Study to Assess the Stability, Efficacy and Safety of the Silent™ Hip Prosthesis in Primary Total Hip Replacement

Inclusion Criteria: 1. Male or female subjects, aged between 25 and 65 years inclusive. 2. Subjects who are able to give voluntary, written informed consent to participate in this investigation and from whom consent has been obtained. 3. 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. 4. Subjects with non-inflammatory osteoarthritis of the hip who require a primary total hip replacement. Exclusion Criteria: 1. Subjects who, in the opinion of the Investigator, have an existing condition that would compromise their participation and follow-up in this study. 2. Women who are pregnant. 3. Subjects who are known drug or alcohol abusers or with psychological disorders that could affect follow-up care or treatment outcomes. 4. Subjects who have participated in a clinical study with an investigational product in the last 6 month(s). 5. Subjects who are currently involved in any injury litigation claims. 6. Subjects who have osteonecrosis of the femoral neck 7. Subjects who have an existing contralateral hip, ankle or knee replacement or an ipsilateral knee or ankle replacement or any metal implant in the lower lumber spine (navigated cases only). 8. Subjects who are greater than 90kg in weight. 9. Subject who have a CCD angle of the anatomical femur less than 125˚ 10. Subjects with significant bone loss or gross deformity in the region of the neck of the femur as identified on the pre-operative radiographs, where in the Investigator's opinion, there could be considerable migration of the prosthesis or a significant chance of fracture of the femoral shaft and/or the lack of adequate bone to support the prosthesis. 11. Subjects with a Charnley C classification. 12. Subjects with an active local or systemic infection. 13. Subjects with loss of musculature, neuromuscular compromise or vascular deficiency in the affected limb rendering the arthroplasty procedure unjustified. 14. Subjects with Paget's disease 15. Subjects who still plan in the future to have children.