Vaulting quantification during level walking of transfemoral amputees

Background: Vaulting is a gait compensatory mechanism used by transfemoral amputees to assist toe clearance during the prosthetic swing phase. It is defined by a plantar flexion of the contralateral ankle during the single-limb support phase. The aim of the study is to propose a method to quantify vaulting of transfemoral amputees. Methods: 17 transfemoral amputees and 28 asymptomatic subjects participated in the data collection. Kinematics and kinetics of thewhole bodywere recordedwhile subjectswerewalking on a level surface. Biomechanical gait analysis was focused on a reduced set of parameters linked to the contralateral ankle, the contralateral knee and the trajectory of the center of pressure. The patients were classified in two groups: with orwithout vaulting using video recordings. Differences between both groups and the control group were analyzed. Findings: A higher generated ankle powerwas found during the single support phase of the contralateral limb of transfemoralamputees presenting vaulting. These subjects presented also a higher dissipated knee flexion power before the peak in ankle flexion power. The trajectory of the center of pressurewas also modified by the vaulting. Interpretation: Vaulting for transfemoral amputees is characterized by a propulsive plantar flexion at the contralateral ankle. Quantifying the ankle flexion power during the contralateral single support phase will help in understanding vaulting.This study was supported by the French National Research Agency, under reference ANR-2010-TECS-020. The authors are deeply grateful to F. Lavaste, N. Martinet, J. Paysant, and N. Rapin for their contribution to the study

Investigating symmetry in amputee gait through the improved harmonic ratio: influence of the stride segmentation method

The quantification of gait symmetry is extremely important in several clinical contexts. Among the many indices used to describe gait symmetry, the Harmonic Ratio (HR), which is based on a stride-b..

Are wearable insoles a validated tool for quantifying transfemoral amputee gait asymmetry?

Background: Amputee gait is known to be asymmetrical, especially during loading of the lower limb. Monitoring asymmetry could be useful in quantifying patient performance during rehabilitation. Wearable insoles can provide normal ground reaction force asymmetry in real-life conditions. Objectives: To characterize the validity of Loadsol® insoles versus force plates in quantifying normal ground reaction force and gait asymmetry. To determine the influence walking speed has on loading asymmetry in transfemoral amputees. Study design: This is a prospective study. Methods: Six transfemoral amputees, wearing Loadsol® insoles, walked at three self-selected speeds on force plates. Validity was assessed by comparing normal ground reaction force data from the insoles and force plates. The Absolute Symmetry Index was used to calculate gait loading asymmetry at each speed. Results: Normalized root mean square errors for the normal ground reaction forces were 6.6% (standard deviation = 2.3%) and 8.9% (standard deviation = 3.8%); correlation coefficients were 0.91 and 0.95 for the prosthetic and intact limb, respectively. The mean error for Absolute Symmetry Index parameters ranged from -2.67% to 4.35%. Loading asymmetry increased with walking speed. Conclusion: This study quantified the validity of Loadsol® insoles in assessing loading asymmetry during gait in transfemoral amputees. The calibration protocol could be improved to better integrate it into a clinical setting. However, our results support the relevance of using such insoles during the clinical follow-up of transfemoral amputees. Clinical relevance: This is the first study to validate Loadsol® insoles versus force plates and report on loading asymmetry during gait at three different speeds in transfemoral amputees. Loadsol® insoles, which provide visual and audio feedback, are clinically easy to use and could have beneficial application in the amputee's rehabilitation and follow-up

Evolution of vaulting strategy during locomotion of individuals with transfemoral amputation on slopes and cross-slopes compared to level walking

Background: Vaulting is a walking strategy qualitatively characterized in clinics by the sound ankle plantiflexion in midstance to assist prosthetic foot clearance. Even though potentially harmful, this strategy is often observed among people with transfemoral amputation to secure clearance of the prosthetic limb during swing phase. The aim of the study is to provide a quantitative analysis of the evolution of the vaulting strategy in challenging situations of daily living. Methods: 17 persons with transfemoral amputation and 17 able-bodied people participated in the study. Kinematic and kinetic gait analyses were performed for level walking, 10% inclined cross-slope walking, 5% and 12% inclined slope ascending. To study vaulting strategy, peak of generated power at the sound ankle at midstance was identified and quantified in the different walking situations. In particular, values were compared to a vaulting threshold corresponding to a peak of generated power superior to 0.15 W/kg. Findings: The vaulting threshold was exceeded for a larger proportion of people with amputation during crossslope locomotion and slope ascent than during level walking. In addition, magnitude of the peak of generated power increased significantly compared to level walking in these situations. Interpretation: Vaulting seems to be widely used by patients with transfemoral amputation in daily living situations. The number of patients using vaulting increased with the difficulty of the walking situation. Results also suggested that patients could dose the amount of vaulting according to gait environment to secure prosthetic toe clearance. During rehabilitation, vaulting should also be corrected or prevented in daily living tasks

Reliability quantification and gait loading asymmetry assessment with wearable insoles in transfemoral amputee people at different speeds

Introduction Amputee people have gait defaults, as for example loading asymmetry, which increase with daily living situations. Replication of realistic daily living environment in a motion analysis laboratory (MAL) is difficult. Wearable pressure insoles, by providing normal ground reaction force (NGrF), can be used to quantify loading gait asymmetry in real life conditions. This asymmetry, considered as an indicator of the quality of the gait, is useful for physicians to monitor the rehabilitation progress or the prosthetic fitting suitability. The study aimed at quantifying the reliability of NGrF measurement and assessing the gait asymmetry of transfemoral amputee people with Pedoped® insoles against force plates. Walking speed effect was also evaluated on gait asymmetry for transfemoral amputee people (TFP). Material and methods In a MAL, five active TFP walked at three self-selected speeds on level ground wearing Pedoped® insoles. Reliability was assessed by comparing NGrF obtained from both systems with Bland-Altman plots, normalized RMSE (NRMSE) and correlation coefficient. Gait loading asymmetry was computed by Absolute Symmetry Index in loading at the three self-selected speeds with insoles. Results The mean NRMSE of NGrF was 7.2% (± 2.8%) and 9.8% (± 3.5%); and coefficient correlation was 0.91 and 0.95 for the prosthetic side and the intact side respectively. Loading asymmetry increased significantly with walking speed for each specific variable of NGrF. Discussion–conclusion After overcoming the calibration problem in amputee population, Pedoped® insoles could be easily used for gait asymmetry follow-up during rehabilitation

Phantom Sensations Influenced by Global and Local Modifications of the Prosthetic Socket as a Potential Solution for Natural Somatosensory Feedback During Walking: A Preliminary Study of a Single Case

Following lower limb amputation, amputees are trained to walk with a prosthesis. The loss of a lower limb deprives them of essential somatosensory information, which is one of the causes of the difficulties of walking with a prosthesis. We here explored whether a solution to this lack of somatosensory feedback could come from natural sensations of the phantom limb, present in most amputees, instead of from substitutive technologies. Indeed, it is known that phantom sensations can be modulated by (i) global mechanical characteristics of the prosthesis socket, and (ii) locally applying a stimulus on an area of the residual limb. The purpose of this pilot study was to verify the feasibility of influencing phantom sensations via such socket modifications in a participant with transfemoral amputation. Four prosthetic interface conditions were studied: a rigid and a semi-rigid socket, each one with and without a focal pressure increase on a specific area of the residual limb. The results show that phantom sensations during walking were different according to the 4 interface conditions. The participant had more vivid phantom sensations in his foot and calf of which some varied as a function of the gait phases. Preliminary gait analysis with wearable sensors shows that these modifications were accompanied by changes in some gait spatiotemporal parameters. This preliminary study of single case demonstrates that phantom sensations can be modulated by the prosthetic interface and can provide natural somatosensory information dynamically varying with gait phases. Although this needs to be confirmed for a larger population of lower limb amputees, it already encourages non-painful phantom sensations to be considered early during the rehabilitation of lower limb amputees

APSIC: Training and fitting amputees during situations of daily living

Today, the prevalence of major amputation in France can be estimated between 90,000 and 100,000 and the incidence is about 8300 new amputations per year (according to French National Authority for Health estimation). This prevalence is expected to increase in the next decade due to the ageing of the population. Even if prosthetic fitting allows amputee people recovering the walking ability, their autonomy remains limited when crossing obstacles such as slopes, stairs or cross-slopes frequently encountered during outdoors displacements. The aim of the project APSIC was to complete scientific knowledge about adaptation strategies to situations of daily living compared to level walking through an extensive motion analysis study of transtibial and transfemoral amputee compared to non-amputee people. APSIC succeeded in identifying physiologic joint functions and current prosthetic joint limitations in the studied situations, which notably resulted in the design of a prototype of ankle-knee prosthesis adapted to multimodal locomotion of transfemoral amputee. Perspectives of the clinical use of motion analysis within the rehabilitation process were explored and proved to be relevant for personalized approach of motor learning

Le retentissement du couple manchon élastique-emboiture sur la vascularisation du membre résiduel chez l'amputé tibial traumatique

Objectifs: L'état de la littérature est pauvre concernant le retentissement de l'appareillage sur la vascularisation du moignon d'amputation. L'objet du travail est d'évaluer l'existence d'un retentissement du couple" manchon élastique-emboîture" sur la vascularisation périphérique et profonde chez des amputés tibiaux d'origine traumatique appareillés par des emboîtures " contact ", et les possibilités thérapeutiques éventuelles (modification de l'appareillage et chirurgie). Matériel et méthode: Chez 17 amputés traumatiques, le remplissage du questionnaire d' Edinburgh modifié et un examen clinique précède une mesure de la TcPO2 réalisée au niveau de la loge antéro-externe du moignon dans quatre conditions: avec et sans manchon au repos couché et assise jambes pendantes. Les valeurs à 20 minutes pour chaque situation sont retenues. Le réflexe veino-artériolaire est recherché. Le diamètre et l'épaisseur pariétale des axes artériels depuis l'artère fémorale commune sont mesurées par l'échodoppler. La réalisation d'un angioscanner avec trois acquisitions (sans prothèse, avec prothèse:l: simulation d'appui) évalue les critères suivants sur l'artère poplitée: empreinte, diminution de rehaussement vasculaire, disparition de la vascularisation au niveau des condyles et des plateaux tibiaux. Les anomalies pariétales de tous les axes vasculaires sont également recueillies. Résultats: Une population "témoin" a pu être isolée, définie par l'absence de limitation fonctionnelle et de symptomatologie. La mesure de la TcPO2 basale est identique à celle de la population saine. Des anomalies pariétales sont présentes sur l'artère poplitée et des signes de compression extrinsèque à l'angioscanner aux acquisitions avec prothèse aussi bien dans la population asymptomatique que dans la population symptomatique. Discussion: Dans la population symptomatique, quatre patients ont des signes cliniques de claudication artérielle par compression extrinsèque de la prothèse confirmés par les différents examens complémentaires, améliorés par les modifications de l'appareillage. Deux patients présentent des fistules artério-veineuses dont une est comprimée par la prothèse et l'autre a été exclue par intervention chirurgicale. Un profil de gravité et les conditions de réalisation des examens ont été établies. Conclusion: Une stratégie diagnostique et thérapeutique est nécessaire devant les résultats de la population "témoin ". Les examens paracliniques ne peuvent supplanter l'examen clinique et l'interrogatoire. Des études ultérieures sont essentielles pour confirmer ces résultats, connaître les modifications (artérielle, veineuse, lymphatique) des moignons appareillés, évaluer le vieillissement vasculaire.NANCY1-SCD Medecine (545472101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Distribution of joint work during walking on slopes among persons with transfemoral amputation

Persons with above-knee amputation have increased energy consumption and greater difficulty in negotiating uphill and downhill slopes. Walking on slopes requires an adaptation of the positive and negative work performed by the joints of the lower limb to propel the center of mass. Modern prosthetic feet and knees can only partially adapt to changes in inclination, and the redistribution of joint work among persons with above-knee amputation is not described in the literature. Level, upslope and downslope walking (at 5% and 12% inclinations) were investigated for twelve subjects with transfemoral amputation fitted with an Energy Storing And Return foot (ESAR) and a Microprocessor controlled Prosthetic Knee (MPK) versus a control group of seventeen asymptomatic subjects. Lower limb joint and individual limb power and work were compared between prosthetic, contralateral and control limbs. The prosthesis dissipates less energy than the joints of the lower limb of the control group when descending the slope, but the demand on the contralateral limb is limited by a lower speed and step length. The huge deficit of positive work produced by the prosthetic ankle cannot be compensated by the residual hip during level and slope ascent which transfers the demand for energy production to the contralateral limb up to 40% on a 12% slope. This study highlights that prosthetic devices (ESAR foot and MPK) for persons with above-knee amputation present some limitations during slope walking that cannot be compensated by the residual hip and increase the work performed by the contralateral limb

The missing link: How is the phantom limb influenced by prosthesis wearing in people with lower-limb amputation?

International audienceBackground: Recent therapeutic and technological solutions aim to improve the daily living of people with limb amputation by considering various aspects of the phantom limb, in particular painless phantom sensations (PS) and voluntary phantom movements (VPM).Objective: Although previous research has explored these phenomena mostly without considering the prosthesis, this study investigates the influence of prosthesis wearing on painless PS, painful PS, and VPM, in people with lower-limb amputation. Study Design: Cross-sectional study based on semi-directed interviews. Methods: Semi-directed interviews were conducted with 111 people with major lower-limb amputations. They described their phantom limb without and with the prosthesis, in a static seated position. The influence of the prosthesis wearing on the intensity of painless PS, painful PS, and on VPM ability was classified into 5 categories: disappearance, decrease, modification, increase, and appearance.Results: Prosthesis wearing leads mostly to an increase of painless PS intensity (44%), a decrease of painful PS intensity (44%), and an improvement of VPM ability (47%). The study also highlights the richness of prosthesis-related changes, including modifications in phantom limb position, shape, and size. The influence of prosthesis wearing on phantom phenomena was not related to the presence of referred sensations, the amputation etiology, the level of amputation, the time since amputation, or the use of medication, but might be related to the pressure applied by the socket on the residual limb. Conclusions: This study provides valuable information on the influence of the prosthesis on PS and may allow for better consideration of this relationship in the context of research, engineering, and rehabilitation