Lower limb amputation causes segmental loss that alters locomotor organization. The human body, designed to function in a multisegmental manner, must adapt to this new configuration where segments are missing, depending on the level of amputation. These adaptations are directly linked to the biomechanical, physiological and proprioceptive alterations caused by the loss of the amputated segments. Without mechanoreceptive afferents essential for regulating locomotion, the sensory system uses alternative information to maintain efficient locomotor function. The prosthesis partially compensates, but remains limited on the biomechanical and proprioceptive levels. Current prosthetic technologies, inspired by biomimicry, aim to imitate evolutionary solutions to restore walking, although current algorithms do not allow real-time modulation. This research aims to characterize post-amputation locomotor adaptations through biomechanical, physiological and proprioceptive exploration to develop a "locomotor characterization" model.
The study authors hypothesize that the post-amputation alterations are exacerbated in contexts of continuous and discontinuous constraints (e.g., ascent/descent and destabilization), and that the addition of a prosthesis, although inspired by biomimicry, only restores partial compensation of locomotor functions.
The patient must have given their free and informed consent and signed the consent form
The patient must be a member or beneficiary of a health insurance plan
Persons with unilateral transtibial or transfemoral amputees followed in the MPR department at the Nîmes University Hospital, RRL department, Grau du Roi University Rehabilitation Hospital.
All etiologies: vascular, traumatic and septic.
The patient is participating in an interventional or a drug/medical device study, or is in a period of exclusion determined by a previous study
The patient unable to express consent
It is impossible to give the patient informed information
The patient is under safeguard of justice or state guardianship
Person with unilateral transtibial or transfemoral amputation and healthy volunteers for control population.
Case-control
Prospective
Biomechanics
Other interventionAmputees and controls will be equipped with measurement sensors to record spatio-temporal, kinetic, kinematic, pressure, electromyographic and physiological parameters of gait in the movement analysis laboratory (GRAIL System). 16 Anatolog FSR sensors will be installed in the amputee population (transtibial, transfemoral on the medial, lateral, anterior and posterior parts of the stump, 4 per side, aligned in the proximal/distal axis. The Anatolog sensors have a sampling frequency of 100Hz. Electromyographic data recording is performed by setting up a number of EMGs depending on the healthy population or the level of amputation. Surface electromyography (sEMG) signals will be recorded from 10 muscles on each lower limb for control subjects and transtibial amputees
Physiological
Other interventionEnergy consumption (VO2), will be performed using the VO2 Master Pro (VO2 Master Health Sensors Inc., Vernon, British Columbia, CA). Each participant will wear a face mask connected to the VO2 Master, which will measure oxygen consumption in real time during the assessment. The mask will be adjusted to prevent air leakage and ensure accurate measurements.
Proprioceptive
Other interventionFor amputees, the joint above the amputation will be measured due to the presence of the proximal insertions of the bi-articular muscles and the absence of their distal insertion (i.e., knee joint for transtibial amputees and hip joint for transfemoral amputees).
Locomotor adaptations induced by amputations on inter-segmental coordination by the evaluation of continuous relative phases under different walking conditions
MARP (Mean Absolute Relative Phase) index of Continuous Relative Phases (movement analysis) where MARP = 0 indicates perfectly synchronization in both segments throughout the gait cycle and elevated MARP indicates poor coordination between the segments
Locomotor adaptations induced by amputations on the impact of locomotor constraints such as inclinations on the explanation of muscular synergies under different walking conditions
Muscle synergy explanation index
Locomotor adaptations induced by amputations on the extent of locomotor constraints such as inclinations on the explanation of muscular synergies under different walking conditions
Number of muscle synergies
Locomotor adaptations induced by amputations on the variability of pressure distributions in the socket under different walking conditions
Variability of pressures in the socket measured with high-pressure Force-Sensing Resistor sensor. The variability will be determined according to the standard deviation of all 16 pressures measured during a walking cycle.
Locomotor adaptations induced by amputations on oxygen consumption under different walking conditions
Average VO2 in the final 30 seconds of walking (mL/mn/kg)
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