During hip replacement surgery, a surgeon removes the damaged sections of your hip joint and replaces them with parts usually constructed of metal and very hard plastic. This artificial joint (prosthesis) helps reduce pain and improve function.

Conditions that can damage the hip joint, sometimes necessitating hip replacement surgery, include:

• Osteoarthritis. Commonly known as wear-and-tear arthritis, osteoarthritis damages the slick cartilage that covers the ends of bones and helps joints move smoothly.
• Rheumatoid arthritis. Caused by an overactive immune system, rheumatoid arthritis produces a type of inflammation that can erode cartilage and occasionally underlying bone, resulting in damaged and deformed joints.
• Osteonecrosis. If there is inadequate blood supply to the ball portion of the hip joint, the bone may collapse and deform.

Artificial knee joints used in knee replacement surgery are typically made of metal and plastic. Metal alloy parts replace the damaged thighbone and shinbone. High-density plastic replaces cartilage on the shin and kneecap components.

Reverse shoulder replacement installs the ball part of the artificial joint onto the shoulder blade and the socket part onto the arm bone.

Learn more about an innovative bone-preserving approach to managing shoulder arthritis in young adults using shoulder replacement from mayoclinic.org.