Normal Walking Research Articles

Scale Production of a Stretchable Fiber Triboelectric Nanogenerator in Customizable Textile for Human Motion Recognition.

Although the fiber-based triboelectric nanogenerator (F-TENG) has been recognized as one of the most promising flexible sensor systems, it is facing a challenge of balancing the performance and the processing scalability. Herein, we develop a hierarchical coaxial F-TENG possessing PU layer, Ag layer, and PA layer from the core to the outer part by an efficient and straightforward two-step braiding method. Owning a small diameter of 1 mm, the F-TENG presents a high linear sensing response, a wide working range of 5 to 150 kPa, and a quick reaction speed of around 200 ms. In addition, it shows high flexibility, cyclic washability, and superior mechanical stability. Furthermore, customizable textiles (e.g., wrist support and socks) that conform perfectly to the human body have been knitted from the F-TENGs as warps or wefts, which are able to monitor human motion signals. Together with an optimized machine learning algorithm, five human motions (stand, slow walk, normal walk, run, and jump) can be analyzed with a precision of up to 99%. In short, this work presents a scalable approach to develop customizable self-powered sensing textiles, offering an excellent wearable digital platform/system for potential motion capture/monitoring, identification, and smart-sports-related applications.

The Effect of Cognitive and Motor Dual Tasks on the Synergy of Lower Limb Muscles During Walking.

Walking is one of the most complex human movements that can be affected by various sources of attention. Dual tasks reduce attention, increase information processing, and may alter control mechanisms such as synergy. However, the effect of dual tasks on muscle synergy remains unknown. Therefore, this study aimed to investigate the effect of cognitive and motor dual tasks on the synergy of lower limb muscles during walking. Twenty-four participants were selected voluntarily. The activity of the eight lower limb muscles was recorded under three different conditions: normal walking without a dual task, walking with a cognitive dual task, and walking with a motor dual task. A nonnegative matrix factorization algorithm and the variance accounted for were used to extract muscle synergy. The repeated-measures analysis of variance test and Pearson's correlation coefficient were performed to analyze the data. In this study, five muscle synergies were extracted from electromyography data using the variance accounted for method under three different conditions. The pattern of muscle synergies showed moderate to strong correlations. Peaks of synergies changed, and a time shift in synergy peaks during walking was observed. However, the number of extracted synergies did not change. The number of recruited muscle synergies remained consistent across different conditions. Dual tasks affect the higher levels of the motor control system, causing interference in information processing that leads to a shift in the tendency of synergy and weight coefficients of the muscles, ultimately resulting in a change in walking mechanics.

Human Pluripotent Stem Cell Colony Migration Is Related to Culture Environment and Morphological Phenotype

Human pluripotent stem cells (hPSCs) are an important tool in the field of regenerative medicine due to their ability to differentiate towards all tissues of the adult organism. An important task in the study of hPSCs is to understand the factors that influence the maintenance of pluripotent and clonal characteristics of colonies represented by their morphological phenotype. Such factors include the ability of colonies to migrate during growth. In this work, we measured and analyzed the migration trajectories of hPSC colonies obtained from bright-field images of three cell lines, including induced hPSC lines AD3 and HPCASRi002-A (CaSR) and human embryonic stem cell line H9. To represent the pluripotent status, the colonies were visually phenotyped into two classes having a “good” or “bad” morphological phenotype. As for the migration characteristics, we calculated the colony speed and distance traveled (mobility measures), meandering index (motion persistence measures), outreach ratio (trajectory tortuosity characteristic), as well as the velocity autocorrelation function. The analysis revealed that the discrimination of phenotypes by the migration characteristics depended on both the cell line and growth environment. In particular, when the mTESR1/Matrigel culture environment was used, “good” AD3 colonies demonstrated a higher average migration speed than the “bad” ones. The reverse relationship between average speeds of “good” and “bad” colonies was found for the H9 line. The CaSR cell line did not show significant differences in the migration speed between the “good” and “bad” phenotypes. We investigated the type of motion exhibited by the colonies by applying two diffusion models to the mean squared displacement dynamics, one model corresponding to normal and the other to anomalous diffusion. The type of diffusion and diffusion parameter values resulting from the model fitting to data demonstrated a similar cell line, environment, and phenotype dependency. Colonies mainly showed a superdiffusive behavior for the mTESR1/Matrigel culture conditions, characterized by longer migration steps compared to the normal random walk. The specific properties of migration features and the patterns of their variation demonstrated in our work can be useful for the development and/or improvement of automated solutions for quality control of hPSCs.

The Kinetic and Kinematic Efficacy of Posterior Leaf Spring Ankle-foot Orthosis in Patients with Drop foot

Background: Dorsi flexor weakness is one of the common consequences of stroke with a negative impact on normal walking. Posterior leaf spring (PLS) Ankle Foot Orthosis (AFO) is the most frequent prescription to assist foot clearance and leg propulsion in these patients. However, the real efficacy of this AFO needs more attention. This study aimed to investigate the efficacy of PLS AFO on gait outcomes as the most common AFO in drop foot post-stroke patients. Methods: The study design was a pre–post-test experiments in which twenty drop foot patients with a mean age of 65 years with a mean age of 58.45 (±5.23) years who were 4/5 years post-stroke. They walked at self-selected walking speed on a 10 meters walk away in two conditions of with their own shoes and PLS AFO. The 3D motion capture gait analysis system including 6 vicon cameras and a Kistler force plate were used in order to measure gait kinetic and kinematic variables. For each trial, each joints (ankle, knee and hip) angle, moment and power were averaged over one-minute walking. Results: Walking with PLS showed a statistically significant improve kinetic and kinematic variables in hip, knee and ankle joints included power, moments and angles at entire gait cycle. P<0.05. Conclusions: In our study of stroke patients who were fitted with a PLS AFO, immediate significant improvements occurred in most kinetic and kinematic than shoes only in sacrifice some others.

Prediction of Femoral Bone Strength in the Presence of Tumors and Tumor-like Lesions Using Finite Element Analysis.

Patients with bone tumors in their femurs are at risk of developing pathological fractures. Tumors with high fracture risk, especially fragile malignant lesions, are treated surgically. However, it is difficult to estimate bone strength based on clinical and radiographic findings. This study aimed to determine whether finite element analysis (FEA) provides useful information on the bone strength of femurs with tumors and tumor-like lesions. Total femoral computed tomography (CT) data (slice thickness, 0.5 mm) were retrospectively obtained from 18 patients with femoral bone tumors. Three-dimensional FEA of femurs were developed using CT data. The virtual femoral head compression test and direct three-point bending test were performed on the femurs using FEA to predict bone strength and fracture location. The compression direction was parallel to the mechanical axis, whereas that of the three-point bending test was applied to the tumor itself. In the femoral head compression test using FEA, 13 out of 18 femurs with bone tumors fractured at the femoral head, while 14 out of 18 femurs fractured at the tumor site during the virtual direct three-point bending test. The median loads predicted using the femoral head compression test were significantly higher than those predicted by the direct three-point bending test. The FEA results indicated that pathological fractures are unlikely to occur during normal walking. Direct external forces applied to the tumor body may lead to fractures.

The effect of knee braces on knee joint kinematics at different exercise speeds

ABSTRACT This study aims to investigate the influence of a new semi-rigid knee joint braces on kinematics using the Opti-knee knee joint kinematic analysis system at various exercise speeds. Twenty-four healthy young male adults were recruited for this study. Participants were randomly assessed while wearing and not wearing knee brace at four different speeds on a treadmill: normal walking (3.6 km/h), brisk walking (5.4 km/h), jogging (9 km/h), and moderate intensity running (10.8 km/h). Six degrees of freedom kinematic data from the knee joint were collected. Paired t-tests were conducted to calculate the kinematic differences. At speeds of 3.6 km/h and 5.4 km/h, wearing the knee brace led to reduced knee joint mobility in anterior-posterior translation, superior-inferior translation, internal-external rotation, and flexion-extension angles during the stance phase (P < 0.05). At 9 km/h, wearing the brace reduced knee joint internal-external rotation and flexion-extension mobility during the stance phase (P < 0.05). At 10.8 km/h, wearing the brace reduced knee joint flexion-extension mobility during the stance phase (P < 0.05). Wearing brace has significant influence on knee kinematics at four speeds, and the effect of brace varies with the speed of movement.

Gait Analysis of Elderly and Young People Based on Joint Angles and Positions

For the elderly, the motor function of walking is significant for the maintenance and improvement of their quality of life (QOL). Walking patterns have been postulated to be associated with a decline in walking ability. The objective of this study was to develop a wearable sensor that can capture changes in walking ability in daily life. To this end, motion capture was employed to measure the lower limb joint angles and the trajectories of the lower limbs and knees for each subject while walking at a normal walking speed and to compare the results between elderly and young patients. The differences in walking patterns between the elderly and young patients were analyzed in terms of elevation angles, and an index was calculated to capture changes during walking based on elevation angles and trajectories.

Experimental study on enhancing pedestrian efficiency and crowd safety with regular sound under open boundaries

Abstract We empirically investigated the impact of regular sound on planar pedestrian movement in open boundary environments, a rarely studied topic. Participants walked to regular sound with different tempos (70 BPM vs. 100 BPM) and types (monotone vs. periodic ‘tick-tack’ rhythm). We found that regular sounds at 100 BPM, close to the normal walking pace, improve pedestrian efficiency. They reduce passing time by 8.41% and increase average flow by 9.50%. This efficiency enhancement is lower compared to single-file experiment with periodic boundaries, where reaching a high-density jammed phase is easier. Additionally, this efficiency enhancement from sound is reduced by unstable step synchronization under open boundaries and turning behavior. Regular sound significantly improves crowd safety in turning areas, where congestion levels (Cls) and crowd danger (Cd) are highest. Cls decrease by 8.27% with the 100 BPM monotone, and Cd decreases by 19.1% with the 100 BPM periodic rhythm. Operationally, regular sounds at 100 BPM can be used to guide pedestrian flow smoothly and effectively in crowd management.

Cognitive functions explain discrete parameters of normal walking and dual-task walking, but not postural sway in quiet stance among physically active older people.

Postural control is dependent on the central nervous system's accurate interpretation of sensory information to formulate and execute adequate motor actions. Research has shown that cognitive functions are associated with both postural control and fall risk, but specific associations are not established. The aim of this study was to explore how specific components of everyday postural control tasks are associated with both general and specific cognitive functions. Forty-six community-dwelling older adults reported their age, sex, physical activity level, falls and fall-related concerns. The following cognitive aspects were assessed: global cognition, executive functions, processing speed and intraindividual variability. Postural control was quantified by measuring postural sway in quiet stance, walking at a self-selected pace, and walking while performing a concurrent arithmetical task. Separate orthogonal projections of latent structures models were generated for each postural control outcome using descriptive and cognitive variables as explanatory variables. Longer step length and faster gait speed were related to faster processing speed and less intraindividual variability in the choice reaction test. Moreover, longer step length was also related to less fall-related concerns and less severe fall-related injuries, while faster gait speed was also related to female sex and poorer global cognition. Lower dual-task cost for gait speed was explained by the executive function inhibition and faster processing speed. Postural sway in quiet stance was not explained by cognitive functions. Cognitive functions explained gait speed and step length during normal walking, as well as the decrease of gait speed while performing a concurrent cognitive task. The results suggest that different cognitive processes are important for different postural control aspects. Postural sway in quiet stance, step time and gait variability seem to depend more on physical and automatic processes rather than higher cognitive functions among physically active older people. The relationships between cognitive functions and postural control likely vary depending on the specific tasks and the characteristics of different populations.

Surface Electromyography and Gait Features in Patients after Anterior Cruciate Ligament Reconstruction.

An important reason for the poor recovery of anterior cruciate ligament (ACL) injuries is the poor recovery of muscle function. Therefore, we used surface electromyography (sEMG) and gait analysis to explore the muscle activation patterns and gait characteristics between lower limbs under different exercise states in patients, following anterior cruciate ligament reconstruction (ACLR). Forty-one adults with unilateral ACL injuries in Binzhou Medical University Hospital from October 2022 to June 2023 were allocated to three groups according to the time after ACL reconstruction: group A (≤3 months, 16), group B (3 months-1 year, 13), and group C (>1 year, 12). Patients were tested by sEMG and gait, while straight leg raising (SLR), walking at normal speed, fast walking, and walking up and down the stairs. Two related sample tests were performed for the normalized root mean square (RMS) values and gait parameters. Muscle function changes varied in different training tasks. The RMS value of the involved side was more than the uninvolved side in biceps femoris and semitendinosus of group A (p < 0.010), and for the bilateral rectus femoris (RS), vastus medialis (VM), and vastus lateralis in group B, only the comparison of the RS was significant in group C during fast walking and going up and down the stairs. The ground impact (0.90 [0.63, 1.33] vs. 0.71 [0.43, 1.02], p = 0.035) of the uninvolved side was significantly decreased compared to those of the involved side in patients with ACLR when going down the stairs. Different muscles need to be focused on at different stages of the postoperative period. sEMG and gait analysis can guide the development of a rehabilitation program.

Different types of mastoid vibrations affect the amount and structure of minimum toe clearance variability differently

BackgroundThe majority of research primarily examines the role of the vestibular system in regulating balance by assessing gait parameters in the transverse plane while neglecting those in the sagittal plane. The present study aimed to examine the impact of various forms of mastoid vibration (MV) on minimum toe clearance (MTC) and its pattern of variability. This study proposed two hypotheses: 1) the application of MV reduced the MTC, and 2) the application of different forms of MV influenced the amount and structure of MTC variability. MethodsA total of twenty young adults participated in this study. A high-resolution motion capture system with eight cameras captured the minimum toe clearance. Three locomotor tasks were randomly assigned to these young participants: 1) walking normally on the treadmill, 2) walking with unilateral MV, and 3) walking with bilateral MV. The dependent variables were the mean of MTC, the amount, and the structure of MTC variability. The amount of MTC variability was calculated by the coefficient of variation represented, and the structure of MTC variability was measured using a sample entropy measure for a total of 200 MTCs. ResultsApplying unilateral and bilateral MV decreased the MTC significantly (-1.6 %, p = 0.038; −4.3 %, p < 0.001) compared to normal walking. Also, applying unilateral MV increased the amount (11.8 %, p = 0.001) and structure of MTC variability (14.3 %, p < 0.001) compared to normal walking. However, applying bilateral MV decreased the amount (-8.8 %, p = 0.001) and structure of MTC variability (-9.0 %, p < 0.001) compared to regular walking. ConclusionAlthough the statistical differences in MTC and MTC variability were observed in the present study, the mean differences among the different MV conditions were relatively small, thereby requiring meticulous deliberation when extrapolating the results when implementing this MTC in the pathological cohort.

Validation of full-length radiograph based musculoskeletal modeling method to estimate medial and lateral knee contact forces

BackgroundAnatomical parameters of the pelvis, femur, and tibia derived from the full-length radiograph can be used to create a more accurate musculoskeletal model compared to marker-based linear scaling method. However, whether this model leads to more accurate estimations of medial knee contact force (MCF) and lateral knee contact force (LCF) than marker-based linear scaling method is still unknown. Research questionThis main purpose of this study was to determine whether musculoskeletal model generated from full-length radiograph improves the estimations of MCF and LCF. MethodsAn open-source dataset including marker trajectories, ground reaction forces, in vivo knee contact forces, and full-length radiograph was used to evaluate the accuracy of full-length radiograph musculoskeletal modeling method. Subject-specific musculoskeletal models were created using anatomical parameters derived from the full-length radiograph or marker-based linear scaling methods. MCF and LCF were estimated using musculoskeletal simulations of normal walking trails. The accuracy of modeling methods was determined by comparing the estimated and in vivo measured MCF and LCF. ResultsCompared to the marker-based linear scaling approach, the full-length radiograph musculoskeletal modeling method exhibited decreases of 38.3 % and 41.3 % in root mean square error for MCF and LCF respectively, as well as reductions of 50.0 % and 49.3 % in mean peak errors for MCF and LCF respectively. SignificanceThe full-length radiograph musculoskeletal modeling method provides a more accurate way to estimate MCF and LCF compared to the traditional maker-based linear scaling approach, which may contribute to understand the initiation, progression, and treatment of OA.

Prediction of abnormal gait behavior of lower limbs based on depth vision

Abstract As a kind of lower-limb motor assistance device, the intelligent walking aid robot plays an essential role in helping people with lower-limb diseases to carry out rehabilitation walking training. In order to enhance the safety performance of the lower-limb walking aid robot, this study proposes a deep vision-based abnormal lower-limb gait prediction model construction method for the problem of abnormal gait prediction of patients’ lower limbs. The point cloud depth vision technique is used to acquire lower-limb motion data, and a multi-posture angular prediction model is trained using long and short-term memory networks to build a model of the user’s lower-limb posture characteristics during normal walking as well as a real-time lower-limb motion prediction model. The experimental results indicate that the proposed lower-limb abnormal behavior prediction model is able to achieve a 97.4% prediction rate of abnormal lower-limb movements within 150 ms. Additionally, the model demonstrates strong generalization ability in practical applications. This paper proposes further ideas to enhance the safety performance of lower-limb rehabilitation robot use for patients with lower-limb disabilities.

A 24-Week Combined Resistance and Balance Training Program Improves Physical Function in Older Adults: A Randomized Controlled Trial

Abstract Jiang, G, Tan, X, Zou, J, and Wu, X. A 24-week combined resistance and balance training program improves physical function in older adults: a randomized controlled trial. J Strength Cond Res XX(X): 000–000, 2024—This randomized controlled trial assessed the feasibility of older adults performing combined resistance and balance training (RBT) and compared the effects of RBT on physical function with those of resistance training (RT) alone and with no exercise training in older adults. In total, 65 community-dwelling adults aged 60–74 years were randomly assigned to an RT (n = 22), RBT (n = 22), or control (n = 21) group. The exercise intervention consisted of RT or RBT for 45 minutes, 3 times per week for 24 weeks. The control group engaged in no exercise training. The compliance rates were 93% in the RT group and 92% in the RBT group. No training-related adverse effect was observed. In the RT and RBT groups, dynamic balance (p = 0.017; p &lt; 0.001, respectively), maximum walking speed (p = 0.014; p &lt; 0.001), upper extremity (p = 0.013; p = 0.009) and lower extremity (p = 0.009; p &lt; 0.001) muscle strength, and spirometry (p = 0.043; p = 0.018) were significantly improved at 24 weeks compared with the control group. Only the RBT group showed significant improvement in normal walking speed (p = 0.002). Compared with the RT group, the RBT group showed additional significant improvements in dynamic balance (p = 0.001) and lower limb muscle strength (p = 0.027). The findings of this randomized controlled trial indicated that RBT was safe and feasible for older adults. Long-term RBT had better effects than either no exercise training or RT alone on improving physical function in older adults. Compared with RT, RBT additionally benefited dynamic balance and lower limb muscle function, which are clinically important factors in preventing falls, frailty, disability, and other geriatric syndromes.

The efficacy of the Novel Hybrid Passive Spring Damper Ankle Foot Orthosis regard to kinetic and kinematic parameters of patients with Multiple Sclerosis: An intervention study

ABSTRACT Drop foot is a common consequence of Multiple Sclerosis (MS), which may be improved somewhat by an ankle-foot orthosis (AFO). This study aimed to examine the immediate effect of using the recently developed Novel Hybrid Passive Spring Damper AFO (the novel HPSDAFO) on the kinetic and kinematic parameters of patients with MS (PwMS) in the sagittal plane. Twelve PwMS who suffered a unilateral drop foot participated in this study and fitted with the novel HPSDAFO. They walked with the novel HPSDAFO on the affected side and shoe on the affected side at a self-selected speed. Walking by the novel HPSDAFO, the symmetry of all of the evaluated sagittal kinetic and kinematic parameters improved noticeably. The range of ankle plantarflexion and knee flexion increased significantly at the stance phase. Power generation increased at all three joints. The peak of ankle dorsiflexion at early stances and the first peak of knee extension moments increased significantly but decreased at the hip joint. Changes in sagittal ROM, moment, and power generation in the plane and the improved symmetry revealed a more normal walking by using the novel HPSDAFO on the affected limb of PwMS.

Beyond Inverse Dynamics: Methods for Assessment of Individual Muscle Function during Gait.

Three-dimensional motion analysis performed in the modern gait analysis laboratory provides a wealth of information about the kinematics and kinetics of human locomotion, but standard gait analysis is largely restricted to joint-level measures. Three-dimensional joint rotations, joint moments, and joint powers tell us a great deal about gait mechanics, but it is often of interest to know about the roles that muscles play. This narrative review surveys work that has been done, largely over the past four decades, to augment standard gait analysis with muscle-level assessments of function. Often, these assessments have incorporated additional technology such as ultrasound imaging, or complex modeling and simulation techniques. The review discusses measurements of muscle moment arm during walking along with assessment of muscle mechanical advantage, muscle-tendon lengths, and the use of induced acceleration analysis to determine muscle roles. In each section of the review, examples are provided of how the auxiliary analyses have been used to gain potentially useful information about normal and pathological human walking. While this work highlights the potential benefits of adding various measures to gait analysis, it is acknowledged that challenges to implementation remain, such as the need for specialized knowledge and the potential for bias introduced by model choices.

Development of an individualized stable and force-reducing lower-limb exoskeleton

In this study, an individualized and stable passive-control lower-limb exoskeleton robot was developed. Users’ joint angles and the center of pressure (CoP) of one of their soles were input into a convolutional neural network (CNN)–long short-term memory (LSTM) model to evaluate and adjust the exoskeleton control scheme. The CNN–LSTM model predicted the fitness of the control scheme and output the results to the exoskeleton robot, which modified its control parameters accordingly to enhance walking stability. The sole’s CoP had similar trends during normal walking and passive walking with the developed exoskeleton; the y-coordinates of the CoPs with and without the exoskeleton had a correlation of 91%. Moreover, electromyography signals from the rectus femoris muscle revealed that it exerted 40% less force when walking with a stable stride length in the developed system than when walking with an unstable stride length. Therefore, the developed lower-limb exoskeleton can be used to assist users in achieving balanced and stable walking with reduced force application. In the future, this exoskeleton can be used by patients with stroke and lower-limb weakness to achieve stable walking.

Machine Learning Based Abnormal Gait Classification with IMU Considering Joint Impairment.

Gait analysis systems are critical for assessing motor function in rehabilitation and elderly care. This study aimed to develop and optimize an abnormal gait classification algorithm considering joint impairments using inertial measurement units (IMUs) and walkway systems. Ten healthy male participants simulated normal walking, walking with knee impairment, and walking with ankle impairment under three conditions: without joint braces, with a knee brace, and with an ankle brace. Based on these simulated gaits, we developed classification models: distinguishing abnormal gait due to joint impairments, identifying specific joint disorders, and a combined model for both tasks. Recursive Feature Elimination with Cross-Validation (RFECV) was used for feature extraction, and models were fine-tuned using support vector machine (SVM), random forest (RF), and extreme gradient boosting (XGB). The IMU-based system achieved over 91% accuracy in classifying the three types of gait. In contrast, the walkway system achieved less than 77% accuracy in classifying the three types of gait, primarily due to high misclassification rates between knee and ankle joint impairments. The IMU-based system shows promise for accurate gait assessment in patients with joint impairments, suggesting future research for clinical application improvements in rehabilitation and patient management.

Design of functionally graded porous lattice structure tibial implant for TAR

Use of porous lattice structures and functionally graded (FG) implants in orthopaedic applications has emerged as a promising solution to reduce stress shielding. However, there is a notable research gap in examining the effects of post-operative scenarios within the lattice pores and different porosity distribution laws in functionally graded porous lattice structure (FGPLS) implants on the biomechanical performance of tibial implant for total ankle replacement (TAR). The objective of the study is to investigates the effects of both post-operative tissues and various porosity distribution laws on the biomechanical performance of tibial implant for TAR and proposes a new design strategy. CAD models for lattice structures at various porosities were developed to incorporate the effects of post-operative tissues such as fibrous tissue, cartilage, immature bone, and mature bone. The pore spaces of these lattice structures were assumed to be filled with the post-operative ingrowth tissues. The lattice structure and these tissues together form the Representative volume element (RVE), whose effective properties were calculated using Asymptotic homogenization (AH) technique. Equations linking mechanical properties and porosity were established and used to assign mechanical properties to macro-FE models of FGPLS tibial implants based on three different power laws i.e. n = 0.1,1 and 5. Macro-FE models for intact and implanted tibia bones were developed using homogeneous properties of cortical bone and heterogeneous cancellous bone properties. The proximal part of the tibia was fixed, and a compressive load was applied through the anterior nodes of the meniscal bearing to represent dorsiflexion loading during normal walking. The Finite Element Analysis (FEA) was utilized to investigate the biomechanical performance of these implanted models in terms of stress distribution in the tibia bone and implant-bone micromotion. A comparison was made between models with solid metallic implants and those with FGPLS implants. Additionally, models with varying post-operative tissues in the pore space were compared, as well as models with different porosity variation laws were also compared. Results demonstrated that models implanted with FGPLS implants having porosity variation based on power law n = 0.1 showed increased bone stress and micromotion compared to those with solid metallic implants. Specifically, in models with FGPLS implants with porosity variation based on a power law of n = 0.1, the bone area with stress ranging from 2–5 MPa increased significantly in the periprosthetic region compared to models with solid metallic implants. The bone stress value for the majority of the region above the medial and lateral peg increased from 1–2 MPa to 2–5 MPa. Although there was a slight increase in micromotion values, they remained below the acceptable threshold of 50 µm. Models with porosity variations based on power laws n = 1 and n = 5 exhibited similar bone stress and micromotion results as solid metallic implants. Additionally, no significant difference in bone stresses was observed for different stages of bone ingrowth at pore space. These findings indicate that both the porous structure and porosity distribution within the implant significantly influence the biomechanical performance of tibial implants for TAR. So, it can be concluded that FGPLS implants with power law n = 0.1 are effective in reducing stress shielding and supporting the long-term survival of TAR by increasing bone stress and reducing the chances of aseptic loosening due to implant induced adaptive bone remodelling.

Changes in rotator movement during early gait acquisition in after total hip arthroplasty

BackgroundIn walking in healthy adults, rotation of the hip joint affects stride length and shifts the center of gravity, but these are not seen in hip osteoarthritis which affects gait. In gait of total hip arthroplasty, there are few reports on changes in the horizontal plane. This study clarified the preoperative and early postoperative gait characteristics of patients undergoing total hip arthroplasty. MethodsThe analysis included 12 females who underwent initial total hip arthroplasty using a posterolateral approach. Gait was measured pre and postoperatively using a three-dimensional motion analysis device. Statistics were compared pre and postoperative range of motion, muscle strength, walking speed, stride length, gravity movement distance, trunk angle, hip joint angle, and joint moment. FindingsThe maximum hip abduction moment and trunk flexion angle to the surgical side were lower than in healthy subjects. The angle of internal rotation during the stance phase was significantly higher in the postoperative period. The distance of the center of gravity shift in the left and right directions was significantly decreased postoperatively. InterpretationGait disturbance was seen preoperatively and remained after surgery. Walking after total hip arthroplasty provides the hip joint rotates inward which is closer to normal walking. However, no change was observed in the external rotation moment of the hip joint during walking. We suspect that the invasiveness of the posterolateral approach of total hip arthroplasty affects the muscles for external rotation of the hip joint. This can also cause in gait disturbances.