A hydraulic prosthetic system including a device implanted in the body of a patient and a control case outside the patient's body; * the implanted device including: - at least one inflatable element that can be inflated in response to a pressure of a fluid; - a tank for the fluid in communication with the inflatable element; - a sealed case in which is mounted a motor-driven pump driven by an electric motor supplied with energy by a wireless energy transfer system, part of which is mounted in the case, this pump being in communication on the one hand with the inflatable element via a one-way discharge obturator and on the other hand with the tank via a one-way suction obturator, the pump ensuring only the circulation of the fluid from the tank to the inflatable element to ensure its inflation; - a manual command for deflating the inflatable element accessible from outside the sealed case and acting on the one-way suction obturator and on the one-way discharge obturator to open the communication between the inflatable element and the tank during its manual actuation; * the control case integrating another part of the energy transfer system and ensuring the control of the operation of the energy transfer system. * the implanted device including: - at least one inflatable element that can be inflated in response to a pressure of a fluid; - a tank for the fluid in communication with the inflatable element; - a sealed case in which is mounted a motor-driven pump driven by an electric motor supplied with energy by a wireless energy transfer system, part of which is mounted in the case, this pump being in communication on the one hand with the inflatable element via a one-way discharge obturator and on the other hand with the tank via a one-way suction obturator, the pump ensuring only the circulation of the fluid from the tank to the inflatable element to ensure its inflation; - a manual command for deflating the inflatable element accessible from outside the sealed case and acting on the one-way suction obturator and on the one-way discharge obturator to open the communication between the inflatable element and the tank during its manual actuation; - at least one inflatable element that can be inflated in response to a pressure of a fluid; - a tank for the fluid in communication with the inflatable element; - a sealed case in which is mounted a motor-driven pump driven by an electric motor supplied with energy by a wireless energy transfer system, part of which is mounted in the case, this pump being in communication on the one hand with the inflatable element via a one-way discharge obturator and on the other hand with the tank via a one-way suction obturator, the pump ensuring only the circulation of the fluid from the tank to the inflatable element to ensure its inflation; - a manual command for deflating the inflatable element accessible from outside the sealed case and acting on the one-way suction obturator and on the one-way discharge obturator to open the communication between the inflatable element and the tank during its manual actuation; * the control case integrating another part of the energy transfer system and ensuring the control of the operation of the energy transfer system.