Fracture Characteristics Research Articles

DETERMINING THE DISTANCE OF DIAPHYSAL FRACTURES OF LONG TUBULAR BONES BASED ON THE RADIOGRAPHY METHOD

Backgraund: the study of skeletal trauma is one of the main ones in the work of a forensic expert when conducting an examination of living persons. In the conditions of the non-obviousness of the crime committed against the health of the individual, the deliberate concealment by those involved in the case of the circumstances and date of injury, and the delayed request for medical help, determining the age of fractures presents certain difficulties. In such cases, an important source of information is the results of x-rays of the damaged bone. Aims: identification of radiological features of diaphyseal fractures of long tubular bones, characteristic of a certain stage of consolidation. Materials and methods: a retrospective study was conducted of 192 radiographs (primary and control, during follow-up) of 56 people (men and women) aged 20 to 80 years with fractures of long tubular bones in conditions of metal osteosynthesis and without it. The dynamics of changes in the X-ray picture of fractures at different stages of consolidation were consistently studied, the main morphological signs were described, their systemic analysis, comparison in groups and structuring were carried out. Results: clear time periods of consolidation have been determined, basic reference signs have been established that allow tracking the dynamics of healing; a consistent change in the morphology of the fracture during healing was established; there is no significant difference in the dynamics of consolidation by gender; the MOS operation did not play a significant role in the speed of consolidation. Conclusions: the X-ray picture of a diaphyseal fracture of a long tubular bone has its own morphological features depending on the duration of the injury. Keywords: duration of fractures of tubular bones, timing of consolidation of diaphyseal fractures, radiological morphological features of fractures.

Managing Low-Velocity Mandibular Gunshot Wounds: An Institutional Review and the "FLOSS" Severity Scoring System.

Management of mandibular ballistic trauma is poorly delineated, given the variable injury complexity. This study examines surgical outcomes and presents a novel scoring system to define and guide the management of low-velocity ballistic mandibular fractures. A retrospective chart review was performed from 2015 to 2022 to collect data on patients who suffered ballistic mandibular fractures. Computerized tomography facial bone scans were analyzed to determine a mandible severity scoring based on the following "F.L.OS.S." variables: fracture description (F), location of fracture (L), other surrounding fractures (OS), and soft tissue involvement (S). Sixty-six patients suffered handgun-related mandibular fractures and 54 underwent surgical intervention. The mean FLOSS score was 7.9 for all surgical patients and significantly differed between treatment groups (P = 0.011). Certain injury-specific variables were significantly associated with higher FLOSS scores including >2 areas of comminution along load bearing, bony gap >10mm, or intraoral involvement with soft tissue avulsion; however, the degree of displacement, bilateral involvement, or presence of concomitant fractures did not predict higher scores. The types of complications did not significantly vary for total FLOSS score or FLOSS subcategories; the only exception being, an association between bony gap (>10mm) and hardware exposure (P = 0.045). Overall surgical complication rate was 26.9% and presence significantly varied between surgical treatments (P = 0.019); specifically, nonunion was the only significant subcategory (P = 0.030). The FLOSS scoring system may be a useful adjunct in defining fracture characteristics that guide appropriate surgical intervention for low-velocity ballistic mandibular injuries.

The Impact of the COVID-19 Pandemic on the Epidemiology and Management Strategies of Forearm Fractures in Children—a Retrospective Study

Background: The COVID-19 pandemic has had a considerable influence over the management strategies in pediatric trauma all over the world. We are making a comparative assessment of all pediatric forearm fracture presentations in a tertiary center in Romania in a pre-pandemic year 2019 (NPG) versus a pandemic year 2021 (PG). Material and Methods: We retrospectively compared the epidemiological, the anatomopathological, and the management features of forearm fractures for the two years. Results: A total of 1403 patients with forearm fractures, 720 in NPG and 683 in PG, ages < 1 year–19 years (mean for NPG = 9.38 years and mean for PG = 9.39 years), were included in the study. There are no differences in demographics of the patients. There was an increase in the angulation ratio in the PG group and no other differences in the anatomopathological features. Most of the patients were treated by non-surgical means with no differences between groups. In PG, titan elastic nails were more often used than K-wire for the stabilization of diaphyseal fractures. There was no difference in terms of complication rates and reinterventions between groups. The number of hospital admissions (p < 0.01) and the length of hospital stay were significantly higher in NPG versus PG, (p < 0.01). Conclusions: The COVID-19 pandemic has had little impact on the epidemiology, anatomopathological features, and management strategies of forearm fractures in children. The only significant change in the medical strategy in our series was towards reducing the hospitalization rate and duration, reducing the follow-up visits.

Femoral shaft fractures in preschool children: external fixation and elastic intramedullary nail treatments in clinical practice.

Surgical intervention in preschoolers with femoral shaft fractures has increased due to the evolving lifestyle. This study aimed to analyze and compare the efficacy of elastic intramedullary nailing and external fixation in treating femoral shaft fractures in children aged 2-5. Ninety-nine pediatric patients were categorized into the external fixator (EF) and the elastic intramedullary nail (ESIN) group based on surgical techniques. Data on follow-up, intraoperative parameters, postoperative complications, fracture features, and demographics were gathered and compared. The mean duration of follow-up was 32 months, ranging from 25 to 48 months. All fractures had healed completely and no instances of nonunion were observed. At the latest follow-up, within the EF group, there were instances of malunion, delayed union, and refracture, each occurring once. One case in every group exhibited a leg length difference above 2 cm. The external fixation group had a shorter operation duration (P = 0.04), fewer intraoperative fluoroscopy times (P < 0.01), earlier partial weight-bearing time (P < 0.01), and full weight-bearing time (P < 0.01), while a greater complication rate (29.8 vs. 14.3%, P = 0.07) compared with the ESIN group. The incidence of pin tract infection in the EF group was 21.1% (12/57) compared with 2.4% (1/42) in the ESIN group (P = 0.07). Eighty percent of the patients' families expressed concern about the residual scar after removing the EF. The ESIN group encounters fewer complications and positive aesthetic effects, making it a preferable treatment option in this specific patient population and fracture pattern. Level of evidence: Class III, retrospective comparative study.

Changes of hip fracture in older patients before and after the COVID-19 pandemic: a retrospective multicentre study in Japan

BackgroundThe COVID-19 pandemic had a significant impact on healthcare systems and the general population. However, it remains unclear to what extent these major societal changes have had an impact on the management of hip fractures in older people in Japan. Therefore, we investigated the effect of the COVID-19 pandemic on the number of patients with hip fractures, their characteristics, and their perioperative management as a retrospective multicentre study.MethodsWe included 1894 patients aged ≥ 65 years who underwent surgery for hip fracture at three hospitals between January 2019–December 2021. Patients were classified according to the time of injury; patients treated between January–December 2019, January–December 2020, and January–December 2021 were divided into the pre-COVID-19 group, early COVID-19 group, and late COVID-19 group, respectively. We compared age, sex, body mass index, preadmission residence, surgical procedure, length of hospital stay, waiting time for surgery, in-hospital complications, and in-hospital death.ResultsOur findings suggested that the early COVID-19 and late COVID-19 groups showed a 6.8% and 7.5% reduction in the number of HF patients, respectively, compared to the pre-COVID-19 group. Waiting days for surgery, length of hospital stay, and in-hospital mortality or complication rates did not significantly change before and after the pandemic. However, infection was increased in the early COVID-19 group regarding the subgroup of complications.ConclusionsThe COVID-19 pandemic altered the characteristics of hip fractures in older individuals.

A new fractal permeability model for the dual-porous medium with a bundle of rough tree-like fracture networks

Shale gas reservoirs are typical dual-porous media where complex pore structures and fracture networks significantly impact gas transport. However, accurately predicting permeability in such media, especially complex fracture networks, remains challenging. The complex fracture network is modeled as of a bundle of rough tree-like fracture networks. The proposed permeability model comprehensively describes the structural characteristics of pores and fractures in shale gas reservoirs, including the fractal distribution of pore diameters and fracture apertures, the rough surface, and branching characteristics of fracture networks. Then, the model's accuracy is validated using reliable experimental permeability data. This model accurately predicts gas permeability and effectively describes gas transport characteristics in shale gas reservoirs with rough tree-like fracture networks. Each parameter has a clear physical meaning and avoids the use of empirical constants. Finally, sensitivity analyses are conducted to explore the effects of structural parameters on the permeability of dual-porous media. The results show that the permeability K of dual-porous media decreases exponentially with the increase in tortuosity fractal dimension Dtp of pores and surface fractal dimension Df of fractures, while it increases as a power function with increasing pore diameter fractal dimension Dp and fracture aperture fractal dimension Dh. The structural parameters of rough tree-like fracture networks significantly impact the permeability of dual-porous media. Increasing the aperture ratio γ, reducing the length ratio β, branching levels m, and the branching angles θ can significantly reduce gas flow resistance, decrease fluid kinetic energy loss, and increase the permeability of dual-porous media. This theoretical model is significant for enhancing permeability models of dual-porous media in shale gas reservoirs, offering reliable theoretical support for understanding gas migration and optimizing shale gas extraction.

Tibial Baseplate Microstructure Governs High Cycle Fatigue Fracture InVivo.

Previous studies report rare occurrences of tibial baseplate fractures following primary total knee arthroplasty (TKA). However, at a microstructural scale, it remains unclear how fatigue models developed invitro apply to fractures invivo. In this study, we asked: (1) do any clinical factors differentiate fracture patients from a broader revision sample; and (2) invivo, how does microstructure influence fatigue crack propagation? We identified three fractured tibial baseplates from an institutional review board exempt implant retrieval program. Then, for comparison, we collated clinical data from the same database for n = 2120 revision TKA patients with tibial trays. To identify mechanisms, we characterized fracture features using scanning electron and digital optical microscopy. Additionally, we performed cross sectional analysis using focused ion beam milling. The fracture cohort consisted of moderately to very active patients with increased implantation time (15.6 years) compared to the larger revision patient sample (5.1 years, p = 0.009). We did not find a significant difference in patient weight between the two groups (p = 0.98). Macroscopic fracture features aligned well with both previous retrieval analysis and invitro baseplate fatigue tests. On a micron scale, we identified striations on each baseplate, demonstrating fatigue as the fracture mechanism. Invivo fatigue fracture processes depended on both the alloy (Ti-6Al-4V vs. CoCrMo) and the microstructure of the alloy formed during manufacturing. For Ti-6Al-4V, the presence of equiaxed or acicular microstructure influenced the fatigue crack propagation, the latter arising from large prior β grains and a Widmanstatten microstructure, degrading fatigue strength. CoCrMo alloy fatigue cracks propagated linearly, crystallographically influenced by planar slip. However, we did not document any features of overload or fast fracture, suggesting a high cycle, low stress fatigue regime. Ultimately, the crack profiles we present here may provide insight into fatigue fractures of modern tibial baseplates.

Evolution characteristics of mining-induced fractures in overburden strata under close-multi coal seams mining based on optical fiber monitoring

Large-scale mining fractures resulting from repeated mining are a major cause of surface water loss in the northern Shaanxi mining area, China. Accurately detecting the evolution of mining-induced fractures is crucial for addressing the fragile ecological environment and ensuring coalmine production safety in this area. This study focuses on the close-multi coal seams mining at the Ningtiaota coalmine, northern Shaanxi, China, investigating the failure types of overburden rock, the evolution of mining-induced fractures, and the height of fracture zones. The results indicate that the failure type of overburden strata transforms from a “trapezoid shape” to an “overlapping trapezoid shape”, with the fracture zone height extending from 64.5 m to 158.5 m due to the superposition of secondary mining. Furthermore, the evolution characteristics of mining-induced fractures shift from a “three-stage and three-step” model to a “three-stage and two-step” model. A characterization model of overburden deformation based on optical fiber sensing is proposed to effectively describe the strain distribution characteristics of overburden failure. This model reveals the spatiotemporal evolution of overburden deformation from the perspective of “horizontal three areas and vertical three zones”, enabling real-time characterization of overburden deformation. The results demonstrate a relative error of less than 5.0 % between optical fiber monitoring and other methods, excluding theoretical calculations. This study offers a technical solution for detecting mining-induced fractures in the northern Shaanxi mining area and holds significant implications for broader studies of overburden deformation and failure under repeated mining.

The generation mechanism of cutting heat and the theoretical prediction model for temperature on the rake face of the cutting tool in Zirconia ceramics

Cutting temperature and its distribution are crucial factors influencing tool strength and wear rate, due to the hardness and brittleness of Zirconia (ZrO2) ceramics, significant challenges arise in both direct temperature measurement in the cutting zone and theoretical analysis of cutting heat. Thus, focusing on the turning characteristics of ZrO2 ceramics, this study analyzes the mechanism of cutting heat generation and proposes utilizing thermodynamic state equations to determine the cutting heat source on rake face of tool. Based on the heat source method, a theoretically prediction model for temperature distribution on rake face is established. This model considers primary cutting parameters, workpiece material properties, crack fracture characteristics of the machined surface, and thermal characterizations of the tool material. The relationship between tool wear and cutting temperature is experimentally analyzed to determine the characteristic temperature that indicates the initial stage of tool wear. The validity of the theoretical model is verified, as the predicted results show high consistency with experimental results within the range of experimental parameters, with a relative error within 15.2 %.The results reveal the highest temperature during brittle cutting occurs within the cutting layer area, with the highest temperature occurring approximately 50 μm from the tool tip, followed by a gradual decrease beyond 150-200 μm. This study also demonstrates that cutting heat in ceramic turning does not solely originate from friction heat between tool flank-workpiece but also includes impact heat from tool rake face-workpiece, which under certain cutting parameters exerts a more significant influence on cutting temperature. This model can facilitate the selection and optimization of cutting process parameters for brittle materials and provide a theoretical basis for analyzing the relationship between tool thermal damage, thermophysical properties, and tool wear.

Rupture Mechanics of Blood Clot Fibrin Fibers: A Coarse-Grained Model Study

Thrombosis, when occurring undesirably, disrupts normal blood flow and poses significant medical challenges. As the skeleton of blood clots, fibrin fibers play a vital role in the formation and fragmentation of blood clots. Thus, studying the deformation and fracture characteristics of fibrin fiber networks is the key factor to solve a series of health problems caused by thrombosis. This study employs a coarse-grained model of fibrin fibers to investigate the rupture dynamics of fibrin fiber networks. We propose a new method for generating biomimetic fibrin fiber networks to simulate their spatial geometry in blood clots. We examine the mechanical characteristics and rupture behaviors of fibrin fiber networks under various conditions, including fiber junction density, fiber tortuosity, fiber strength, and the strain limit of single fiber rupture in both tension and simple shear cases. Our findings indicate that the stress-strain relationship of the fibrin fiber network follows a similar pattern to that of individual fibers, characterized by a shortened entropy stretching phase and an extended transition phase. Fiber junction density, fiber strength, and single fiber rupture limit predominantly influence the stress of the network, while fiber tortuosity governs the strain behavior. The availability of more fibers in shear cases to bear the load results in delayed rupture compared to tension cases. With consideration of different factors of fibrin fibers in networks, this work provides a more realistic description of the mechanical deformation process in fibrin fiber networks, offering new insights into their rupture and failure mechanisms. These findings could inspire novel approaches and methodologies for understanding the fracture of fibrin networks during a surgical thrombectomy.

Investigation of fracture performance of asphalt mixtures considering size effect law and equivalent crack propagation law

The integration of the Size Effect Law (SEL) and the equivalent Linear Elastic Fracture Mechanics (LEFM) in characterizing the fracture behavior of asphalt mixtures has received limited attention. This study presents a preliminary exploration into the application of equivalent LEFM on the fracture characteristics of two asphalt mixtures, AC10 and AC16, accounting for variations in specimen size. Semi-circular Bending (SCB) tests were conducted on specimens with four different diameters (D = 76 mm, 100 mm, 125 mm, and 150 mm) and three notch-to-radius ratios (α = 0.2, 0.4, and 0.6) at a temperature of −10 °C. The equivalent crack propagation (ECP) length, crack growth resistance, and the size of the Fracture Process Zone (FPZ) were determined and subjected to analysis. The findings revealed a size effect on the ECP length, crack growth resistance, and FPZ size, with an increase in specimen size leading to a corresponding increase in these parameters. Conversely, an increase in α resulted in a decrease in all three types of data. A power law relationship was established between the ECP length and crack growth resistance. It was observed that AC16 demonstrated superior fracture resistance compared to AC10, particularly in terms of crack growth resistance. The initial notch length, ECP length, and FPZ size were found to be of the same order of magnitude, suggesting that the equivalent LEFM can produce more accurate fracture results under low temperatures than the traditional LEFM.

Coupling effects of loading rate and temperature on mode I dynamic fracture characteristics of ductile cast iron

Engineering structures made of ductile cast iron (DCI) have a potential risk of failure due to extreme service environments such as high velocity impacts and sub-zero temperatures. Therefore, it is of great importance to investigate the dynamic fracture behavior of DCI under the coupling effect of rate and temperature. In this paper, two sets of impact velocities (5 m/s and 13.5 m/s), and four sets of temperatures (20 °C, −40 °C, −60 °C, and −80 °C) were specially designed to investigate the coupling effect on the mode I dynamic fracture toughness (DFT). The results show that DFT is positively correlated with impact velocity at 20 °C, −40 °C and −60 °C. However, at −80 °C, the rate effect is reversed. Moreover, DFT decreases with decreasing temperature regardless of impact velocity. With microscopic analysis, the phenomenon of ductile–brittle transition (DBT) was observed in the failure of the material, and it’s verified by dynamic tensile tests. The ductile–brittle transition temperature (DBTT) of DCI is determined as −39.7 °C by comparing the DFT with the strain energy density (SED) characterization method.

Research on Propagation Characteristics of Fracture Grouting in Clay Formation

Splitting grouting is a highly effective technique for reinforcing tunnels and underground structures, ensuring their operational stability and facilitating long-term maintenance. It has been widely adopted in the prevention and remediation of geological hazards. However, the theoretical research on the diffusion mechanisms of split grouting lags behind its practical applications. This study addresses several key scientific challenges in understanding the diffusion behavior of split grouting. By integrating experimental design, numerical simulations, and theoretical analysis, we conduct a systematic investigation into the diffusion process and vein morphology of split grouting in both homogeneous and heterogeneous formations. We first employed a self-developed two-dimensional grouting test system to perform diffusion experiments on cohesive strata, focusing on the influence of various factors such as grout density, water/cement ratio, soil consistency, and fracture characteristics. The results provide insights into the diffusion patterns, morphology, soil pressure distribution, and surface uplift behavior of the grout veins. Subsequently, a numerical simulation program, developed in-house, based on the finite element method (FEM) and the volume of fluid (VOF) approach, was employed to model the entire process of fracturing grouting within clay strata. The experimental and numerical results indicate that grout vein diffusion in layered soil follows a Y-shaped pattern with an inclined deflection. In uniform strata, the surface uplift curve displays both symmetrical and asymmetrical “convex” elevations, while in heterogeneous soft and hard strata, the uplift is characterized by distinct “convex” deformations. Finally, based on these findings and the principles of contact mechanics, we analyze the underlying mechanisms. The results suggest that weak contact zones undergo tensile cracking and horizontal deflection prior to the formation of grout veins. Additionally, local stress rotations in the soil can induce tilting and deflection. The theoretical insights derived from this study provide valuable guidance for practical engineering applications.

Numerical study of influence of karst fracture water on heat transfer performance of borehole heat exchanger

Groundwater flow within karst fractures can significantly enhance the heat exchange efficiency between a borehole heat exchanger (BHE) and the surrounding rock. The development of artificial fractures to intensify heat transfer between the BHE and rock has emerged as a promising direction in geothermal exploration. This study presents a three-dimensional finite element simulation model that integrates fracture flow with BHE heat transfer, accounting for various characteristics of horizontal fractures. Data analysis was conducted using range analysis and multi-criteria comprehensive evaluation, based on the principles of orthogonal experiments. The results indicate: (i) Fracture water flow substantially improves BHE heat transfer performance in summer, with even the lowest-performing configuration in the orthogonal test showing a 5.36 % increase in heat transfer per unit length of the BHE (HPLU) compared to the natural control group without fractures; (ii) The influence of different fracture characteristics on BHE heat transfer performance follows this order: fracture water velocity > fracture aperture > fracture depth > fracture flow direction > fracture water temperature; (iii) The optimal configuration enhances HPLU by 16.95 % over the natural control group, demonstrating that developing well-designed artificial fractures in karst regions can substantially improve BHE heat transfer efficiency.

Numerical investigation on bending characteristic and ductile fracture of AA7075 thin-walled beam using advanced orthotropic plasticity and fracture models

Thin-walled structures manufactured from the 7075 aluminum alloy are gaining tremendous attention in the automotive industry for their potential to reduce vehicle weight. However, the bending characteristics and rupture behavior of the AA7075 thin-walled beams under unexpected collision events have not been extensively studied. This study aims to fill that gap through a detailed numerical investigation of the bending deformation and failure mechanism of AA7075 thin-walled beams under quasi-static three-point bending at room temperature. Full-size, three-dimensional numerical simulations of laboratory-scale AA7075-T6 hat-shaped beam were conducted using the ABAQUS/Explicit solver. The material elastic–plastic response is described by a rate-independent constitutive description, incorporating advanced non-quadratic orthotropic plasticity and anisotropic ductile fracture criteria via VUMAT subroutines. Results indicate that the simulations accurately reproduced experimental observations, including the loading-displacement curves and deformation patterns. The bending behavior of the AA7075-T6 thin-walled beams aligns with typical bending collapse mechanisms, consistent with Kecman’s theory. The rupture process exhibits ductile fracture characteristics, with heterogeneous stress distribution across the material thickness affecting crack initiation rates between the upper and lower surfaces. Notably, the stress state at the fracture’s half-thickness section approximates an equi-biaxial tension condition. These findings provide essential insights into the bending deformation and failure mechanisms of AA7075 thin-walled structures under unexpected impact loading.

Study on the influence of primary peak temperature on the microstructure and impact properties of heat affected zone of a 1000 MPa grade hydropower steel

ABSTRACT The microstructure of various zones in the heat-affected zone (HAZ) of 1000 MPa grade ultra-high-strength steel were investigated by welding thermal simulation. The results showed that the grain sizes were smallest at 950°C, when it was at the fine grain section in HAZ. The continuous reduction in grain size was due to the recovery and recrystallization. Samples subjected to thermal cycles at lower than 950°C exhibited high impact absorption energy of more than 100 J, with distinct fibrous zones and shear lips on the fracture surfaces, indicative of high impact toughness. However, the impact toughness of samples from the CGHAZ, which underwent thermal cycles at higher than 1100°C, decreased significantly to about 10 J, with the fracture surfaces showing macroscopic brittle fracture features and covered entirely by cleavage planes. Microstructural analysis revealed that coarse grains and brittle martensite were the primary causes of embrittlement in the CGHAZ.

Fracture Line Morphology and a Novel Classification ofPilon Fractures.

Currently, there is no research that includes a comprehensive three-dimensional fracture mapping encompassing all types of Pilon fractures. Moreover, the existing classification systems for Pilon fractures exhibit only moderate to fair consistency and reproducibility. Additionally, some of these classification systems fail to accurately depict the morphological characteristics of the fractures. This study aimed to create a fracture map encompassing all types of Pilon fractures by three-dimensional fracture mapping. In addition, this study conducted a finite element analysis of the normal ankle joint, and based on the distribution of fracture lines and the stress distribution at the distal tibia, proposed a new classification for Pilon fractures. A retrospective analysis of Pilon fractures in our hospital from January 2018 to January 2024 was performed. A total of two hundred forty-four Pilon fractures were included, and their fracture lines were transcribed onto the tibia and fibula templates, and fracture maps and heat maps were created. A nonhomogeneous model of the ankle joint was constructed and verified, and the stress distribution on the distal tibia articular surface was measured and analyzed in three models (neutral, dorsiflexed, and plantarflexed model). Based on the fracture map and stress distribution, a five-column classification system for Pilon fractures was proposed, and the intraobserver and interobserver reliability was calculated using Cohen and Fleiss k statistics. The fracture line on the distal tibia articular surface showed a V-shaped distribution. One branch extended from the junction of the medial malleolar articular surface and the inferior tibial articular surface toward the medial malleolus. The other branch extended from the middle of the fibular notch to the posterior part of the medial ankle, toward the tibial shaft. The fibula fracture line mainly extended from the anterior and lower part of the lateral malleolus to the posterior and upper part. As evidenced by the neutral, dorsiflexed, and plantar flexion models, the stress on the posterolateral articular surface (posterolateral column) was low, while the majority of the stress was concentrated in the center. Three-column fractures were the most common, followed by two-column fractures. Using the five-column classification, the K-weighted values of interobserver and intraobserver analysis were 0.653 (p < 0.001) and 0.708 (p < 0.001), respectively. In this study, the fracture line and morphological characteristics of Pilon fractures were analyzed in detail by three-dimensional mapping. In addition, this study conducted a finite element analysis of the stress distribution on the distal tibial joint surface of the normal ankle joint. Moreover, a novel classification system was proposed to reflect these findings. The new classification not only exhibits greater consistency, facilitating accurate communication of fracture characteristics among surgeons, but also aids in understanding the mechanisms of injury and formulating surgical strategies.

Radiological features of the carpometacarpal joint in hamate body fracture on anteroposterior hand X-ray image

BackgroundHamate body fractures are rare and can be overlooked due to the diagnostic difficulty on X-ray. We focused on the carpometacarpal joint space width (CMC-JSW) and examined the features of this fracture on versatile anteroposterior hand X-ray images, initially taken for hand trauma cases. MethodsTen patients (nine males and one female; mean age, 34 years) diagnosed with a hamate body fracture on CT in our facility between January 2013 and October 2023 were included in this study. The fracture types were dorsal type in six cases and shear type in four cases. The 4th and 5th CMC-JSWs were measured on anteroposterior hand radiography and CT sagittal sections. If the metacarpal and hamate bones appeared to overlap due to depression, the width was expressed as a negative value (overlap sign). CMC-JSWs were compared between the types or unaffected sides using the Mann–Whitney U test. The correlation with X-ray and CT measurements was analyzed using the Spearman test. ResultsThe average CMC-JSWs (IV: −0.52 mm, V: −1.33 mm) in hamate body fractures on X-ray were minus and these values were significantly lower than unaffected side (IV: 1.51 mm, V: 1.48 mm) (p < 0.05, p < 0.001). CMC-JSW (IV: −1.64 mm) and CMC-JSW (V: −2.70 mm) of dorsal type were significantly lower than shear type (IV: 1.17 mm, V: 0.72 mm) (p < 0.05). CMC-JSW values on X-ray were positively correlated with those on CT (IV: ρ = 0.796, V: ρ = 0927). ConclusionsDecreased CMC-JSW, correlated with CT sagittal sections, and “overlap sign” on anteroposterior hand X-ray were possible radiological characteristics of hamate body fracture. Care should be taken to avoid overlooking shear-type fractures because of subtle CMC-JSW decreases.

Fractures in Oxford unicompartmental knee arthroplasty are associated with a decreased medial keel-cortex distance of the tibial implant

PurposeThis retrospective single-center study aimed to investigate incidence and risk factors influencing tibial periprosthetic fractures (TPF) in Oxford unicompartmental knee arthroplasty (UKA), with a specific focus on tibial component positioning and sizing.MethodsA total of 2063 patients with medial UKA using the Oxford® mobile partial knee implant were analyzed between July 2014 and September 2022. Various preoperative and postoperative radiographic parameters determining pre- and postoperative alignment and implant positioning, incidence and characteristics of periprosthetic fractures, and patient demographics were assessed. Statistical analyses, including Mann–Whitney U test and logistic regression, were conducted to identify significant associations and predictors of tibial fractures.ResultsOf the 1853 cases that were finally included in the study, 19 (1%) patients experienced TPF. The fracture group presented with a significantly shorter relative mediolateral and posteroanterior distance between the keel and cortex [mediolateral: 23.3% (23.2–24.8%) versus 27.1% (25.7–28.3%), p < 0.001; posteroanterior: 8.4% (6.3–10.3%) versus 10.0% (9.8–10.1%), p = 0.004]. Additionally, an increased posterior tibial slope in pre- and postoperative radiographs [preoperative: 10.4° (8.6–11.1°) versus 7.7° (5.4–10.0°), p < 0.001; postoperative 9.1° ± 3.1° versus 7.5° (5.9–9.0°), p = 0.030] was observed in the fracture group. Furthermore, the use of smaller-sized implants (AA) was associated with higher fracture rates (p < 0.001). Anatomical variants, such as a medial overhanging tibial plateau, were not observed.ConclusionsIn UKA, type Oxford TPF are linked to shorter mediolateral and posteroanterior keel-cortex distances, increased pre- and postoperative PTS, and small implant sizes (AA). Fracture lines often extend from the distal keel to the medial tibial cortex. These findings emphasize the importance of precise implant positioning and sizing to minimize fracture risk.Level of evidence Retrospective single-center study, III.

Effects of nanosilica and aggregate type on the mechanical, fracture and shielding features of heavyweight concrete

With recent developments in nuclear technology, the safety versus nuclear radiations with negative environmental influences is of great importance. Heavyweight concrete (HWC) is an effective absorbent material, capable of providing adequate shielding versus nuclear radiations because of its acceptable structural characteristics. However, the role of aggregate type in the shielding and fracture characteristics of HWC has not been explored comprehensively. On the other hand, nanosilica is one of the reactive pozzolans which is employed for improvement of concrete properties. Thus, in this investigation, the influences of aggregate type (magnetite and hematite) and nanosilica on the mechanical, fracture and shielding features of HWC were studied. Four different cement replacements by nanosilica (0, 2, 4 and 6 %) were used to evaluate its influence on the properties of HWC. The results depicted that the fracture energies increase 18.8 and 16.8 % for heavyweight magnetite and hematite concretes with increasing nanosilica up to 6 wt% (wt.%) of cement, respectively. Furthermore, characteristic length declines from 385.6 to 364.8 mm and from 562.6 to 522.9 mm for heavyweight magnetite and hematite concretes with increasing nanosilica up to 6 wt% of cement, respectively. The results also showed that application of magnetite aggregates in HWC can more effectively shield against nuclear radiations than hematite ones which this issue becomes more obvious with increasing nanosilica content to 4 wt% of cement.