Search Results (30)

Webbed-foot gliding water entry is a characteristic water-landing strategy employed by swans and other large waterfowls, demonstrating exceptional low-impact loading and remarkable motion stability. These distinctive biomechanical features offer significant potential for informing the design of cross-medium vehicles’ (CMVs’) water-entry systems. To analyze the hydrodynamic mechanisms and flow characteristics during swan webbed-foot gliding entry, the three-dimensional bionic webbed-foot water-entry process was investigated through a computational fluid dynamics (CFD) method coupled with global motion mesh (GMM) technology, with a particular emphasis on elucidating the regulatory effects of entry parameters on dynamic performance. The results demonstrated that the gliding water-entry process can be divided into two distinct phases: stable skipping and surface gliding. During the stable skipping phase, the motion trajectory exhibits quasi-sinusoidal periodic fluctuations, accompanied by multiple water-impact events and significant load variations. In the surface-gliding phase, the kinetic energy of the bionic webbed foot progressively decreases while maintaining relatively stable load characteristics. Increasing the water-entry velocity will enhance impact loads while simultaneously increasing the skipping frequency and distance. Increasing the water-entry angle will primarily intensify the impact load magnitude while slightly reducing the skipping frequency and distance. An optimal pitch angle of 20° provides maximum glide-skip stability for the bio-inspired webbed foot, with angles exceeding 25° or below 15° leading to motion instability. This study on webbed-foot gliding entry behavior provided insights for developing novel bio-inspired entry strategies for cross-medium vehicles, while simultaneously advancing the optimization of impact-mitigation designs in gliding water-entry systems. Full article

Background and Objectives: In-toeing and out-toeing gait are rotational deformities commonly observed in children with neuromuscular conditions. These gait abnormalities often result from internal tibial torsion, increased femoral anteversion, and metatarsus adductus. This study was conducted to create a comprehensive evaluation of the effectiveness of lower extremity orthotics as a non-operative treatment option, given their regular use in clinical settings. The aim of this literature review was to understand the efficacy of various orthotic devices in correcting rotational deformities in the transverse plane, thereby improving ambulation stability and 3D joint motion. Materials and Methods: Literature published after 1 January 1990 was reviewed, utilizing databases such as CENTRAL (Wiley), CINAHL (EBSCO), Medline (OVID), Scopus (Elsevier), and Web of Science (Clarivate). In totality, 13 studies were included, evaluating 365 participants with neuromuscular conditions using various orthotic devices. Results: Among these studies, two were randomized control trials (Level 1), nine were quasi-experimental studies (Level 2), and two were case studies (Level 4). Quality assessment determined that 69% of the included studies had a low risk of bias, while 31% demonstrated a moderate risk. Compression garments and rotational systems showcased the greatest change in proximal lower extremity rotation at 19.73° ± 1.57 and 24.13° ± 8.49, respectively. The most significant difference in foot progression angle is through the use of rotational systems, 19° ± 26.87. Conclusions: In a short-term treatment, children with neuromuscular disorders exhibiting in-toeing or out-toeing gait may benefit from different types of orthoses. Compression garments may aid joint alignment and enhance proprioception, rotational systems correct alignment with precise adjustability, AFOs that achieve effective stabilization can deliver benefits in the transverse plane, and foot orthotics may be appropriate for mild gait abnormality management. Full article

Instrumented gait analysis is widely used in clinical settings for the early detection of neurological disorders, monitoring disease progression, and evaluating fall risk. However, the gold-standard marker-based 3D motion analysis is limited by high time and personnel demands. Advances in computer vision now enable markerless whole-body tracking with high accuracy. Here, we present vGait, a comprehensive 3D gait assessment method using a single RGB-D sensor and state-of-the-art pose-tracking algorithms. vGait was validated in healthy participants during frontal- and sagittal-perspective walking. Performance was comparable across perspectives, with vGait achieving high accuracy in detecting initial and final foot contacts (F1 scores > 95%) and reliably quantifying spatiotemporal gait parameters (e.g., stride time, stride length) and whole-body coordination metrics (e.g., arm swing and knee angle ROM) at different levels of granularity (mean, step-to-step variability, side asymmetry). The flexibility, accuracy, and minimal resource requirements of vGait make it a valuable tool for clinical and non-clinical applications, including outpatient clinics, medical practices, nursing homes, and community settings. By enabling efficient and scalable gait assessment, vGait has the potential to enhance diagnostic and therapeutic workflows and improve access to clinical mobility monitoring. Full article

A non-proportional reduction in strength parameters is widely used in slope stability assessment, but the current asynchronous reduction in strength parameters only considers the cohesion c and internal friction angle φ, which is suitable for slope stability assessment under static loads. Under seismic loads, however, tension at the rear edge of the slope often accompanies the appearance of ground cracks. In order to consider the relationship between tensile strength, cohesion, and the internal friction angle reduction coefficient, starting with the linear softening attenuation law of soil material strength parameters, a functional relationship between cohesion and internal friction angle is obtained. Then, considering that the failure of microelements in the tensile and shear zones conforms to the tension and shear of joint failure, the relationship between tensile strength, cohesion, and the internal friction angle reduction coefficient is derived. By establishing a homogeneous slope model and comparing and analyzing the progressive instability failure modes of slopes under static and seismic conditions, the stability and potential slip surface differences of slopes under two different working conditions are explored. The research results indicate that slope instability is a gradual, cumulative failure process under both static and dynamic conditions. The instability mode of the slope under static conditions is shear failure. In contrast, under dynamic loads, the instability failure of the slope is manifested as shear failure upward at the foot of the slope and tensile failure downward at the top of the slope. The stability coefficient of slopes under earthquake conditions is reduced by 17.3% compared to that under static conditions. Under earthquake conditions, the potential sliding surface under an asynchronous reduction in strength parameters is shallower than that under static conditions and deeper than that without an asynchronous reduction in strength parameters. Overall, the research results provide a reference for slope stability analysis and support design optimization under earthquake loads. Full article

Background: Femoral torsional malalignment is a common cause of in-toeing and out-toeing in children, often leading to gait disturbances, functional limitations, and increased risk of falls. Traditionally, osteotomy was the only surgical option for correction. A minimally invasive technique known as rotational guided growth (RGG) has recently been introduced to address these malalignments. This study aims to assess the effectiveness of rotational femoral malalignment correction by rotational epiphysiodesis with tension band 8-plates (Orthofix, Verona, Italy). Methods: Eleven patients with in-toeing and out-toeing (19 femurs) were treated using RGG with 8-plates. The 8-plates were applied laterally and medially, with screws placed above and below the growth plate of the distal femur, angled obliquely to the long axis of the bone in opposite directions. Changes in foot progression angle (FPA), femoral version, the alteration in the angle between the 8-plates, and the rate of correction were recorded. Results: All patients reported functional gait improvement. The FPA was corrected from a mean of 32 degrees to 7 degrees, the femoral version improved from a mean of 60 degrees to 22 degrees. The angle between the 8-plates changed from a mean of 75 degrees to 28 degrees, with a correction rate of 4.1 degrees per month. The average time for correction was 11 months. No complications were observed during the treatment. Conclusions: RGG using 8-plates is a novel, minimally invasive surgical technique that effectively corrects rotational femoral deformities and may serve as a preferred alternative to derotational osteotomy in growing patients. Full article

Background: Knee-related injuries often result from poor movement patterns that destabilize the joint and increase stress on knee structures. Understanding the influence of foot positioning on knee biomechanics is critical for identifying high-risk movement patterns and preventing injuries. Methods: Twenty healthy male participants performed side-cutting movements at three different foot progression angles. One participant’s data were used to develop and validate a knee finite element model with high-speed dual fluoroscopic imaging (DFIS). Combined with a musculoskeletal analysis, the model simulated internal knee loads under various foot-positioning conditions. Results: The analysis revealed that, as the external foot progression angle increased, the ankle plantarflexion decreased, while the ankle internal rotation and knee valgus moments increased. Higher stress concentrations were observed on the ACL, lateral meniscus, lateral tibial cartilage, and medial collateral ligament, particularly at the femoral–tibial ACL attachments. Conclusion: The findings suggest that a toe-out foot position elevates the risk of knee injuries by increasing stress on key structures, whereas a toe-in position may enhance joint stability, reduce the ACL injury risk, and promote favorable muscle activation patterns. Full article

Background: Recent studies utilizing weight-bearing computed tomography have identified abnormal internal rotation of the talus in advanced varus ankle arthritis (VAA) with a large talar tilt (TT), influenced by the posterior tibial tendon (PTT). This study aimed to evaluate the clinical and radiographic results of supramalleolar osteotomy (SMO) combined with PTT release and lateral ligament augmentation for VAA with a large TT. Methods: From January 2015 to September 2018, 15 patients with VAA and a large TT (greater than 5°) underwent SMO combined with PTT release. Clinical results, including visual analog scale (VAS) for pain, American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, and ankle osteoarthritis scale (AOS), were assessed. Radiographic results were assessed with various parameters, including medial distal tibial angle (MDTA), anterior distal tibial angle (ADTA), talar tilt (TT), talus center migration (TCM), Meary angle, hindfoot alignment angle (HAA), and hindfoot moment arm (HMA) on foot and ankle weight-bearing radiographs. Clinical and radiographic results were evaluated preoperatively and at the last follow-up. Results: VAS, AOFAS ankle-hindfoot score, and AOS improved significantly from 7.5, 54.4, and 72.6 preoperatively to 3.1, 82.5, and 34.5 postoperatively, respectively. All radiographic parameters exhibited significant changes postoperatively, with the exception of the Meary angle, which demonstrated no significant change. Four patients exhibited improvement in radiographic stage postoperatively; however, average radiographic stage did not significantly improve postoperatively in all patients. One patient progressed to end-stage arthritis postoperatively, necessitating additional ankle arthrodesis. Conclusions: In conclusion, lengthening and lateral ligament augmentation combined with bony realignment procedures may be a reasonable option for treating VAA with a large TT greater that 5°. Full article

Persons with Multiple Sclerosis (pwMS) are at a high risk of falling, with abnormal gait pattern. The upper limbs play an important role in postural control and gait stability. The presence of arm swing changes during walking in pwMS, especially in the early period, may be an indicator of balance problems. The current study aimed to assess arm swing during walking in early MS. A total of 18 pwMS were evaluated in two time points. The first time was after their first (stable) diagnosis (pre-evaluation) and the second time was 3 months after the pre-evaluation. In addition, 10 healthy controls were evaluated once. Arm swing analysis during walking, using video recording, was applied to both groups. Additionally, the MS group performed the Two-Minute Walk Test, Timed Up and Go, and Timed 25-Foot Walk Test. The pwMS showed similar joint angles at both the first and second evaluations. Only the elbow ROM value on the least affected side was lower in pwMS than healthy controls at the second evaluation (p = 0.027). The early MS patients showed altered arm swing pattern. As walking speed and mobility scores did not change over time, the decrease in elbow amplitude over a 3-month period indicates that the arm swing may present a pattern resulting from MS-specific disorders rather than being a compensatory mechanism in walking. From the earliest stages of the disease, variations in arm swing movements during walking may be considered as a disease progression-predictor for MS. Full article

The aim of the study was to verify the effects of foot progression angle (FPA) modification during walking on the internal moments of the ankle and knee joints in individuals with knee osteoarthritis (OA). Biomechanical changes such as increased knee adduction moment (KAM) during walking are known to be involved in the development and severity of knee OA. Although various FPA modifications during gait have been applied to reduce peak KAM, few studies have investigated the effects of applying toe-in or toe-out walking modifications for knee OA on peak KAM and three-dimensional (3D) moments of the ankle joint. Kinetic moment variables were acquired from 35 individuals with medial knee compartment OA. A 3D motion analysis system and two force platforms were used to acquire KAM and 3D moments of both ankle joints during gait. Visual3D was used to obtain final moment data for statistical processing. Repeated-measures analysis of variance with Bonferroni adjustment was used to compare kinetic and kinematic values for each FPA walking condition. There was a significant decrease (p < 0.01) in first peak KAM when walking with an internal rotation foot position compared to normal foot position walking. Also, there was a significant decrease (p < 0.01) in second peak KAM when walking with an external rotation foot position compared to normal foot position walking. Compared to a normal foot position, peak ankle inversion moment of the external rotation foot position walking showed a significant decrease (p < 0.05). There were no interactive effects between FPA condition and limb sides for any KAM values (p > 0.05). The results showed no significant increase in the ankle joint moment value during gait for FPA modification conditions. Thus, the clinical implications of this study suggest that modification of the FPA in patients with OA to reduce KAM does not negatively impact the 3D ankle moments. Full article

The collapse failure of rock surrounding caverns involves a progressive collapse process. Based on the nonlinear Hoek–Brown failure criterion and the upper limit theorem, the whole process curve of the progressive collapse of the surrounding rock of a large-span cavern is outlined in this paper. The progressive collapse process of the surrounding rock of the large-span cavern is experimentally studied using an independently developed visualized large-span-cavern geomechanical model test device with variable angles. The results show that, through theoretical calculation and model tests, the surrounding rock at the top of the large-span cavern undergoes three collapses. Under the condition of rock mass and the shape of the cavern, the larger the span of the cavern, the more times the surrounding rock collapses; with the increase in surrounding rock pressure, the first collapse occurs in the middle part of the arch roof. When the overlying load reaches a certain level, the arch foot becomes the weakest part, and the rock undergoes shear failure along the arch foot, gradually extending upwards, accompanied by multiple collapses, forming a progressive collapse process. The theoretical calculation results of this paper are basically consistent with the scope of the model test, and the research results can provide a basis for the construction and support design of the large-span cavern. Full article

Subtalar distraction arthrodesis (SDA) is a surgical procedure designed to treat hindfoot deformities associated with isolated subtalar joint arthritis. In 1996, Fitzgibbons was the first to observe that, in some cases, hindfoot fusion appeared to be associated with the development of tibiotalar valgus tilt. Since then, few studies have addressed this issue. Given that hindfoot fusion can be performed using various techniques, this study investigated the potential tibiotalar joint frontal or sagittal modifications resulting from the modified Grice–Green technique. All the consecutive patients who underwent the modified Grice–Green procedure were included. The patient records were reviewed to extract demographic data. Weight-bearing foot and ankle radiographs were assessed to measure the talar tilt angle and the tibiotalar ratio on the same picture archiving and communication system by three independent observers. A total of 69 patients met the criteria for inclusion. The mean talar tilt showed no substantial changes, since the increase from 1.46 ± 1.62 preoperatively to 1.93 ± 2.19 at a minimum of 8 months postoperatively was not statistically significant (p = 0.47). The average preoperative tibiotalar ratio significantly increased from 33.4 ± 4.4% to 35 ± 4% postoperatively (p = 0.007), although remaining within the normal range, indicating a possible realignment of the posterior facet of the subtalar joint. In conclusion, this study highlights the effectiveness of the modified Grice–Green procedure in achieving a favorable realignment without impacting the ankle joint, particularly regarding tibiotalar valgus tilt. Full article

Understanding the implications of decreased femoral torsion on gait and running in children and adolescents might help orthopedic surgeons optimize treatment decisions. To date, there is limited evidence regarding the kinematic gait deviations between children with decreased femoral torsion and typically developing children, as well as the implications of the same on the adaptation of walking to running. A three-dimensional gait analysis study was undertaken to compare gait deviations during running and walking among patients with decreased femoral torsion (n = 15) and typically developing children (n = 11). Linear mixed models were utilized to establish comparisons within and between the two groups and investigate the relationship between clinical examination, spatial parameters, and the difference in hip rotation between running and walking. Patients exhibited increased external hip rotation during walking in comparison to controls, accompanied by higher peaks for the same as well as for knee valgus and external foot progression angle. A similar kinematic gait pattern was observed during running, with significant differences noted in peak knee valgus. In terms of variations from running to walking, patients internally rotated their initially externally rotated hip by 4°, whereas controls maintained the same internal hip rotation. Patients and controls displayed comparable kinematic gait deviations during running compared to walking. The passive hip range of motion, torsions, and velocity did not notably influence the variation in mean hip rotation from running to walking. This study underlines the potential of 3D gait kinematics to elucidate the functional implications of decreased FT and, hence, may contribute to clinical decision making. Full article

The use of midfoot wedges for the correction of flatfeet disorders, such as progressive collapsing foot disorder, has increased greatly in recent years. However, the wedge material/composition has yet to be standardized. Metallic wedges offer advantages such as comparable elasticity to bone, reduced infection risk, and minimized osseous resorption, but a comprehensive review is lacking in the literature. Therefore, the objective of this systematic review was to organize all studies pertaining to the use of metallic wedges for flatfoot correction to better understand their efficacy and safety. This systematic review adhered to PRISMA guidelines, and articles were searched in multiple databases (PubMED, SPORTDiscus, CINAHL, MEDLINE, and Web of Science) until August 2023 using a defined algorithm. Inclusion criteria encompassed midfoot surgeries using metallic wedges, observational studies, and English-language full-text articles. Data extraction, article quality assessment, and statistical analyses were performed. Among 11 included articles, a total of 444 patients were assessed. The average follow-up duration was 18 months. Radiographic outcomes demonstrated that patients who received metallic wedges experienced improvements in lateral calcaneal pitch angle and Meary’s angle, with an enhancement of up to 15.9 degrees reported in the latter. Success rates indicated superior outcomes for metallic wedges (99.3%) compared to bone allograft wedges (89.9%), while complications were generally minor, including hardware pain and misplacement. Notably, there were no infection complications due to the inert nature of the metallic elements. This review summarizes the effectiveness, success rates, and safety of metallic wedges for flatfoot correction. Radiographic improvements and high success rates highlight their efficacy. Minor complications, including pain and mispositioning, were reported, but the infection risk remained low. Our results demonstrate that metallic midfoot wedges may be a viable option over allograft wedges with proper planning. Future research should prioritize long-term studies and standardized measures. Full article

This paper presents experimental and numerical investigations on the progressive collapse behavior of a two-story glulam frame when the middle column is exposed to ISO834 standard fire. The stress characteristics, temperature distributions, and deformation relationship curves of the bottom middle column after a fire are obtained. The collapse resistance performance and the mechanism of the glulam structure under local fire are studied in combination with the failure mode of the frame. The experimental results show that the failure time of the middle column in fire is 16.8 min, and the time to determine the progressive collapse of the structure is 17.17 min when the rotation angle exceeds the limit. The structure can remain stable for some time after the failure of the fire column, but as the fire continues to spread, the structure will collapse further. In addition, a temperature-field analysis model with the grid element type of DC3D8 and a structural field analysis model with the grid element type of C3D8R was established by using ABAQUS software under the experimental conditions. The numerical simulation is carried out by means of thermal–mechanical sequential coupling. The numerical simulation results show that the temperature of the beam end rose to more than 300 °C in about 15 min although it was not directly exposed to fire. The temperature of the whole connector at the pillar foot in the bottom column reached more than 700 °C when the fire time reached 60 min. The numerical simulation results agree well with the experimental results. The analysis results show that, in the failure process of the fire column, the junction of beam ends begins to produce stretching force to form a catenary effect. As the fire time increases, the catenary effect eventually fails. The stretching force at the beam end rapidly decreases and withdraws from the work, causing the progressive collapse of the frame. Full article

Background and purpose: Patients with type 2 diabetes mellitus (T2DM) are prone to developing diabetic peripheral neuropathy (DPN) with an increased risk of injuries while walking, potentially leading to plantar ulcers. We aimed to assess the early gait changes in T2DM patients without clinical signs of DPN in comparison to age-matched healthy controls (HC). Subjects and Methods: One hundred T2DM patients (78 women, mean age: 66.4 ± 11.5 years) and 50 age-matched HC (34 women, mean age 62.1 ± 7.9 years) were evaluated with the PODOSmart^® gait analysis device. Anthropometric and biochemical data, as well as dietary habits were collected for all participants. T2DM patients also completed the Diabetes Distress (DS) self-report validated questionnaire. Results: One patient was excluded from the study due to lack of recent biochemical data. Among the T2DM patients, 88.9% reported little or no DS and 11.1% moderate DS. The T2DM group had higher body mass index, waist circumference, systolic blood pressure, glycated hemoglobin A1c, sodium, white blood cell count, triglycerides and low-density lipoprotein cholesterol, but lower high-density lipoprotein cholesterol than HC (p < 0.05 for all comparisons). The MedDiet score was satisfactory in both groups (p > 0.05). Significant differences were found between the two study groups in gaitline heel off, propulsion speed, foot progression angle, time taligrade phase, stride length, walking speed, angle attack, oscillation speed, pronation-supination toe off and clearance. Conclusions: The T2DM patients without self-reported DS or clinical signs of DPN may exhibit significant differences in several gait parameters analyzed with PODOSmart^®. Whether gait analysis can be used as an early diagnostic tool of T2DM complications should be further explored. Full article