A Randomised Study to Compare Metal Ion Release and Long-term Performance of the Pinnacle™ Cup With a Ceramic-on-Metal or a Metal-on-Metal Bearing

Inclusion Criteria: * Skeletally mature male or female subjects, aged between 20 and 75 years inclusive at the time of surgery. * Subjects who are able to give voluntary, written informed consent to participate in this investigation and from whom consent has been obtained. * Subjects who, in the opinion of the Investigator, are able to understand this investigation co-operate with the investigational procedures and are willing to return to the hospital for all the required post-operative follow-ups. * Subjects undergoing unilateral primary total hip replacement who are suitable for a cementless acetabular component and whose femoral and acetabular bone stock is suitable to receive implants, without the requirement for a bone graft. * Subjects with radiographic evidence and primary diagnosis of non-inflammatory degenerative joint disease (NIDJD). * Subjects with a pre-operative Harris Hip Score of less than or equal to 70 and a pain rating of at least moderate for the operative hip. Exclusion Criteria: * Subjects who, in the opinion of the Investigator, have an existing condition, such as active infections, highly communicable diseases, neurological or musculoskeletal disorders that might affect weight-bearing and metastatic or neoplastic disease, that would compromise their participation and follow-up in this study. * Subjects who currently have other metallic foreign bodies including trauma products and joint arthroplasties, unless known to be titanium alloy only. * Patients who have received a total hip arthroplasty in the contralateral hip within the previous 12 months unless known to be titanium alloy only. * Subjects who have undergone previous hip surgery on the operative hip (including previous hip/surface replacements, resection arthroplasty or surgical fusion of the hip). * Subjects requiring a simultaneous bilateral hip operation. * Subjects who, in the opinion of the investigator, will possibly require a separate joint replacement operation within the next two years, including revision operations. * Subjects with an acute femoral neck fracture of the operative hip. * Subjects who have undergone above knee amputation of the contralateral and/or ipsilateral leg. * Subjects with compromised renal function. * Subjects with a known allergy to metal (eg, jewellery). * Subjects with an occupational exposure to cobalt, chromium, molybdenum, titanium or nickel. * Subjects who have ingested medication or vitamins containing cobalt, chromium, molybdenum, titanium or nickel within the last 12 months, or intend to ingest such substances over the next 2 years. * Subjects who have undergone systemic steroid therapy, excluding inhalers, in the three months prior to surgery. * Women who are pregnant. * Subjects who are prisoners, known drug or alcohol abusers or with psychological disorders that could affect follow-up care or treatment outcomes. * Subjects who have participated in a clinical study with an investigational product in the last 12 months. * Subjects who are currently involved in any injury litigation claims.