Contribution of Near-InfraRed Spectroscopy (NIRS) to the Evaluation of Healing After Amputation of the Leg

Inclusion Criteria: All groups: * Patients who have agreed to take part in the study * Patients with National Health Insurance cover, * Patients (men or women aged between 18 and 85 years, presenting unilateral transtibial amputation for PAD. * Able to understand simple instructions Procedure 1: * Stabilized patients with their definitive prosthesis, with no modification of the prosthesis in the previous 3 months and at least 6 months after the amputation. * Definitive prosthesis with a contact socket. * Patients able to do a 2-minute walk test. Procedure 2: \- Patients in the initial phase of post-amputation (temporary prosthesis, rehabilitation) following unilateral transtibial amputation. Exclusion Criteria: * Patients without national health insurance cover. * Patients under guardianship. * Patients with associated chronic motor deficiency, of a neurological origin (examples: sequelae of stroke, balance and coordination disorders), or osteo-articular disease (examples: knee or hip osteoarthritis), given their secondary functional impact, making it impossible for amputees to walk with a prosthesis. * Severe medical disorder that significantly impairs functional abilities (severe heart failure, respiratory failure, non-stabilized metabolic disorders, such as progressive kidney failure) and diseases with an impact on short or medium-term survival (progressive neoplastic disease, non-stabilized systemic disease). * Complications, other than microcirculatory, with the stump, able to affect the use of a contact socket: hematoma, formation of cysts, fluid build-up, calcifications of soft tissues, bone spur, infection (skin, abscess), neurinoma, deterioration of the knee joint of the amputated limb, angle of the tibial cut leading to specifically painful osteo-cutaneous impingement, venous thrombosis, abnormal shape of the stump making it unsuitable for a socket (flexum of the knee, "pear shaped" stumps or stumps with severe invaginations )… * Local skin disorders in the measurement zone (summit of the antero-external area) of the stump compromising the quality of the signals picked up by the electrode (NIRS and TcPO2) : severe edema, hyperkeratosis, ulceration, inflammatory and infectious phenomena.