We have a 1970s-era 
Endolite prosthetic leg in our History of Medicine Collection.
The earliest example of a prosthesis ever discovered is a big toe, belonging to a noblewoman in Egypt and dated to between 950-710 B.C.
In 1529, French surgeon Ambroise Pare (1510-1590) introduced amputation as a lifesaving measure in medicine. Soon after, Pare started developing prosthetic limbs.
In 1975, Ysidro M. Martinez made a significant breakthrough that avoided some of the problems associated with conventional artificial limbs. His prosthetic leg was light in weight to help with movement and reduce friction. The foot was also much shorter, which reduced friction and pressure.
Listen to Max Ortiz, Professor of Electrical Engineering and Head of the Bionics Research Unit at Chalmers University of Technology, here: