Total joint replacement is a surgical procedure in which certain parts of an arthritic or damaged joint, such as a hip, knee or shoulder joints, are removed and replaced with a plastic or metal device called a prosthesis. The prosthesis is designed to enable the artificial joint to move just like a normal, healthy joint.
Hip replacement involves replacing the femur (head of the thighbone) and the acetabulum (hip socket). Typically, the artificial ball with its stem is made of a strong metal, and the artificial socket is made of polyethylene (a durable, medical grade plastic). In total knee replacement, the artificial joint is composed of metal and polyethylene and it is used to replace the diseased joint. The prosthesis is anchored into place with bone cement or is covered with an advanced material that allows bone tissue to grow into it.