Search Results (747)

Hip joint position sense (JPS), a key component of neuromuscular function arising from muscle spindle and periarticular mechanoreceptor input, remains underexplored, with no standardized and reliable clinical protocol available to assess hip proprioception. This study evaluated the intra- and inter-rater reliability of a laser- and inclinometer-based active hip JPS protocol and established preliminary references in healthy adults. A two-phase reliability study was conducted in accordance with GRRAS and COSMIN guidelines: 17 participants for reliability analyses and 57 for preliminary references. Six movement directions were assessed (flexion, extension, abduction, adduction, medial and lateral rotations). Reliability was quantified using intraclass correlation coefficients with their 95% confidence intervals, using two-way random-effects models with absolute agreement (ICC(3,1) for intra-rater and ICC(2,1) for inter-rater analyses), interpreted as poor (<0.50), moderate (0.50–0.70), or good (≥0.70). Absolute measurement error was reported as standard error of measurement (SEM%) and 95% minimal detectable change (MDC95%), normalized to target amplitudes to allow direct cross-direction comparison. Intra-rater reliability ranged from poor to moderate, with experienced raters reaching ICC = 0.64 (95% CI [0.39; 0.80]) for medial rotation. Inter-rater reliability improved across sessions, peaking for medial rotation (ICC = 0.78; 95% CI [0.50; 0.91]). Rotational movements yielded the lowest SEM% (3–6%), indicating high measurement precision despite trial-to-trial variability (MDC% 9–31%). Normative errors were largest in flexion (21.4 cm) and smallest in rotations (≈2.2–2.3°). Despite overall low-to-moderate reliability, the protocol achieved clinically acceptable measurement precision (SEM% < 10%) for rotational tasks, whereas the laser-based sagittal and frontal-plane components remained exploratory. The protocol provides preliminary reference values for hip JPS in healthy adults and requires further validation before clinical use. Full article

Background: Three-level anterior cervical discectomy and fusion (ACDF) is widely used for multilevel cervical degenerative disc disease; however, the relationship between postoperative alignment trajectories, adjacent segment degeneration (ASD), and late patient-reported outcomes remains incompletely defined. This study evaluated plane-specific radiological alignment changes, MRI-based ASD, and late functional outcomes in a homogeneous three-level ACDF cohort. Methods: This single-center observational cohort included 29 patients who underwent three-level ACDF between January 2018 and December 2023 and had complete radiographic follow-up. Radiological data were collected retrospectively from institutional records and imaging archives. Cervical sagittal and coronal alignment were assessed using Cobb angles on radiographs obtained preoperatively and at 6 months, 1 year, and 2 years postoperatively. ASD was evaluated at the superior adjacent segment on 2-year MRI. Late patient-reported clinical outcomes were assessed at a mean follow-up of 42.6 ± 6.8 months using the Visual Analog Scale (VAS), Neck Disability Index (NDI), and Nottingham Health Profile (NHP). Results: Sagittal Cobb angle changed significantly over time (χ²(3) = 12.60, p = 0.006; Kendall’s W = 0.145), whereas coronal Cobb angle showed a statistically significant reduction over time, although the absolute magnitude of change was small (χ²(3) = 28.74, p < 0.001; Kendall’s W = 0.330). Lower sagittal Cobb angle correlated with worse NDI (r = −0.46, p = 0.004), and greater coronal Cobb angle correlated with worse physical activity scores (r = 0.52, p = 0.006). Higher Pfirrmann grade correlated with worse NDI (r = 0.49, p = 0.004) and pain scores (r = 0.44, p = 0.021). In exploratory regression analysis, sagittal Cobb angle and Pfirrmann grade were retained in the model for NDI, but these findings should be interpreted as hypothesis-generating. Conclusions: After three-level ACDF, sagittal and coronal alignment followed different postoperative trajectories. Lower sagittal alignment and greater adjacent disc degeneration were associated with worse late neck-related disability. However, given the modest sample size and exploratory nature of the regression analysis, these findings should be interpreted as hypothesis-generating. Larger prospective studies are needed to confirm whether sagittal alignment and MRI-based adjacent segment degeneration independently contribute to late functional outcomes. Full article

The squat is a critical component of numerous rehabilitation and functional assessment protocols, playing a significant role in enhancing athletic performance and activities of daily living. Although some of the characteristics gathered during the squat need additional confirmation, Kinovea provides a free two-dimensional squat motion analysis tool that is simple to use in clinical practice. This analytical, cross-sectional reliability study aimed to evaluate the intra-rater and test–retest reliability (with a 20 min interval between performances) of loaded squat kinematics in a sample of women using Kinovea. Twenty women performed a loaded back squat; intra-rater reliability was assessed by re-analyzing the same video one week apart, and test–retest reliability was assessed across two performances separated by 20 min. The results showed good to excellent intra-rater reliability (ICC: 0.75–0.99; SEM: 0.16 cm to 5.14°; MDC: 0.44 cm to 14.24°), and moderate to excellent test–retest reliability (ICC: 0.64–0.98; SEM: 0.36 cm to 14.29°; MDC: 0.99 cm to 39.61°). Variables tracked in the sagittal plane showed high precision. Conversely, the head angle and knee angle in the frontal plane exhibited greater variability, reflected by higher SEM and MDC values. In conclusion, Kinovea is a reliable and accessible tool for clinical kinematic assessment of the squat, particularly in the sagittal plane parameters. However, due to the elevated measurement error observed in head angles and frontal-plane knee dynamics, the integration of 3D motion capture is recommended over 2D digital protocols for these variables. Full article

Background/Objectives: Optimal trajectories for S2-alar-iliac (S2AI) screw placement have been widely studied; however, in fluoroscopy-assisted free-hand techniques, exact reproduction is rarely achievable. This study aimed to quantify direction-specific safety margins around patient-specific optimal trajectories and to determine their relationship with pelvic parameters. Methods: We retrospectively analyzed patients who underwent S2AI screw fixation with available preoperative and postoperative CT imaging. Pelvic parameters, including pelvic tilt (PT), sacral slope (SS), and pelvic incidence (PI), were measured. Optimal transverse and sagittal screw angles were determined using CT-based planning. Postoperative CT was used to assess actual screw trajectories and cortical violations. Direction-specific generalized estimating equation models were used to evaluate associations between trajectory deviation and screw malposition. Receiver operating characteristic (ROC) analysis was performed to determine cutoff values for safe deviation. Results: A total of 62 patients (105 screws) were included in axial analysis and 41 patients (76 screws) in sagittal analysis. PT and PI showed significant inverse correlations with both optimal transverse and sagittal angles (all p < 0.001). Greater lateral and medial deviations were significantly associated with corresponding cortical violations (OR 2.33, 95% CI 1.51–3.59; and OR 2.10, 95% CI 1.40–3.15 per degree, respectively; both p < 0.001). Inferior deviation was significantly associated with violation in the sagittal plane (OR 1.39, 95% CI 1.18–1.65 per degree; p < 0.001), whereas superior deviation was not significant. ROC analysis demonstrated asymmetric safety margins: 1.5° lateral (AUC = 0.972), 8.1° medial (AUC = 0.965), and 18.5° inferior (AUC = 0.897). Conclusions: S2AI screw placement may be conceptualized as a tolerance-based process centered on a patient-specific optimal trajectory. Safety margins are direction-dependent and asymmetric, with a narrow tolerance for lateral deviation. These findings provide practical guidance for intraoperative trajectory adjustment in free-hand techniques. Full article

Flexible strain sensors have attracted considerable attention in gait recognition owing to their ability to adhere directly to the skin near joints and transduce local deformation. In existing work, however, sensor placement and orientation are largely determined by anatomical experience, while multi-channel classification still relies on back-end digital processors, whose power consumption and latency constrain system practicality in wearable scenarios. This paper presents an integrated design path that proceeds from skin-mechanics theory through sensor-layout optimization to analog-domain front-end inference. On the layout side, the lines-of-non-extension (LoNE) theory is employed to convert the selection of sensor attachment angles from empirical judgment into a calculable mechanics problem; guided by the spatial course of LoNE in the ankle and knee regions, the positions and angles of the nine sensors are determined individually—channels perpendicular to the LoNE capture maximum strain, channels offset by 45 degrees supplement non-sagittal-plane information, and a channel aligned along the LoNE provides a near-zero-strain reference. On the circuit side, the mathematical equivalence between the weighted summation of a linear classifier and Kirchhoff’s current law (KCL) nodal current superposition is exploited to map the classification operation onto current aggregation in an analog circuit, yielding an in-sensor computing (ISC) front end in which the nine-channel weighted summation is completed in a single analog step. The sensors are fabricated by screen-printing a liquid-metal–polymer composite conductive ink onto a TPU film substrate, with a gauge factor RSD of $6.8\%$ and a tensile linearity $R^2>0.99$. Using walking, running, and stair descent as verification targets, the analog classifier reaches 99% accuracy at the circuit-level functional-verification stage. On real multi-subject data, it achieves $87.0\%\pm 8.4\%$ accuracy under intra-subject cross-session validation, with an analog-domain inference response faster than $100\mathsf{\mu }\mathrm{s}$. This design path is not bound to a specific joint or sensor material; when the layout methodology is extended to additional joint regions and the circuit architecture incorporates multiple outputs to cover more classification categories, the same workflow remains applicable, offering a promising low-power, lightweight technical solution for wearable motion monitoring. Full article

Background: Traditional gait assessments in adult degenerative scoliosis (ADS) often rely on prohibitively expensive, laboratory-bound optoelectronic systems that lack clinical accessibility. This research aims to independently evaluate both lower limbs using a wearable Inertial Measurement Unit (IMU) system, in contrast to studies that employ a unilateral reference, thereby elucidating the unique bilateral asymmetries and dynamic stability patterns exhibited in ADS. Methods: Gait patterns of 20 ADS patients and 15 healthy controls were analyzed using the Rokoko Smartsuit Pro. Segmental kinematic data were integrated with anthropometric mass distribution models to calculate the total body center of mass (CoM). Spatiotemporal parameters, joint range of motion (RoM), and CoM excursions in three planes were statistically compared between the groups. Results: ADS patients exhibited a cautious gait strategy characterized by significantly reduced step speed, shortened step lengths, and increased step width ($p<0.05$). Temporal analysis showed prolonged stride, stance, and double support time ($p<0.001$), while cadence remained comparable to healthy controls. A triple-joint deficit, including hip, knee, and ankle, was identified in the sagittal plane, especially with peak flexion reductions reaching up to 55% in the left knee and 38% in the right knee, highlighting profound functional asymmetry ($p<0.001$). Additionally, the CoM analysis reflected these stability restrictions, showing increased horizontal excursion and reduced vertical oscillation. Conclusions: Our findings suggest that ADS is associated with distinct, bilateral alterations in the lower limb kinematic chain and notable adaptations in dynamic balance parameters, characterized by a cautious gait strategy and profound sagittal triple-joint asymmetries. These findings highlight the feasibility of full-body wearable IMU technology in capturing objective, bilateral gait alterations, providing a foundational baseline that could complement standard static radiography in future clinical evaluations. Full article

Background/Objectives: Brain tumor analysis using magnetic resonance imaging (MRI) remains a challenging task due to tumor heterogeneity, complex anatomical structures, and reliance on expert interpretation. Although deep learning approaches have shown promising results in medical image analysis, many existing studies focus on either tumor classification or segmentation independently, limiting their applicability in comprehensive automated brain tumor analysis workflows. This study proposes an integrated dual-task deep learning framework for automated brain tumor classification and segmentation using MRI scans. The framework aims to provide complementary diagnostic support by combining tumor-type prediction and tumor boundary delineation within an integrated workflow. Methods: The proposed framework utilizes EfficientNet-based convolutional neural networks for multi-class brain tumor classification and U-Net++ architectures with EfficientNet encoders for tumor segmentation. Experiments were conducted using the BRISC2025 dataset, consisting primarily of 6000 T1-weighted 2D MRI slices collected from axial, coronal, and sagittal planes. Standard preprocessing, augmentation, transfer learning, and selective fine-tuning strategies were applied. Multiple architectures were systematically evaluated using evaluation metrics. Results: EfficientNet-B1 achieved a classification accuracy of 99.70% with near-perfect precision, recall, and F1-scores across glioma, meningioma, pituitary tumor, and no-tumor classes. For segmentation, U-Net++ with an EfficientNet-B1 encoder achieved a Dice score of 0.9055, an IoU score of 0.8442, and an HD95 value of 12.21 pixels on the held-out test set. The proposed framework demonstrated robust performance in detecting small and low-contrast tumor regions while maintaining strong generalization performance across diverse MRI samples. Conclusions: The proposed integrated framework demonstrated strong performance in both brain tumor classification and segmentation tasks, effectively detecting small and low-contrast tumor regions while maintaining good generalization across diverse MRI samples. These findings suggest that the framework may serve as a reliable decision-support tool for automated brain tumor analysis in clinical practice. Full article

Background: Changes in the rearfoot calcaneal position affect the foot “arch structure” during the stance phase of gait and hence influence reactions in the plantar fascia thickness and stiffness during weight bearing. However, previous research has focused on the non-weight-bearing assessment of plantar fascia thickness (PFT) and stiffness (PFS) and has not linked these measurements to rearfoot position. Methods: This study aims to investigate if a change in the weight-bearing rearfoot position influences the PFT and PFS. A linear actuator-driven 3D-printed platform was utilised to reliably move the rearfoot through a range of frontal (F (4,12) = 19,585.8, p = 0.00) and sagittal plane angles (F (2,6) = 11,751.32, p = 0.00) whilst weight bearing. An ultrasound probe capable of shear wave elastography was incorporated into the platform for the closed-chain weight-bearing assessment of the PF. The PFT and PFS were collected for 13 (26 feet) participants (11 male, two female; age 35.62 ± 15.04; BMI: 30.31± 6.22 Kg/m²) from a convenience sample who met the inclusion criteria. Results: The data were subject to appropriate statistical, collective and cluster analysis. Individual participant data analysis showed a strong nonlinear correlation between PFT and PFS in the relaxed calcaneal position. The rearfoot sagittal plane cluster demonstrated an auxetic property in 54.3% of the group, where both the PFT and PFS increased. The frontal plane cluster demonstrated an auxetic property in 76% of the group, where the PFT increased as the PFS increased. Conclusions: The results suggest that the PF does have a specific response to changes in the rearfoot position for individuals, which, in some, can show an auxetic property. Full article

Many older residential toilet designs may pose substantial biomechanical demands for older adults with reduced lower-extremity strength, as standard seat heights often require increased joint range of motion (ROM) and compensatory upper-limb support during sit-to-stand (STS) transfer. This exploratory, repeated-measures biomechanical study evaluated the effects of a biomimetic Stand-assist Toilet Seat (BSTS) designed to facilitate STS movement through a forward-and-upward curvilinear lifting trajectory. Thirty community-dwelling older adults were stratified into high-, moderate-, and low-functioning groups according to normative 30 s Chair Stand Test performance. Participants completed repeated STS trials under conventional and BSTS-assisted seating conditions in randomized order. A synchronized multimodal assessment integrating MediaPipe Pose-based motion tracking for sagittal-plane kinematic analysis was used to quantify lower-limb kinematics and upper-limb kinetics. Mixed-design ANOVA revealed significant main effects of seating condition on hip and knee ROM (all p < 0.001, η²p > 0.70), indicating reduced lower-limb joint motion requirements under the BSTS condition. Significant reductions were also observed in peak arm-support force (F (1,27) = 14.57, p = 0.001, η²p = 0.35) and arm-support impulse (F (1,27) = 20.21, p < 0.001, η²p = 0.42), demonstrating decreased upper-limb loading during STS transfer. No significant interaction effects between seating condition and functional group were identified. These findings suggest that the BSTS modified STS movement patterns and reduced upper-limb loading demands in community-dwelling older adults. The combined kinematic and kinetic assessment approach may provide a practical method for biomechanical evaluation of assistive seating technologies in rehabilitation and aging-related applications. Full article

Background and Objectives: Although the anterior mandible is generally considered a safe region for implant placement, injury to the medial lingual foramen (MLF) may result in significant vascular complications. Accurate identification of this structure is challenging due to its small size, low volumetric representation, and anatomical variability. This study aimed to evaluate the anatomical characteristics of the MLF using cone-beam computed tomography (CBCT) and to develop and validate a deep learning-based approach for its automated detection and segmentation. Materials and Methods: A total of 106 CBCT scans were retrospectively analyzed to assess the morphology and position of the MLF. Manual pixel-wise annotations of the complete canal trajectory were performed on sagittal slices and used to train convolutional neural network models based on a U-Net-derived framework. Multiple configurations, including multi-class, binary, two-dimensional, and three-dimensional approaches, were evaluated. Given the extremely limited volumetric representation of the MLF, severe class imbalance represented a major challenge during model training and evaluation. Model performance was assessed using the Dice similarity coefficient, precision, recall, and Hausdorff distance. External validation was performed on an independent dataset of 10 CBCT scans. Results: The MLF was identified in all patients, with a single canal observed in 63% of cases. The sagittal-plane binary segmentation model achieved the best performance, with a test Dice score of 0.79, precision of 0.88, and recall of 0.73. External validation demonstrated a Dice score of 0.81, precision of 0.89, and recall of 0.71. The 95th percentile Hausdorff distance was 2.6 mm, and the mean center-point localization error was 1.2 mm. The model correctly detected the MLF in 90% of external cases. Conclusions: Deep learning-based segmentation of the MLF is feasible and may support automated localization assistance during preoperative CBCT assessment. Performance was influenced by the alignment between the annotation strategy and model input, highlighting an important consideration for small-structure segmentation. Further validation on larger multicenter datasets is required before clinical implementation can be considered. Full article

Resisted sprint training (RST) is widely used to enhance acceleration capacity; however, evidence concerning on long-term effects to RST in professional women’s remains limited. Methods: This study examined the chronic effects of a six-week resisted sled sprint training intervention using a single-group longitudinal pilot design in professional female soccer players. Twenty-two players were assessed at baseline (T1), with fourteen completing the post-intervention assessment (T2) and seven available at the two-month follow-up (T3). Athletes completed one weekly RST session with loading progressively increasing from 20% to 80% of body mass and total sprint volume ranging from 100 to 200 m per session. Sprint performance and kinematic variables of the first three acceleration steps for both limbs were assessed before the intervention, immediately after and at a two-month follow-up. Within-group changes across time were analyzed using a one-way ANOVA with Bonferroni post hoc comparisons, with the level of significance set at p ≤ 0.05. Results: Sprint times significantly improved following the intervention (T1-T2), with a 2.61% improvement in acceleration performance over the 0-20 m phase. This improvement was accompanied by increases in center of mass projection angle and toe-off distance, resulting in a more forward-oriented sprint posture. At follow-up, sprint performance showed partial retention of these changes. These adaptations were accompanied by greater hip and knee extension of the ipsilateral limb at toe-off, without evidence of adverse sagittal-plane kinematic alterations during the early acceleration phase. Conclusions: The results indicate that once-weekly RST was associated with preliminary improvements in acceleration performance in professional female soccer players and induces technical adaptations that did not appear to negatively affect sprint mechanics during the initial acceleration phase. Given the absence of a control group and the substantial attrition at follow-up, these findings should be interpreted as exploratory. Full article

Lower-limb amputation remains a significant clinical and socio-economic challenge, while the high cost of microprocessor-controlled prostheses (MPKs) limits their widespread accessibility. This paper presents the design and preliminary laboratory-scale evaluation of a low-cost microprocessor-controlled ankle prosthesis intended as a feasibility-oriented alternative platform for future active prosthetic system development. Building upon the previously developed V1 mechanical architecture, an updated CAD model was created in the SolidWorks 2024 environment, and the kinematic configuration was refined using a ball-screw transmission (SFU1204-300) driven by a NEMA 17 stepper motor. The electronic control system integrates an ESP32 microcontroller, an MPU9250 inertial measurement unit (IMU), a limit switch for initial-position detection, and a WiFi-based REST API interface for communication and control. Laboratory no-load experiments demonstrated controlled positional behavior, repeatable angular response, and successful operation of the homing procedure within a motion range of 0–4200 motor steps. The prototype actively generated dorsiflexion–plantar flexion motion in the sagittal plane, while a passive inversion–eversion mechanism was incorporated and intended to improve structural adaptability. IMU-based measurements enabled preliminary monitoring of angular displacement and positional behavior during the experiments. The presented prototype represents an initial engineering feasibility study of a low-cost active ankle actuation architecture and provides a foundation for future investigations involving load-bearing experiments, biomechanical gait analysis, and closed-loop control implementation. Full article

Background: Human locomotion requires coordinated torque production across multiple joints, yet conventional gait analysis typically evaluates joint behavior independently, limiting insight into inter-joint coordination. This study aimed to quantify task-dependent reorganization of ankle–knee mechanical coordination using a moment–moment phase space framework. Methods: A normative dataset of healthy adults (N = 50) performing natural-speed walking, toe walking, heel walking, stair ascent, and stair descent was analyzed. Sagittal-plane external ankle and knee moments were extracted from time-normalized stride cycles and z-score normalized within each stride to emphasize coordination topology. Ankle–knee trajectories were represented in moment–moment space and characterized using three geometric metrics: loop magnitude (|Area|), principal axis orientation, and anisotropy. Metrics were aggregated within subject and analyzed using linear mixed-effects models with planned contrasts against walking. Results: Loop magnitude differed significantly across tasks (p < 0.001), with the largest increases observed during toe walking (+3.45 relative to walking) and stair descent (+2.41). Principal axis orientation also showed a significant task effect (p = 0.026), with stair descent producing the largest rotation of the coordination axis (−29.8°). Anisotropy varied significantly across tasks (p < 0.001), indicating systematic changes in the dimensionality and strength of inter-joint torque coupling. Conclusions: Locomotor tasks induce structured, task-dependent reorganization of ankle–knee coordination topology. Moment–moment phase space analysis provides a compact and interpretable framework for quantifying inter-joint torque coupling, with potential applications in biomechanics research and the development of activity-aware assistive technologies. Full article

Unicompartmental knee arthroplasty (UKA) is an effective treatment for anteromedial osteoarthritis in carefully selected patients. Increasing attention has recently been directed toward restoration of pre-arthritic coronal alignment, supported by the use of the arithmetic hip–knee–ankle angle (aHKA) to estimate constitutional lower limb alignment. In medial UKA, kinematic alignment principles derived from the original technique described by Cartier et al. may help to reproduce native joint-line orientation while preserving physiological soft-tissue balance. This technical note details the indications, preoperative assessment, planning strategy, and operative steps of the procedure. Preoperative long-leg weight-bearing radiographs are used to estimate constitutional alignment through the aHKA and to plan the coronal inclination of the tibial cut. Intraoperatively, the distal position of the extramedullary guide is reproduced according to the preoperative planning in order to restore the native inclination of the medial tibial plateau. The sagittal tibial cut, posterior tibial slope, distal femoral cut, component sizing, gap assessment, and cementation technique are described, with emphasis on anatomical landmarks and technical pearls to improve reproducibility. The described technique provides a practical method for approximating constitutional coronal alignment in medial UKA without the use of robotic or navigated systems. The key feature of the procedure is accurate planning and execution of the tibial cut in both the coronal and sagittal planes in order to reproduce native joint-line orientation and preserve appropriate ligament balance. Full article

It is commonly noted in the literature that reducing mass and moment of inertia lowers the requirements for powerful electromechanical hardware and improves the overall energy efficiency of legged robots. For this reason, the humanoid robot RB2, the second of its kind at Balikesir University, has been developed iteratively. The motivation for this research is to design a lightweight, low-power humanoid robot to gain physical insight into the viability of using Delrin and 3D-printed ABS parts in its support structure and to enhance the robot’s efficiency in terms of weight and, as a result, power requirements. The number of degrees of freedom and the order of the joint motions of the planes are optimised to reduce moments of inertia and increase the range of motion of the robot’s legs. Additionally, the mechanical structure incorporates design features to facilitate assembly and maintenance. The newer robot’s weight is reduced to 25% of our first humanoid robot’s, while maintaining the same joint range of motion. Full article