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1.
J Neuroeng Rehabil ; 18(1): 151, 2021 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-34663392

RESUMO

BACKGROUND: As hyperactive muscle stretch reflexes hinder movement in patients with central nervous system disorders, they are a common target of treatment. To improve treatment evaluation, hyperactive reflexes should be assessed during activities as walking rather than passively. This study systematically explores the feasibility, reliability and validity of sudden treadmill perturbations to evoke and quantify calf muscle stretch reflexes during walking in children with neurological disorders. METHODS: We performed an observational cross-sectional study including 24 children with cerebral palsy (CP; 6-16 years) and 14 typically developing children (TD; 6-15 years). Short belt accelerations were applied at three different intensities while children walked at comfortable speed. Lower leg kinematics, musculo-tendon lengthening and velocity, muscle activity and spatiotemporal parameters were measured to analyze perturbation responses. RESULTS: We first demonstrated protocol feasibility: the protocol was completed by all but three children who ceased participation due to fatigue. All remaining children were able to maintain their gait pattern during perturbation trials without anticipatory adaptations in ankle kinematics, spatiotemporal parameters and muscle activity. Second, we showed the protocol's reliability: there was no systematic change in muscle response over time (P = 0.21-0.54) and a bootstrapping procedure indicated sufficient number of perturbations, as the last perturbation repetition only reduced variability by ~ 2%. Third, we evaluated construct validity by showing that responses comply with neurophysiological criteria for stretch reflexes: perturbations superimposed calf muscle lengthening (P < 0.001 for both CP and TD) in all but one participant. This elicited increased calf muscle activity (359 ± 190% for CP and 231 ± 68% for TD, both P < 0.001) in the gastrocnemius medialis muscle, which increased with perturbation intensity (P < 0.001), according to the velocity-dependent nature of stretch reflexes. Finally, construct validity was shown from a clinical perspective: stretch reflexes were 1.7 times higher for CP than TD for the gastrocnemius medialis muscle (P = 0.017). CONCLUSIONS: The feasibility and reliability of the protocol, as well as the construct validity-shown by the exaggerated velocity-dependent nature of the measured responses-strongly support the use of treadmill perturbations to quantify stretch hyperreflexia during gait. We therefore provided a framework which can be used to inform clinical decision making and treatment evaluation.


Assuntos
Paralisia Cerebral , Criança , Estudos Transversais , Humanos , Reflexo Anormal , Reflexo de Estiramento , Reprodutibilidade dos Testes
2.
Sensors (Basel) ; 21(19)2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34640956

RESUMO

Stumbling during gait is commonly encountered in patients who suffer from mild to serious walking problems, e.g., after stroke, in osteoarthritis, or amputees using a lower leg prosthesis. Instead of self-reporting, an objective assessment of the number of stumbles in daily life would inform clinicians more accurately and enable the evaluation of treatments that aim to achieve a safer walking pattern. An easy-to-use wearable might fulfill this need. The goal of the present study was to investigate whether a single inertial measurement unit (IMU) placed at the shank and machine learning algorithms could be used to detect and classify stumbling events in a dataset comprising of a wide variety of daily movements. Ten healthy test subjects were deliberately tripped by an unexpected and unseen obstacle while walking on a treadmill. The subjects stumbled a total of 276 times, both using an elevating recovery strategy and a lowering recovery strategy. Subjects also performed multiple Activities of Daily Living. During data processing, an event-defined window segmentation technique was used to trace high peaks in acceleration that could potentially be stumbles. In the reduced dataset, time windows were labelled with the aid of video annotation. Subsequently, discriminative features were extracted and fed to train seven different types of machine learning algorithms. Trained machine learning algorithms were validated using leave-one-subject-out cross-validation. Support Vector Machine (SVM) algorithms were most successful, and could detect and classify stumbles with 100% sensitivity, 100% specificity, and 96.7% accuracy in the independent testing dataset. The SVM algorithms were implemented in a user-friendly, freely available, stumble detection app named Stumblemeter. This work shows that stumble detection and classification based on SVM is accurate and ready to apply in clinical practice.


Assuntos
Atividades Cotidianas , Membros Artificiais , Marcha , Humanos , Máquina de Vetores de Suporte , Caminhada
3.
Clin Biomech (Bristol, Avon) ; 89: 105455, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34454328

RESUMO

BACKGROUND: Patients with knee osteoarthritis can adapt their gait to unload the most painful knee joint in order to try to reduce pain and improve physical function. However, these gait adaptations can cause higher loads on the contralateral joints. The aim of the study was to investigate the interlimb differences in knee and hip frontal plane moments during gait in patients with knee osteoarthritis and in healthy controls. METHODS: Forty patients with knee osteoarthritis and 19 healthy matched controls were measured during comfortable treadmill walking. Frontal plane joint moments were obtained of both hip and knee joints. Differences in interlimb moments within each group were assessed using statistical parametric mapping and discrete gait parameters. FINDINGS: No interlimb differences were observed in patients with knee osteoarthritis and control subjects at group level. Furthermore, the patients presented similar interlimb variability as the controls. In a small subgroup (n = 12) of patients, the moments in the most painful knee were lower than in the contralateral knee, while the other patients (n = 28) showed higher moments in the most painful knee compared to the contralateral knee. However, no interlimb differences in the hip moments were observed within the subgroups. INTERPRETATION: Patients with knee osteoarthritis do not have interlimb differences in knee and hip joint moments. Patients and healthy subjects demonstrate a similar interlimb variability in the moments of the lower extremities. In this context, differences in knee pain in patients with knee osteoarthritis did not induce any interlimb differences in the frontal plane knee and hip moments.

4.
Disabil Rehabil ; : 1-10, 2021 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-34365883

RESUMO

PURPOSE: Previous studies investigating the effectiveness of exergame balance-training (using video-games) in children with cerebral palsy (CP) yielded inconsistent results that could be related to underpowered studies. Therefore, in this multicenter intervention study, we investigated whether exergaming improves balance clinically in spastic CP. MATERIALS AND METHODS: In total, 35 children with unilateral or bilateral spastic CP (GMFCS-level I-II) were included (age-range: 7-16 years); 16 at VUMC (trial: NTR6034), 19 at UHG (trial: NCT03219112). All participants received care as usual. The intervention group (n = 24) additionally performed exergame-training; 6-8 weeks home-based X-box One Kinect training focused on balance. Balance performance was assessed with the pediatric balance scale (PBS) and two subscales of the Bruininks-Oseretsky Test of Motor Proficiency-2nd edition ("balance" [BOTbal] and "running speed and agility" [BOTrsa]). Mixed model ANOVAs with between and within factors were used to test differences between and within groups. RESULTS: On group level, no post-intervention differences were found between the intervention and control group (PBS: p = 0.248, ηp2 = 0.040; BOTbal: p = 0.374, ηp2 = 0.024; BOTrsa: p = 0.841, ηp2 = 0.001). Distribution of CP-symptoms (unilateral versus bilateral) did not affect training (PBS: p = 0.373, ηp2 = 0.036; BOTbal: p = 0.127, ηp2 = 0.103; BOTrsa: p = 0.474, ηp2 = 0.024). Children with low baseline balance performance (based on PBS) in the intervention group showed improvements in balance performance after training (PBS: p = 0.003, ηp2 = 0.304; BOTbal: p = 0.008, ηp2 = 0.258), whereas children with high baseline balance performance did not. CONCLUSIONS: This exergame-training resulted in balance improvements for the current population of CP that had a low baseline function.IMPLICATIONS FOR REHABILITATIONExergame-training (training using video-games) shows mixed results in children with cerebral palsy (CP).Children with spastic CP (GMFCS level I-II) with a high baseline balance-level did not show functional balance improvements after this home-based exergame-training, suggesting that these children should not be enrolled in this type of exergame-training protocol.Children with spastic CP (GMFCS level I-II) with a low baseline balance-level showed clinically relevant functional balance improvements after this home-based exergame-training, suggesting that these children can benefit from enrolment in this type of exergame-training protocol to improve their balance.The distribution of CP-symptoms did not affect the effectiveness of this balance exergame-training in children with spastic CP with GMFCS-level I and II.

5.
J Electromyogr Kinesiol ; 60: 102572, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34273728

RESUMO

PURPOSE: To compare the responses in knee joint muscle activation patterns to different perturbations during gait in healthy subjects. SCOPE: Nine healthy participants were subjected to perturbed walking on a split-belt treadmill. Four perturbation types were applied, each at five intensities. The activations of seven muscles surrounding the knee were measured using surface EMG. The responses in muscle activation were expressed by calculating mean, peak, co-contraction (CCI) and perturbation responses (PR) values. PR captures the responses relative to unperturbed gait. Statistical parametric mapping analysis was used to compare the muscle activation patterns between conditions. RESULTS: Perturbations evoked only small responses in muscle activation, though higher perturbation intensities yielded a higher mean activation in five muscles, as well as higher PR. Different types of perturbation led to different responses in the rectus femoris, medial gastrocnemius and lateral gastrocnemius. The participants had lower CCI just before perturbation compared to the same phase of unperturbed gait. CONCLUSIONS: Healthy participants respond to different perturbations during gait with small adaptations in their knee joint muscle activation patterns. This study provides insights in how the muscles are activated to stabilize the knee when challenged. Furthermore it could guide future studies in determining aberrant muscle activation in patients with knee disorders.


Assuntos
Marcha , Músculo Esquelético , Eletromiografia , Voluntários Saudáveis , Humanos , Articulação do Joelho , Caminhada
6.
J Biomech ; 126: 110629, 2021 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-34320419

RESUMO

Understanding the effect of individual marker misplacements is important to improve the repeatability and aid to the interpretation of multi-segment foot models like the Oxford and Rizzoli Foot Models (OFM, RFM). Therefore, this study aimed to quantify the effect of controlled anatomical marker misplacement on multi-segment foot kinematics (i.e. marker placement sensitivity) as calculated by OFM and RFM in a range of foot sizes. Ten healthy adults and nine children were included. A combined OFM and RFM marker set was placed on their right foot and a static standing trial was collected. Each marker was replaced ± 10 mm in steps of 1 mm over the three axes of a foot coordinate system. For each replacement the change in segment orientation (tibia, hindfoot, midfoot, forefoot) was calculated with respect to the reference pose in which no markers were replaced. A linear fit was made to calculate the sensitivity of segment orientation to marker misplacement in °/mm. Additionally, the effect of foot size on the sensitivity was determined using linear regressions. For every foot segment of both models, at least one marker had a sensitivity ≥ 1.0°/mm. Highest values were found for the markers at the posterior aspect of the calcaneus in OFM (1.5°/mm) and the basis of the second metatarsal in RFM (1.4°/mm). Foot size had a small effect on 40% of the sensitivity values. This study identified markers of which consistent placement is critical to prevent clinically relevant errors (>5°). For more repeatable multi-segment models, the role of these markers within the models' definitions needs to be reconsidered.


Assuntos
Calcâneo , , Adulto , Fenômenos Biomecânicos , Criança , Marcha , Humanos , Rotação , Tíbia
7.
J Neuroeng Rehabil ; 18(1): 97, 2021 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-34103064

RESUMO

BACKGROUND: In people with calf muscle weakness, the stiffness of dorsal leaf spring ankle-foot orthoses (DLS-AFO) needs to be individualized to maximize its effect on walking. Orthotic suppliers may recommend a certain stiffness based on body weight and activity level. However, it is unknown whether these recommendations are sufficient to yield the optimal stiffness for the individual. Therefore, we assessed whether the stiffness following the supplier's recommendation of the Carbon Ankle7 (CA7) dorsal leaf matched the experimentally optimized AFO stiffness. METHODS: Thirty-four persons with calf muscle weakness were included and provided a new DLS-AFO of which the stiffness could be varied by changing the CA7® (Ottobock, Duderstadt, Germany) dorsal leaf. For five different stiffness levels, including the supplier recommended stiffness, gait biomechanics, walking energy cost and speed were assessed. Based on these measures, the individual experimentally optimal AFO stiffness was selected. RESULTS: In only 8 of 34 (23%) participants, the supplier recommended stiffness matched the experimentally optimized AFO stiffness, the latter being on average 1.2 ± 1.3 Nm/degree more flexible. The DLS-AFO with an experimentally optimized stiffness resulted in a significantly lower walking energy cost (- 0.21 ± 0.26 J/kg/m, p < 0.001) and a higher speed (+ 0.02 m/s, p = 0.003). Additionally, a larger ankle range of motion (+ 1.3 ± 0.3 degrees, p < 0.001) and higher ankle power (+ 0.16 ± 0.04 W/kg, p < 0.001) were found with the experimentally optimized stiffness compared to the supplier recommended stiffness. CONCLUSIONS: In people with calf muscle weakness, current supplier's recommendations for the CA7 stiffness level result in the provision of DLS-AFOs that are too stiff and only achieve 80% of the reduction in energy cost achieved with an individual optimized stiffness. It is recommended to experimentally optimize the CA7 stiffness in people with calf muscle weakness in order to maximize treatment outcomes. Trial registration Nederlands Trial Register 5170. Registration date: May 7th 2015. http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=5170 .


Assuntos
Órtoses do Pé , Tornozelo , Articulação do Tornozelo , Fenômenos Biomecânicos , Peso Corporal , Marcha , Humanos , Debilidade Muscular , Caminhada
8.
Gait Posture ; 88: 225-230, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34119777

RESUMO

BACKGROUND: Walking speed is a confounding factor in biomechanical analyses of gait, but still many studies compare gait biomechanics at comfortable walking speed (CWS) that is likely to differ between groups or conditions. To identify gait deviation unrelated to walking speed, methods are needed to correct biomechanical data over the gait cycle for walking speed. RESEARCH QUESTION: How to compare knee kinetics over the gait cycle at different walking speeds? METHODS: 22 asymptomatic subjects walked on a dual-belt treadmill at CWS and 4 fixed speeds. Knee moments in sagittal (KFM) and frontal plane (KAM) were calculated via inverse dynamics. The net moment differences between CWS and fixed speed were expressed as a root-mean-square error (RMSE) normalized to the range of the variable. Two methods to correct for walking speed were compared. In method 1, KFM and KAM values were estimated based on interpolation between speeds at each percentage of the gait cycle. In method 2, principal component analysis was used to extract speed related features to reconstruct KFM and KAM at the speed of interest. The accuracy of both methods was tested using a leave-one-out cross validation. RESULTS: Walking speed influenced the magnitude and shape of KFM and KAM. To account for these speed influences using both methods, leave-one-out cross validation showed low normalized RMSE (< 5 %), with little difference between the two methods. RMSE for both reconstruction methods were up to 60 % lower than the RMSE between CWS and fixed speed. SIGNIFICANCE: Both methods could accurately correct knee kinetics over the gait cycle for the effects of walking speed. Walking speed dependency should be incorporated in each gait laboratory's reference dataset to be able to identify gait deviations unrelated to gait speed.


Assuntos
Osteoartrite do Joelho , Velocidade de Caminhada , Fenômenos Biomecânicos , Marcha , Humanos , Cinética , Articulação do Joelho , Caminhada
9.
Front Hum Neurosci ; 15: 659415, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34149378

RESUMO

The first years of life might be critical for encouraging independent walking in children with cerebral palsy (CP). We sought to identify mechanisms that may underlie the impaired development of walking in three young children with early brain lesions, at high risk of CP, via comprehensive instrumented longitudinal assessments of locomotor patterns and muscle activation during walking. We followed three children (P1-P3) with early brain lesions, at high risk of CP, during five consecutive gait analysis sessions covering a period of 1 to 2 years, starting before the onset of independent walking, and including the session during the first independent steps. In the course of the study, P1 did not develop CP, P2 was diagnosed with unilateral and P3 with bilateral CP. We monitored the early development of locomotor patterns over time via spatiotemporal gait parameters, intersegmental coordination (estimated via principal component analysis), electromyography activity, and muscle synergies (determined from 11 bilateral muscles via nonnegative matrix factorization). P1 and P2 started to walk independently at the corrected age of 14 and 22 months, respectively. In both of them, spatiotemporal gait parameters, intersegmental coordination, muscle activation patterns, and muscle synergy structure changed from supported to independent walking, although to a lesser extent when unilateral CP was diagnosed (P2), especially for the most affected leg. The child with bilateral CP (P3) did not develop independent walking, and all the parameters did not change over time. Our exploratory longitudinal study revealed differences in maturation of locomotor patterns between children with divergent developmental trajectories. We succeeded in identifying mechanisms that may underlie impaired walking development in very young children at high risk of CP. When verified in larger sample sizes, our approach may be considered a means to improve prognosis and to pinpoint possible targets for early intervention.

10.
Sensors (Basel) ; 21(8)2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33921544

RESUMO

Early brain lesions which produce cerebral palsy (CP) may affect the development of walking. It is unclear whether or how neuromuscular control, as evaluated by muscle synergy analysis, differs in young children with CP compared to typically developing (TD) children with the same walking ability, before and after the onset of independent walking. Here we grouped twenty children with (high risk of) CP and twenty TD children (age 6.5-52.4 months) based on their walking ability, supported or independent walking. Muscle synergies were extracted from electromyography data of bilateral leg muscles using non-negative matrix factorization. Number, synergies' structure and variability accounted for when extracting one (VAF1) or two (VAF2) synergies were compared between CP and TD. Children in the CP group recruited fewer synergies with higher VAF1 and VAF2 compared to TD children in the supported and independent walking group. The most affected side in children with asymmetric CP walking independently recruited fewer synergies with higher VAF1 compared to the least affected side. Our findings suggest that early brain lesions result in early alterations of neuromuscular control, specific for the most affected side in asymmetric CP.


Assuntos
Paralisia Cerebral , Fenômenos Biomecânicos , Paralisia Cerebral/diagnóstico , Criança , Pré-Escolar , Eletromiografia , Marcha , Humanos , Lactente , Músculo Esquelético , Caminhada
11.
Artigo em Inglês | MEDLINE | ID: mdl-33861038

RESUMO

The ankle-foot-orthosis (AFO), originally called Codivilla Spring, is an orthotic device prescribed to the patients with foot drop due to neurological diseases in order to control the range of motion of the ankle joint, to compensate for the muscle weakness/spasticity thus optimizing the gait function. In this paper, a historical revision of the most known and used AFO worldwide from the origin of its name and the first applications at the Rizzoli Orthopedic Institute to the most advanced solutions in use today is covered. Through the critical analysis of historical documents available, the paper reports on the controversy about the true inventor of the Codivilla Spring during the first decades of the twentieth century. Main current adult and child AFOs, in terms of their design and indications are presented. Finally, possible approaches for the selection of the correct orthosis and the individual prescription are discussed in order to manage specific mechanical neuromuscular deficiencies of the subject's ankle-foot complex optimizing walking efficiency.

12.
Gait Posture ; 86: 64-69, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33684617

RESUMO

BACKGROUND: To analyse and interpret gait patterns in pathological paediatric populations, accurate determination of the timing of specific gait events (e.g. initial contract - IC, or toe-off - TO) is essential. As currently used clinical identification methods are generally subjective, time-consuming, or limited to steps with force platform data, several techniques have been proposed based on processing of marker kinematics. However, until now, validation and standardization of these methods for use in diverse gait patterns remains lacking. RESEARCH QUESTIONS: 1) What is the accuracy of available kinematics-based identification algorithms in determining the timing of IC and TO for diverse gait signatures? 2) Does automatic identification affect interpretation of spatio-temporal parameters?. METHODS: 3D kinematic and kinetic data of 90 children were retrospectively analysed from a clinical gait database. Participants were classified into 3 gait categories: group A (toe-walkers), B (flat IC) and C (heel IC). Five kinematic algorithms (one modified) were implemented for two different foot marker configurations for both IC and TO and compared with clinical (visual and force-plate) identification using Bland-Altman analysis. The best-performing algorithm-marker configuration was used to compute spatio-temporal parameters (STP) of all gait trials. To establish whether the error associated with this configuration would affect clinical interpretation, the bias and limits of agreement were determined and compared against inter-trial variability established using visual identification. RESULTS: Sagittal velocity of the heel (Group C) or toe marker configurations (Group A and B) was the most reliable indicator of IC, while the sagittal velocity of the hallux marker configuration performed best for TO. Biases for walking speed, stride time and stride length were within the respective inter-trial variability values. SIGNIFICANCE: Automatic identification of gait events was dependent on algorithm-marker configuration, and best results were obtained when optimized towards specific gait patterns. Our data suggest that correct selection of automatic gait event detection approach will ensure that misinterpretation of STPs is avoided.


Assuntos
Algoritmos , Marcha/fisiologia , Transtornos dos Movimentos/diagnóstico , Fenômenos Biomecânicos , Criança , Bases de Dados Factuais , Feminino , Humanos , Masculino , Padrões de Referência , Reprodutibilidade dos Testes , Estudos Retrospectivos
13.
J Biomech ; 120: 110359, 2021 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-33730563

RESUMO

Movement of skin markers with respect to their underlying bone (i.e. soft tissue artifacts (STAs)) might corrupt the accuracy of marker-based movement analyses. This study aims to quantify STAs in 3D for foot markers and their effect on multi-segment foot kinematics as calculated by the Oxford and Rizzoli Foot Models (OFM, RFM). Fifteen subjects with asymptomatic feet were seated on a custom-made loading device on a computed tomography (CT) table, with a combined OFM and RFM marker set on their right foot. One unloaded reference CT-scan with neutral foot position was performed, followed by 9 loaded CT-scans at different foot positions. The 3D-displacement (i.e. STA) of each marker in the underlying bone coordinate system between the reference scan and other scans was calculated. Subsequently, segment orientations and joint angles were calculated from the marker positions according to OFM and RFM definitions with and without STAs. The differences in degrees were defined as the errors caused by the marker displacements. Markers on the lateral malleolus and proximally on the posterior aspect of the calcaneus showed the largest STAs. The hindfoot-shank joint angle was most affected by STAs in the most extreme foot position (40° plantar flexion) in the sagittal plane for RFM (mean: 6.7°, max: 11.8°) and the transverse plane for OFM (mean: 3.9°, max: 6.8°). This study showed that STAs introduce clinically relevant errors in multi-segment foot kinematics. Moreover, it identified marker locations that are most affected by STAs, suggesting that their use within multi-segment foot models should be reconsidered.


Assuntos
Artefatos , , Articulação do Tornozelo , Fenômenos Biomecânicos , Pé/diagnóstico por imagem , Humanos , Caminhada
14.
J Neuroeng Rehabil ; 18(1): 37, 2021 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-33596942

RESUMO

BACKGROUND: The foot progression angle is an important measure used to help patients reduce their knee adduction moment. Current measurement systems are either lab-bounded or do not function in all environments (e.g., magnetically distorted). This work proposes a novel approach to estimate foot progression angle using a single foot-worn inertial sensor (accelerometer and gyroscope). METHODS: The approach uses a dynamic step frame that is recalculated for the stance phase of each step to calculate the foot trajectory relative to that frame, to minimize effects of drift and to eliminate the need for a magnetometer. The foot progression angle (FPA) is then calculated as the angle between walking direction and the dynamic step frame. This approach was validated by gait measurements with five subjects walking with three gait types (normal, toe-in and toe-out). RESULTS: The FPA was estimated with a maximum mean error of ~ 2.6° over all gait conditions. Additionally, the proposed inertial approach can significantly differentiate between the three different gait types. CONCLUSION: The proposed approach can effectively estimate differences in FPA without requiring a heading reference (magnetometer). This work enables feedback applications on FPA for patients with gait disorders that function in any environment, i.e. outside of a gait lab or in magnetically distorted environments.


Assuntos
Análise da Marcha/instrumentação , Dispositivos Eletrônicos Vestíveis , Acelerometria/instrumentação , Adulto , Fenômenos Biomecânicos , Pé/fisiopatologia , Humanos , Masculino
15.
J Biomech ; 118: 110325, 2021 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-33601186

RESUMO

Knee joint instability is frequently reported by patients with knee osteoarthritis (KOA). Objective metrics to assess knee joint instability are lacking, making it difficult to target therapies aiming to improve stability. Therefore, the aim of this study was to compare responses in neuromechanics to perturbations during gait in patients with self-reported knee joint instability (KOA-I) versus patients reporting stable knees (KOA-S) and healthy control subjects. Forty patients (20 KOA-I and 20 KOA-S) and 20 healthy controls were measured during perturbed treadmill walking. Knee joint angles and muscle activation patterns were compared using statistical parametric mapping and discrete gait parameters. Furthermore, subgroups (moderate versus severe KOA) based on Kellgren and Lawrence classification were evaluated. Patients with KOA-I generally had greater knee flexion angles compared to controls during terminal stance and during swing of perturbed gait. In response to deceleration perturbations the patients with moderate KOA-I increased their knee flexion angles during terminal stance and pre-swing. Knee muscle activation patterns were overall similar between the groups. In response to sway medial perturbations the patients with severe KOA-I increased the co-contraction of the quadriceps versus hamstrings muscles during terminal stance. Patients with KOA-I respond to different gait perturbations by increasing knee flexion angles, co-contraction of muscles or both during terminal stance. These alterations in neuromechanics could assist in the assessment of knee joint instability in patients, to provide treatment options accordingly. Furthermore, longitudinal studies are needed to investigate the consequences of altered neuromechanics due to knee joint instability on the development of KOA.


Assuntos
Instabilidade Articular , Osteoartrite do Joelho , Fenômenos Biomecânicos , Marcha , Humanos , Articulação do Joelho
16.
Gait Posture ; 85: 84-87, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33517041

RESUMO

INTRODUCTION: In three-dimensional gait analysis, anatomical axes are defined by and therefore sensitive to marker placement. Previous analysis of the Oxford Foot Model (OFM) has suggested that the axes of the hindfoot are most sensitive to marker placement on the posterior aspect of the heel. Since other multi-segment foot models also use a similar marker, it is important to find methods to place this as accurately as possible. The aim of this pilot study was to test two different 'jigs' (anatomical alignment devices) against eyeball marker placement to improve reliability of heel marker placement and calculation of hindfoot angles using the OFM. METHODS: Two jigs were designed using three-dimensional printing: a ratio caliper and heel mould. OFM kinematics were collected for ten healthy adults; intra-tester and inter-tester repeatability of hindfoot marker placement were assessed using both an experienced and inexperienced gait analyst for 5 clinically relevant variables. RESULTS: For 3 out of 5 variables the intra-tester and inter-tester variability was below 2 degrees for all methods of marker placement. The ratio caliper had the lowest intra-tester variability for the experienced gait analyst in all 5 variables and for the inexperienced gait analyst in 4 out of 5 variables. However for inter-tester variability, the ratio caliper was only lower than the eyeball method in 2 out of the 5 variables. The mould produced the worst results for 3 of the 5 variables, and was particularly prone to variability when assessing average hindfoot rotation, making it the least reliable method overall. CONCLUSIONS: The use of the ratio caliper may improve intra-tester variability, but does not seem superior to the eyeball method of marker placement for inter-tester variability. The use of a heel mould is discouraged.


Assuntos
Pontos de Referência Anatômicos , Análise da Marcha/instrumentação , Análise da Marcha/métodos , Calcanhar/anatomia & histologia , Modelos Anatômicos , Impressão Tridimensional , Adulto , Fenômenos Biomecânicos , Feminino , Pé/anatomia & histologia , Pé/fisiologia , Voluntários Saudáveis , Calcanhar/fisiologia , Humanos , Masculino , Variações Dependentes do Observador , Projetos Piloto , Reprodutibilidade dos Testes , Rotação
17.
Front Physiol ; 11: 528522, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33329011

RESUMO

Gait of children with spastic paresis (SP) is frequently characterized by a reduced ankle range of motion, presumably due to reduced extensibility of the triceps surae (TS) muscle. Little is known about how morphological muscle characteristics in SP children are affected. The aim of this study was to compare gastrocnemius medialis (GM) muscle geometry and extensibility in children with SP with those of typically developing (TD) children and assess how GM morphology is related to its extensibility. Thirteen children with SP, of which 10 with a diagnosis of spastic cerebral palsy and three with SP of unknown etiology (mean age 9.7 ± 2.1 years; GMFCS: I-III), and 14 TD children (mean age 9.3 ± 1.7 years) took part in this study. GM geometry was assessed using 3D ultrasound imaging at 0 and 4 Nm externally imposed dorsal flexion ankle moments. GM extensibility was defined as its absolute length change between the externally applied 0 and 4 Nm moments. Anthropometric variables and GM extensibility did not differ between the SP and TD groups. While in both groups, GM muscle volume correlated with body mass, the slope of the regression line in TD was substantially higher than that in SP (TD = 3.3 ml/kg; SP = 1.3 ml/kg, p < 0.01). In TD, GM fascicle length increased with age, lower leg length and body mass, whereas in SP children, fascicle length did not correlate with any of these variables. However, the increase in GM physiological cross-sectional area as a function of body mass did not differ between SP and TD children. Increases in lengths of tendinous structures in children with SP exceeded those observed in TD children (TD = 0.85 cm/cm; SP = 1.16 cm/cm, p < 0.01) and even exceeded lower-leg length increases. In addition, only for children with SP, body mass (r = -0.61), height (r = -0.66), muscle volume (r = - 0.66), physiological cross-sectional area (r = - 0.59), and tendon length (r = -0.68) showed a negative association with GM extensibility. Such negative associations were not found for TD children. In conclusion, physiological cross-sectional area and length of the tendinous structures are positively associated with age and negatively associated with extensibility in children with SP.

18.
Bone Jt Open ; 1(7): 384-391, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33215128

RESUMO

Aims: To assess if older symptomatic children with club foot deformity differ in perceived disability and foot function during gait, depending on initial treatment with Ponseti or surgery, compared to a control group. Second aim was to investigate correlations between foot function during gait and perceived disability in this population. Methods: In all, 73 children with idiopathic club foot were included: 31 children treated with the Ponseti method (mean age 8.3 years; 24 male; 20 bilaterally affected, 13 left and 18 right sides analyzed), and 42 treated with primary surgical correction (mean age 11.6 years; 28 male; 23 bilaterally affected, 18 left and 24 right sides analyzed). Foot function data was collected during walking gait and included Oxford Foot Model kinematics (Foot Profile Score and the range of movement and average position of each part of the foot) and plantar pressure (peak pressure in five areas of the foot). Oxford Ankle Foot Questionnaire, Disease Specific Index for club foot, Paediatric Quality of Life Inventory 4.0 were also collected. The gait data were compared between the two club foot groups and compared to control data. The gait data were also correlated with the data extracted from the questionnaires. Results: Our findings suggest that symptomatic children with club foot deformity present with similar degrees of gait deviations and perceived disability regardless of whether they had previously been treated with the Ponseti Method or surgery. The presence of sagittal and coronal plane hindfoot deformity and coronal plane forefoot deformity were associated with higher levels of perceived disability, regardless of their initial treatment. Conclusion: This is the first paper to compare outcomes between Ponseti and surgery in a symptomatic older club foot population seeking further treatment. It is also the first paper to correlate foot function during gait and perceived disability to establish a link between deformity and subjective outcomesCite this article: Bone Joint Open 2020;1-7:384-391.

19.
Gait Posture ; 82: 126-132, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32920448

RESUMO

BACKGROUND: The Oxford Foot Model (OFM) and Rizzoli Foot Model (RFM) are the two most frequently used multi-segment models to measure foot kinematics. However, a comprehensive comparison of the kinematic output of these models is lacking. RESEARCH QUESTION: What are the differences in kinematic output between OFM and RFM during normal gait and typical pathological gait patterns in healthy adults?. METHODS: A combined OFM and RFM marker set was placed on the right foot of ten healthy subjects. A static standing trial and six level walking trials were collected for normal gait and for four voluntarily adopted gait types: equinus, crouch, toe-in and toe-out. Joint angles were calculated for every trial for the hindfoot relative to shank (HF-SH), forefoot relative to hindfoot (FF-HF) and hallux relative to forefoot (HX-FF). Average static joint angles of both models were compared between models. After subtracting these offsets, the remaining dynamic angles were compared using statistical parametric mapping repeated measures ANOVAs and t-tests. Furthermore, range of motion was compared between models for every angle. RESULTS: For the static posture, RFM compared to OFM measured more plantar flexion (Δ = 6°) and internal rotation (Δ = 7°) for HF-SH, more plantar flexion (Δ = 34°) and inversion (Δ = 13°) for FF-HF and more dorsal flexion (Δ = 37°) and abduction (Δ = 12°) for HX-FF. During normal walking, kinematic differences were found in various parts of the gait cycle. Moreover, range of motion was larger in the HF-SH for OFM and in FF-HF and HX-FF for RFM. The differences between models were not the same for all gait types. Equinus and toe-out gait demonstrated most pronounced differences. SIGNIFICANCE: Differences are present in kinematic output between OFM and RFM, which also depend on gait type. Therefore, kinematic output of foot and ankle studies should be interpreted with careful consideration of the multi-segment foot model used.


Assuntos
Fenômenos Biomecânicos/fisiologia , Pé/fisiopatologia , Marcha/fisiologia , Adulto , Feminino , Transtornos Neurológicos da Marcha , Humanos , Masculino
20.
IEEE Trans Neural Syst Rehabil Eng ; 28(10): 2296-2304, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32833637

RESUMO

In persons with calf muscle weakness, walking energy cost is commonly increased due to persistent knee flexion and a diminished push-off. Provided ankle-foot orthoses (AFOs) usually lower walking energy cost. To maximize the reduction in energy cost, AFO bending stiffness should be individually optimized, but this is not common practice. Therefore, we aimed to evaluate whether individually stiffness-optimized AFOs reduce walking energy cost compared to conventional AFOs in persons with non-spastic calf muscle weakness and, secondarily, whether stiffness-optimized AFOs improve walking speed and gait biomechanics. Thirty-seven persons with non-spastic calf muscle weakness using a conventional AFO were included. Participants were provided a new, individually stiffness-optimized AFO. Walking energy cost, speed and gait biomechanics were assessed, at delivery and 3-months follow-up. Stiffness-optimized AFOs reduced walking energy cost with 9.2% (-0.42J/kg/m, 95%CI: 0.26 to 0.57) compared to the conventional AFOs while walking speed increased with 5.2% (+0.05m/s, 95%CI: 0.03 to 0.08). In bilateral affected persons the effects were larger compared to unilateral affected persons (difference effect energy cost: 0.31J/kg/m, speed: +0.09m/s). Although individually gait biomechanics changed considerably, no significant group differences were found (p > 0.118). We demonstrated that individually stiffness-optimized AFOs considerably and meaningfully reduced walking energy cost compared to conventional AFOs, which was accompanied by an increase in walking speed. Especially in bilateral affected persons large effects of stiffness-optimization were found. The individual differences in gait changes substantiate the recommendation that the AFO bending stiffness should be individually tuned to minimize walking energy cost.


Assuntos
Órtoses do Pé , Caminhada , Tornozelo , Fenômenos Biomecânicos , Marcha , Humanos , Estudos Prospectivos
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