Search Results (500)

Background: Clubfoot represents a prevalent congenital deformity of the foot and ankle complex that may significantly compromise a child's walking ability. Contemporary treatment protocols encompass serial manipulations and casting procedures designed to achieve gradual correction of the deformity. Various casting materials have been employed in this therapeutic approach, with plaster of Paris and fiberglass constituting the two predominant options. This study aimed to evaluate the comparative effectiveness of these casting materials and determine whether material selection influences the rate of correction and the clinical indications, specifically regarding the number of casts required before percutaneous Achilles tenotomy. Methods: We conducted a retrospective analysis of prospectively collected data on paediatric patients treated at our tertiary-level institution with both plaster of Paris (POP) and semirigid fiberglass (SRF) by a single orthopaedic surgeon between 2010 and 2020. Treatment was initiated within the first 30 days of life (median age 12 days, range 0–28 days). To reduce confounding bias related to baseline aetiology (e.g., rigid syndromic feet), the primary comparative analysis was restricted to the idiopathic clubfoot subgroup. The Pirani score was used to assess deformity severity at each clinical visit. Results: A cohort of 84 patients (137 feet) was enrolled and treated, comprising patients with a Pirani score ≥ 4.5, excluding non-idiopathic cases. The mean number of casts required was 5.8 ± 1.0 for POP and 5.7 ± 1.2 for SRF, with no statistically significant difference (p = 0.91). Conclusions: Both plaster of Paris and semirigid fiberglass are highly effective casting materials for the initial phase of Ponseti treatment. Both achieve comparable correction sufficient to proceed with Achilles tenotomy. Accordingly, material selection should be guided by clinician proficiency, institutional cost-effectiveness, and patient comfort. Further investigation is needed to evaluate long-term outcomes and the relative benefits of each material in clubfoot management. Full article

Background/Objectives: Neurological impairments in children with Cerebral Palsy (CP) often lead to altered muscle architecture and function, resulting in calf muscle contractures. Orthotic immobilization aims to promote muscle–tendon unit lengthening through sustained stretch but may also induce disuse atrophy. This study investigated whether combining immobilization with daily activity yields different effects on muscle strength and gait function compared with immobilization alone. Methods: Fourteen ambulant children with spastic CP and equinus deformity (8 unilateral, 6 bilateral; mean age 9.93 ± 3.0 years; GMFCS I: 10, GMFCS II: 4) participated in a 12-week randomized controlled trial. Participants were assigned to either continuous immobilization (23 h/day) using a dynamic ankle–foot orthosis or a combined protocol consisting of 14 h/day immobilization and 10 h/day of activity involving ankle mobility and calf muscle activation. Outcomes included isometric muscle strength, joint range of motion, gait parameters, and functional measures (Gait Outcomes Assessment List (GOAL) and the Paediatric Outcome Data Collection Instrument (PODCI)). Data were analyzed using linear mixed models with Bonferroni correction. Results: Significant time effects were observed for the knee angle at initial contact (IC), the ankle angle at IC, maximum dorsiflexion, and maximum dorsiflexion during swing. A significant group × time interaction was found only for hindfoot-tibia angle at IC. Within-group improvements were noted in activities of daily living, body image and self-esteem, and basic mobility. No significant changes were found for muscle strength or for most questionnaire subscales. Conclusions: The findings indicate time-related improvements in gait, with no consistent advantage of the combined intervention. Further studies with larger samples are needed to evaluate potential long-term effects. Full article

Aims: The purpose of this study was to clarify the prevalence of diabetic foot lesions and their association with lower-limb amputations and/or foot ulcers. Materials and Methods: In this cross-sectional study, 968 patients with diabetes were surveyed. Diabetic foot lesions were defined according to the broad national criteria, which encompass both mild abnormalities and more advanced conditions. Based on this definition, foot lesions were assessed using a questionnaire comprising the following 10 items: a history of lower-limb amputations, a history of treatment of foot lesions, numbness/loss of sensation/pain, skin discolorations, skin symptoms, nail abnormalities, foot ulcers/gangrene, foot deformities, foot infection, and intermittent claudication. Logistic regression analysis was used to examine risk factors for foot lesions. Area under the curve (AUC) of the number of foot lesions for lower-limb amputations or foot ulcers/gangrene was calculated using the receiver operating characteristic curve (ROC) analysis. Results: Approximately two-thirds of the patients had at least one type of diabetic foot lesion. Logistic regression analysis revealed that women, past or current smoking, a history of cardiovascular disease, and nephropathy were associated with the risk of diabetic foot lesions. According to the ROC analysis, the optimal cut-off point of number of diabetic foot lesions was three for identifying patients with a history of lower-limb amputation and/or the presence of foot ulcers or gangrene (AUC 0.80 (95% CI, 0.70–0.91), p < 0.01). Conclusions: Diabetic foot lesions are common in patients with diabetes and the prevalence of diabetic foot lesions was higher in patients with a history of lower-limb amputations and/or the presence of foot ulcers or gangrene. Early detection and care of diabetic foot lesions are necessary to prevent lower-limb amputations and foot ulcers. Full article

The foot arch functions as a dynamic biomechanical system, maintained by the integrated actions of bones, ligaments, and muscles. A large body of clinical evidence indicates that, in addition to congenital foot deformities, acquired variations in the foot arch caused by factors such as poor gait, aging, weight, or injury can significantly affect quality of life. Early intervention upon detection of foot arch changes can help mitigate progression and prevent further deterioration. Despite the availability of multimodal sensor-integrated running platforms for gait analysis, such systems are inherently bulky and not conducive to routine walking measurement. To overcome the above limitations, this study employed a flexible plantar pressure insole with an integrated accelerometer and a dedicated acquisition circuit to capture plantar pressure and acceleration data. This smart insole system acquires plantar data, performs feature extraction via time–domain and wavelet analysis, and then employs machine learning to classify the foot arch type as a normal foot, flatfoot, or high-arched. A Random Forest classifier was then established to categorize foot arch types based on the collected data, which integrates numerous decision trees through bootstrap aggregation and random feature selection, with final classification determined by majority voting. A total of 30 volunteers participated, including 11 with normal arches, 11 with flat feet, and 8 with high arches. Compared with support vector machine, K nearest neighbors, and decision tree, the Random Forest achieved the highest recognition accuracy of 92%. This system reveals the patterns of plantar pressure distribution and acceleration fluctuations during walking across three foot arches and demonstrates that wavelet entropy can effectively quantify the changes in signal complexity included in foot arch differences. Compared with laboratory force plates, this system features lower cost and a smaller form factor, making it suitable for real-time monitoring. This system can lay the technical foundation for personalized foot orthopedics and health monitoring. Full article

Background: Prolonged standing can lead to musculoskeletal disorders, especially in the lower extremities, when appropriate footwear is not used. The aim of this study is to investigate the relationship between footwear styles, foot problems, and pain characteristics related to lower extremities in individuals with prolonged standing. Methods: A descriptive, cross-sectional study design was employed, using a random sample of individuals with prolonged standing (n = 159). Participants were asked questions about their footwear choices. They were asked to mark the lower extremity pain localization on the McGill Pain Map. In addition, foot deformities were evaluated by physical examination. Results: The findings revealed that most females (n = 88) and males (n = 71) preferred flat/sports footwear styles in both summer and winter. There was no significant difference between footwear styles and foot pain duration, intensity, and localization in both genders (p > 0.05). However, a statistically significant difference was observed among males between their summer footwear styles and pain related to lower extremities (low back pain and knee pain), and among females between their summer footwear styles and foot problems (bone deformities, skin pathologies and soft tissue issues) (p < 0.05). Conclusions: The results of this study show that the preferred footwear style was associated with lower extremity pain and foot problems, which emphasized the importance of footwear selection and footwear evaluation in the musculoskeletal evaluation of the lower extremities. Full article

Background: Flatfoot deformity is associated with altered lower extremity biomechanics and functional impairment during gait. However, evidence describing spatio-temporal gait alterations remains heterogeneous and has not been consistently synthesized across studies. Methods: A systematic review was conducted in accordance with PRISMA guidelines. MEDLINE (via PubMed) and Scopus were searched through 24 March 2025 for studies evaluating gait characteristics in individuals with flatfoot or progressive collapsing foot deformity. Studies reporting spatio-temporal parameters in both flatfoot and healthy control cohorts were included in quantitative synthesis. Random-effects meta-analyses were performed to evaluate gait velocity, stance duration, stride length, and cadence. Results: Fifteen studies met inclusion criteria, of which five provided sufficient data for meta-analysis. Compared with healthy controls, individuals with flatfoot demonstrated longer stance duration and shorter stride length. No differences were observed in gait velocity or cadence. Substantial heterogeneity was present across all pooled outcomes (I² > 80%), reflecting variability in study populations, disease characteristics, and gait analysis methodologies. Conclusions: Flatfoot is associated with consistent spatio-temporal gait adaptations characterized by longer stance duration and reduced stride length. Despite heterogeneity among included studies, these findings suggest consistent spatio-temporal gait adaptations that may serve as clinically relevant markers of altered gait mechanics and functional impairment. Further studies with standardized protocols are needed to refine the role of gait analysis in the assessment and management of flatfoot. Full article

Objectives: Flat feet is a very common deformity in children. Often, radiologic evaluation for children with flat feet is made. Although the measurement reliability of some angles in flat feet has been evaluated in the literature, none of them have been performed in the age range of 3-7 years, when the deformity is most common. Our aim is to evaluate the interobserver and intraobserver reliability of the 7 angles that are used for assessing flat feet. Methods: Radiologic angles were measured by four independent observers (two specialists and two residents) in two separate sessions on the foot radiographs of 50 children aged 3-7 years with clinically diagnosed flat feet in the appropriate position and intra-class correlation coefficient was evaluated. Thus, interobserver and intraobserver reliability was measured. Results: High reliability values were found in the AP talus - 1st metatarsal (APT1MT) angle and calcaneus inclination (Cl) angle, while the reliability was moderate in the other angles. Intraobserver reliability values tended to be higher than interobserver values, which is consistent with other studies. Conclusions: It is useful to keep in mind that the measurement reliability is moderate except for APT1MT and CI when angles are measured in this specific age group. No positive effect of experience on measurement reliability was found in our study. Full article

Compliant mechanisms have contributed to many advances in soft robotics, and there is strong motivation to translate these ideas to assistive devices where adaptive motion at the human interface is required. This work presents novel reconfigurable compliant joints (RCJs) as a parameterized joint element for functional biomimicry in lower-extremity joints for prosthetic knees and ankle–foot orthoses, with concepts that extend to other limb joints. The RCJ uses a rigid hub and outer ring joined by an array of flexible links with centerlines defined by cubic Bézier curves. Link shapes are organized into four Bézier classes (A–D), with base types using 10, 12, or 14 uniformly distributed link slots and variants generated by modifying active-link count and distribution, forming a structured morphology space of 12 configurations for machine design. Dual-extrusion 3D-printed prototypes are characterized by a custom testing apparatus using a 2.2 kN load cell at 25 mm/s over a 0–90° rotation range across six recorded load cycles to measure torque–angle curves and stiffness under large deformations. Angle-dependent stiffness is evaluated over three fixed intervals (0–30°, 30–60°, and 60–90°) to quantify multi-stage behavior. A 2-dimensional corotational frame model and a Simscape Multibody model, including a rolling-contact knee configuration, use the same parameterization to relate geometry, nonlinear mechanics, and system-level motion. Experiments and simulations show multi-stage torque–angle profiles and predictable stiffness modulation across all configurations, with both magnitude and transition angle tunable through Bézier class and active-link distribution, positioning the RCJ as a CAD/CAE-compatible joint architecture for assistive devices or wearable robotic systems and a basis for advancing functional biomimicry in compliant mechanism design. Full article

The emergence of classicality through quantum decoherence is commonly described from complementary perspectives emphasizing stability (environment-induced superselection), objectivity (Quantum Darwinism), or physical feasibility (information thermodynamics). In realistic open quantum systems, however, these aspects coexist and compete under finite physical resources. In this work we argue that classical structure selection is most naturally understood as a resource-constrained, multi-objective process. We introduce the Informational Economy Functional (IEF), an effective accounting framework that places loss of distinguishability, energetic dissipation, and the generation of redundantly accessible records on equal footing. The associated Principle of Informational Economy characterizes emergent classical structures as those achieving an optimal compromise among stability, objectivity, and energetic feasibility. Classicality is thus neither maximally stable, nor maximally redundant, nor maximally energy-efficient, but instead reflects a Pareto-optimal balance shaped by environmental constraints. The IEF yields falsifiable predictions concerning pointer-structure variability, redundancy deformation, and resource-sensitive trade-offs, and suggests concrete experimental tests in continuously monitored quantum platforms. Classical reality is thereby reinterpreted as the most economical configuration in which information can stably form, propagate, and persist. Full article

Background/Objectives: Progressive collapsing foot deformity (PCFD) is driven by multiplanar peritalar instability. This study evaluated the clinical and radiographic outcomes of a standardized four-component reconstruction protocol designed to facilitate immediate postoperative weight-bearing in Stage 1a/1b PCFD. Methods: This single-center retrospective study included 20 patients treated between 2015 and 2023 with medializing calcaneal osteotomy, spring ligament repair, flexor digitorum longus (FDL) tendon transfer with internal brace augmentation, and subtalar arthroereisis. Clinical (VAS, AOFAS) and radiographic parameters (anteroposterior and lateral Meary angles, calcaneal pitch, and talonavicular coverage angle) were assessed longitudinally, with subgroup analysis comparing implant removal versus retention. Results: The protocol yielded significant overall improvements. Mean VAS decreased by 4.37 points (p < 0.001), and final AOFAS reached 84.7 ± 7.6 at the final follow-up. Although subtalar arthroereisis was removed in 45% of patients due to symptomatic irritation, subgroup analysis revealed no significant loss of radiographic correction (p > 0.05). Notably, a significant interaction effect was observed for VAS scores (p = 0.002) and AOFAS scores (p = 0.041), with the removal group demonstrating a pronounced functional recovery trajectory following explantation. No major complications occurred. Conclusions: A standardized four-in-one reconstruction provides reliable multiplanar correction in Stage 1a/1b PCFD. The maintenance of structural alignment despite a high implant removal rate supports the role of arthroereisis as a temporary but valuable adjunct for early mobilization. This strategy offers a reproducible framework for joint-preserving PCFD management. Full article

Background: Pes planovalgus affects 44–54% of preschool children and represents one of the most common concerns in pediatric orthopedic practice. Aim: This narrative review synthesizes the evidence linking increased femoral antetorsion to pediatric flatfoot deformity. Methods: A comprehensive literature search was conducted in PubMed, Scopus, and Web of Science through January 2026. The initial search yielded 847 records; after screening, 52 studies were included, 29 of which are directly cited. Search terms included combinations of: “femoral antetorsion” OR “femoral anteversion” AND “flatfoot” OR “pes planovalgus” AND “children” OR “pediatric”. Results: Strong correlations exist between flatfoot and increased internal hip rotation (as a proxy for femoral antetorsion) in preschool children (r = 0.53–0.77), suggesting an association, though direct causation remains unproven. Both deformities share similar developmental trajectories with spontaneous resolution by school age. The biomechanical model proposes that elevated antetorsion reduces gluteus medius moment arms by 40–50%, necessitating compensatory hip internal rotation; however, this derives from computational models and cerebral palsy populations, with limited direct validation in typically developing children. Femoral derotation osteotomy improves the foot progression angle, though transfer efficiency is incomplete (~54% of surgical correction manifests distally). Conclusions: Femoral antetorsion and pes planovalgus are strongly associated in preschool children, though whether this represents a direct mechanistic cascade or parallel manifestations of common developmental factors remains uncertain. This understanding supports watchful waiting in preschool children and, in persistent cases, prioritizes the assessment of the entire rotational profile before intervention. Full article

Lower-limb rehabilitation exoskeletons must balance biomechanical compatibility, structural safety, and low mass to enable practical, repeatable gait assistance. This paper proposes a planar pantograph-derived exoskeleton leg driven by a Chebyshev Lambda linkage and develops an integrated workflow from mechanism synthesis to manufacturable optimization and experimental verification. A mannequin-coupled multibody model was built in MSC ADAMS to evaluate joint kinematics, end-point (foot) trajectories, and joint reaction forces under multiple scenarios (fixed-frame, ramp, stair ascent, and inclined-plane walking). The extracted joint loads were transferred to a parametric finite element model in ANSYS Workbench 2019, where response surface surrogates and a multi-objective genetic algorithm (MOGA) were used to minimize mass under stiffness and strength constraints. For the optimized load-bearing link, the selected minimum-mass design reached a component mass of 0.542 kg while respecting the imposed structural limits, i.e., a maximum total deformation below 0.2 mm and a maximum equivalent (von Mises) stress below 50 MPa (e.g., ~0.188 mm deformation and ~39 MPa stress in the optimal candidate). A rapid prototype was manufactured by 3D printing and experimentally evaluated using CONTEMPLAS high-speed video tracking, providing measured X_M(t) and Y_M(t) trajectories and joint-angle histories for quantitative comparison with simulations via RMSE metrics. Full article

Background: Hallux valgus (HV) is a complex forefoot deformity influenced by interactions between osseous alignment, ligamentous restraint, and muscle–tendon forces. While the biomechanical role of ligament laxity and bone geometry has been extensively investigated, the contribution of tibialis anterior (TA) tendon insertion variability to medial column mechanics remains insufficiently understood. Materials and Methods: A patient-specific finite element model of the foot was developed from high-resolution computed tomography data. Five anatomically documented TA distal insertion configurations were modeled, representing different distributions of attachment to the medial cuneiform and first metatarsal base. All simulations were performed under identical boundary and loading conditions representative of the stance phase of gait. Global (full-foot) and local (first bone and first metatarsal) mechanical responses were quantified using total deformation, equivalent von Mises stress, and strain distributions. Results: Marked differences in mechanical behavior were observed across TA insertion types. The metatarsal-dominant configuration (Type 3) demonstrated the highest global and local deformation values (global deformation: 1.0928 mm; first bone deformation: 1.0928 mm) and elevated strain distributions, whereas the medial-dominant configuration (Type 2) showed minimal deformation (global: 0.0727 mm; first bone: 0.0350 mm) but the highest global equivalent von Mises stress (5.7698 MPa). The single-band insertion to the medial cuneiform (Type 5) produced the greatest localized stress in the first bone region (3.8634 MPa). Representative strain maps revealed distinct spatial redistribution patterns within the medial column associated with TA insertion geometry. Conclusions: This patient-specific finite element analysis indicated that distal TA insertion variability alone can substantially modify deformation, stress, and strain patterns within the medial column. These findings suggested that TA insertion anatomy may act as a biomechanical modulator of first-ray mechanics and should be considered in future studies investigating hallux valgus pathomechanics and personalized treatment strategies. Full article

Tibial torsion significantly influences knee biomechanics, yet its interaction with ACL reconstruction history in elite alpine skiers remains under-investigated. In this cross-sectional observational study, we analyzed 20 elite alpine skiers (7 ACL-reconstructed, 13 non-injured) using a markerless motion capture system during dynamic tasks (Squat, Single-Leg Squat, Lunge). Static tibial torsion was assessed via the Transmalleolar Axis and Thigh–Foot Angle. The results revealed a critical divergence in biomechanical strategies based on tibial alignment (p < 0.05). Skiers with rotational deformity adopted a pattern we describe as a “Stiffness Strategy”, characterized by suppressed knee valgus and hip rotation, but relied on excessive ankle dorsiflexion (39.5°)—a compensatory mechanism that may become limited when constrained by rigid ski boots. In contrast, ACL-reconstructed skiers with normal alignment exhibited what we term an “Instability Strategy”, showing dynamic valgus collapse and persistent asymmetry. These findings suggest that “one-size-fits-all” rehabilitation may be insufficient. We propose that injury prevention protocols may benefit from incorporating anatomical screening, focusing on decoupling mobility for skiers with tibial torsion and enhancing dynamic stability for those with normal alignment. Full article