A simple geometrical method to minimise crosstalk during clinical gait analysis

XV International Symposium on 3-D Analysis of Human Movement, MANCHESTER, ROYAUME-UNI, 03-/07/2018 - 06/07/2018Stereophotogrammetry has been widely used for measuring gait. Conventional gait analysis systems tend to be based on the Davis marker-set [1]. This marker-set is dependent on the position of a wand on the thigh to define medial-lateral thigh axis. This wand is supposed to lie in the frontal plane of the thigh and can be difficult to position properly. A poor positioning leads to axis misorientation which can cause errors known as crosstalk. Crosstalk corresponds to an unphysiological knee Abduction Adduction (AA) amplitude correlated with knee Flexion-Extension (FE) [2]. This phenomenon also affects hip Internal External Rotation (IER) which is a parameter of high interest in clinical gait analysis (CGA). Several methods have been proposed previously to better define the medial-lateral axis of the thigh and improve the quality of both hip and knee kinematics. However, the corrections were not always satisfying or difficult to implement [2-3]

Correcting lower limb segment axis misalignment in gait analysis: A simple geometrical method

Background Obtaining precise and repeatable measurements is essential to clinical gait analysis. However, defining the thigh medial-lateral axis segment remains a challenge, with particular implications for the hip rotation profile. Thigh medial-lateral axis misalignment modifies the hip rotation profile and can result in a phenomenon called crosstalk, which increases knee adduction-abduction amplitude artificially. Research question This study proposes an a posteriori geometrical method based solely on segment anatomy that aims to correct the thigh medial-lateral axis definition and crosstalk-related error. Methods The proposed method considers the thigh medial-lateral axis as the normal to the mean sagittal plane of the lower limb defined by hip, knee and ankle joint centres during one gait cycle. Its performance was compared to that of an optimisation method which repositions the axis to reduce knee abduction-adduction variance. An existing dataset was used: 75 patients with a knee prosthesis undergoing gait analysis three months and one-year post-surgery. Three-dimensional hip and knee angles were computed for two gait analysis sessions. Crosstalk was quantified using both the coefficient of determination (r²) between knee flexion-extension and adduction-abduction and the amplitude of knee adduction-abduction. The reproducibility of hip internal-external rotation was also quantified using the inter-trial, inter-session and inter-subject standard deviations and the intraclass coefficient (ICC). Results Crosstalk was significantly reduced from r²?=?0.67 to r²?=?0.51 by the geometrical method but remained significantly higher than with the optimisation method with a r²

Can the evaluation of marker placement confidence be used as an indicator of gait kinematic variability?

IntroductionThree-dimensional gait analysis is widely used for the clinical assessment of movement disorders. However, measurement error reduces the reliability of kinematic data and consequently assessment of gait deviations. The identification of high variability is associated with low reliability and those parameters should be ignored or excluded from gait data interpretation. Moreover, marker placement error has been demonstrated to be the biggest source of variability in gait analysis and may be affected by factors intrinsic to the evaluators such as the evaluator's expertise which could be appraised through his/her experience and confidence in marker placement.ObjectivesIn the present study, we hypothesized that confidence in marker placement is correlated with kinematic variability and could potentially be used as part of a score of reliability. Therefore, we have proposed a questionnaire to evaluate qualitatively the confidence of evaluators in lower-limb marker placement. The primary aim of this study was to evaluate the reliability and validity of the presented questionnaire. The secondary objective was to test a possible relationship between marker placement confidence and kinematics variability.MethodsTo do so, test-retest gait data were acquired from two different experimental protocols. One protocol included data from a cohort of 32 pathological and 24 asymptomatic subjects where gait analysis was repeated three times, involving two evaluators. A second protocol included data from a cohort of 8 asymptomatic adults with gait analysis repeated 12 times, per participant, and involving four evaluators with a wider range of experience.ResultsResults demonstrated that the questionnaire proposed is valid and reliable to evaluate qualitatively the confidence of evaluators in placing markers. Indeed, confidence scores were correlated with the actual variability of marker placement and revealed the evaluator's experience and the subjects' characteristics. However, no correlation was observed between confidence scores and kinematic variability and the formulated hypothesis was not supported

Modèle cinématique et dynamique tridimensionnel du membre inférieur : Estimation des forces musculaires et des réactions articulaires au cours de la phase d'appui de la marche.

My research work is based on two subject areas: Firstly, I am working on the kinematics and inverse dynamic motion analysis model established in our laboratory. This model allows the calculation of joint angle amplitude and intersegmentary mechanical action of the lower limb in the three planes. It is based on a robotic formalism using the concept of homogenous matrix developed by Legnani. The aim of my work is to improve and validate this model through various clinical applications. For the record of movements, we use a non-invasive opto-electronic Motion Analysis system (Motion AnalysisTM) including five real time cameras synchronized an AMTI force platform (AMTITM), and an electromyographic device (MegawinTM). Motion Analysis allows the recording the 3D trajectories of the markers glued on specific anatomical points which defining referential for each body segments. During my doctoral research, I have learnt the use of precise techniques in order to produce accurate and reproducible results. I am working in the field of orthopaedic paediatric surgery (with the orthopaedic paediatric surgeon, Doctor B.Dohin), more specifically regarding cerebral palsy in order to validate a 3D biomechanical model as an evaluation tool of the effect on gait of botulinium toxin in children with cerebral palsy. At the laboratory we have the chance to participate at multiple experimental protocols with the Motion Analysis system, for example in the fields of sport, handicapped subjects, kinematics and clinical analysis. A specific kinematic model is developed for each protocol. The second part of my research work is based on the modelling of the muscles of the lower limb (and more particularly the knee) during the stance phase of gait. In fact, the human leg is susceptible to damage through both injury and disease. In order to properly assess this pathology and develop treatments, there is interest in developing an accurate dynamic computational model of the movements and forces involved in human gait. The two possible approaches to the development of such a model are the forward- and inverse-dynamics methods: we have developed an inverse dynamic model. The aim of this modelling is to estimate the muscular forces by the mean the optimisation by multiple constraints. The accuracy of the optimization of muscle force values is dependent on the musculoskeletal model used to define the insertion and origin points of the muscles. I have established a new protocol in order to obtain data specific to each subject, thereby improving the accuracy of the model. An optimisation process is used to solve the indeterminate equations defining the individual muscle forces in the limb. This usually consists of minimizing or maximizing a given ‘objective function', commonly a function of the sum of the forces at the joint. The optimization process is subjected to constraining criteria that serve to keep the calculated forces within physically realistic bounds. The optimization process is static or ‘quasi-static' when none of the factors considered in either the optimization parameters or the constraining criteria is considered as functions of time. A static optimisation process is then used to calculate the musculoskeletal forces in the lower limb. It is assumed that each segment of the leg is a rigid body, and joints are treated as simple hinges. In order to take into account the active stiffness of the knee, a Hill-type model (modified by Hoy and Zajac and in the course of this study) will be used to calculate the force in each muscle at each time step. This force will then be included in the optimisation process by altering the objective function to minimise the difference between the forces calculated by static optimisation.L'objectif de ce travail a été d'acquérir une meilleure connaissance de la motricité humaine tant au niveau clinique que fondamentale à travers deux études bien précises. La première portait sur une étude clinique à savoir, l'influence d'injection ciblée de toxine botulique au niveau du couple musculaire rectus fémoris – semitendinosus sur la vélocité mise en jeu au cours de la marche globale d'enfants infirmes moteurs cérébraux (IMC). La deuxième portait quant à elle sur une question plus fondamentale, à savoir, la modélisation biomécanique avancée du système musculo-squelettique au cours de la phase d'appui de la marche. En ce qui concerne l'étude clinique, le but a donc été à la fois biomécanique et clinique. D'un point de vue expérimental, plusieurs étapes ont été nécessaires avant la mise en place du protocole final utilisé à l'heure actuelle. De plus, un long travail d'analyse a été réalisé avec le clinicien responsable de ce projet, le docteur Dohin, afin d'établir et de sélectionner les critères cinématiques et cinétiques qui nous ont semblés pertinents. Ainsi, cette étude a été l'occasion de valider les critères discriminatifs d'évaluation en analyse quantifiée de la marche (AQM) pour des résultats visant à améliorer ou à restaurer la marche chez les enfants infirmes moteurs cérébraux. Au niveau fondamental, le but de notre étude a été la mise en place d'un protocole expérimental et des méthodes de calculs permettant d'évaluer quantitativement le fonctionnement du système ostéo-articulaire et musculaire non pathologique. Pour cela, une modélisation avancée a été développée afin d'appréhender le rôle des différentes structures : géométrie articulaires, ligaments, muscles, dans le fonctionnement des articulations humaines à travers des mouvements tel que la marche. D'un point de vue expérimental, l'acquisition de via points directement sur le sujet, permettant ainsi la personnalisation des bras de levier selon la morphologie de notre sujet, a été une étape importante et originale de notre travail. Afin de vérifier la pertinence de nos bras de levier « personnalisés », nous avons dans un premier temps, utilisé une technique d'optimisation statique « classique » visant à minimiser le critère : sommes des contraintes musculaires au carré. Les résultats obtenus sont tout à fait cohérents avec ceux présentés dans la littérature et avec le mouvement étudié. D'un point de vue modélisation, nous avons décidé d'affiner la représentation numérique du comportement du muscle pour rendre le modèle plus proche de la réalité. Ainsi, le comportement mécanique du complexe musculo-tendineux c'est-à-dire les relations forces longueurs, forces vitesses d'élongations et forces activations ont été prises en compte grâce au modèle rhéologique de Hill. Pour cela une étude bibliographique poussée a été nécessaire afin de cerner les nombreuses contraintes liées aux comportements mécaniques du complexe musculo-tendineux. Suite à cette étude bibliographique, nous avons sélectionné la modélisation mathématique la mieux adaptée à nos besoins. Les équations mathématiques mises en place dans notre travail contiennent donc de nombreux paramètres physiques tel que : la force isométrique maximale, la section physiologique, la longueur optimale de la fibre musculaire, l'angle de pennation, la longueur du tendon à partir de laquelle une force est développé... Une fois les forces musculaires calculées à partir du modèle rhéologiques de type Hill, ces dernières ont été implémentées dans la fonction d'optimisation classique. Plusieurs critères ont été alors testés. Le but étant d'essayer de comprendre l'influence du critère sur nos résultats et lequel serait à utiliser afin de prédire au mieux les forces musculaires mises en jeu au de la phase d'appui de la marche. Puis pour finaliser notre étude, les réactions articulaires au niveau de la cheville et du genou ont été calculées à partir des différentes configurations. Dans un premier temps, à partir des forces musculaires prédites par l'optimisation statique classique puis à partir de l'optimisation statique avec le critère modifié. Ceci nous a permis de voir au niveau de la réaction articulaire l'influence de la prise en compte des paramètres physiologiques des muscles. Cette donnée est très importante dans le domaine de la rééducation fonctionnelle et pour les concepteurs de prothèse

GDI and GPS Reference Dataset - Patients Data

AbstractKinematic data of fifty cerebral palsy patients from the Kinesiology Laboratory database. These data was used to compute GDI and GPS scores for the paper: How many observations in the reference dataset are required to compute a consistent Gait Deviation Index & Gait Profile Score? (https://doi.org/10.1016/j.gaitpost.2022.10.012

Influence of different degrees of bilateral emulated contractures at the triceps surae on gait kinematics ::the difference between gastrocnemius and soleus

Introduction : Ankle plantarflexion contracture results from a permanent shortening of the muscle-tendon complex. It often leads to gait alterations. The objective of this study was to compare the kinematic adaptations of different degrees of contractures and between isolated bilateral gastrocnemius and soleus emulated contractures using an exoskeleton. Methods : Eight combinations of contractures were emulated bilaterally on 10 asymptomatic participants using an exoskeleton that was able to emulate different degrees of contracture of gastrocnemius (biarticular muscle) and soleus (monoarticular muscle), corresponding at 0°, 10°, 20°, and 30° ankle plantarflexion contracture (knee-flexed and knee-extended). Range of motion was limited by ropes attached for soleus on heel and below the knee and for gastrocnemius on heel and above the knee. A gait analysis session was performed to evaluate the effect of these different emulated contractures on the Gait Profile Score, walking speed and gait kinematics. Results : Gastrocnemius and soleus contractures influence gait kinematics, with an increase of the Gait Profile Score. Significant differences were found in the kinematics of the ankles, knees and hips. Contractures of soleus cause a more important decrease in the range of motion at the ankle than the same degree of gastrocnemius contractures. Gastrocnemius contractures cause greater knee flexion (during the stance phase) and hip flexion (during all the gait cycle) than the same level of soleus contractures. Conclusion : These results can support the interpretation of the Clinical Gait Analysis data by providing a better understanding of the effect of isolate contracture of soleus and gastrocnemius on gait kinematics

Assessment of the influence of foot orthoses in the hip loading conditions during walking: a single case study

Despite their large clinical application, the understanding of the effects of foot orthoses on the lower limb kinematics and kinetics is limited. In this context, we propose an advanced musculoskeletal model to assess the influence of foot orthoses in the loading conditions within an osteoarthritic hip joint during gait. Experimental data are collected for a single pathological subject presenting a coxarthrosis (with and without orthoses), and a healthy subject during walking. An inverse dynamic approach coupled with an optimisation method evaluates the forces developed by 14 muscles and the hip contact reaction force. Contact reaction and muscular force magnitudes are closed whether the patient is walking with or without foot orthoses. Nevertheless, contact reaction amplitudes and orientations show differences in relation to those calculated for the healthy subject. The results obtained allow us to formulate some assumptions concerning the causes of coxarthrosis evolution and treatment

Toe-walking and its impact on first and second rocker in gait patterns with different degrees of artificially emulated soleus and gastrocnemius contracture

Background : Toe-walking is one of the most common gait deviations (due to soleus and/or gastrocnemius muscle contractures), compromising the first (heel rocker) and second (ankle rocker) of the foot during walking. The aim of this study is to evaluate the effect of emulated artificially gastrocnemius and soleus contractures on the first and second rocker during walking. Method : An exoskeleton was built to emulate contractures of the bilateral gastrocnemius and soleus muscles. Ten healthy participants were recruited to walk under the following conditions: without emulated contractures or with bilateral emulated contractures at 0°,10°, 20° and 30° of plantarflexion of the soleus or gastrocnemius in order to create an artificial restriction of dorsiflexion ankle movement. A linear regression from the ankle plantar-dorsiflexion angle pattern was performed on 0–5 % of the gait cycle (first rocker) and on 12–31 % of the gait cycle (second rocker) to compute the slope of the curve. The proportion of participants with the presence of the first and second rocker was then computed. A Statistical Parametric Mapping (SPM) analysis assessed the kinematic variations among different degrees of emulated contractures. Findings : The first and second rockers are completely absent from 10° of plantarflexion emulated contracture. The data indicate there was a non-linear shift of the gait pattern of the ankle kinematics and an important shift toward plantarflexion values with the loss of the rockers. Interpretation : This study suggests that toe-walking in the experimental simulation situation is not necessarily due to a high emulated contracture level and can occur with a small emulated contracture by an adaptation choice. This study may improve interpretation of clinical gait analysis and shows that the link between the level of gastrocnemius/soleus emulated contracture and progression of toe-walking (increased plantarflexion during gait) is not linear

Gastrocnemius / soleus contracture: influence on first and second rocker during walking

22nd Congress of the European Society of Biomechanics (ESB), LYON, FRANCE, 10-/07/2016 - 13/07/2016Contracture is a permanent shortening of the muscle - tendon - ligament complex that limits joint mobility. Contracture is involved in many diseases (cerebral palsy (CP), stroke, etc.) and can impair walking. Ankle equinus is one of the most common gait deviations (due to soleus and gastrocnemius muscle contractures) in cerebral palsy compromising the first (heel rocker) and second (ankle rocker) rockers of the foot during walking. Moreover, soleus and gastrocnemius contractures have different effects on gait kinematics and these effects are dependant of the degree of contracture. Thus, a good understanding of gait deviations is important to choose the best therapeutic approach, especially to optimise surgical procedures. This study aimed to evaluate the effect of gastrocnemius and soleus contractures on the first and second rocker during walking

Feasibility and reliability of using an exoskeleton to emulate muscle contractures during walking

Contracture is a permanent shortening of the muscle–tendon–ligament complex that limits joint mobility. Contracture is involved in many diseases (cerebral palsy, stroke, etc.) and can impair walking and other activities of daily living. The purpose of this study was to quantify the reliability of an exoskeleton designed to emulate lower limb muscle contractures unilaterally and bilaterally during walking. An exoskeleton was built according to the following design criteria: adjustable to different morphologies; respect of the principal lines of muscular actions; placement of reflective markers on anatomical landmarks; and the ability to replicate the contractures of eight muscles of the lower limb unilaterally and bilaterally (psoas, rectus femoris, hamstring, hip adductors, gastrocnemius, soleus, tibialis posterior, and peroneus). Sixteen combinations of contractures were emulated on the unilateral and bilateral muscles of nine healthy participants. Two sessions of gait analysis were performed at weekly intervals to assess the reliability of the emulated contractures. Discrete variables were extracted from the kinematics to analyse the reliability. The exoskeleton did not affect normal walking when contractures were not emulated. Kinematic reliability varied from poor to excellent depending on the targeted muscle. Reliability was good for the bilateral and unilateral gastrocnemius, soleus, and tibialis posterior as well as the bilateral hamstring and unilateral hip adductors. The exoskeleton can be used to replicate contracture on healthy participants. The exoskeleton will allow us to differentiate primary and compensatory effects of muscle contractures on gait kinematics