The device (1) for the treatment of joint instability and dyskinesia comprises: an inertial sensor (11, 12) for detecting the movements of a limb (2) of a person, adapted to produce movement signals; an electrostimulation element (14) that can be positioned at a predetermined point of the patient's body so as to electrically stimulate muscles involved in the movement of the limb (2); a waveform generator (15) for supplying the electrostimulation element (14); and a processing means (4) connected to the inertial sensor (11, 12) and to the generator (15), comprising: a position module (41) configured to determine positions of the limb (2) on the basis of the movement signals; and a stimulation module (42) configured to produce stimulation signals adapted to control the operation of the generator (15), on the basis of one or more positions of the limb (2) determined by the position module (41).