This document discusses orthopedic implants. It begins by defining orthopedic implants as medical devices used to restore function to joints, bones, and the spine. It then discusses the historical evolution of implant materials from ivory and glass to modern alloys and polymers. The document outlines the increasing need for implants due to an aging population and injuries. It proceeds to describe various implant types including total hip replacements, internal fixation devices like plates, pins, screws, and intramedullary nails. The materials used for implants like stainless steel, titanium alloys, and cobalt-chrome alloys are also mentioned.