A number of different factors could lead to you needing a joint replacement. Heredity is one such factor, as some people are simply born more prone to these problems. In other cases, abnormalities can form while the joints are forming, leading to issues as you age. Finally, injuries are a factor in joint replacement. In some cases, minor, repetitive injuries are the cause, while in other situations a severe trauma damages the joint.
About 24,000 Americans have their hips replaced every year. In the majority of cases, hip replacement therapy is required after the surgery. Usually, hip replacement is performed when severe arthritis makes changes to the hip joint, making it almost impossible to walk without pain.