Joint Structure Research Articles

Influence of axial load on structure and strength of a heterogeneous joint of titanium alloy Ti-6Al-4V and aluminum alloy Al-6Zn-2Mg-2Cu formed by friction stir welding

Influence of axial load on structure and strength of a heterogeneous joint of titanium alloy Ti-6Al-4V and aluminum alloy Al-6Zn-2Mg-2Cu formed by friction stir welding

Public insight into knee osteoarthritis: a cross-sectional study from the West Bank, Palestine.

Osteoarthritis (OA) is a significant global health concern and is characterized by the degeneration of joint structures, leading to pain, stiffness, and functional limitations It is estimated that 654.1million individuals are affected by osteoarthritis worldwide, with females, especially those older than 60 years of age, being the population most impacted. However, there remains a gap in understanding the awareness of knee osteoarthritis among specific populations, such as the Palestinian community in the West Bank, thus, highlighting the need for targeted research to address this health disparity. A cross-sectional survey was conducted in the West Bank from August to September 2024. Participants were recruited from 11 cities and a validated questionnaire adapted from a previous study was used to collect the data. The reliability of the questionnaire was assessed using Cronbach's alpha, yielding a value of standard alpha = 0.71, which is an acceptable value. The survey collected demographic data, clinical characteristics, knowledge of osteoarthritis risk factors, symptoms, and attitudes towards treatment options. R Statistical Software was used for data analysis, which included descriptive statistics, chi-square tests, and logistic regression to explore the relationships between demographic factors and osteoarthritis knowledge, whereby a p-value of ≤ 0.05 was set up as a significance level. A total of 725 valid responses were included in our study. Among the participants, 569 were female, predominantly aged 25 or younger (66%, n = 479), and 62% (n = 450) were single. Knowledge assessment revealed that 80% (n = 580) recognized knee osteoarthritis as a chronic disease, while only 51% (n = 369) understood its impact on joint involvement. The majority identified high BMI (87%, n = 632), advancing age (94%, n = 683), and previous knee injury (72%, n = 520) as risk factors, although only 42% (n = 306) acknowledged genetics as one. Most participants were aware of the management strategies, including analgesics (70%, n = 510) and physiotherapy (80%, n = 579). However, 66% (n = 478) scored low for overall knowledge regarding knee osteoarthritis. This study emphasizes the critical importance of raising awareness and knowledge about osteoarthritis within the Palestinian community. Despite being widely known as a long-term issue, there are still noticeable gaps in the understanding of the joint impact, potential risks, and effective treatment methods for osteoarthritis. The use of informal sources highlights the importance of specific educational programs by healthcare providers.

Friction Stir Welding in Aircraft Structures: Current and Future Prospects

Friction stir welding (FSW) has significant potential to enhance the efficiency of air transportation systems; however, determining and applying its parameters continues to pose challenges. This article review explores current and future challenges, trends, and practices that facilitate the integration of competitive production into new aircraft structure joints. An overview of friction stir welding techniques used for the design and manufacture of aircraft structures are presented, focusing on product optimization through lightweight and high-strength properties. The implementation of various design solutions and advanced manufacturing technologies can enhance metallic fuselage systems’ performance without compromising risk and cost. The paper presents examples of successfully addressed challenges and those driving the development of new practices, design solutions, methods, and tools. Ultimately, aircraft structure joints become more integrated when systems engineering approaches are linked with various design solutions and advanced manufacturing technologies (e.g., Vertical Compensation Friction Stir Welding) in a reusable manner, balancing product performance and producibility. Nevertheless, the field remains in active development, posing challenges for research, development, and practice.

Considering the effect of temperature-moisture coupling on the global sensitivity and failure probability of mechanical properties of metal-composite bolt joint structures

Considering the effect of temperature-moisture coupling on the global sensitivity and failure probability of mechanical properties of metal-composite bolt joint structures

Resident synovial macrophages in synovial fluid: Implications for immunoregulation.

Resident synovial macrophages (RSMs) are anti-inflammatory, self-renewing macrophages that provide physical immune sequestration of the joint space from the peripheral immune system. Increased permeability of this structure is associated with peripheral immune cells in the synovial fluid (SF). Direct measures of synovial barrier integrity are possible with tissue histology, but after barrier breakdown, if these cells perpetuate or initiate chronic inflammation in SF remains unknown. We sought to identify RSM in human SF as an indirect measure of synovial barrier integrity. To validate findings, we created a novel ex vivo explant model using human synovium. scRNA-seq revealed these SF RSMs upregulated pro-fibrotic and pro-osteoclastic pathways in inflammatory arthritis, but not septic arthritis. Increased frequencies of RSMs in SF was associated with increased sRANKL regardless of underlying pathology. These findings suggest the frequency of RSMs in SF may correlate with synovial barrier damage and in turn, potential damage to joint structures.

Knowledge Error Detection via Textual and Structural Joint Learning

Knowledge Error Detection via Textual and Structural Joint Learning

Advances in the pathology and treatment of osteoarthritis.

Osteoarthritis (OA), a widespread degenerative joint disease, predominantly affects individuals from middle age onwards, exhibiting non-inflammatory characteristics. OA leads to the gradual deterioration of articular cartilage and subchondral bone, causing pain and reduced mobility. The risk of OA increases with age, making it a critical health concern for seniors. Despite significant research efforts and various therapeutic approaches, the precise causes of OA remain unclear. This paper provides a thorough examination of OA characteristics, pathogenic mechanisms at various levels, and personalized treatment strategies for different OA stages. The review aims to enhance understanding of disease mechanisms and establish a theoretical framework for developing more effective therapeutic interventions. This review systematically examines OA through multiple perspectives, integrating current knowledge of clinical presentation, pathological mechanisms, and associated signaling pathways. It assesses diagnostic methods and reviews both pharmacological and surgical treatments for OA, as well as emerging tissue engineering approaches to manage the disease. While therapeutic strategies such as exercise, anti-inflammatory drugs, and surgical interventions are employed to manage symptoms and modify joint structure, none have been able to effectively halt OA's advancement or achieve long-lasting symptom relief. Tissue engineering strategies, such as cell-seeded scaffolds, supportive matrices, and growth factor delivery, have emerged as promising approaches for cartilage repair and OA treatment. To combat the debilitating effects of OA, it is crucial to investigate the molecular basis of its pathogenesis and seek out innovative therapeutic targets for more potent preventive and treatment strategies.

A Novel Virtual Planned-Orthodontic-Surgical Approach for Proportional Condylectomy in Condylar Hyperplasia

Background/Objectives: Condylectomy is a delicate and intricate procedure commonly employed in the management of temporomandibular joint (TMJ) disorders, osteochondromas, condylar hyperplasia, hemimandibular hyperplasia, and other pathologies affecting the condylar region. The advent of surgical cutting guides has introduced a new dimension to condylectomy procedures as they enable surgeons to plan and execute precise cuts with a heightened level of accuracy. In the literature already exists cases of cutting guide-based condylectomy, but they only depend on the mere mirroring procedure in virtual planning, which has accuracy limitations because it does not consider asymmetry of peri-condylar structures at the level of the ramus, body, and mandibular angle. Methods: CAD-CAM orthodontic preparation through the NEMOFAB Software was performed to correct the canting of the occlusal plane, following the “orthodontic first” technique. The same software was used for VSP of the surgical cutting guide to perform the condylectomy, basing not to the mere mirroring of the opposite side but considering the whole condylar-TMJ-glenoid fossa structure. Results: At 6 months follow-up, the patient showed good occlusion and an almost totally recovered lower third symmetry as median-upper and lower interincisive lines coincide with each other and with the chin median. A good occlusal and masticatory outcome was obtained. The joint structure was preserved with remodeling of the glenoid cavity caused by the presence of the joint disc, which was preserved during surgery. Conclusions: The goal of this study is to propose a method of therapeutic management of condylar hyperplasia that benefits from accurate pre-operative orthodontic treatment (orthodontics first) to maximize the results of proportional condylectomy, reducing post-operative orthodontic care as well as any need for any adjuvant orthognathic surgery. A new virtual surgical planning method is also proposed for creating a cutting guide that not only takes advantage of the mirroring technique to accurately calculate the amount of condyle to be cut but also considers the entire condyle–TMJ complex to perform a condylectomy that is more precise.

Shear properties of jointed dual-pylon of the cable-stayed bridge with separated unequal-width decks under asymmetric load

The significant load disparity between the two decks of a cable-stayed bridge with separated unequal-width decks results in complex asymmetric static effects in the jointed dual-pylon. To investigate the structural behaviour and reliability of the jointed dual-pylon under asymmetric loads, a 1:30 scaled model test and numerical simulation were conducted based on the world's first road-railway same-level cable-stayed bridge with jointed pylons. The test results indicate when the unbalanced horizontal force of the jointed dual-pylon structure reaches its maximum during the service phase, the stress at the dual-pylon connectivity node remains relatively low, indicating good shear resistance of the dual-pylon connectivity node. Structural failure occurs when the load reaches 1.82 times the maximum shear stress at the tower column merging section, and the railway beam will experience severe cracking and stiffness degradation, ultimately leading to loss of bearing capacity. The calculation results further reveal that under the combined action of dead load, full-span moving load, and lateral wind load, the minimum calculated nonlinear stability coefficient of the dual-pylon connectivity node is 1.65. Moving load and longitudinal wind load have minimal impact on the nonlinear stability coefficient, and the dead load and lateral wind load primarily govern the failure of the dual-pylon connectivity node.

Formation of al-zn-cu-mg alloy joint structure under friction stir welding with additional liquid cooling and subsequent artificial aging

Formation of al-zn-cu-mg alloy joint structure under friction stir welding with additional liquid cooling and subsequent artificial aging

Prediction of the Moment-Rotation Relationship of Dovetail Mortise-Tenon Joint Based on Support Vector Regression

ABSTRACT This study proposes a machine learning-based approach to predict the moment-rotation relationship of dovetail mortise-tenon joints in ancient wooden structures using Support Vector Regression (SVR). Finite element models were developed in ABAQUS and validated against experimental data to ensure accuracy. A dataset of 328 moment-rotation relationships was generated by varying material properties and joint dimensions. The SVR model was optimized through grid search and cross-validation, and its interpretability was analyzed using SHAP, revealing that geometric features such as tenon dimensions significantly impact bending resistance, while material properties play a lesser role. The SHAP analysis further demonstrated that the looseness gap negatively affects load-bearing capacity, whereas increasing parameters like tenon neck width or shoulder width enhances the bending resistance. The results show that the constructed SVR model can quickly and accurately predict the moment-rotation relationship of dovetail mortise-tenon joints, with determination coefficients exceeding 0.989 in the testing set under different deformation conditions, offering higher prediction accuracy, better generalization ability, and computational efficiency compared to traditional theoretical formulas.

Assessment of Joint Behaviour of Immersed Tunnel with Prefabricated Push-Out Closure Joint under Differential Settlement

The deformation behaviour of immersed tunnels with prefabricated push-out closure joint remains unclear. In this study, four model tests were conducted to simulate immersed tunnels subjected to differential settlements. The impact of different settlement crossings on joint behaviours was analyzed. Results indicate that differential settlement directly at the joint position causes significant shear displacement, with decreased perpendicular axial movement. The closure joint shows bidirectional axial movement, while the flexible joint primarily undergoes unidirectional compression. The direction and magnitude of joint rotation depend on the settlement location. Differential settlement at a flexible joint significantly influences the rotation of other joints simultaneously. Premature leakage could occur in adjacent flexible joints when differential settlement occurs at the closure joint. Controlling the axial movement of flexible joint is the most effective approach to manage joint opening and prevent leakage under small differential settlements. A closed-form solution was proposed for estimating the axial movement between closure joint and lining structure. It suggests that the interface shear strength should be greater than 0.25 MPa to limit the maximum axial movement of closure joint within the tolerance. Compared to frictional resistance, more attention should be given to the bonding strength provided by post-construction grouting.

Effectiveness of the ARTHE-e app for exercise adherence in people with knee osteoarthritis: protocol for a randomised controlled trial

IntroductionOsteoarthritis, the most prevalent joint disease, poses a significant challenge due to its progressive nature and impact on the whole joint and periarticular structures. Although exercise is crucial for symptom...

Pragmatic performance, its relationship with symptom severity, and early clinical predictors of pragmatics in 5 ~ 6-year-old children with autism spectrum disorder

BackgroundPragmatic language refers to using spoken language to convey messages effectively across diverse social communication contexts. However, minimal longitudinal research has focused on defining early predictors of pragmatic development in children with autism spectrum disorder (ASD).MethodsIn the present study, 71 children with ASD and 38 age- and gender- matched 24- to 30-month-old typically developing (TD) children were enrolled. Social-communication, language, and parent‒child interaction measures were collected for the ASD group at baseline. Three years later, all subjects were assessed for pragmatic ability via the Chinese version of the Language Use Inventory (LUI-Mandarin). First, the differences in pragmatic performance between the ASD and TD groups at follow-up were analyzed. Second, pragmatic performance was correlated with autism symptomatology at follow-up, as well as the structural language difficulties and joint engagement (JE) levels at baseline in the ASD group. Furthermore, hierarchical multiple regression analyses and machine learning techniques were performed to explore the effects of early potential predictors of pragmatic development in the ASD group.ResultsFirst, our results revealed that performance was significantly lower in the ASD than in the TD group with respect to the LUI-Mandarin total scores and subscale scores (except for subscale C). Second, correlation analysis revealed that more severe symptoms of ASD at follow-up were associated with lower LUI-Mandarin total scores and better language performance on the Gesell Developmental Schedules (GDS). Additionally, increased proportions of supported JE (SJE) states were associated with higher LUI-Mandarin total scores. In contrast, increased proportions of unengaged (UE) states were associated with lower LUI-Mandarin total scores in the ASD group. Third, hierarchical multiple regression analyses and machine learning techniques indicated that the proportions of SJE during parent‒child interactions, as well as the degree of social symptoms and structural language impairments, were significant contributors to pragmatic development for the ASD group in the prediction models.ConclusionIn summary, our findings suggest that pragmatic language difficulties are present in children with ASD as early as preschool age. Additionally, given the close correlation between the LUI-Mandarin score and symptom severity on the ADOS/ADI-R, the LUI-Mandarin might be a good way to triage children who need to wait a long time for a more extensive evaluation. Furthermore, this study provides new insights into potential targets for pragmatic interventions, and interventions can be designed to promote SJE between caregivers and children in future work.

Anterior Cruciate Ligament Reconstruction: Analysis of Grafts, Associated Injuries, And Anesthetic Strategies

Objective: This study analyzed the clinical and surgical outcomes of patients undergoing anterior cruciate ligament (ACL) reconstruction, evaluating associated injuries, graft types, anesthetic strategies, and tourniquet time. Methods: Sixteen patients with ACL injuries were included, and their medical records were reviewed to collect data on the variables. Associated injuries were categorized, the types of grafts used were recorded, and anesthetic practices and tourniquet times were analyzed. Results: Associated injuries were identified in 60% of patients, with meniscal injuries being the most common (40% with sutures). The patellar tendon was the most used graft (80%), while anesthetic methods such as spinal anesthesia combined with continuous additional block (BCA) were applied in 40% of cases. The average tourniquet time was 68 minutes, remaining within safe limits according to the literature. Conclusion: ACL reconstruction requires meticulous surgical planning, considering clinical and technical variables. Graft selection and anesthetic strategies, combined with the preservation of joint structures, are essential for favorable functional outcomes and the prevention of complications.

Fretting wear modeling of bolted joint interface with microscopic roughness using the 1D microslip friction model and equivalent thin layer

In this work, an improved 1D microslip model at the frictional joint interface considering the effect of surface topography is developed, which is further used to evaluate the fretting wear performance of the joint structure. The rough surface contact of the joint interface is characterized by the micro-asperity Greenwood and Williamson statistical contact model (GW model). A thin layer with elastic tangential stiffness, exhibiting equivalent properties to accord with the micro-asperity contact of the rough interface, is supposed to connect with the two components comprising the joint interface. The nonuniform clamping pressure distribution is considered and the resulted stick-slip transitions along the interface are derived using the continuum elastic beam model. The tangential stiffness of micro-asperities for rough surface contact is derived and incorporated into the continuum beam model to obtain the relative slip displacement along the interface. Fretting wear depth resulted from the cyclic microslip at the interface is evaluated based on the relative sliding distance and the Archard wear model. Results show that the minimum tangential force causing microslip motion increases with surface roughness and preload. The slip length increases with the tangential force whilst decreases with the increased surface roughness. The wear depth progressively increases from stuck region to slip region, and decreases as the surface roughness and preload increase. Experimental validation is performed and excellent agreement is observed between model predictions and experimental results. The developed model provides important new insights into the prediction of fretting wear and loosening behavior of the bolted joints.

Problems with and Alternatives to Permeable (Open-Graded) Subbases for Use in Jointed Plain Concrete Pavement Structures

Due to their intuitive advantage to quickly remove water from a pavement structure, permeable (open-graded) subbases (subbases with a permeability greater than about 350 ft/day (107 m/day) in laboratory tests) have been a common design element in jointed plain concrete pavement structures since the 1990s. Despite this assumed advantage, permeable subbases are no longer recommended for inclusion in jointed plain concrete pavement structures for various reasons discussed in this paper. Freedraining subbases (subbases with more fines than permeable subbase and, thus, with a permeability less than 350 ft/day (107 m/day) in laboratory tests) that are daylighted are the reasonable alternative to permeable subbases with edge drainage systems.

Anterior Cruciate Ligament Mechanical Response to Load in the Setting of Changes to the Medial Meniscus.

The anterior cruciate ligament (ACL) is a major ligament in the knee joint, and its function is crucial for both the movement and stability of the knee. Our research takes a novel approach by investigating the effect of meniscus tears on the ACL, how such tears will impact the stress on the ACL, and its overall compensation in response to the changes in the meniscus. Hypothesis/Purpose: This study aims to investigate how the ACL compensates for the change in knee joint stability and contact pressures due to partial horizontal cleavage tears (HCTs) in the meniscus, such as partial meniscectomy and partial transplantation on knee joint stability and contact pressures. We hypothesize that HCTs will increase contact pressures and decrease joint stability, thereby inducing compensatory stress on the anterior cruciate ligament (ACL). Method: Seven freshly frozen human cadaveric knees were used in a study to investigate the effects of different meniscal conditions and surgical interventions on the meniscus itself. Four testing scenarios were established: intact knees, knees with partial horizontal cleavage tears (HCTs) of the meniscus, knees with partial meniscectomy, and knees with partial transplantation. Axial loading was applied, and the medial meniscus contact pressures were measured at 0° and 30° of flexion. Additionally, a mathematical 3D finite element model was created to evaluate the behavior of the ACL under different meniscus scenarios, which could not have been measured experimentally. Results: ACL contact pressure and stress analysis across various meniscal conditions demonstrated substantial variability. Horizontal cleavage tears (HCTs) resulted in heightened contact pressures and diminished joint stability, as evidenced by increased ACL stress attributed to compensatory mechanisms in the presence of meniscal tears. Conversely, transplantation procedures exhibited a mitigating effect, maintaining joint mechanics closer to intact conditions and minimizing alterations in ACL forces. These trends persisted at 30 degrees of knee flexion, where significant increases in ACL forces were observed in partial and complete HCT conditions. Conclusions: This study uncovers the biomechanical impacts of meniscal injuries, demonstrating how the ACL compensates for various meniscus conditions. In contrast, transplantation and repair conditions only slightly increase the stress on the ACL, putting much less strain on the ACL and supporting structures of the knee joint than an unrepaired tear.

Mechanical Design and System Construction of Ankle Rehabilitation Robots

The ankle joint is the most heavily loaded joint in the human body and plays a crucial role in daily activities, making it susceptible to injuries. Currently, rehabilitation robots for the ankle joint facilitate the assessment of rehabilitation outcomes and the adjustment of rehabilitation programs, demonstrating significant practical value and application prospects. This paper reviews the mechanical structure design and control system construction of existing ankle rehabilitation robots. In this narrow review, we first analyze the characteristics and issues of current mechanical designs of ankle rehabilitation robots based on the analysis of physiological structure of the ankle joint. Subsequently, we examine design aspects aimed at enhancing precision based on the movement characteristics of the ankle joint, suggesting directions for further research. The control system is categorized into three types based on the driving method: passive, active, and assistive, with an explanation of their mechanisms of action. Finally, we summarize our findings and propose perspectives about the future development of ankle rehabilitation robots

Orthognathic surgery-related condylar resorption in patients with skeletal class III malocclusion versus class III malocclusion: a systematic review and meta-analysis

BackgroundOrthodontic-orthognathic treatment is the standard of care for moderate and/or severe skeletal class III (SCIII) malocclusion. Following orthognathic surgery, morphological changes in the temporomandibular joint structures (TMJ) may contribute to condylar resorption (CR).ObjectivesThis systematic review aimed to identify the morphological signs of condylar resorption (changes in the condylar head, position, neck, disk, and joint space) following orthognathic surgery in patients with SCIII compared with those with skeletal class II (SCII) malocclusion. Furthermore, surgical techniques were assessed to investigate the extent to which orthognathic surgery may be related to TMJ disorders and potential muscular changes.MethodsA systematic search was conducted using Medline, Pubmed, Scopus, Cochrane Library, Web of Science, and Grey Open literature databases [May 2023; PROSPERO: CRD42021293105)]. Articles that met the eligibility criteria were assessed for quality and the risk of bias using MINORS. A meta-analysis was also conducted.ResultsEleven of the 1014 studies met the eligibility criteria. Of the eligible studies, 10 were considered high-quality. Our results indicated that the incidence of condylar resorption was higher in the SCII group (46.7%) than in the SCIII group (37.2%). The condylar angle was preoperatively higher in the SCII group, and this tendency did not change during the follow-up period. No statistically significant differences in condylar width (95% CI: − 0.62 to 0.43; p = 0.72), height changes (95% CI: − 0.92 to 0.46; p = 0.46), ramus angle (95% CI: − 0.63 to 2.56; p = 0.24) were found between groups. The results suggested that TMJ symptoms were similar between the groups pre- and postoperatively. However, the SCII group showed a higher incidence of anterior disc displacement. Furthermore, postoperative cross-sectional measurements of the lateral pterygoid, medial pterygoid, and masseter muscles were significantly different between the groups.ConclusionCR could be related to specific skeletal pattern, and the extension of surgical movements may be a risk factor. However, the definition of CR remains vague, and no categorization system regarding SCIII patients has been reported to date.