Knee and Hip Replacement Surgery is a procedure in which a doctor surgically removes a painful hip joint with arthritis and replaces it with an artificial joint often made from metal and plastic components. It usually is done when all other treatment options have failed to provide adequate pain relief Reasons : Rheumatoid arthritis (a disease that causes joint pain, stiffness, and swelling) Osteonecrosis (a disease that causes the bone in joints to die) Injury of the hip joint Bone tumors that break down the hip joint. Benefits : Relieve pain Help the hip joint work better Improve walking and other movements.