Total Hip Replacement

Total hip joint replacement through the use of super alloys has been a medical success story, enabling hundreds of thousands of people to live fuller, more active lives.
Using metal alloys, orthopaedic surgeons can replace a painful, dysfunctional joint with a highly functional, long-lasting prosthesis.
Over the past half-century, there have been many advances in the design, construction, and implantation of artificial hip joints, resulting in a high percentage of successful long-term outcomes.
The hip joint is called a ball-and-socket joint because the spherical head of the thighbone (femur) moves inside the cup-shaped hollow socket (acetabulum) of the pelvis.
To duplicate this action, a total hip replacement implant has three parts: the stem, which fits into the femur; the ball, which replaces the spherical head of the femur; and the cup, which replaces the worn out hip socket. Each part comes in various sizes to accommodate various body sizes and types.

Cobalt/chromium-based alloys   are the preferred super alloy of choice in the stem portion of hip implants in ball and stem hip joint for people needing hip replacement.   The Cobalt/chromium based stem comes in different shapes and some have porous surfaces to allow for bone ingrowth.

The cobalt-base superalloys have their origins in the Stellite alloys patented in the early 1900’s by Elwood Haynes.

Cobalt/chromium-based alloys have higher melting points than other alloys such as nickel (or iron) alloys. This gives them the ability to absorb stress to a higher absolute temperature.
Cobalt/chromium based alloys give superior hot corrosion resistance to gas turbine atmospheres, this is due to their high chromium content.
Cobalt/chromium based alloys show superior thermal fatigue resistance and weldability over other alloys like nickel alloys for example.

Cobalt/chromium-based alloys are termed austenitic in that the high temperature “Face Centred Cubic” phase is stabilised at room...