The hip and knee joints are among the most mobile joints in the body and play an important role in supporting body weight and in allowing daily activities such as walking and climbing stairs. Due to accidents or pathologies, like osteoarthritis, such joints can be damaged. In severe cases, where motor functions are limited, the patient must undergo an arthroplasty surgery, which must then be followed by a rehabilitation program for the recovery of lost muscle strength. The aim of this project is to define two rehabilitation protocols for patients with hip and knee prostheses that can be implemented by FES.