A Prosthetist and Orthotist, as defined by The World Health Organization, is a healthcare professional with overall responsibly of Prosthetics & Orthotics treatment, who can supervise and mentor the practice of other personnel. They are clinicians trained to assess the needs of the user, prescribe treatment, determine the precise technical specifications of prosthesis and Orthosis, take measurements and image of body segments, prepare model of the evaluation, fit devices and evaluate treatment outcome.

A prosthetist is a person who has been qualified and certified to treat a person by using prostheses to residual limbs of the upper and lower extremities. The fitting of lower extremity prostheses, for example, involves making a socket that fits the residuum as a first step. The socket is usually manufactured out of fiberglass or carbon fiber infused with acrylic resin. Also made from thermoplastics over a positive model of the residuum. The socket is connected to a foot or ankle assembly and in the case of above knee amputation, an artificial knee. The connecting components are usually an aluminum tube with two part pyramid alignment devices one at each end. One of the devices connects to the ankle and the other one to the socket. They allow the foot to be placed in proper position to support the person's weight with the least possible lateral forces acting through the system. Prostheses are aligned with the client walking, while the prosthetist observes the gait and corrects for any deviations from optimized movement when the leg is in the air and for its position at heel strike and toe off.