Institution nationale des invalides

Saint-Juéry, France

Institution nationale des invalides

Saint-Juéry, France
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Pillet H.,Arts et Metiers ParisTech | Drevelle X.,Institution Nationale des Invalides | Bonnet X.,La Redoute | Villa C.,Arts et Metiers ParisTech | And 8 more authors.
IRBM | Year: 2014

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. © 2014 Elsevier Masson SAS.

Villa C.,Institution Nationale des Invalides | Villa C.,Arts et Metiers ParisTech | Drevelle X.,Institution Nationale des Invalides | Bonnet X.,La Redoute | And 4 more authors.
Clinical Biomechanics | Year: 2015

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 cross-slope 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. © 2015 Elsevier Ltd.

Drevelle X.,Institution Nationale des Invalides | Villa C.,Arts et Metiers ParisTech | Bonnet X.,La Redoute | Fode P.,Institution Nationale des Invalides | Pillet H.,Arts et Metiers ParisTech
Clinical Biomechanics | Year: 2014

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 the whole body were recorded while subjects were walking 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 or without vaulting using video recordings. Differences between both groups and the control group were analyzed. Findings A higher generated ankle power was found during the single support phase of the contralateral limb of transfemoral amputees 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 pressure was 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. © 2014 Elsevier Ltd.

Sauret C.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Vaslin P.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Lavaste F.,Arts et Metiers ParisTech | Lavaste F.,Institution Nationale des Invalides | And 3 more authors.
Medical Engineering and Physics | Year: 2013

Currently, rolling resistance and wheelchair stability during manual wheelchair propulsion can be assessed from the loads applied on the front and rear wheels, which are determined in a static condition. However, a user's actions on the wheelchair would change these loads during locomotion, which should affect both the rolling resistance and wheelchair stability. The goal of this study was to verify these assumptions and assess how much the rolling resistance and wheelchair stability are affected by the user's actions during propulsion. For that purpose, a mechanical model was developed using measurements of an instrumented wheelchair equipped with several six-component dynamometers. Experiments were performed by three subjects propelling the instrumented wheelchair over flat ground. The results showed variations over wide ranges of the fore-aft distribution of the total load, rolling resistance, wheelchair stability, wheelchair velocity and mechanical power dissipated by the rolling resistance during the propulsion cycle. In addition, the time courses of all these variables differed with the subject. Finally, this study demonstrated the possibility of assessing intra-cycle values of both rolling resistance and wheelchair stability during manual wheelchair displacements in the field, which provides a technical step towards evaluating a wheelchair user in his daily environment. © 2012 IPEM.

Thomas-Pohl M.,Service de medecine physique et de readaptation | Rogez D.,Service de medecine physique et de readaptation | Thefenne L.,Service de medecine physique et de readaptation | Azoulay D.,Institution nationale des Invalides | Lapeyre E.,Service de medecine physique et de readaptation
Lettre de Medecine Physique et de Readaptation | Year: 2013

Prosthesis of amputees is a medicotechnical and economic challenge. Technological advances are opening up a new market, the bionic knees, in which artificial intelligence would allow the prediction of the patient's movements. Three soldiers, polytraumatised in 2010 with transfemoral amputation at different levels, primary or secondary, caused by traffic accident or improvised explosion device, were fitted this year with the bionic knee Genium® after a specific rehabilitation at theMilitary Hospital of Percy. The main purpose of this study, with an open survey after six months of experiment with the Genium®, is to know whether the promised features of the Genium® knee are acquired and used in everyday practice. These new bionic knees are living up to the expectations of the patients froma mechanical (more physiological gait, trampling and walking backwards possible, overcoming obstacles and steep downhill slope facilities, etc.) and psychological perspective. The ownership of a prosthesis and a fortiori of an advanced technology knee requires specific rehabilitation. However, the integrated automatic movements should remain manageable and controllable by the patient, with the challenge of bringing new fluid, natural and unconscious movements. The association of human body with the prosthetic foot still needs to be studied to improve movements on slopes and stairs. Not listed as refundable products by French health insurance, there is currently no standardized validation and evaluation criteria for bionic knees and the economic aspect remains a major obstacle to their prescription (associative funding for our patients). © 2013 Springer-Verlag France.

Sauret C.,Arts et Metiers ParisTech | Bascou J.,Arts et Metiers ParisTech | Bascou J.,Institution Nationale des Invalides | de Saint Remy N.,Arts et Metiers ParisTech | And 4 more authors.
Journal of Rehabilitation Research and Development | Year: 2012

This article proposes a simple and convenient method for assessing the subject-specific rolling resistance acting on a manual wheelchair, which could be used during the provision of clinical service. This method, based on a simple mathematical equation, is sensitive to both the total mass and its fore-aft distribution, which changes with the subject, wheelchair properties, and adjustments. The rolling resistance properties of three types of front casters and four types of rear wheels were determined for two indoor surfaces commonly encountered by wheelchair users (a hard smooth surface and carpet) from measurements of a three-dimensional accelerometer during field deceleration tests performed with artificial load. The average results provided by these experiments were then used as input data to assess the rolling resistance from the mathematical equation with an acceptable accuracy on hard smooth and carpet surfaces (standard errors of the estimates were 4.4 and 3.9 N, respectively). Thus, this method can be confidently used by clinicians to help users make trade-offs between front and rear wheel types and sizes when choosing and adjusting their manual wheelchair.

Fode P.,Institution nationale des invalides | Bohn G.,Institution nationale des invalides | Forfert C.,Institution nationale des invalides | Pawlowski A.,Institution nationale des invalides
Lettre de Medecine Physique et de Readaptation | Year: 2012

The choice of electric wheelchair (EW) is often a compromise between the needs of the patient, in terms of their impairment and the environment, on the one hand, and the manufacturers' technical possibilities made available on the market, on the other. When making their selection, the specifier should take the various components of the EW into account: the control unit, the support system for the body (when seated) and the power base. A multifunction joystick enables the wheelchair to move forward and change direction, but can also alter the position of the occupant. An adjustable multifunction colour screen ensures visual feedback. Changing the various parameter settings (maximum or minimum speed, forward, backward acceleration and deceleration, cornering) enables the drive and the behaviour of the wheelchair to be modified to meet the needs of the user. External or home automation control devices can be installed to the control unit, which will react to the environment or the software. The maximum speed for EW stated in the list of products and performance (LPP) in view of their reimbursement is limited to 10 km/h (6 mph), with a minimum range of 12 km (7. 5 miles). The harmonized European Standard NF EN 12184 defines three classes of electric wheelchairs: Class A, for inside use only, Class B for mixed use and Class C for outside use, depending on the capacity of the chair to clear obstacles and the gradient. EWs with a folding or convertible chassis, depending on the means of propulsion, have smaller overall dimensions and are manoeuvrable inside. They can be taken apart or folded for transportation by car; however they have a poor range and are not particularly comfortable. EWs with rigid chassis most often have powered wheels at the back (EW propulsion), equipped with tyres especially for indoor use, or, better still, pneumatic tyres to make clearing obstacles easier. EWs with powered front wheels (EW traction) are very manoeuvrable inside and perform efficiently outside, too. Six-wheel wheelchairs (central powered wheels) pivot on the spot and are therefore very beneficial for inside use. There are currently more than 150 different models of electric wheelchair on the market. In addition, at the point of selection, the specifier must define a recommended specification, taking into account the user-specific requirements (impairment, morphology, cognitive capacity, etc.) and the conditions of use (environment, life expectancy, etc.). © 2012 Springer-Verlag France.

Benisty S.,Institution Nationale des Invalides
Geriatrie et Psychologie Neuropsychiatrie du Vieillissement | Year: 2013

Vascular dementias, VD, are dementias due to cerebrovascular lesions. Subgroups of VD include multi-infarct dementia, single infarct (or strategic infarct) dementia, subcortical ischemic vascular dementia, hemorrhagic dementia, hypoperfusion dementia. VD are also related to post-stroke dementia, mixed Alzheimer's disease and vascular dementia and vascular cognitive impairment. These various entities allow to characterize more homogenous subgroups within the heterogeneous group of vascular dementias. However, ambiguities in their definitions, associated with frequent overlaps as well as lack of consensual definition for mixed dementia limit both their theoretical value and use in clinical practice. The diagnosis of cerebrovascular diseases should be dissociated from that of dementia, which could be associated with other pathologies.

Bonnet X.,Arts et Metiers ParisTech | Villa C.,Arts et Metiers ParisTech | Fode P.,Institution Nationale des Invalides | Lavaste F.,Arts et Metiers ParisTech | And 2 more authors.
Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine | Year: 2014

The greater metabolic demand during the gait of people with a transfemoral amputation limits their autonomy and walking velocity. Major modifications of the kinematic and kinetic patterns of transfemoral amputee gait quantified using gait analysis may explain their greater energy cost. Donelan et al. proposed a method called the individual limb method to explore the relationships between the gait biomechanics and metabolic cost. In the present study, we applied this method to quantify mechanical work performed by the affected and intact limbs of transfemoral amputees. We compared a cohort of six active unilateral transfemoral amputees to a control group of six asymptomatic subjects. Compared to the control group, we found that there was significantly less mechanical work produced by the affected leg and significantly more work performed by the unaffected leg during the step-to-step transition. We also found that this mechanical work increased with walking velocity; the increase was less pronounced for the affected leg and substantial for the unaffected leg. Finally, we observed that the lesser work produced by the affected leg was linked to the increase in the hip flexion moment during the late stance phase, which is necessary for initiating knee flexion in the affected leg. It is possible to quantify the mechanical work performed during gait by people with a transfemoral amputation, using the individual limb method and conventional gait laboratory equipment. The method provides information that is useful for prosthetic fitting and rehabilitation. © IMechE 2013.

Bonnet X.,Arts et Metiers ParisTech | Pillet H.,Arts et Metiers ParisTech | Fode P.,Institution Nationale des Invalides | Lavaste F.,Arts et Metiers ParisTech | And 2 more authors.
Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine | Year: 2012

Energy-storing prosthetic feet are designed to store energy during mid-stance motion and to recover it during latestance motion. Gait analysis is the most commonly used method to characterize prosthetic foot behaviour during walking. In using this method, however, the foot is generally modelled as a rigid body. Therefore, it does not take into account the ability of the foot to deform. However, the way this deformation occurs is a key parameter of various foot properties under gait conditions. The purpose of this study is to combine finite element modelling and gait analysis in order to calculate the strain, stress and energy stored in the foot along the stance phase for self-selected and fast walking speeds. A finite element model, validated using mechanical testing, is used with boundary conditions collected experimentally from the gait analysis of a single transtibial amputee. The stress, strain and energy stored in the foot are assessed throughout the stance phase for two walking speed conditions: a self-selected walking speed (SSWS), and a fast walking speed (FWS). The first maximum in the strain energy occurs during heel loading and reaches 3 J for SSWS and 7 J for FWS at the end of the first double support phase. The second maximum appears at the end of the single support phase, reaching 15 J for SSWS and 18 J for FWS. Finite element modelling combined with gait analysis allows the calculation of parameters that are not obtainable using gait analysis alone. This modelling can be used in the process of prosthetic feet design to assess the behaviour of a prosthetic foot under specific gait conditions. © IMechE 2011.

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