A hip or knee replacement will eventually fail. The reasons for revision surgery are many but the most common is loosening of the implants. Wear of the bearing surface combined with fluid pressure effects around the joint will cause the components to loosen from the bone over time. The usual symptom is pain in a joint that has been previously fine for many years. Revision surgery is more complex than a first time joint replacement. It takes longer and the complication rates are higher. Reconstruction techniques required are dictated by the amount of bone loss encountered.