A prosthetist, as defined by The American Board for Certification in Orthotics, Prosthetics and Pedorthics, Inc., is a person who measures, designs, fabricates, fits, or services a prosthesis as prescribed by a licensed physician, and who assists in the formulation of the prosthesis prescription for the replacement of external parts of the human body lost due to amputation or congenital deformities or absences.
A prosthetist is a person that has been certified to fit 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 by glass or carbon fiber infused with acrylic resin or 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 devises one at each end. One of the devises connects to the ankle and the other one to the socket. They allow the foot to be placed in proper position to support the persons 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.
In the United States, a Certified Prosthetist (CP) is a prosthetist who has passed the psychometrically validated certification standards and met the established educational criteria of The American Board for Certification in Orthotics, Prosthetics and Pedorthics, Inc. and maintains certification through mandatory continuing education program and adherence to the Code of Professional Responsibility. The Board for Orthotic Certification also has a designation (boco) for people who have passed their test.