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

50 patients will be included for each of the 2 procedures: \- For procedure 1: Patients will be selected during multidisciplinary consultations for amputees who are stabilized with their definitive prosthesis and have returned to their usual place of residence. The aim of this procedure is to show the validity and reproducibility of measurements of tissue oxygenation using NIRS (TcPO2 being the reference measurement), to determine the way in which NIRS measurements are more precise (i.e. in terms of validity and reproductibility) (values at rest with the patient lying perfectly flat or with the amputated limb raised 30°). These patients will require a single visit which will include measurements by NIRS and TCPO2, a walk test and the completion of 2 questionnaires (visual scale). \- For procedure 2: The patients will be included in the initial phase of postamputation rehabilitation, during the period of in-hospital rehabilitation. The main problems of healing and tolerance to the temporary prosthesis arise during this phase. The specific objectives will be: To show that measurement by NIRS predicts the quality of healing in trans-tibial amputees; to show that the zone of uncertainty concerning the predictive values for the viability of the stump is smaller with NIRS than with TcPO2 (better discrimination). NIRS and TCPO2 measurements as well as the evaluation of stump healing will be done 15, 30 and 45 days after the amputation.