Common Materials Used in Orthopaedic ImplantsGenerally, the most common materials used in orthopaedic implants are metals and a type of plastic called polyethylene. These two material types are combined in most joint implants, that is, one component is made from metal, and one from polyethylene. When properly designed and implanted, the two components can rub together smoothly while minimizing wear. While some pure metals have excellent characteristics for use as implants, most metal implants are made from a mixture of two or more metals. These mixed metals are called alloys. By combining metals, a new material can be created that has a good balance of the desired characteristics. The most common metal alloys used in orthopaedic implants are stainless steels, cobalt-chromium alloys, and titanium alloys.