Joint Orientation Research Articles

Impact of dorsal closing wedge calcaneal osteotomy on hindfoot alignment and biomechanics of patients with insertional achilles tendinopathy; A weightbearing CT-based simulation study

PurposeDorsal closing wedge calcaneal osteotomy (DCWCO) is purported to enhance both the biological and mechanical aspects of insertional Achilles tendinopathy (IAT) by altering its insertional anatomy. The biomechanical impacts of shifting the Achilles insertion, however, are not fully understood. This study aimed to analyze the effect of DCWCO on hindfoot alignment and gastrocnemius-soleus (G-S) power. MethodsSix weightbearing ankle CTs of patients diagnosed with IAT were segmented and standardized planes were used to conduct DCWCOs with six variations, resulting in a total of 42-foot models including the 6 preoperative original model. Two distinct representations of plantar osteotomy starting points were defined. One was 1 cm anterior to plantar calcaneal tubercle (posterior osteotomy) and the other was 2 cm anterior (anterior osteotomy). The osteotomies were extended to 1 cm anterior of posterosuperior calcaneal tuberosity with 6-, 10-, or 14-mm dorsal wedges. Pre-defined Achilles insertion points were used to create computational Achilles tendon models. Multiple automated measurements were performed to calculate the change in foot alignment and biomechanics. ResultsBoth anterior and posterior osteotomy locations resulted in decreased lateral talocalcaneal and calcaneal pitch angles, more substantially so with the anterior osteotomy (p = 0.028). Distance change between Achilles and Haglund was much greater with posterior osteotomy using 6- and 10-mm wedges as compared to the anterior alternative (p = 0.028). Anterior osteotomy caused a significant decrease in the Böhler angle (p < 0.001). The subtalar joint orientation was observed to change up to 3.8° in anterior osteotomy and the decrease in G-S power was found to be a maximum of 2–3 %. ConclusionA posteriorly placed starting point can provide more Achilles decompression while an anteriorly placed starting point can affect foot alignment more significantly. DCWCO can change the subtalar joint orientation predisposing the joint to increased loads. Decrease in G-S power was low and will presumably not have clinical impact.

High variability exists in 3D leg alignment analysis, but underlying principles that might lead to agreement on a universal framework could be identified: A systematic review.

To (1) investigate the hypothesis that there is high variability in the reported methods to derive axes and joint orientations from three-dimensional (3D) bone models to (a) perform 3D knee-related leg alignment analysis and (b) define coordinate systems for the femur, tibia and leg and (2) identify underlying principles that might lead to agreement on a universal 3D leg alignment analysis framework. A systematic review of the literature between January 2006 and June 2024 was performed. Articles explicitly reporting methods to derive axes and joint orientations from CT-based 3D bone models for alignment parameters and/or coordinate systems of the femur, tibia and leg were included. Study characteristics and reported methods were extracted and presented as a qualitative synthesis. A total of 93 studies were included. There was high variability in the reported methods to derive axes and joint orientations from 3D bone models. Nevertheless, the reported methods could be categorized into four groups, and several underlying principles of the four groups could be identified. Furthermore, the definitions of femoral and tibial coordinate systems were most frequently based on the mechanical axis (femoral, 13/19 [68%]; tibial, 13/26 [50%]) and a central medial-lateral axis (femoral, 16/19 [84%]; tibial, 12/26 [46%]); no leg coordinate system was reported. Interestingly, of the included studies that reported on leg alignment parameters (76/93, 82%), only a minority reported expressing these in a complete coordinate system (25/76, 33%). There is high variability in 3D knee-related leg alignment analysis. Therefore, universal 3D reference values for alignment parameters cannot yet be defined, and comparison of alignment parameter values between different studies is impossible. However, several underlying principles to the reported methods were identified, which could serve to reach more agreement on a future universal 3D framework for leg alignment analysis. Level I (1).

Establishing Joint Orientation Angles of the Limbs in Korean Raccoon Dogs (Nyctereutes procyonoides koreensis) Using Computed Tomographic Imaging

Studies are being conducted on the anatomical structures of various wild animals. Despite the ecological importance of the Korean raccoon dog (Nyctereutes procyonoides koreensis), limited research has been conducted on its anatomical structure. This study is the first to establish a reference range for joint orientation angles in the limbs of the Korean raccoon dog. Joint orientation angles are an unexplored concept not only in Korean raccoon dogs but also in other wildlife. However, they are important in the examination of the skeletal anatomy of humans and companion animals, such as dogs and cats. Because this type of measurement is still emerging in wildlife research, we applied the methodology used in the domestic dog (Canis lupus familiaris). Angles were measured between the mechanical or anatomical axis and the joint orientation lines in the thoracic and pelvic limbs of Korean raccoon dogs. No significant differences were observed between the sexes or between the left and right sides. These findings are consistent with those observed in domestic dogs. Based on this study, a reference range of joint orientation angles could be established for Korean raccoon dogs.

Optimal mine pitwall profiles in jointed anisotropic rock masses

ABSTRACT A new methodology based on the limit analysis upper bound method for the topological optimisation of slopes is presented, to determine geotechnically optimal slope profiles in anisotropic jointed rock masses. The methodology accounts for the effects of discontinuities such as joints, bedding planes, and tension cracks. We applied this methodology to the context of open pit mines, with the goal of achieving geotechnically optimal pitwall profiles. The optimal profiles maximise the Overall Slope Angle (OSA) while maintaining a prescribed Factor of Safety (FoS) and satisfying the geometric constraints imposed by benches and ramps. The method, implemented in the software OptimalSlope, utilises direction-dependent cohesion and internal friction angle parameters to replicate the effect of joints on slope stability. Key inputs include joint orientation, non-persistence, and probability of occurrence. We tested the methodology on a Mexican open pit mine to be excavated into Cretaceous siltstone featuring eight different joint sets and a primary bedding plane. Optimal pitwall profiles were determined for various combinations of bedding dip angles (0°, 15°, 30°, 45°, 60°, 75°, 90°) and mine pitwall orientations (hanging wall, footwall, side walls), considering the three-dimensional kinematics of the joints through anisotropic functions of cohesion and friction angle. Results indicate that the optimal pitwall profiles generally exhibit higher OSA compared to planar profiles with the same FoS, except in one bedding dip direction. Additionally, stability analyses performed using Rocscience Slide2 independently verified the FoS values of the optimal profiles.

Delineating aquitard characteristics within a Silurian dolostone aquifer using high-density hydraulic head and fracture datasets

Fractured aquifers are heterogeneous due to the variable frequency, orientation, and intersections of rock discontinuities. A ~100-m-thick Silurian dolostone sequence provides a bedrock aquifer supplying the city of Guelph, Canada. Here, fracture network characteristics and associated influences on hydraulic head were examined using several data types obtained from 24 cored holes in a study that is novel for the quantity and quality of data. High (50–90°) angle joint orientations, heights, and terminations relative to bedding features were determined from acoustic televiewer logs and outcrop scanlines. These data were compared to high-resolution hydraulic head profiles showing head loss over depth-discrete intervals identifying zones with lower vertical hydraulic conductivity. This study reveals that the marl-rich Vinemount Member, traditionally considered the principal aquitard, corresponds to head loss in only 62% of the 24 boreholes. The vertical position of head loss varies across the 90-km2 study area and occurs in any of the lithostratigraphic units of the Lockport Group. Within this sedimentary sequence, aquitards are laterally discontinuous or “patchy” at variable depths and relate to: (1) the frequency of the high-angle joints; (2) shorter joint height; and (3) the type of joint terminations. The head loss occurs in thin (2–2.5 m) intervals where the frequency of the high-angle joints is low. Where a large proportion of small joints cross-cut marl bedding planes, head loss is negligible, suggesting that the vertical hydraulic conductivity is not reduced. Overall, these findings are potentially applicable to assessing aquitard and cap rock integrity in carbonate sedimentary sequences worldwide.

Temporal characteristics of turbulent flow and moth orientation behaviour patterns with fluent simulation and moth-based moving model simulation

ObjectivePrevious research has explored the pheromone release patterns of female moths, revealing species-specific release frequencies and the transmission of temporal information through odourant plumes in turbulent flows. Varying the release frequency during the orientation process results in distinct orientation behaviours. Studies on moth movement patterns have determined that encounters and deviations from odour plumes elicit distinct reactions; the time interval between each movement pattern is measured as the “reaction time,” and the interval between each detection and loss of odourant plume is measured as the “gap length.” MethodsWe simulated turbulent flow at various release frequencies. Our efforts focused on establishing a model that could simulate the joint orientation movement under turbulent flow and intermittent plumes. We built an agent moving mechanism, including wind velocity information, with particular reference to the temporal parameter and orientation success efficiency. ResultsWe calculated the time threshold of each burst in different simulations under different wind velocities and release frequencies. The time structure characteristics of the plume along the turbulent flow vary depending on the distance from the source. We simulated walking agents in a turbulent environment and recorded their behaviour processes. The reaction time, release interval, and time threshold were related to the orientation results. ConclusionOn the basis of previous experimental results and our simulations, we conclude that the designated interval time likely enhances search efficiency. The complex and dynamic natural environment presents various opportunities for using this unique odour-source searching capability in different scenarios, potentially improving the control systems of odour-searching robots.

Exploring joint orientation effects on rock wedge stability: Experimental and discrete element analysis

The primary objective of this study was to examine and analyze the sliding behavior of rock wedge slopes with the interaction of three joint sets, considering the influence of plunge angles, included wedge angles between joints, and gravity conditions. The discontinuity planes with varying dip directions relative to the wedge's plunge direction were analyzed. The stability assessment of wedge failure was initially reviewed, explicitly focusing on limit equilibrium (LE) analysis and in-house physical tests. Centrifuge tests and discrete element analysis using the 3DEC software were then performed to explore the factors influencing the failure characteristics of the slopes. Additionally, two mitigation strategies were proposed to enhance the stability of the rock wedge slopes. The key findings include the significant impact of plunge angle on wedge slope stability compared to the included wedge angle between joints, the strong effect of gravitational conditions on the collapsing ratio of wedge units, and the higher risk posed by wedge slopes with discontinuity planes dipping out of the slope. The numerical simulation results highlighted the importance of considering joint spacing in slope stability assessments. Mitigation methods such as fixing key wedge blocks were found to effectively reduce the wedge collapsing ratio and improve rock slope stability under more realistic stress levels. This study provides valuable insights for formulating prevention and mitigation strategies, useful for enhancing safety and reducing the potential damage caused by rock wedge failure events.

Does the distal radioulnar joint orientation influence the outcome of ulnar shortening osteotomy: a retrospective study.

The aim of this retrospective study was to evaluate the long-term outcome of ulnar shortening osteotomy. A total of 66 patients treated with an ulnar shortening osteotomy for a primary or post-traumatic ulnar impaction syndrome were included, with a median follow-up time of 75 months.There was a positive correlation between the sigmoid notch angle and the final QuickDASH score, but no correlation with final range of motion, grip strength or pain level. Radiological signs of osteoarthritis of the distal radioulnar joint were seen in 20% of patients, yet there was no correlation between the development of distal radioulnar joint osteoarthritis and the sigmoid notch angle. No symptomatic distal radioulnar joint osteoarthritis was observed.Ulnar shortening osteotomy is a good option to treat patients with ulnar impaction syndrome regardless of the distal radioulnar joint angle.Level of evidence: IV.

Exploring Machine Learning Techniques for Open Stope Stability Prediction: A Comparative Study and Feature Importance Analysis

The stability of underground excavations is essential for ensuring the safety of mining operations. Classical stability assessment methods, established in empirical formulas and rock mass classification systems, have long been employed for evaluating stope stability in underground mining. Stability graphs, a popular empirical approach, utilize factors like rock stress, joint orientation, and surface orientation to calculate stability numbers critical for stope design. However, modern advancements in machine learning present new opportunities for enhancing predictive capabilities and understanding complex relationships influencing stope stability. Building upon research demonstrating the feasibility of using machine learning for stability prediction, our study investigates and compares several machine learning algorithms. By analyzing a dataset comprising stope dimensions and geomechanical properties, we explore the potential of machine learning models such as Random Forest, Support Vector Machine, AdaBoost, XGBoost, LightGBM, and Artificial Neural Network in predicting stope stability. Evaluation metrics including accuracy, precision, recall, and F1 score are employed to assess model performance, with the Artificial Neural Network emerging as the most effective. Furthermore, SHapley Additive exPlanations (SHAP) analysis enhances interpretability by explaining the contribution of individual features to model predictions.

Knee valgus deformity: indications and outcomes for a high tibial medial closing-wedge osteotomy

IntroductionTraditionally, knee valgus deformities have been corrected through distal femur osteotomies. The advances in preoperative planning allow surgeons to understand the leading site of deformity better and, therefore, propose corrections at the appropriate anatomical location. ObjectivesThe purpose of this evaluation is to present a case of a knee valgus deformity where most of the deformity resulted from the joint and the proximal tibia. A medial closing wedge tibial osteotomy corrected the proximal tibia deformity, while a fresh osteochondral allograft aimed to improve the surface of the lateral compartment of the knee, optimizing the joint lateral convergence angle. In addition, indications, outcomes and a scoping review of the literature for closing wedge high tibial osteotomy for knee valgus deformity is reviewed. MethodsA clinical case report example of a patient with knee valgus deformity requiring closing wedge high tibial osteotomy is presented. Detailed discussion of preoperative templating, planning and surgical completion is reviewed. A systematic review of previous studies and outcomes after closing wedge high tibial osteotomy was undertaken and summarized. ResultsThe case presented demonstrates an example of a valgus knee deformity with alignment correction vis a proximal tibial ostetomy. A review of and summary of previous case reports and outcomes studies for similar pathology demonstrates a high degree of success for this surgical approach. ConclusionsClosing wedge high tibial osteotomy is a viable treatment option for knee valgus deformity with an abnormal mechanical medial proximal tibial angle (mMPTA). A thorough evaluation of joint orientation angles is necessary to appropriately address limb deformity at the specific locations(s) of significant anatomic abnormality.

Distal Radioulnar Joint Orientation and Lunate Morphology as Protective Factors of Symptomatic Idiopathic Ulnar Impaction Syndrome in Ulnar-Positive Variant Patients

Abstract Background Ulnar-positive variance is widely recognized as a risk factor for idiopathic ulnar impaction syndrome (UIS). However, not all patients with ulnar-positive variance progress to symptomatic UIS. Other factors, such as the shape of the lunate or the distal radioulnar joint (DRUJ), may also play a role. This study aims to elucidate the relationship between the shape of the lunate and the structure of the DRUJ and idiopathic UIS. Patients and Methods A cohort of 40 cases diagnosed with idiopathic UIS (UIS group) and 87 control subjects with ulnar-positive variance but without symptoms were compared. Lunate shape was assessed by measuring the lunate type and radiolunate angle (RLA), whereas DRUJ morphology was evaluated using the sigmoid notch angle, DRUJ subluxation ratio, and DRUJ inclination. Independent t-tests were conducted to analyze differences in radiographic metrics between the two groups, and logistic regression analyses were used to examine risk factors for idiopathic UIS. Receiver operating characteristic curves were utilized to determine the cutoff values for statistically significant variables. Results Significant differences were observed between the two groups in terms of RLA, DRUJ subluxation ratio, and DRUJ inclination (p &lt; 0.05). Logistic multiple regression analysis revealed a negative correlation between idiopathic UIS occurrence and both RLA (odds ratio [OR]: 0.92; 95% confidence interval [CI]: 0.87–0.96; p &lt; 0.001) and the DRUJ subluxation ratio (OR: 0.01; 95% CI: 0–0.07; p = 0.002). Conversely, a positive correlation was found between UIS occurrence and DRUJ inclination (OR: 1.06; 95% CI: 1.01–1.12; p = 0.021). Conclusion In patients with ulnar-positive variance, the incidence of symptomatic UIS decreases when the lunate extends more relative to the radius and when the DRUJ subluxation ratio increases or DRUJ inclination decreases. Level of Evidence Level III, case–control study.

The Rocker Technique for Atlantoaxial Dislocation With or Without Basilar Invagination: A Prospective Observational Study.

Atlantoaxial dislocation (AAD) poses a complex surgical challenge. Surgical approaches vary for reducible and irreducible cases. Challenges persist in reducing the atlantodental interval, especially in cases with oblique or vertical C1-C2 joints. The Rocker instrument (MJ Surgical), a less-explored technique, seeks to simplify instrumentation, reduce complexity, and enhance translation and retroflection reduction of AAD. This prospective observational study was conducted from January 2022 to July 2023 at a tertiary neurosurgical center. Inclusion criteria covered all age groups with AAD, with or without basilar invagination. Exclusions included medically unstable patients and severe osteoporotic spine conditions. Preoperative assessments included dynamic X-rays, magnetic resonance imaging, and computed tomography scans. The Rocker technique was used, and patients were followed up for 6 to 12 months. Fifty-five patients (30 males, 25 females) underwent surgery. The mean age was 40.41 ± 15.01 years. Successful Rocker technique application was observed in 53 cases. Functional outcomes, assessed using Modified Ranawat grading, showed improvement postoperatively. Radiological outcomes revealed a significant reduction in the anterior atlantodental interval (7.21 ± 0.94 to 2.98 ± 0.78). Basilar invagination was reduced in all cases, whenever present. The technique exhibited versatility, applicability in various joint orientations, and cost-effectiveness. The Rocker technique is a safe and effective alternative for managing both reducible and irreducible AADs, with or without basilar invagination. It simplifies the reduction process, offering advantages over established techniques. Further trials, especially in rotational deformities, are warranted for validation.

Flexural behavior of finger joint connected glulam wooden beams strengthened with CFRP strips

Laminated wood beams have become a preferred solution compared to standard solid beams due to their ability to carry larger loads and in larger spans (greater distances). The increase in wood usage and the varieties of its applications have highlighted the necessity for the enhancement of the maximum load-carrying capacity and overall load-displacement behavior of laminated wood beams. Among the various strengthening options applied to increase the maximum load-carrying capacity and material performance, the most commonly preferred choice is strengthening with CFRP (Carbon Fiber Reinforced Polymer). Within the scope of this study, a total of 26 glulam wooden beam test specimens were produced. Variations were introduced in terms of the number of laminated layers, the distance between finger joint connection points, finger joint orientation, the use or lack of use of strenghthening, and distance between CFRP strips. The specimens were subjected to monotonic static loading through a four-point bending test, allowing for an examination of how these variables influenced the bending behavior. The values obtained from the experimental study and the numerical study conducted using the finite element software ABAQUS were compared and interpreted. These values included ultimate load capacity, displacement at ultimate load, initial stiffness, displacement ductility, and energy dissipation capacity. Based on the conducted analyses, it was observed that the strengthening method involving CFRP strips developed within the extent of this study significantly increased the load-bearing capacity of finger jointed glulam wooden beams. Furthermore, it was shown to have a highly positive impact on the overall load-displacement behavior.

VR-HandNet: A Visually and Physically Plausible Hand Manipulation System in Virtual Reality.

This study aims to allow users to perform dexterous hand manipulation of objects in virtual environments with hand-held VR controllers. To this end, the VR controller is mapped to the virtual hand and the hand motions are dynamically synthesized when the virtual hand approaches an object. At each frame, given the information about the virtual hand, VR controller input, and hand-object spatial relations, the deep neural network determines the desired joint orientations of the virtual hand model in the next frame. The desired orientations are then converted into a set of torques acting on hand joints and applied to a physics simulation to determine the hand pose at the next frame. The deep neural network, named VR-HandNet, is trained with a reinforcement learning-based approach. Therefore, it can produce physically plausible hand motion since the trial-and-error training process can learn how the interaction between hand and object is performed under the environment that is simulated by a physics engine. Furthermore, we adopted an imitation learning paradigm to increase visual plausibility by mimicking the reference motion datasets. Through the ablation studies, we validated the proposed method is effectively constructed and successfully serves our design goal. A live demo is demonstrated in the supplementary video.

Stability assessment of jointed rock capturing roughness degradation under cyclic loading with special reference to railway formation

Repeated train loading on a jointed rock subgrade can cause excessive displacements of certain discontinuities leading to instability. Repeated shearing of discontinuities leads to a gradual reduction in joint roughness (i.e. wearing of asperities), which is quantified by the change in the joint roughness coefficient (JRC). This process reduces the joint shear strength over time. In this study, the classical shear strength criterion proposed by Barton and Choubey (1977) is extended to capture the influence of cyclic loading on joint degradation and the corresponding shear strength reduction, also considering the scale effect. This modified cyclic shear strength is implemented in FLAC-3D and validated with conventional cyclic triaxial data available from selected past studies. The model is applied to a simulated real-life track operating over a jointed sandstone formation commonly found towards the eastern coast of NSW. A modified limit equilibrium approach based on an Equivalent Factor of Safety (EFOS) is introduced and adopted to quantify the extent of instability, whereby an increase in the number of loading cycles affects a decrease in the EFOS of an unstable block. For a specific joint strike inclined to the track, the potential adversities are exacerbated when the joint dip angle is greater and when the initial JRC is smaller. In this paper, alternative geometrical combinations and different initial joint properties are considered to determine the worst combination of JRC and joint orientation upon cyclic train loading. As most past studies adhere to traditional static load analyses, the extended shear strength criterion described in this study is novel, and it offers significant practical benefit for railways that are subjected to prolonged cyclic loading.

Geotechnical Study for Assessing Slope Stability at the Proposed Weito Dam Site in Ethiopia: Implications for Environmental Sustainability and Resilience

There is a proposed dam at Weito in Ethiopia’s Southern Nations Nationalities and People Regional State. This embankment-type dam primarily serves irrigation purposes. Weito’s proposed dam’s slope stability is the primary focus of this investigation. The objective is to assess the geological and geotechnical conditions influencing slope stability using the slope mass rating (SMR) classification system. This study examined various slope stability parameters. Uniaxial compressive strength, rock quality designation, joint condition, discontinuity spacing, joint orientation, and groundwater conditions were measured. An analysis of field data, including geological structures and lithology, was used to generate a structural discontinuity map. The slope mass rating was calculated to assess rock mass stability. The study area was examined for faults, joints, fractures, and shear zones during fieldwork. Schmidt hammer tests indicated a range of 10.5–50 MPa uniaxial compressive strength. Rock quality designation values were also within 72.5% to 95%. Additionally, the joint spacing of rocks varied from 3.95 cm to 47.5 cm. Rock mass ratings ranged from 39% to 62%. The study contributes to the understanding of the geological conditions at the Weito dam site and ensures the dam’s safe design and construction.

Ultra low-power, wearable, accelerated shallow-learning fall detection for elderly at-risk persons

This work focuses on the development and manufacturing of a wireless, wearable, low-power fall detection sensor (FDS) designed to predict and detect falls in elderly at-risk individuals. Unintentional falls are a significant risk in this demographic, often resulting from diminished physical capabilities such as reduced hand grip strength and complications from conditions like arthritis, vertigo, and neuromuscular issues. To address this, we utilize advanced low-power field-programmable gate arrays (FPGAs) to implement a fixed-function neural network capable of categorizing activities of daily life (ADLs), including the detection of falls. This system employs a Convolutional Neural Network (CNN) model, trained and validated using the Caffe deep learning framework with data collected from human subjects experiments. This system integrates an ST Microelectronics LSM6DSOX inertial measurement unit (IMU) sensor, embedded with an ultra-low-power Lattice iCE40UP FPGA, which samples and stores joint acceleration and orientation rate. Additionally, we have acquired and published a dataset of 3D accelerometer and gyroscope measurements from predefined ADLs and falls, using volunteer human subjects. This innovative approach aims to enhance the safety and well-being of older adults by providing timely and accurate fall detection and prediction.In this paper, we present an innovative approach to utilizing a compact Convolutional Neural Network (CNN) core for accelerating convolutional operations on a machine learning model, suitable for deployment on an ultra-low power FPGA.

Elastic Stable Intramedullary Nailing in Length Stable Versus Unstable Pediatric Femoral Shaft Fractures: A Comparison of Clinical, Radiographic, and Pedobarographic Outcomes.

Pediatric diaphyseal femoral fracture (PDFF) is one of the most common injuries requiring hospitalization. Elastic stable intramedullary nailing (ESIN) is commonly used for PDFFs in ages 5 to 11. The optimal treatment method for length unstable PDFF is a subject of ongoing debate. This study aimed to compare clinical, radiographic, and pedobarographic outcomes of ESIN between length stable and unstable PDFF. We retrospectively reviewed patients undergoing ESIN treatment for isolated PDFF between 2016 and 2021. Exclusion criteria were (1) history of ipsilateral or contralateral lower extremity fractures, (2) highly comminuted or segmental fractures, (3) body weight >50kg, and (4) comorbidities affecting bone quality, range of motion, or neurologic status. The patients were divided into 2 groups according to length stability. Clinical, radiographic, and pedobarographic data were then assessed to compare groups. Twenty-five patients were included (17 length stable and 8 length unstable PDFF) with a mean age of 73.6±17.8 months. There was no significant difference between groups in age, side of injury, body weight, follow-up duration, and nail-canal diameter ratio. Mean deformity in the fracture site in the early postoperative x-rays was not significantly different between groups ( P =0.661). After a mean follow-up of 27.8±14.2 months (range, 12-67), there was no significant difference in mechanical axis deviation, distal femur joint orientation angle, or limb-length discrepancy in both groups. The pedobarographic assessment revealed that the length unstable group had a significantly higher external foot progression angle in the injured extremity (9.8°±6.9° vs. 1.3°±5.6°, P =0.031). However, the length stable group had no significant difference in the foot progression angle (4.9°±5° vs. 3°±4.3°, P =0.326). There was no significant difference in either group for other pedobarographic parameters. ESIN is a safe and effective option for length-unstable PDFF, yet attention should be paid to the rotational alignment. Although significant external rotation deformity occurs in length-unstable PDFF, it has no implications for the other pedobarographic parameters. Level IV.

Three-dimensional finite element simulation and reconstruction of jointed rock masses for bench blasting

During the numerical simulation of blasting in jointed rock masses, the accuracy of joint geometric parameters is one of the key factors affecting the numerical results. To facilitate the numerical simulation, most of the previous studies on blasting in jointed rock masses were conducted on regular jointed rocks, which is not conducive to fully revealing the dynamic responses and blast-induced damage characteristics of jointed rock mass. In this study, scanline sampling and borehole sampling were employed to obtain the surface and internal joint structures of the rock bench. To represent the joint geometry, a reconstruction technique for three-dimensional (3D) jointed rock masses in LS-DYNA was proposed utilizing MATLAB code. In the process, the elements on joint surfaces were identified and assigned mechanical parameters of joints to construct the 3D jointed rock model, where the geometrical properties of generated joints obey the statistical distribution obtained from the scanline survey. Taking an open-pit limestone mine as an example, a statistical analysis of the 3D distribution of joints was carried out and used to construct a 3D jointed rock numerical model for bench blasting. Comparisons between the bench slope extracted from the numerical model and the actual joint trace mapping from a rock exposure are performed, and the similarity between the two contour plots of joint orientations reaches 91.6 %. For comparison tests, the bench blasting was simulated by an intact rock model and the jointed rock model. The results indicate that the dynamic responses and blast-induced damage characteristics of jointed rocks are significantly affected by the geometry of joints. Compared with the intact rock model, the presence of joints causes stress concentration and local strengthening of rock damage between adjacent joints, which results in a 30.5 % increase in the damage volume. Furthermore, a field blasting test was conducted to analyze the accuracy of the jointed rock model. The results show that the fragment size distributions obtained from the jointed rock numerical model and the filed test are generally consistent, and the error between them in the proportion of rock fragments with a size of 0 ∼ 100 mm is only 12.8 %. These findings indicate that the proposed reconstruction method of the jointed rock model is considerably robust for characterizing the joint geometry of in situ rock masses and simulating the bench blasting in jointed rock masses.

Laboratory Tests of Large-Scale Block Models on the Load Transfer and Failure Mechanisms of Rock Masses Subjected to Anchor Loading

This paper presents a laboratory testing rig designed to investigate the failure mechanisms and load transfer of rock masses under rock anchor loading. The study revealed that joint patterns significantly affect the strength and capacity of the rock mass, with existing design approaches based on apex angles of 90∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{\\circ }$$\\end{document} or 60∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{\\circ }$$\\end{document} found to be potentially overly conservative. Joint orientation and spacing should be included in the anchor design to obtain a more precise design criterion. In all the studied patterns, increasing the horizontal and vertical stress increased the block models’ capacity, and load arching did not occur in the model with an unfavourable joint orientation. This study also revealed that the failure surface followed the joints in all tests and that the block model capacity was significantly higher than estimated with the design principle based on the weight of the overlying rock. The findings of this work have important implications for designing rock anchoring systems in mining and civil engineering demonstrate that joint orientation and block size significantly affect the rock mass capacity. This study confirms the need to consider the influence of in situ stresses on rock mass capacity when designing of rock anchors. Overall, this work guides the development of more precise design criteria for rock anchors, contributing to more efficient and effective rock engineering practices.