<qa>  What is the purpose of the study?The purpose of this study is to monitor the stability of a total hip replacement within the thigh bone when used in artificial hip joints implanted with two different bone cements, AcrylocTM and Palacos R, in the treatment of patients with hip joint disease requiring a total hip replacement. Patients who enter the study will be randomly allocated to AcrylocTM or Palacos R and will be evaluated at regular intervals following hip surgery using patient, clinical, x-ray assessments and special x-rays which allow the stability of the hip implant to be determined 