Search Results (119)

Continuum robots offer inherent compliance and dexterity for operation in confined and unstructured environments; however, achieving hybrid multi-segment functionality typically requires application-specific redesign and tightly coupled architectures. To address this limitation, this study proposes a reconfigurable hybrid continuum robot architecture based around a multi-lumen central integration backbone that supports multiple actuation modalities and robot configurations. The proposed design combines external tendon-driven disk modules for proximal actuation with a pneumatically actuated distal tip, while internal lumens allow routing of pneumatic lines and the insertion of optional stiffening elements without structural interference. The reconfigurability of the architecture is demonstrated through two configurations: Concept-1, a two-segment hybrid system, and Concept-2, a miniaturized three-segment configuration achieved by reducing the disk diameter and extending tendon actuation to the backbone. Experimental evaluations are conducted to characterize segment-wise actuation, coupled deformation behavior, and workspace capabilities, hysteresis response, tip contact force, and phantom-based target reachability. Results show that the integration of tendon-driven and pneumatic actuation significantly expands and reorients the reachable workspace. Additional functional tests showed repeatable loading–unloading behaviour of the tendon-driven segment, a maximum pneumatic tip contact force of approximately 0.45 N, and successful access to five representative targets within a stomach-like phantom using Concept-2. A kinematic model based on a constant-curvature formulation is validated against experimental data, yielding root-mean-square errors (RMSE) of 5.44 mm and 6.12 mm for Concept-1 and Concept-2, respectively. These results demonstrate consistent model accuracy across different configurations and scales. Overall, the proposed architecture enables modular, scalable, and reconfigurable hybrid continuum robots, providing a flexible framework for applications ranging from large-scale manipulation to gastroscopy-inspired minimally invasive procedures. Full article

Background/Objectives: Comparative studies evaluating minimally invasive surgery (MIS) and open repair for acute Achilles tendon rupture have predominantly relied on mean-based statistical comparisons, which may not adequately capture whether outcomes are clinically meaningful from the patient perspective. This study aimed to compare 12-month outcomes between MIS using the internal splinting technique and open repair, establish anchor-based minimal clinically important difference (MCID) thresholds, and compare patient-centered responder outcomes between techniques. Methods: This retrospective non-randomized comparative cohort study included 70 patients allocated to MIS (n = 35) or open repair (n = 35). Outcomes were assessed using VAS, AOFAS, ATRS, and Thermann score. Anchor-based MCID thresholds were determined via ROC curve analysis using the Global Rating of Change (GROC) scale as the external anchor. Patient Acceptable Symptom State (PASS) was assessed using a dichotomous anchor question. Results: Both groups demonstrated significant improvements across all outcome measures at 12 months (p < 0.001). No significant between-group differences were observed in mean functional scores, MCID achievement rates, PASS rates, or GROC-defined clinical success (p > 0.05 for all). AUC values ranged from 0.975 to 0.984. The MCID threshold for pain relief was identified as a VAS reduction > 4.8 points (AUC: 0.975, 95% CI: 0.906–0.998), while ROC-derived functional MCID thresholds were identified as an AOFAS increase >38 points (AUC: 0.984, 95% CI: 0.920–0.999), an ATRS increase >38 points (AUC: 0.984, 95% CI: 0.920–0.999), and a Thermann score increase >37 points (AUC: 0.984, 95% CI: 0.920–0.999). These thresholds should be considered exploratory and require validation in larger independent cohorts. MCID achievement rates were 42.9% for VAS in both groups, whereas MCID achievement for functional outcome measures (AOFAS, ATRS, and Thermann scores) was 62.9% in the MIS group and 57.1% in the open repair group. PASS-positive rates were 85.7% and GROC-defined clinical success 71.4% in both groups. Complication rates were low in both groups; however, the small number of events limits the strength of this conclusion, and larger studies are needed to evaluate potential between-group differences. Conclusions: Both techniques were associated with substantial clinically meaningful recovery at 12 months, and neither approach demonstrated a clear clinical advantage in patient-centered outcomes. The population-specific MCID thresholds derived in the present cohort may provide clinically interpretable benchmarks for future research, although external validation is required before broader application. Surgical decision-making may rely on surgeon expertise and patient factors rather than anticipated differences in patient-centered outcomes. Full article

Injuries of the gastrocnemius muscle and the common calcaneal tendon in dogs require effective stabilization of the tarsocrural joint to allow proper healing and prevent mechanical overload. This report described a novel minimally invasive technique for temporary internal tarsal stabilization using synthetic tape in two dogs. No comparison with other stabilization techniques was carried out. Both dogs presented with hindlimb lameness and partial plantigrade stance secondary to a subtotal injury of the lateral myotendinous gastrocnemius, and were treated without primary tenorrhaphy. Internal stabilization was achieved by placing polypropylene tape (Bühner’s tape) between the tibial tuberosity and the calcaneus, acting as a flexion-limiting device. A clinical, radiographic, and ultrasonographic follow-up was carried out for 5–9 months. Both dogs showed progressive clinical improvement with restoration of near-normal tarsal angles. Ultrasonography demonstrated progressive healing with fibrous tissue bridging the myotendinous junction. No major complications or radiographic signs of osteoarthrosis were observed. This technique may represent a promising option for selected cases; however, additional studies are needed to compare it with established external or rigid internal fixation methods. Full article

Tendon-driven manipulators possess obvious advantages compared to rigid-link manipulators, such as lighter weight, greater flexibility, and adaptability to confined spaces. To solve the problems of backlash and improve the accuracy of motion in specific application environments, this paper proposes a novel single-tendon-driven design for each joint of the manipulator. Kinematic modeling of the manipulator is systematically derived. Then, a decoupling algorithm is designed to mitigate motion coupling effects and enable accurate mapping between motor inputs and joint motions. Moreover, to improve the accuracy of trajectory tracking control for the tendon-driven manipulator, this paper proposes a nonsingular terminal sliding mode (NTSM) control scheme based on time-delay estimation (TDE). TDE is used to estimate unknown disturbances. An adjustable parameter was introduced based on TDE technology, which can enhance the system’s robustness against uncertainties and external disturbances. The stability of the closed-loop control system is verified through Lyapunov stability theory. Finally, decoupling experiments are conducted to validate the kinematic model and the feasibility of the proposed design. And comparative experiments are performed to prove the advantages of the proposed control scheme. Full article

Background/Objectives: This study aimed to evaluate the femoral rotation angle (FRA) before and after THA using a single approach and to identify its influencing factors through three-dimensional measurements. Methods: This retrospective study analyzed patients undergoing 108 primary unilateral THA via the anterolateral-supine approach (ALSA) from May to October 2023. Patients with hip contractures, femoral deformities, or other specific conditions were excluded for precise FRA measurements. Preoperative and postoperative CT scans were used for measurements of the FRA, anteversion, leg lengthening, and global offset. FRA was defined as the angle between the posterior condylar line and the line connecting the bilateral anterosuperior iliac spines, with external rotation as positive. Multiple linear regression, adjusted for age, sex, body mass index, and stem design, assessed the influence of anteversion change, leg lengthening, global offset change, and soft tissue release on the difference in FRA. Results: The mean FRA changed significantly from −2.8° preoperatively to −11.8° postoperatively (p < 0.001), demonstrating an average internal rotation of 9.0° after THA. Anteversion increased by a mean of 9.0° (p < 0.001), leg length increased by 9.0 mm (p < 0.001), and global offset decreased by 1.7 mm (p < 0.001). Multivariate analysis revealed that anteversion change (β = −0.41, p < 0.001) and global offset change (β = 0.40, p = 0.022) were significantly associated with FRA differences. Leg lengthening and ischiofemoral ligament or conjoint tendon resection were not significant (p = 0.089, p = 0.917, and p = 0.750, respectively). Conclusions: ALSA THA significantly rotates the femur internally, associated with an increase in anteversion and a decrease in global offset. Full article

The torsional characteristics of human tendons are recognized to have functional and clinical relevance, but are underexplored due to the limited in vivo assessment methods available to measure the dynamic torsion characteristics of a tendon during movement. This study aimed to validate the use of transverse plane ultrasound speckle tracking (ST) for measuring dynamic torsion on silicone phantoms, and to evaluate the capability and reliability of ST in measuring dynamic torsion of the human tibialis posterior tendon (TPT) in vivo. Of the ten silicone phantoms tested in the validation study, ST measurement results strongly correlated with the referencing marker tracking method (R² = 0.81–0.95) and had measurement error similar to or smaller than the hypothesized accuracy of 3° (p > 0.045). Subsequently, when ST was applied to nineteen healthy participants’ TPT in vivo, it was capable of characterizing the dynamic external torsion of the TPT during 0–20° passive foot pronation. Strong correlations were found between the ST-measured angle and the foot pronation angle (R² = 0.98–0.99), and the test–retest reliability was moderate to good (ICC = 0.73–0.87). These findings suggested that ST is a valid and reliable method for measuring dynamic tendon torsion characteristics. Full article

Prosthetic hands have seen significant improvements in recent years, enabling increasingly more natural interactions between patients with upper limb loss and their environment. Nonetheless, progress is continuously being made to enhance user acceptance, which remains a major drawback in such systems. The efficiency of the actuation mechanism is a critical parameter when designing these devices. Maximising actuation approach efficiency enables the use of smaller and lighter motors, thus decreasing the overall weight of the solution. Simultaneously, increased efficiency contributes to more precise motor control. Within this context, the present work introduces a novel actuation concept. Conventional tendon–pulley mechanisms are often susceptible to tendon slippage; therefore, a hobbed tendon–pulley approach was investigated to maintain cable tension more consistently and efficiently. This approach aims to provide smoother operation, improved reliability, and a reduced risk of mechanical failure due to tendon slippage. Simultaneously, the capability of holding and maintaining a set force is of utmost importance in these systems, and the force-feedback system is usually a major concern. The present work also focuses on comparing current and pressure-based control methodologies for the developed prosthesis. The current-based approach had the significant advantage of not requiring external sensors to be assembled on the prosthesis and not relying on the point of application of force being inside the sensor’s active area. During these tests, the prosthesis successfully grasped various objects of different sizes, shapes, stiffnesses, and weights using a current-based approach, without observable tendon slippage. Full article

The fire performance of existing reinforced concrete (RC) bridge decks strengthened by external prestressing systems is investigated, with particular attention to the vulnerability of externally applied tendons under realistic fire scenarios. Fire exposure represents a critical condition for such retrofitted structures, as the structural response is strongly influenced by load level, prestressing effectiveness, and thermal degradation of the strengthening system. A comprehensive assessment framework is proposed, combining thermal and mechanical analyses applied to representative highway overpass bridges. The thermal input adopted for the analyses is first validated through computational fluid dynamics (CFD) simulations, aimed at evaluating temperature development in typical RC beam–girder grillage decks subjected to fire from below. The CFD study considers variations in clearance height and span length and confirms that, in the case of hydrocarbon tanker accidents with fuel spilled on the roadway, conventional fire curves commonly adopted in the literature provide a reliable and conservative representation of both the temperature levels reached and their rate of increase within structural elements, thus supporting their use for rapid and simplified assessments. The validated thermal input is then employed in an analytical fire safety procedure applied to several realistic bridge case-studies. A parametric investigation is carried out by varying deck geometry, span length, reinforcement layout, and the presence of external prestressing retrofit, allowing the evaluation of the reduction in bending capacity and the time-dependent degradation of mechanical properties under fire exposure. The results highlight the critical role of external prestressing in fire scenarios, showing that significant loss of prestressing effectiveness may occur within the first minutes of fire, potentially leading to critical conditions even at service load levels. Finally, a multi-hazard assessment is performed by combining fire effects with pre-existing aging-related deterioration, such as reinforcement corrosion and long-term prestressing losses, demonstrating a marked increase in failure risk and, in the most severe cases, the possibility of premature collapse under dead loads. Full article

Background/Objectives: Non-traumatic (degenerative) rotator cuff tendinopathy with partial supraspinatus tear (NT-RCTT) is a common source of shoulder pain and disability. Comparative evidence between radial extracorporeal shock wave therapy (rESWT) and multimodal physical therapy modalities (PTMs) remains scarce. Methods: In this single-center randomized controlled trial, 60 adults with MRI-confirmed NT-RCTT were assigned (1:1) to rESWT (one session weekly for six weeks; 2000 impulses per session, 2 bar air pressure, positive energy flux density 0.08 mJ/mm²; 8 impulses per second) or a multimodal PTM program (interferential current, shortwave diathermy and magnetothermal therapy; five sessions weekly for six weeks). All participants performed standardized home exercises. The primary outcome was the American Shoulder and Elbow Surgeons (ASES) total score; secondary outcomes included pain (visual analog scale, VAS), satisfaction, range of motion (ROM), supraspinatus tendon (ST) thickness and acromiohumeral distance (AHD). Assessments were conducted at baseline, and at week 6 (W6) and week 12 (W12) post-baseline. Results: Both interventions significantly improved all outcomes, but rESWT produced greater and faster effects. Mean ASES total scores increased by 31 ± 5 points with rESWT versus 26 ± 6 with PTMs (p < 0.05). VAS pain decreased from 5.2 ± 0.7 to 1.0 ± 0.7 with rESWT and from 5.2 ± 0.8 to 1.7 ± 0.8 with PTMs (p < 0.01). rESWT achieved higher satisfaction and larger gains in abduction, flexion and external rotation. Ultrasound showed reduced ST thickness and increased AHD after rESWT but not after PTMs. No serious adverse events occurred. Conclusions: rESWT yielded superior pain relief, functional recovery and tendon remodeling compared with a multimodal PTM program, with markedly lower treatment time and excellent tolerability. Full article

Physical activity is widely recognized for its health benefits; however, it also increases the risk of musculoskeletal soft tissue injuries, with muscle-related cases constituting a considerable proportion. These injuries impair well-being, athletic performance, and career longevity while creating substantial social and economic burdens. Their multifactorial etiology involves internal and external risk factors, and evidence suggests a heritable component influencing tissue integrity, recovery, and overall susceptibility. While genetic contributions to ligament and tendon damage are relatively established, knowledge regarding muscle injuries remains limited. This review critically summarizes current evidence on polymorphisms associated with sport-related muscle injury susceptibility. A systematic search of PubMed, Scopus, and Web of Science identified studies examining genetic markers in physically active individuals with documented muscle injuries. To date, 37 single nucleotide polymorphisms in 32 genes have been significantly linked to injury risk, recurrence, severity, and recovery. These genes cluster into categories involving muscle structure, growth and regeneration, metabolism, inflammatory and stress responses, membrane stability, signaling, and vascular regulation. By integrating available findings and outlining knowledge gaps, this review highlights promising directions for advancing personalized prevention and rehabilitation strategies in sports medicine. Full article

The control of tendon-driven robotic fingers presents significant challenges due to their inherent underactuation, coupled with complex non-linear dynamics arising from tendon elasticity, friction, and external disturbances. Therefore, achieving precise control of finger motion and contact interactions necessitates advanced modeling, estimation, and control strategies capable of addressing uncertainties in tendon tension, routing, and elasticity. This paper presents a comprehensive comparative study of three distinct control paradigms: feedback linearization with Proportional-Derivative (FBL-PD) control, feedback linearization with super-twisting sliding-mode algorithm (FBL-STA), and deep-deterministic reinforcement learning (DDPG-RL), for the precise trajectory tracking of a three-link tendon-driven robotic finger. Through extensive simulations, the performance of each controller is rigorously evaluated based on trajectory-tracking accuracy and robustness to varying disturbances. The results indicate that under disturbance-free conditions, the FBL-PD and FBL-STA controllers, when properly tuned, achieve precise tracking of the reference trajectory; however, they produce noticeably noisy control signals. When subjected to external disturbances, these controllers exhibit increased sensitivity, producing even noisier responses. In contrast, the DDPG-RL maintains smooth control dynamics and achieves sufficiently accurate tracking in both scenarios. This comparative analysis elucidates the strengths and weaknesses of each control strategy, offering critical insights and practical guidelines for the design and implementation of advanced control systems for dexterous tendon-driven robotic fingers. Full article

Composite steel–concrete beams have gained significant attention in modern construction due to their superior structural efficiency, economic viability, and adaptability to diverse applications. This paper presents a comprehensive review of research developments related to both conventional and post-tensioned composite beam systems. Emphasis is placed on the structural behavior, design considerations, and performance improvements achieved through external post-tensioning using high-strength tendons. Such systems enhance ultimate load capacity, extend the elastic range before yielding, and reduce the required amount of structural steel, thereby improving material efficiency and reducing construction costs. The review also examines the influence of tendon application timing, connection type, and load conditions in both positive and negative bending regions. By synthesizing experimental and analytical findings, this study identifies key advantages, limitations, and research needs in optimizing the design and performance of steel–concrete composite beams. The insights presented herein aim to guide engineers, researchers, and practitioners in advancing the application of composite beam strengthening techniques in modern infrastructure. Full article

Concrete slabs in composite bridges are inevitably subjected to heavy vehicular loads during their service life. To evaluate the fatigue performance of the prestressed concrete slabs in composite bridges, two full-scaled models of prestressed concrete slabs were first designed and tested, with the load amplitude was selected as the variable. To simulate the damage caused by the initial passage of heavy vehicles, this was simplified into the form of a static cyclic load. The mechanical deformation state and crack distribution of the slab were analyzed. Further, a finite-element model was established, and a parametric analysis based on the variation in loading form, such as monotonic displacement loading, static cyclic loading followed by monotonic displacement loading, and cyclic displacement loading, was conducted to discuss the performance-enhancement mechanism of prestressed concrete slabs. Finally, in consideration of the influence of static cyclic damage on the fatigue performance of prestressed concrete slabs, evaluation parameters were proposed to account for static cyclic damage by considering the effects of stresses in concrete, tensile rebar, prestressed tendons, and external loading. A comprehensive fatigue performance evaluation method for prestressed concrete slabs, which neglects the tensile hardening behavior of cracked concrete in the tension zone, was established and verified by test results. The results indicate that the damage caused by static cyclic loading has a significant influence on the fatigue performance of the slab. Applying prestress can significantly mitigate the influence of initial damage on the mechanical and deformation behavior of the slab, which benefits from the prestress compensating for the cracking stress at the bottom of the slab. The proposed fatigue performance-evaluation method for prestressed concrete slabs, which considers static cyclic damage, can predict fatigue deformation behavior with an error of less than 10%, while reasonably determining the fatigue life and failure modes of prestressed concrete slabs. The parametric analysis reveals that when the prestress value exceeds 9 MPa, the failure mode of the prestressed concrete slab transfers from rebar fracture to concrete failure. Full article

Grout voids in external tendons of post-tensioned bridges are a critical issue, as they may result in the corrosion of the steel strands and significantly reduce tendon strength. Therefore, preventing tendon failure necessitates thorough inspection for these voids during both construction and operation. Terahertz electromagnetic wave testing is an effective method for detecting voids between the protective duct and the grout in external tendons, as terahertz waves can penetrate through the protective duct. This study introduces a D-band electronic frequency-modulated continuous-wave terahertz A-scanner for enhanced real-time inspection. The proposed method offers key advantages such as miniaturization, cost-effectiveness, and robustness, while providing effective detection of voids beneath the duct in external tendons. It is indicated that voids with a thickness of approximately 2.5 mm or greater can be detected using the D-band THz A-scanner. Full article

Deep Gluteal Syndrome (DGS) has traditionally been defined as a clinical entity caused by sciatic nerve (SN) entrapment. However, recent anatomical and imaging studies suggest that muscle- and tendon-origin pathologies—including enthesopathy—may also serve as primary pain generators. This narrative review aims to broaden the current understanding of DGS by integrating muscle and tendon pathologies into its diagnostic and therapeutic framework. The literature was selectively reviewed from PubMed, Cochrane Library, Google Scholar, PEDro, and Web of Science to identify clinically relevant studies illustrating evolving concepts in DGS pathophysiology, diagnosis, and management. We review clinical features and diagnostic tools including physical examination, MRI, and dynamic ultrasonography, with special attention to deep external rotator enthesopathy. Treatment strategies are summarized, including conservative therapy, ultrasound-guided injections, hydrodissection, and prolotherapy. This narrative synthesis underscores the importance of recognizing muscle-origin enthesopathy and soft-tissue pathologies as significant contributors to DGS. A pathophysiology-based, multimodal approach is essential for accurate diagnosis and effective treatment. Full article