Double Plate Research Articles

Effective of phage cocktail against Klebsiella pneumoniae infection of murine mammary glands

Phage therapy has potential to combat antibiotic-resistant bacteria causing bovine mastitis. Our objective was to use 3 Klebsiella lytic phages to create a phage cocktail, and to compare bactericidal activity of this phage cocktail versus an individual phage, both in vitro and in vivo. Based on transmission electron microscopy, phage CM_Kpn_HB154724 belonged to Podoviridae and on double agar plates, it formed translucent plaques on the bacterial lawn of Klebsiella pneumoniae KPHB154724. In one-step growth curves, this phage had a latent period of 40 min, an outbreak period of 40 min, a burst size of 1.2 × 107 PFU/mL, and an optimal multiplicity of infection (MOI) of 1. Furthermore, it was inactivated under extreme conditions (pH ≤ 3.0 or ≥ 12.0 and temperatures of 60 or 70 °C). It had a host range of 90% and had 146 predicted genes (Illumine NovaSeq). Based on histopathology and expression of inflammatory factors interleukin-1β, tumor necrosis factor-α, interleukin-6, and prostaglandin, phage cocktail therapy had better efficiency than an individual phage in K. pneumoniae-infected murine mammary glands. In conclusion, we used 3 Klebsiella lytic phages to create a phage cocktail and confirmed its effectiveness against K. pneumoniae both in vitro (bacterial lawn) and in vivo (infected murine mammary glands).

Study on the parameters of detached dual splitter plates and comparison with single plate for VIV suppression

In the actual marine engineering environment, vortex-induced vibration will affect the safety of cylindrical structures. Rigid splitter plates have become one of the suitable VIV suppression solutions due to their simple structure and low maintenance costs. Therefore, on the basis of numerical simulation, this paper analyses the influence of the gap between parallel and non-parallel double splitter plates and the arrangement angle of non-parallel double splitter plates on the VIV suppression effect at a fixed flow rate. In addition, the VIV suppression effect of the single and dual splitter plates with the same parameter combination is evaluated under the condition of multi-flow velocity. It is found that the parallel dual splitter plate cannot provide good VIV suppression, especially when the gap exceeds the cylinder diameter, the suppression effect begins to deteriorate. However, on the basis of a certain gap between the plates, the dual splitter plate with arrangement angle is more effective than the single splitter plate in suppressing the transverse vibration of the cylinder. Therefore, when using dual splitter plates for VIV suppression, the parallel dual splitter plates should be avoided. When a better transverse vibration suppression effect is required, the arrangement angle can be appropriately changed.

Axial-flexural strength of steel-concrete composite shear walls

A predictive equation is proposed for the axial-flexural strength of rectangular and flanged Composite Plate Shear Walls-Concrete Filled (C-PSW/CF), with and without endplates and boundary elements. The proposed equation is based on plastic stress distribution, adjusted by coefficients to account for influential design parameters. The adjustment coefficients are established by a regression analysis performed on the data developed using an extensive numerical parametric study. The continuum-based finite element model used for the simulations is first validated using the available test data. The effects of various design variables, including the aspect ratio, slenderness ratio, reinforcement ratio, axial load ratio, infill concrete compressive strength, and yielding strength of the steel faceplates on axial-moment are then numerically examined. Four cross-sections, including double skin plate, double skin plate with endplates, double skin plate with boundary elements, and double skin plate with flanges, are considered. The results are used to develop a new predictive equation to obtain the flexural strength of C-PSW/CFs in presence of axial loading. The proposed equation is finally validated using the experimental test data and its accuracy is evaluated by comparing it to available predictive equations and the method proposed by the 2016 AISC Seismic Provisions. The results show that the proposed design equation can well predict the flexural moment capacity of C-PSW/CFs with various cross-sections in presence of axial loading.

The double-plate fixation technique prevents varus collapse in AO type C3 supra-intercondylar fracture of the distal femur

IntroductionVarus collapse followed by osteosynthesis for distal femoral fractures with conventional implants has been well documented but is seldom mentioned in fractures managed with locking plates. The purpose of this study was to assess the incidence of varus collapse after treating complex supra-intercondylar fractures of the distal femur (AO type C3) using a Single Plate (SP) or Double Plate (DP) fixation technique.Materials and methodsWe retrospectively reviewed 357 patients with distal femoral fractures who were treated at our hospital between 2006 and 2017. After excluding cases of infection, malignancy, periprosthetic fracture, revision surgery, pediatric fracture, and extra-articular fracture, 54 patients were included in the study. All demographic data and radiological and clinical outcomes were reviewed and analyzed.ResultsThere were 54 patients enrolled into this study with age from 15 to 85 years old (mean 41.6, SD = 19.9), and 32 of them were open fractures (59%). The patients were further divided into either an SP (n = 15) or a DP group (n = 39). Demographics, including age, sex, injury severity score, and open fracture type, were all compatible between the two groups. The overall nonunion rate was 25.9% (n = 14; 6 from the SP and 8 from the DP group; p = 0.175). The varus collapse rate was 9.3% (n = 5; 4 from the SP and 1 from the DP group (p = 0.018).ConclusionsThe varus collapse rate after osteosynthesis with a single lateral locking plate could be as high as 26.7% in AO type C3 fractures of the distal femur, which would be decreased to 2.6% by adding a medial buttress plate. Surgeons should consider DP fixation to avoid varus collapse in severely comminuted complete intra-articular fractures of the distal femur.

Material properties of ITRAC and cyclic behavior of double steel plate composite shear wall filled with ITRAC

An innovative iron tailing and recycled aggregate concrete (ITRAC)-filled double steel plate composite shear wall (ITRAC-CSW) was proposed to promote the application of the fabricated composite structures and the green build materials. Firstly, the mix proportion of ITRAC was studied through the test of six groups of ITRAC samples by changing the recycled coarse aggregate (RCA) replacement ratio and water-binder ratio. Favorable mechanical properties and the corresponding mix proportion was obtained. The elastic modulus calculation and the constitutive model of the ITRAC were obtained based on the test results. Subsequently, three full-scale ITRAC-CSW specimens were fabricated using ITRAC with the 100% RCA replacement ratio and tested under the cyclic lateral load and constant axial load. The failure mode and deformation mechanism of the specimens were analyzed through experimental phenomena. The seismic performance of the specimen was explored by comparing the load–displacement curves, stiffness degradation, and energy dissipation capacity. The analysis revealed that the ITRAC-CSW exhibits good bearing capacity, stiffness, and energy dissipation capacity which can be used in practical project.

Experimental investigation on steel bracing members with bolted gusset plate connections

In concentrically braced frames, low-cycle fatigue failure may occur in the brace or bolted connection due to accumulated damage from multiple earthquakes. However, the current research on the hysteretic behavior and fatigue life of H-shaped bracing members with bolted gusset plate connections is lacking, and there is a notable omission regarding the impact of bolt slippage and plastic deformation within the connection. The objective of this study is to address the aforementioned limitation through pseudo-static tests of 8 steel bracing members with bolted gusset plate connections under different clearances, connection coefficients (akin to Ry used in brace design under AISC 341-16 Seismic Provisions), and loading patterns. Results showed that not all loading patterns were suitable for such tests due to bolt slippage. The strength capacity, energy dissipation capacity and deformability of specimens with five types of clearances displayed small variation in tests. It has been demonstrated that utilizing a connection coefficient (1.03) lower than the prescribed value (1.3) can still result in a favorable hysteretic performance. The effective length factor of the bracing member under double bolted gusset plate connections is estimated to be 0.79, which can provide valuable information for optimizing the brace design. Additionally, a method for predicting the fatigue life of test specimens is proposed. The fatigue performance and failure mode of the bracing members under bolted connections with clearances of 0t, -2t, -4t and -6t (where t represents the thickness of the gusset plate) are superior to those under welded connections.

Fungicidal and plant growth-promoting traits of Lasiodiplodia pseudotheobromae, an endophyte from Andrographis paniculata.

Fungal endophytes are widespread and dwell inside plant cells for at least part of their life without producing any symptoms of infection. Distinct host plants may have different fungal endophyte rates and community compositions. Despite this, the endophytic fungi connected with the host plant and their hostile behaviors, remain unknown. The objective of the current research was to isolate and identify endophytic fungal species from the root of Andrographis paniculata. The effects of fungal isolate APR5 on the mycelial growth of phytopathogens and the production of plant-promoting traits were assessed. Endophytic fungal isolate APR5 showed higher inhibitory efficacy in dual and double plate assay against the tested phytopathogenic fungi. The scanning electron microscope analysis demonstrated that the phytopathogenic fungal hyphae were coiled by endophytes which makes them shrink and disintegrate. Further, an ethyl acetate crude extract effectively suppressed the mycelium growth of Rhizoctonia solani by 75 ± 0.1% in an agar well diffusion assay. The fungal isolate APR5 was identified as Lasiodiplodia pseudotheobromae using the nuclear ribosomal DNA internal transcribed spacer (ITS) region and qualitatively evaluated for their capacity to produce plant growth-promoting hormones. Gas chromatography-mass spectrometry was implemented to acquire a preliminary understanding of the secondary metabolic profile of ethyl acetate crude extract. 1-octadecene, erythritol, niacin, oleic acid, phenol, pantolactone, phenyl ethyl alcohol, p-cresol, and tbutyl hydroquinone are the metabolites analyzed in a crude extract of APR5 isolate and are reported to have antimicrobial properties.

Free Fibula Flap in Traumatic Femoral Bone Reconstruction: A 10-year Review.

The loss of femoral bone substance represents a major therapeutic issue. When the loss of bone substance is extensive, or the local condition is unfavourable, there are few satisfactory solutions. In this study, we share our experience of large femoral bone reconstruction by free fibula flap. A retrospective monocentric chart review (2007-2017) was performed for 26 patients after receiving a pure bone-free fibula flap operation. The times of consolidation and hypertrophy of the graft were analysed according to the fixation with a 2-year follow-up. The time to consolidation was 8.7 months (range, 6-15) for double plates, 7.2 months (range, 5-11) for locked plates, 6 months (range, 5-7) for external fixators and plate blades and 8 months (range, 7-9) for intramedullary nails.Full weight-bearing was resumed at an average of 6.5 months (range, 5-10) postoperatively. It was authorised at 7 months (range, 5-10) for patients fixed by double plate, at 6.3 months (range, 5-9) for those fixed by a locked plate, at 5.5 months (range, 5-6) for those fixed by an external fixator or plate blade and at 7 months for those fixed by an intramedullary nail. Free fibula flap remains reliable in the face of a great loss of bone material after trauma, with high consolidation rates. The choice of fixation must be reasoned and should offer a compromise between stability, allowing consolidation and hypertrophy of the graft, and rigidity, exposing the risk of massive osteosynthesis dismantling. Other multicentric studies, including more patients, should be carried out to compare the techniques of fixation. Viaud-Ambrosino S, Bargemon JBV, Kachouh N, et al. Free Fibula Flap in Traumatic Femoral Bone Reconstruction: A 10-year Review. Strategies Trauma Limb Reconstr 2023;18(1):44-50.

Study of natural convection heat transfer for a cylindrical and semicylindrical heat transfer system geometry

The paper presents the experimental and numerical study of the heat transfer parameters for the heated tube bank and arc-shaped plate made up of four tubes and four arc protrusions arranged one above the other. To evaluate the local heat transfer coefficients, the holographic interferometry is used as the experimental method, while the numerical simulations are performed by the Ansys Fluent software. The tube bank supplemented by the fin of different thickness and the double arc-shaped plate is further considered to improve the heat transfer parameters and the numerical results are compared with the basic arrangements. Considering the natural convection, the Rayleigh numbers are specified in the range of 16,460 to 46,340. It is observed that the tube bank achieves a higher average Nusselt number in the range of 37%–82% compared with the other arrangements depending on the Rayleigh number. The tube bank with fins does not increase the heat transfer parameters; however, there is an increase in average heat flux compared to the tube bank without fins. The double arc-shaped plate arrangement slightly increases the heat transfer and markedly increases the average heat flux compared to the single one. The highest average heat flux is achieved for the double arc-shaped plate and tube bank with fins in the range of 27.430 Wm-2 to 126.139 Wm-2.

Biomechanical influence of plate configurations on mandible subcondylar fracture fixation: a finite element study.

Mandible subcondylar fractures have very high complication rate, yet there is no consensus on suitable plate design for optimal patient outcomes. Our study is aimed at comparing single mini, trapezoid, lambda, strut and double mini plates. A finite-element (FE) model of intact mandible was developed based on healthy CT-scan data, which was further virtually osteotomized and fixated with plates. The cortical and cancellous bones were assigned region-specific orthotropic and heterogenous isotropic material properties respectively. The models were subjected to six load cases representing the mastication cycle. Under opposite lateralities, the tensile and compressive mandibular strain distributions were found as the opposite, with tensile strains at the posterior border under ipsilateral molar clenching (RMOL) resulting in lesser mandibular strain in reconstructed mandible with single mini plate under RMOL but highest mandibular strain under the contralateral molar clenching (LMOL). Owing to the reduced mandibular strains under LMOL than RMOL, the contralateral chewing is preferred during the immediate post-surgery period for patients. Under LMOL, the peak von Mises stresses in the plate decreased with increase in the number of screws. Furthermore, the presence of two arms in double mini and trapezoid plates seems beneficial to neutralise the tensile and compressive strains across load cases.

Dynamic biomechanical investigation of a novel sulcus bicipitalis plate in combination with a conventional locking plate for the treatment of complex proximal humerus fractures

BackgroundComplex proximal humerus fractures place high demands on osteosynthetic treatment. In some cases, double plating has already been used to increase primary stability of the osteosynthesis. This approach was advanced in the present study by developing an additive plate for the sulcus bicipitalis. To demonstrate the superior primary stability of the newly developed plate osteosynthesis, a biomechanical comparison against a conventional locking plate with an additional calcar screw was performed. MethodsTen pairs of cadaveric humeri were treated proximally with a locking plate (PENTA plate small fragment, INTERCUS). Each had a two-part fracture model with a fracture gap of 10 mm. All right humeri were treated with an additive novel plate that extends along the bicipital sulcus and encircles the lesser tuberosity proximally. First, the specimens were loaded sinusoidally at 250 N in 20° abduction for 5000 cycles. Afterwards quasi-static loading until failure was applied. FindingsThe movement at the fracture gap due to the cyclic loading occurred mainly as rotation around the z-axis, corresponding to a tilt medially and distally. The double plate osteosynthesis reduces the rotation by approximately 39%. For all load cycles observed, except 5000 cycles, medial and distal rotation of the head was significantly reduced by the double plate. The failure loads showed no significant differences between the groups. InterpretationIn the tested scenario under cyclic loading, the novel double plate osteosynthesis showed a significant superiority of primary stability over the conventional treatment with one locking plate. Furthermore, the study showed the advantages of cyclic load application over quasi-static load application until failure.

Investigation of shock wave propagation and water cavitation in a water-filled double plate subjected to underwater blast

Water-filled double hulls are a prevalent design for underwater warships. Studying the propagation of underwater shock wave in such structures is essential to comprehend their shock resistance. The aim of this paper is to investigate the propagation of underwater shock wave and water cavitation in a water-filled double plate. To achieve this objective, the paper establishes a Eulerian compressible fluid model that combines the isentropic single fluid model and Newton's second law. The accuracy of the numerical solver is confirmed through validation tests. The reflection and transmission characteristics of shock wave, the dynamic response of the plate, and the cavitation in external and gap water are analyzed. It also examines the effects of the supporting springs of outer and inner plates and the area density of the outer plate on the shock wave propagation and cavitation evolution. The findings indicate that the transmitted wave in the gap water is influenced by the area density and supporting spring of the outer plate. A thicker outer plate can reduce the peak value of the transmitted wave, and a stiffer supporting spring can decrease the transmitted impulse. On the other hand, if the outer plate is freestanding or softly supported, it has minimal effects on the response of the inner plate. Moreover, the water cavitation is determined by the supporting spring of the inner plate in the case of a softly supported outer plate, and the cavitation initially develops in the gap water near the inner plate before expanding towards the external water. When the supporting spring of the outer plate is stiff, it significantly reduces the occurrence of cavitation in the external water, while the cavitation in the gap water is still determined by the support spring of the inner plate. These research findings are valuable for analyzing the shock resistance of typical double-hull submarines.

Investigation of the Cold Flow Field in a Flow Reversal Reactor through Computational Fluid Dynamics Models

AbstractTo optimize the flow field in a tubular reactor, new flow deflectors were added by using flow reversal technology. Two optimization structures, namely asterisk plate and composite plate, were designed. Numerical simulation was combined with physical experiments to verify the effectiveness of the flow field optimization. The results showed that the flow field uniformity of the reactor could be greatly improved by single plate and double plate. The uniformity index of the velocity in the axial section is greater than 0.95 within 15 cm, and the physical simulation results conform to the overall trend of the numerical simulation. However, the length of the optimized area of the single plate is about 5 cm shorter than that of the double plate, and it has better stability in the physical model.

Double-panel metastructure lined with porous material for broadband low-frequency sound insulation

Insulating low-frequency sound using lightweight structures is very difficult according to the classical mass law. To challenge this problem, we present a comprehensive theoretical analysis and experimental verification of the sound transmission loss (STL) of double-panel metastructures (DPMSs) composed of two layers of metamaterial plates lined with a porous material (PM) layer. To facilitate the analysis, an efficient semi-analytical approach based on the transfer matrix method is proposed to predict the normal, oblique and diffuse field STL of the DPMS with PM. The effects of various structural and material parameters on the STL of the DPMS are analyzed. Some parameters that have significant influences are revealed. Based on semi-analytical predictions and experimental measurements, we demonstrate that an appropriately designed large-scale DPMS lined with PM can achieve a diffuse field STL being much higher than the mass law over a broadband low-frequency range below 500 Hz. More interestingly, compared with the conventional double layer homogeneous plates lined with PM (with the same total mass and thickness), the DPMS lined with PM also has a significantly improved diffuse field STL at broadband low frequencies below 500 Hz.

Експериментальні дослідження величини прогину пластини для корекції лійкоподібної деформації грудної клітки під впливом згинаючого навантаження

One of the leading methods of reconstruction of the funnel-shaped deformity of the chest is nonresection thoracoplasty, or Nuss surgery. For its implementation, implanted systems consisting of one or two corrective plates are used. The technique is minimally invasive, does not require large incisions and resection of ribs. But there are complications related to the insufficient strength of bone tissue, which according to the literature is defined in a very wide range. Purpose - to determine the dependence of the amount of deflection of single and double plates for the correction of sternum deformity on the amount of bending load; to develop a method of determining the corrective load that the plate exerts on bone structures during correction. Materials and methods. Experimental studies of plates for correction of sternum deformities were performed. We used 6 plates. In the first part of the experiment, each plate was tested separately. In the second part, the plates were connected in pairs, and each pair was tested for bending. In total, 3 pairs of plates were tested. The bending force was gradually increased from 0 N in increments of 50 N. At each step, the deflection of the plate was recorded. Results. The results of experimental studies of single plates showed that the deviation of deflection values did not differ statistically significantly (p>0.05) from the calculated values over the entire range of bending loads. The studies of the twin plates for the correction of sternum deformities also did not reveal statistically significant (p>0.05) differences in the deflection values of the samples obtained in the experiment from the calculated values. The results of the study made it possible to develop a methodology for calculating the force with which the plate acts on the sternum when correcting its deformation. Conclusions. A methodology has been developed for determining the force with which the plate acts on the sternum when correcting a deformation of a certain magnitude. It is confirmed that the calculated data on the deflection of the plate under the influence of bending load and the data obtained in the experiment do not differ statistically significantly. The data obtained can be useful for selecting the size of the corrective plate, the method of its attachment to the ribs, as well as for modeling the options for applying plates to correct various sternum deformities. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the institution mentioned in the paper. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.

Medial and lateral dual plating of native distal femur fractures: a systematic literature review.

Lateral locked plating (LLP) development has improved outcomes for distal femur fractures. However, there is still a modest rate of nonunion in fractures treated with LLP alone, with higher nonunion risk in high-energy fractures, intra-articular involvement, poor bone quality, severe comminution, or bone loss. Several recent studies have demonstrated both the safety and the biomechanical advantage of dual medial and lateral plating (DP). The purpose of this study was to evaluate the clinical outcomes of DP for native distal femoral fractures by performing a systematic review of the literature. Studies reporting clinical outcomes for DP of native distal femur fractures were identified and systematically reviewed. Publications without full-text manuscripts, those solely involving periprosthetic fractures, or fractures other than distal femur fractures were excluded. Fracture type, mean follow-up, open versus closed fracture, number of bone grafting procedures, nonunion, reoperation rates, and complication data were collected. Methodologic study quality was assessed using the Coleman methodology score. The initial electronic review and reverse inclusion protocol identified 1484 publications. After removal of duplicates and abstract review to exclude studies that did not discuss clinical treatment of femur fractures with dual plating, 101 potential manuscripts were identified and manually reviewed. After final review, 12 studies were included in this study. There were 199 fractures with average follow-up time of 13.72 months. Unplanned reoperations and nonunion occurred in 19 (8.5%) and 9 (4.5%) cases, respectively. The most frequently reported complications were superficial infection (n = 6, 3%) and deep infection (n = 5, 2.5%) postoperatively. Other complications included delayed union (n = 6, 3%) not requiring additional surgical treatment and knee stiffness in four patients (2%) necessitating manipulation under anesthesia or lysis of adhesions. The average Coleman score was 50.5 (range 13.5-72), suggesting that included studies were of moderate-to-poor quality. Clinical research interest in DP of distal femoral fractures has markedly increased in the past few decades. The current data suggest that DP of native distal femoral fractures is associated with favorable nonunion and reoperation rates compared with previously published rates associated with LLP alone. In the current review, DP of distal femoral fractures was associated with acceptable rates of complications and generally good functional outcomes. More high-quality, directly comparable research is necessary to validate the conclusions of this review.

Experimental study of plate-buckling type earthquake-resilient prefabricated steel beam-column joints with replaceable double flange cover plates

The damage control and post-earthquake repair of beam-column joints is a hot research topic in the seismic field. Therefore, a new type of earthquake-resilient prefabricated steel beam-column joint with replaceable double flange cover plates (RFCP-ERPSJ) was proposed. The yield load of this joint can be controlled by the buckling or slip of plates, so it can be divided into plate-slipping type and the plate-buckling type. Considering that the yield load of the plate-buckling type RFCP-ERPSJ is stable, firstly, a practical design procedure and design theory of the newly plate-buckling type joint is proposed in this paper. Then, to study the seismic performance and post-earthquake repairability of this RFCP-ERPSJ, a total of 6 full-size specimens are designed and subjected to a low-cycle reciprocating loading test and constant-amplitude low-cycle fatigue test. The effects of the thickness of FCPs, the material strength of FCPs, dog-bone width, amount of FCPs connecting bolts, and bolt spacing at the middle row on the seismic performance and energy dissipation performance of the joint are studied. The experimental results are also compared with the theoretical results. The research showed that the plastic hinge of the joint could be concentrated on the replaceable FCPs, so as to protect the beams and columns. By replacing damaged FCPs and bolts, the repaired joint had the same performance as the original joint. After comparison, the theoretical yield load is in good agreement with the experimental yield load. Besides, the small thickness and dog-bone width of FCPs can reduce the load carrying capacity and energy dissipation capacity of joints, and improving the material strength of FCPs will reduce the ductility of joints and increase the risk of plastic damage to the beams and columns. If the amount of FCPs connecting bolts is reduced, the specimens mainly dissipate energy by the slip of FCPs, and the load carrying capacity will descend. Excessive bolt spacing at the middle row will reduce the load carrying capacity and energy dissipation capacity.

Clinical study of double plate system in the treatment of complex proximal humeral fractures in the elderly

To explore the clinical outcomes of anteromedial combined with lateral locking plate for complex proximal humeral fractures in the eldery. From June 2018 to October 2020, 30 patients who underwent surgical treatment for Neer grade 3 to 4 proximal humeral fractures, including 8 males and 22 females, aged from 51 to 78 years old with an average of (61.5±7.5) years old. Of them, 15 patients had fractures fixed with anteromedial combined with lateral locking plate(ALLP group), whereas 15 received internal fixation with proximal humerus locking plate only(PHLP group). The clinical data, simple shoulder test (SST), humeral head height loss, varus angle and shoulder range of motion were compared between the two groups. All fractures were healed. The follow-up time ranged from 12 to 24 months, with an average of(14.3±2.9) months. The operation time of ALLP group was longer than that of PHLP group (P<0.05). There was no significant difference in intraoperative blood loss between the two groups (P>0.05). There was no significant difference in SST score between the two groups at 1, 3 and 12 months after operation (P>0.05). In terms of radiographic measurement, there was no significant difference in humeral head height loss and varus angle between the two groups at 1 and 3 months after operation (P>0.05). At 12 months after operation, the height loss and varus angle of humeral head in ALLP group were lower than those in PHLP group (P<0.05). In shoulder range of motion, the range of forward elevation in ALLP group was larger than that in PHLP group 1 year after operation(P<0.05). There was no significant difference in external rotation between the two groups. Anteromedial combined with lateral locking plate in the treatment of complex proximal humeral fractures in the elderly can increase the stability of the medial column and obtain a good fracture prognosis. But there are also disadvantages such as longer operation time, so it should be individualized according to the fracture type of the patient.

Double screw versus angular stable plate fixation of scaphoid waist nonunions in combination with intraoperativeextracorporeal shockwave therapy (ESWT).

Over the past years, different fixation techniques focused on rotational stability in order to increase stability and stimulate union rates. Additionally, extracorporeal shockwave therapy (ESWT) has gained importance in the treatment of delayed and nonunions. Purpose of this study was to compare the radiological and clinical outcome of two headless compression screws (HCS) and plate fixation in scaphoid nonunions, in combination with intraoperative high energy ESWT. Thirty-eight patients with scaphoid nonunions were treated by using a nonvascularized bone graft from the iliac crest and stabilization with either two HCS or a volar angular stable scaphoid plate. All patients received one ESWT session with 3000 impulses and energy flux per pulse of 0.41mJ/mm2 intraoperatively. Clinical assessment included range of motion (ROM), pain according to the Visual Analog Scale (VAS), grip strength, disability of the Arm Shoulder and Hand Score, Patient-Rated Wrist Evaluation Score, Michigan Hand Outcomes Questionnaire and modified Green O'Brien (Mayo) Wrist Score. To confirm union, a CT scan of the wrist was performed. Thirty-two patients returned for clinical and radiological examination. Out of these, 29 (91%) showed bony union. All patients treated with two HCS compared to 16 out of 19 (84%) patients treated by plate showed bony union on the CT scans. The difference was not statistically significant.However, at a mean follow-up interval of 34months, no significant differences could be found in ROM, pain, grip strength and patient-reported outcome measurements between the two HCS and plate group. Height-to-length ratio and capitolunate angle improved significantly in both groups compared to preoperative. Scaphoid nonunion stabilization by using two HCS or angular stable volar plate fixation and intraoperative ESWT results in comparable high union rates and good functional outcome. Due to the higher rate for a secondary intervention (plate removal), HCS might be preferable as first choice, whereas the scaphoid plate fixation should be reserved for recalcitrant (substantial bone loss, humpback deformity or failed prior surgical intervention) scaphoid nonunions.

A Novel Locking Buttress Plate Designed for Simultaneous Medial and Posterolateral Tibial Plateau Fractures: Concept and Comparative Finite Element Analysis.

The complex tibial plateau fractures involving both medial and posterolateral columns are of frequent occurrence in clinics, but the existing fixation system cannot deal with medial and posterolateral fragments simultaneously. Therefore, a novel locking buttress plate named as medial and posterior column plate (MPCP) was designed in this study to fix the simultaneous medial and posterolateral tibial plateau fractures. Meanwhile, the comparative finite element analysis (FEA) was conducted to investigate the discrepancy between MPCP and traditional multiple plates (MP + PLP) in their biomechanical characteristics. Two 3D finite element models of simultaneous medial and posterolateral tibial plateau fracture fixed with MPCP and MP + PLP system, respectively, was constructed. To imitate the axial stress of knee joint in ordinary life, diverse axial forces with 100, 500, 1000, and 1500 N were applied in the two fixation models, and then the equivalent displacement and stress nephograms and values were obtained. The similar trend of displacement and stress increasing with the loads was observed in the two fixation models. However, several heterogeneities of displacement and stress distribution were found in the two fixation models. The max displacement and von Mises stress values of plates, screws, and fragments in the MPCP fixation model were significantly smaller than that in the MP + PLP fixation model, except for the max-shear stress values. As a single locking buttress plate, the MPCP system showed the excellent benefit on improving the stability of the simultaneous medial and posterolateral tibial plateau fractures, compared with the traditional double plate fixation system. However, the excessive shear stress around screw holes should be paid attention to prevent trabecular microfracture and screw loosening.