planning CT patient position at the time of treatment, including removal of rotational offsets. A device prototype was evaluated for potential clinical use to correct rotational positional offsets in image-guided radiotherapy workflow. Analysis was carried out with a prototype device "RPS head" by gKteso GmbH, rotatable up to 4° in three dimensions by hand wheels. A software tool accounts for the nonrectangular rotation axes and also indicates translational motions to be performed with the standard couch to correct the initial offset and translational shifts introduced by the rotational motion. The accuracy of angular corrections and positioning of an Alderson RANDO head phantom using the prototype device was evaluated for nine treatment plans for cranial targets. Corrections were obtained from cone beam computed tomography (CBCT) imaging. The phantom position was adjusted and the final position was then verified by another CBCT. The long-term stability of the prototype device was evaluated. Attenuation by the device along its three main axes was assessed. A planning study was performed to evaluate if regions of high-density material can be avoided during plan generation. The device enabled the accurate correction of rotational offsets in a clinical setup with a mean residual angular difference of (0.0±0.1)° and a maximum deviation of 0.2°. Translational offsets were less than 1mm. The device was stable over a period of 20 min, not changing the head support plate position by more than (0.7±0.6) mm. The device contains high-density material in the adjustment mechanism and slightly higher density in the support structures. These can be avoided during planning generation maintaining comparable plan quality. The head positioning device can be used to correct rotational offsets in a clinical setting.

Microstructure and Properties of AISI 316L Steel Processed by Selective Laser Melting Technology (SLM) and Hot Isostatic Pressing Technology (HIP)

The aim of our study was to determine changes in the microstructure and mechanical properties of AISI 316L steel processed by additive SLM technology which will be induced by additional processing using HIP technology and solution annealing. The specimens for this experiment were made in the form of bars with a diameter of 5 mm for tensile testing. The specimens were additively manufactured in the vertical direction with respect to the position of the build plate using standard process parameters. The HIP processing of the specimens was performed at a temperature of 1150 °C and pressure of 150 MPa. Some of the specimens were heat treated using solution annealing at 1150 °C after the SLM and HIP processes. The analyses performed consisted of metallographic analysis of the microstructure using light and scanning electron microscopy methods, which were further complemented by basic mechanical property tests, namely tensile testing and HV1 hardness measurements. The tensile test showed that the solution annealing of the printed specimens reduced the ultimate strength from 545±6.2 MPa to 508±0.0 MPa and increased the ductility from 44±5.4 % to 56±0.4 %. The HIP process reduced the ultimate strength to 522±2.7 MPa and the further annealed specimens to 514±1.8 MPa. The ductility of the specimens after HIP treatment was higher than that of the additively manufactured specimens, corresponding to 52±0.3 %. After solution annealing, it reached values like those of the specimens annealed after 3D printing. The metallographic analysis carried out showed a positive effect of the HIP process on the porosity achieved after 3d printing, whose volume was reduced as a result.

Is a Novel Fluoroscopic Intraoperative Reference System Superior to Conventional Management for Distal Radius Fracture Reduction? A Propensity-matched Comparative Study.

Is a Novel Fluoroscopic Intraoperative Reference System Superior to Conventional Management for Distal Radius Fracture Reduction? A Propensity-matched Comparative Study.

Study on the Suppression Effect on Vortex-Induced Vibration of Double-Deck Truss Girder by the Spatial Position of the Deflector Plate

This paper carried out wind tunnel tests and numerical analysis to study the effect of the spatial position of deflector plates on the vortex-induced vibration (VIV) of a double-deck truss girder. The wind tunnel tests found that setting the web deflector plate and the lower chord deflector plate significantly suppressed the VIV. In order to study the suppression mechanism of the deflector plate on VIV, numerical simulations were conducted using the computational fluid dynamics (CFD) method. We analyzed the suppression mechanism of the deflector plate on VIV by combining the vertical amplitude obtained by numerical simulation with the change in the vorticity magnitude and direction. The results showed that the flow velocity around the lower surface of the airflow was reduced, resulting in significantly lower vorticity at the exact position of the lower chord deflector plate and web deflector plate section compared to the original section. The web deflector plate and the lower chord deflector plate broke the vortex shedding mode in the wake flow region, and the vortex shedding frequency was far away from the self-oscillation frequency of the double-deck truss girder, thus suppressing the VIV.

Effect of plate position on tibial displacement and posterior tibial slope after cyclic loading in medial open wedge high tibial osteotomy: A biomechanical study using porcine tibia

BackgroundMedial open wedge high tibial osteotomy is currently the most common osteotomy, but its complication is an increased posterior tibial slope over time. However, no study has clarified whether the plate position of medial open wedge high tibial osteotomy could reduce the increase in posterior tibial slope after cyclic loading. MethodsFourteen porcine bones were biomechanically evaluated by performing medial open wedge high tibial osteotomy and placing TOMOFIX medially and anteromedially. Cyclic testing was performed to investigate the posterior tibial slope over time for medial open wedge high tibial osteotomy with medial or anteromedial plate. The displacement along the mechanical axis during cyclic testing from 10 to 100th, 100–500th, 500–1000th, 1000–1500th, and 1500–2000th cycles, and changes in anterior and posterior gaps after 2000 cycles were compared between plate position. FindingsThere were no significant differences in displacement. A significant difference was found in posterior gap changes (−0.20 ± 0.84 mm in group of using medial plate, 1.07 ± 0.82 mm in group of using anteromedial plate) (P = 0.014), but none was found in anterior gap changes. InterpretationMedial plate placement in medial open wedge high tibial osteotomy resulted in significantly less increased posterior tibial slope than anteromedial plate placement after cyclic loading.

Experimental investigations on the position of plates in friction stir welding of dissimilar alloys

Friction Stir Welding (FSW) is a solid-state welding procedure that involves heating and stirring the surfaces of two metal components to cause them to fuse together. The paper aims to present the influence of the plate position in friction stir welding of dissimilar aluminum alloys, of the same family. Friction stir welding experiments are conducted on AA6061 and AA6082 for different plate positions. The results of mechanical and microstructural characterization reveal that AA6082 on the advancing side provides better strength due to the material properties, temperature developed, and distribution along and across the weldments.

Mechanically tunable multi-band terahertz absorber based on overlapping graphene nanoribbon arrays

With promising applications in broadband communication, terahertz (THz) imaging, biochemical sensing, nondestructive testing and other fields, THz absorbers have become a hot research topic in recent years. Although a number of graphene-based multi-band THz absorbers with tunable performances have been reported, the tuning methods are mostly limited to electrical tuning. Here, we report a mechanically tunable multi-band THz absorber, which is based on overlapping graphene nanoribbon arrays. By adjusting the horizontal position of the upper cover plate with graphene nanoribbon array, the frequencies of the absorption peaks can be tuned in a wide range. In addition to the absorption peaks originating from even-order lateral Fabry-Pérot resonance (LFPR) modes, there are also absorption peaks originating from inductor-capacitor (LC) oscillations. An equivalent LC circuit model is developed and theoretical results match well with simulated values. The proposed mechanically tunable THz absorber may provide a reference for tunable THz absorbers that can be applied in various fields.

Hardware design of electrostatic levitation accelerometer control system

The electrostatic levitation accelerometer is a high-precision inertial instrument for measuring small displacement and acceleration, and it plays a very important role in global gravity field measurement, space gravitational wave detection, and other space missions as a key payload for satellites. It can realize the measurement of three-axis linear acceleration and three-axis angular acceleration. The open loop is unstable, and the control system needs to control six degrees of freedom at the same time so that the test mass can be stably suspended in the center position of the capacitive pole plate. For the demand of multi-channel simultaneous control of electrostatic levitation accelerometer, this paper designs an eight-channel digital control system hardware circuit with DSP as the core and FPGA as the co-processor, which can realize the data acquisition and feedback control of six degrees of freedom, writes the driver using hardware description language (Verilog), and simulates and analyzes the driver timing by the timing simulation software Modelsim. Finally, the hardware circuit was tested for the onboard drive. The results show that the system can work normally, the average sampling error of ADC is 0.00198 V, and the output error of DAC is 0.004 V, which is small enough to meet the system requirements.

Study on the CFRP nanosecond laser cutting damage and efficiency by aspiration system assisted method

In the present work, the aspiration system assisted method is investigated on low-damage and high-efficiency carbon fiber reinforced polymer (CFRP) nanosecond laser cutting. Experiments parameters with three aspiration system assisted conditions (no aspiration system assisted, unilateral aspiration system assisted, bilateral aspiration system assisted), different frequencies, and overlap rates are designed. The analysis focuses on the cutting time of through-cut, heat affect zone (HAZ) on the entrance surface, roughness, and microdefect on sidewall of cutting holes. The results indicate aspiration system assisted can reduce the HAZ of laser cutting hole, the sidewall roughness, and cutting time. The cutting time with bilateral aspiration system assisted is shortest, with a maximum reduction of 24.8 % compared to no aspiration system assisted at a frequency of 100 kHz and an overlap rate of 85 %. Aspiration system assisted reduces the HAZ, and its placement has an effect on cutting hole quality, proximal HAZ 11.11 μm is greater than distal HAZ 6.96 μm with unilateral aspiration system assisted. All sidewalls of cutting holes have a ladder-like interface, and an interface height difference up to 43 μm. It appears in the intermediate position of CFRP plate or exit of cutting holes. With no aspiration system assisted, large voids appear below a ladder-like boundary surface, and the maximum value of voids reaches 290 μm. Aspiration system assisted remove the carbon fiber debris and the plasma plume generated by laser cutting, avoiding accumulation and combustion in the slit, reducing the absorption of laser energy by carbon fiber debris and plasma plume, effectively improving cutting quality and efficiency.

The Clinical Efficacy of Contouring Periarticular Plates on a 3D Printed Bone Model.

We report our experience of preoperative plate contouring for periarticular fractures using three-dimensional printing (3DP) technology and describe its benefits. We enrolled 34 patients, including 11 with humerus midshaft fractures, 12 with tibia plateau fractures, 2 with pilon fractures, and 9 with acetabulum fractures. The entire process of plate contouring over the 3DP model was videotaped and retrospectively analyzed. The total time and number of trials for the intraoperative positioning of precontoured plates and any further intraoperative contouring events were prospectively recorded. The mismatch between the planned and postoperative plate positions was evaluated. The average plate contouring time was 9.2 min for humerus shaft, 13.8 min for tibia plateau fractures, 8.8 min for pilon fractures, and 11.6 min for acetabular fractures. Most precontoured plates (88%, 30/34) could sit on the planned position without mismatch. In addition, only one patient with humerus shaft fracture required additional intraoperative contouring. Preoperative patient specific periarticular plate contouring using a 3DP model is a simple and efficient method that may alleviate the surgical challenges involved in plate contouring and positioning.

Risk Factors for Complications in Ulnar Shortening Osteotomies: A Multicenter Retrospective Review

Ulnar shortening osteotomy (USO) is commonly performed to alleviate pathologies causing ulnar-sided wrist pain. Surgical complications include nonunion and hardware removal, with rates up to 18% and 45%, respectively. The primary objective of the study was to report the overall complication rate of USO. The secondary objective was to identify risk factors for complications. A retrospective multicenter cohort review was undertaken, including six Canadian cities over a 6-year period (January 2013-December 2018). Chart review was used to collect demographic data, surgical technique, implant used, and postoperative complications. Descriptive statistics of demographics and operative characteristics, including plate positioning, type of osteotomy, plate type, and ulnar variance (mm), were analyzed. Univariate analyses were used to select predictor variables for nonunion and hardware removal. These predictor variables were then entered into an adjusted multivariable logistic regression model. A total of 361 USOs were performed. Mean age was 46 ± 16 years (60.7% men). The overall complication rate was 37.1%, hardware removal rate was 29.6%, and nonunion rate was 9.4%. There was a workers' compensation claim associated with 21.6% of all complications, and it was a risk factor for both hardware removal (odds ratio [OR]= 3.81) and nonunion (OR= 2.88). Neither smoking nor diabetes was associated with complication rates. Seventy percent of plates were placed volarly, 25.5% dorsally, and 3.9% directly ulnar. Osteotomies were oblique in 83.7% of cases and transverse in 15.5%. Adjusted multivariate regression analysis revealed that younger age (OR= 0.98) was a risk factor for hardware removal and male sex (OR= 0.40) was a risk factor for nonunion. A surgical factor associated with hardware removal was direct ulnar plate placement (OR= 9.93). No surgical factors were associated with nonunions. There are substantial rates of complications with USOs. Direct ulnar plate placement should be avoided. Patients should be thoroughly counseled on the risks of complications prior to proceeding with USO. Therapeutic IV.

Development of patient-specific osteosynthesis including 3D-printed drilling guides for medial tibial plateau fracture surgery

PurposeA substantial proportion of conventional tibial plateau plates have a poor fit, which may result in suboptimal fracture reduction due to applied -uncontrolled- compression on the bone. This study aimed to assess whether patient-specific osteosyntheses could facilitate proper fracture reduction in medial tibial plateau fractures.MethodsIn three Thiel embalmed human cadavers, a total of six tibial plateau fractures (three Schatzker 4, and three Schatzker 6) were created and CT scans were made. A 3D surgical plan was created and a patient-specific implant was designed and fabricated for each fracture. Drilling guides that fitted on top of the customized plates were designed and 3D printed in order to assist the surgeon in positioning the plate and steering the screws in the preplanned direction. After surgery, a postoperative CT scan was obtained and outcome was compared with the preoperative planning in terms of articular reduction, plate positioning, and screw direction.ResultsA total of six patient-specific implants including 41 screws were used to operate six tibial plateau fractures. Three fractures were treated with single plating, and three fractures with dual plating. The median intra-articular gap was reduced from 6.0 (IQR 4.5–9.5) to 0.9 mm (IQR 0.2–1.4), whereas the median step-off was reduced from 4.8 (IQR 4.1–5.3) to 1.3 mm (IQR 0.9–1.5). The median Euclidean distance between the centre of gravity of the planned and actual implant was 3.0 mm (IQR: 2.8–3.7). The lengths of the screws were according to the predetermined plan. None of the screws led to screw penetration. The median difference between the planned and actual screw direction was 3.3° (IQR: 2.5–5.1).ConclusionThis feasibility study described the development and implementation of a patient-specific workflow for medial tibial plateau fracture surgery that facilitates proper fracture reduction, tibial alignment and accurately placed screws by using custom-made osteosynthesis plates with drilling guides.

Silver ion beam formation and implantation on nano-pyramidal template for isolated nano-dot formation

We report the development of silver (Ag) ion-beam by Electron Cyclotron Resonance (ECR) plasma sputtering and synthesis of Ag nano-dot arrays by implantation of the Ag+ ions on a pre-fabricated silicon nano-template. Ag atoms are mixed with the argon plasma by sputtering a biased silver plate placed inside the ECR chamber. The extracted and mass-separated Ag+ ions are transported to a UHV target chamber for implantation. The variation of the flux of Ag+ ion beam is studied by changing the various parameters, such as applied bias voltage of Ag plate, microwave power, argon gas pressure and specifically, the position of silver plate from the ECR plasma center. It is observed that the sputtering rate of Ag and thereby the final Ag beam current strongly depends on the applied bias and position of the plate. The dependence of microwave power and gas pressure on beam intensity is also investigated and explained in terms of ionization and mean free path of the ionized atoms. Finally, 6 keV Ag+ ions are implanted on pre-patterned nano-pyramidal templates to form an array of Ag nano dots on a large area, by exploiting the geometrical shape of the templates and the directionality of the ion beam.

Newly Developed Resorbable Magnesium Biomaterials for Orbital Floor Reconstruction in Caprine and Ovine Animal Models-A Prototype Design and Proof-of-Principle Study.

orbital floor fractures have not been reconstructed using magnesium biomaterials. To test technical feasibility, ex vivo caprine and ovine heads (n = 5) were used. Head tissues were harvested from pubescent animals (n = 5; mean age: 3.2 years; mean mass: 26.3 kg) and stored below 11 degrees for 7-10 days. All procedures were performed in a university animal resource facility. Two experienced maxillofacial surgeons performed orbital floor procedures in both orbits of all animals in a step-by-step preplanned dissection. A transconjunctival approach was chosen to repair the orbital floor with three different implants (i.e., magnesium implants; titanium mesh; and polydioxanone or PDO sheets). The position of each implant was evaluated by Cone-beam computed tomography (CBCT). Axial, coronal, and sagittal plane images showed good positioning of the magnesium plates. The magnesium plates had a radiographic visibility similar to that of the PDO sheets but lower than that of the titanium mesh. The prototype design study showed a novel indication for magnesium biomaterials. Further testing of this new biomaterial may lead to the first resorbable biomaterial with good mechanical properties for extensive orbital wall defects.

Biomechanical analysis of internal fixation system stability for tibial plateau fractures.

Background: Complex bone plateau fractures have been treated with bilateral plate fixation, but previous research has overemphasized evaluating the effects of internal fixation design, plate position, and screw orientation on fracture fixation stability, neglecting the internal fixation system's biomechanical properties in postoperative rehabilitation exercises. This study aimed to investigate the mechanical properties of tibial plateau fractures after internal fixation, explore the biomechanical mechanism of the interaction between internal fixation and bone, and make suggestions for early postoperative rehabilitation and postoperative weight-bearing rehabilitation. Methods: By establishing the postoperative tibia model, the standing, walking and running conditions were simulated under three axial loads of 500N, 1000N, and 1500N. Accordingly, finite element analysis (FEA) was performed to analyze the model stiffness, displacement of fractured bone fragments, titanium alloy plate, screw stress distribution, and fatigue properties of the tibia and the internal fixation system under various conditions. Results: The stiffness of the model increased significantly after internal fixation. The anteromedial plate was the most stressed, followed by the posteromedial plate. The screws at the distal end of the lateral plate, the screws at the anteromedial plate platform and the screws at the distal end of the posteromedial plate are under greater stress, but at a safe stress level. The relative displacement of the two medial condylar fracture fragments varied from 0.002-0.072mm. Fatigue damage does not occur in the internal fixation system. Fatigue injuries develop in the tibia when subjected to cyclic loading, especially when running. Conclusion: The results of this study indicate that the internal fixation system tolerates some of the body's typical actions and may sustain all or part of the weight early in the postoperative period. In other words, early rehabilitative exercise is recommended, but avoid strenuous exercise such as running.

Surgical treatment of intra-articular calcaneus fractures with plate osteosynthesis via the sinus tarsi approach

Surgical treatment of intra-articular calcaneus fractures via aminimally invasive approach. Intra-articular dislocated calcaneus fractures. Fracture older than 14days; poor soft tissue quality in the surgical area. Patient in lateral position. Identifying the anatomic landmarks. Incision (3-5 cm) from the tip of the fibula to metatarsalIV. Preparation through the subcutis. Retraction of the peroneal tendons. Preparation of the lateral calcaneal wall and later plate position via raspatory. Placement of aSchanz screw in the calcaneal tuberosity from lateral or posterior as areduction aid for restoring of the calcaneal length and reduction of the hindfoot varus. Reduction of the sustentaculum fragment with the help of fluoroscopy from lateral. Elevation of the subtalar articular surface. Positioning of the calcaneal plate and fixation of the sustentaculum fragment by placing acannulated screw through the long hole. Afterwards, definite internal fixation of the reduction with locking screws. Completion of the operation with final X‑rays and, if available, an intraoperative computed tomography. Wound closure with closing of the peroneal sheath. Lower leg-foot orthoses. Mobilization with partial weight-bearing of the injured foot with 15 kg for 6-8weeks; subsequently increased load bearing. Due to the smaller incision and the associated lower soft tissue trauma, the risk of wound healing complications can be reduced. Radiographic and functional outcomes are comparable to the outcomes of calcaneal fractures treated via the extended lateral approach.

Managing Recurrent Clavicle Nonunion and Construct Failure: A Case Report

Case A 36-year-old male who suffered a left midshaft clavicle fracture, following a fall from a mountain bike, was treated unsuccessfully with two ORIF surgeries. Smoking cessation and management of hypovitaminosis was addressed preoperatively before final revision with a dual plate construct and tibial autologous bone graft. Follow-up radiographs taken at 12 months from the initial surgery showed intact hardware and full bone healing. Conclusion Successful management of clavicle nonunions can be optimized through optimal plate selection, plate positioning, number of plates, construct biomechanics, biologic augmentation, and preoperative risk optimization. Efforts to minimize controllable risk factors for nonunion, such as smoking cessation or vitamin D supplementation, should be utilized both preoperatively and postoperatively.