ABSTRACT
Biomaterials have an integral role in orthopaedic surgery. There are four major classes of biomaterials such as metals, polymers, ceramics and natural materials. Metallic alloys are the combination of metallic and non-metallic elements. The metallic bonds are stronger the closer the atoms are together in the higher density face-centred cubic and hexagonal close-packed crystalline arrangements. Stainless steel, cobalt chrome and titanium are alloys widely used in orthopaedic surgery. The chapter summarizes their composition, material properties, advantages and disadvantages. Chromium provides stainless steel corrosion resistance by forming an oxide layer. Due to the poor wear resistance of stainless steel in metal-on-metal articulation, cobalt chrome was introduced with the McKee-Farrar prosthesis and is now routinely coupled with polyethylene. Titanium has an elastic modulus of 110 GPa and femoral stems do not suffer from stress shielding as much as stainless steel and cobalt chrome.
