Influence of physical capacities of males with transtibial amputation on gait adjustments on sloped surfaces

The aim of the study was to investigate how kinematic and kinetic adjustments between level and slope locomotion of persons with transtibial amputation are related to their individual muscular and functional capacities. A quantified gait analysis was conducted on flat and slope surfaces for seven patients with transtibial amputation and a control group of eight subjects to obtain biomechanical parameters. In addition, maximal isometric muscular strength (knee and hip extensors) and functional scores were measured. The results of this study showed that most of the persons with transtibial amputation could adapt to ramp ascent either by increasing ankle, knee, and hip flexion angles of the residual limb and/or by recruiting their hip extensors to guarantee enough hip extension power during early stance. Besides, 6-minute walk test score was shown to be a good predictor of adaptation capacities to slope ascent. In ramp descent, the increase of knee flexion moment was correlated with knee extensor strength and residual-limb length. However, no correlation was observed with functional parameters. Results show that the walking strategy adopted by persons with transtibial amputation to negotiate ramp locomotion mainly depends on their muscular capacities. Therefore, muscular strengthening should be a priority during rehabilitation.This material was based on work supported by the French National Research Agency (grant ANR-2010-TECS-020)

Feedback Control of an Exoskeleton for Paraplegics: Toward Robustly Stable Hands-free Dynamic Walking

This manuscript presents control of a high-DOF fully actuated lower-limb exoskeleton for paraplegic individuals. The key novelty is the ability for the user to walk without the use of crutches or other external means of stabilization. We harness the power of modern optimization techniques and supervised machine learning to develop a smooth feedback control policy that provides robust velocity regulation and perturbation rejection. Preliminary evaluation of the stability and robustness of the proposed approach is demonstrated through the Gazebo simulation environment. In addition, preliminary experimental results with (complete) paraplegic individuals are included for the previous version of the controller.Comment: Submitted to IEEE Control System Magazine. This version addresses reviewers' concerns about the robustness of the algorithm and the motivation for using such exoskeleton

Impact of combined microprocessor control of the prosthetic knee and ankle on gait termination in unilateral trans-femoral amputees. Limb mechanical work performed on centre of mass to terminate gait on a declined surface using linx prosthetic device

The major objective of this thesis was to investigate how the use of a recently developed microprocessor-controlled limb system altered the negative mechanical work done by the intact and prosthetic limb when trans-femoral amputees terminated gait. Participants terminated gait on a level surface from their self-selected walking speed and on declined surface from slow and customary speeds, using limb system prosthesis with microprocessor active or inactive. Limb negative work, determined as the integral of the negative mechanical (external) limb power during the braking phase, was compared across surface, speed and microprocessor conditions. Halting gait was achieved predominantly from negative work done by the trailing/intact. Trailing versus leading limb mechanical work imbalance was similar to how able body individuals halted gait. Importantly, the negative limb work performed on the prosthetic side when terminating gait on declined surface was increased when the microprocessor was active for both slow and customary speeds (no difference on level surface) but no change on intact limb. This indicates the limb system’s ‘ramp-descent mode’ effectively/dynamically altered the hydraulic resistances at the respective joints with evidence indicating changes at the ankle were the key factor for increasing the prosthetic limb negative work contribution. Findings suggest that trans-femoral amputees became more assured using their prosthetic limb to arrest body centre of mass velocity when the limb system’s microprocessor was active. More generally findings suggest, trans-femoral amputees should obtain clinically significant biomechanical benefits from using a limb system prosthesis for locomotion involving adapting to their everyday walking where adaptations to an endlessly changing environment are required.Higher Committee of Education Development in IRAQ (HCED

Biomechanical adaptations involved in ramp descent: Impact of microprocessor-controlled ankle-foot prothesis. Kinetic and kinematic responses to using microprocessor-controlled ankle-foot prosthesis in unilateral trans-tibial amputees during ramp descent

Ramp descent is a demanding task for trans-tibial amputees, due to the difficulty in controlling body weight progression over the prosthetic foot. A deeper understanding of the impact of foot function on ramp descent biomechanics is required to make recommendations for rehabilitation programs and prosthetic developments for lower-limb amputees. The thesis aim was to determine the biomechanical adaptations made by active unilateral trans-tibial amputees (TT) using a microprocessor-controlled ankle-foot prosthesis in active (MC-AF) compared to non-active mode (nonMC-AF) or elastically articulated ankle-foot device. A secondary aim was to determine the biomechanical adaptation made by able-bodied individuals when ankle motion was restricted using a custom made ankle-foot-orthosis and provide further insight into the importance of ankle dynamics when walking on ramps. Kinetic and kinematic data were recorded from nine TT’s and twenty able-bodied individuals. Able-bodied participants, ankle restriction, led to an increase in involved limb loading response knee flexion that is accompanied by the increased knee power generation during the single-limb-support phase that correlates to TTs results. TT’s use of an MC-AF reduced the ‘plantar-flexion’ resistance following foot contact allowing foot-flat to be attained more quickly. Followed by the increased ‘dorsi-flexion’ resistance which reduced the shank/pylon rotation velocity over the support foot, leading to an increase in negative work done by the prosthesis. These findings highlight the importance of having controlled ankle motion in ramp descent. Use of an MC-AF can provide TTs controlled motion for descending ramps and hence provide biomechanical benefits over using more conventional types of ankle-foot devices.Engineering and Physical Science Research Council (EPSRC) via Doctoral Training Account (DTA) (EP/P504821/1) Chas. A. Blatchford and Sons Ltd., Basingstoke, UK provided the prosthetic hardware, prosthetist support, and facilitated the attendance of the TT participants for this stud

Understanding the underlying biomechanical mechanisms and strategies in dysvascular lower-limb amputees during Gait Initiation : implications for Gait analysis

Un grand nombre de paramètres biomécaniques sont disponibles pour quantifier la marche mais aucun consensus n’existe quant aux paramètres les plus pertinents à mesurer lors de l’analyse de la marche chez les sujets sains. Le premier objectif de cette thèse était donc de réaliser une revue systématique afin de déterminer les paramètres les plus pertinents pour l’analyse de la marche chez les adultes sains. Les résultats ont permis de confirmer que les paramètres spatiaux-temporaux, et plus spécifiquement la vitesse de marche, sont les paramètres les plus souvent mesurés par le plus grand nombre d’articles pour l’analyse de la marche chez les adultes sains. De futures études sont nécessaires afin de pouvoir comparer ces résultats chez d’autres populations et déterminer leur pertinence clinique. Lors de l’initiation à la marche, les ajustements posturaux anticipatoires (APA) permettent le transfert du poids du corps et la propulsion, tout en gardant l’équilibre et, au premier pas, de 75% à 90% de la vitesse de marche moyenne (SSWV) est atteinte. Bien que la population d’amputés transtibiaux pour cause dysvasculaire (DTTA) est importante et grandissante, aucune étude n’a, à ce jour, examiné les APA et le patron du premier pas lors de l’initiation à la marche chez cette population. Les deuxième et troisième objectifs de cette thèse étaient donc de comparer le patron des APA et la cinétique du premier pas chez 10 DTTA et 10 sujets contrôles lors de l’initiation à la marche. Les sujets ont initié la marche avec la jambe droite et gauche jusqu’à ce que la SSWV soit atteinte. Les résultats de la deuxième étude démontrent une augmentation du temps en phase APA chez les DTTA, une stratégie pour compenser la force réduite en augmentant l’impulsion. Le résultat le plus important chez le DTTA est qu’en A/P, un déplacement total antérieur a été observé sous la jambe prothétique, une stratégie qui semble être spécifiquement associé à l’amputation dysvasculaire. Les résultats de la troisième étude démontrent que lors du premier pas, l’impulsion de propulsion de la jambe prothétique était réduite par rapport à la jambe intacte et aux sujets contrôles. Cette réduction d’impulsion de propulsion est directement reliée à la perte des muscles fléchisseurs-plantaires au niveau de la jambe amputée. Curieusement, pour la force verticale maximale lors de la mise en charge et le taux de chargement, aucune différence n’a été observée entre la jambe intacte et la jambe des sujets contrôles ce qui supporte l’idée que les DTTA profitent d’un facteur protecteur contre le risque d’ostéo-arthrite au niveau de la jambe intacte. Les spécialistes travaillant avec les DTTA devraient promouvoir l’initiation de la marche avec les deux jambes afin de bien préparer le DTTA aux perturbations de la vie quotidienne. Également, l’augmentation de la SSWV ne devrait pas nécessairement être un objectif de la réadaptation. De prochaines études devraient s’intéresser à comparer le patron de marche chez les DTTA aux amputées pour cause traumatique ainsi que s’intéresser au patron de terminaison de la marche.A large number of biomechanical parameters are readily available with which to quantify gait but no consensus on the most relevant parameters for gait analysis in healthy adults exists with which to compare these results. The first objective of this thesis was therefore to complete a systematic review in order to establish those parameters most relevant for gait analysis in healthy adults. Results showed spatio-temporal parameters, specifically walking velocity, to be the most often measured biomechanical parameters and reported by the greatest number of articles for gait analysis in the healthy adult population. Further research should aim to compare these results to those of other populations and determine their clinical relevance. In gait initiation, anticipatory postural adjustments (APA) allow for body weight to be transferred and propulsion while maintaining balance. As well, the first step accounts for 75% to 90% of the steady-state walking velocity (SSWV). Though the dysvascular transtibial amputee (DTTA) is the most sizeable and growing amputee population, no studies have yet investigated the APA’s and first step gait initiation pattern in this specific population. Thus, the second and third objectives of this thesis were aimed at comparing the APA’s pattern and underlying first step kinetics in 10 DTTA with 10 healthy controls prior during gait initiation. Participants were asked to initiate gait with their right then left limb leading until they reached SSWV. In the second study, the increased APA time observed in the DTTA support the strategy to improve impulse by increasing time in the presence of diminished force production. The most important result is with regards to A/P total APA, as a total anterior displacement was observed in the prosthetic limb and would appear to be related to further reductions in propulsion specifically associated with dysvascular amputation. Lastly, the results of the third study showed that propulsive impulse was significantly reduced in the prosthetic limb when compared to intact and control limbs. The reduction in propulsive impulse testifies of the missing plantarflexor muscles of the prosthetic limb. Interestingly, with regards to maximum vertical force at weight acceptance and loading rate there was no difference between the intact limb and the control limb. Though the DTTA are able to produce less intact limb vertical force, this may also place them at a reduced osteoarthritis risk in the intact limb. Rehabilitation specialists should focus on both prosthetic and intact leading limb for gait initiation to aid the DTTA with everyday perturbations. As well, increasing SSWV should perhaps not be a goal of rehabilitation. Future research should focus on comparing gait initiation in the DTTA when compared to the traumatic TTA counterpart as well as understanding gait termination in the DTTA

Assessing Ground Reaction Forces and Degenerative Changes of Sound Limb in Unilateral Lower Extremity Amputees: A Systematic Review

Abstract Background: There is a rising number of individuals undergoing lower extremity amputation (LEA) and is associated with increased risk of comorbidities. Osteoarthritis (OA) and Degenerative Joint Disease (DJD) are conditions that cause reduction in an individual’s function, independence, and quality of life. Research Design: A search of multiple databases using terms associated with possible functional declines as evidenced by the International Classification of Functioning, Disability and Health (ICF), followed by assessment of evidence using the PEDro scoring method will be conducted. Multiple reviewers will screen, sort, rate and extract data from articles. Methods: A computer-aided literature search of PubMed, CINAHL, and Google Scholar was performed to identify studies published beginning in 2009 that investigated factors that contribute to degenerative changes in the contralateral limb of a unilateral LEA. Results: A total of 21 studies were selected from a total of 56 collected studies. Predictors of osteoarthritis (OA) following lower limb amputation include age, etiology, level of amputation, gender, Body Mass Index (BMI), comorbidity, pain, phantom pain, streng and OA. The impact of ground reaction forces on the sound limb varies between studies. In general, poor gait mechanics and resulting compensatory mechanisms are significant contributors to the occurrence of OA. Conclusion: There is a dearth of information relating to the prevention of degenerative changes in those with LEA and protocols for pain management and training pre- and post-joint replacement. The incidence of OA in the contralateral limb is still not fully understood. Further investigation into the biomechanics of compensatory mechanisms is necessary to fully understand the functional impact on the population. It is imperative to develop thorough physical therapy protocols for individuals in early onset of OA and those undergoing joint replacement due to degeneration

Kinematic differences exist between transtibial amputee fallers and non-fallers during downwards step transitioning.

Stair negotiation is biomechanically more challenging than level gait. There are few biomechanical assessments of transtibial amputees descending stairs and none specifically related to falls. Stair descent may elicit more differences than level gait in amputees with and without a previous falls history