Confinement to bed, which occurs in many pathological situations, induces a muscle atrophy and a loss of muscle strength. Muscle atrophy is associated to impaired performance in motor tasks, such as posture and locomotion, and is therefore a major cause of loss of autonomy. It requires a stay in follow-up and rehabilitation service, and thus lengthens the duration of hospitalisation.

Data underline the importance of afferent input integrity in the maintenance of muscle characteristics and postural control, and suggest that countermeasure programs based on the stimulation of proprioceptive inputs could be efficient to prevent muscle atrophy and falls. In particular, fundamental studies performed in rodents by the investigators laboratory have demonstrated that the adverse structural and functional adaptations which occur during muscle deconditioning can be counteracted through adequate physiological stimuli such as activation of proprioceptors. Based on this scientific expertise, the investigators aim is thus to prevent muscle atrophy and its functional consequences on posture and locomotion, following a surgical intervention in humans .

The investigators will develop a device allowing stimulation of foot and ankle proprioceptors. In order to facilitate the evaluation of its efficiency, the device will be tested on a selected population confined to bed during a post-operative period (knee replacement). It efficiency will be evaluated by means of three parameters: muscle force of ankle plantar flexor, muscle volume of lower limb muscles, functional outcome (gait and balance analysis).

The technique developed in the present project could bring benefits to patients confined to bed, or in elderly. Preventing or retarding development of muscle atrophy will beneficiate to health and quality of life of these patients. In addition, this device might allow to consider therapeutic strategies for prevention of atrophy in neuromuscular pathologies.

The aim of the study is to study the efficacy of a proprioceptive stimulation device on prevention of calf muscle atrophy after a total knee replacement.

The investigators developped a safe vibration and pressure stimulation device for le lower limb. The investigators want to carry out a RCT in order to demonstrate the efficacy of the stimulation device, compared to a not stimulated controle group.

Inclusion Criteria:

• patients waiting for knee replacement

Exclusion Criteria:

• neurologic disease