ATX Register Accolade Stem & Trident/Tritanium Cup With X3 Insert

Inclusion Criteria: 1. Male and non-pregnant female patients between 18-75 years of age. 2. Patients requiring uncemented primary Total Hip Arthroplasty (THA), suitable for the use of the Accolade stem and Trident/Tritanium cup. 3. Patients with a diagnosis of osteoarthritis (OA). 4. Patients who understand the conditions of the study and are willing and able to comply with the post-operative scheduled clinical and radiographic evaluations and the prescribed rehabilitation. 5. Patients who signed the Ethics Committee approved Informed Consent Form prior to surgery. Exclusion Criteria: 1. Patients who require revision of a previously implanted hip prosthesis. 2. Patients who had a THA on contralateral side within the last 6 months. 3. Patients who had a THA on contralateral side more than 6 months ago and the rehabilitation period outcome was considered unsatisfactory or not good (Harris Hip Score \< 85). 4. Patients who will need lower limb joint replacement for another joint within one year. 5. Patients requiring bilateral hip replacement. 6. Patients who have had a prior procedure of acetabular osteotomy. 7. Patients with acute femoral fractures 8. Obese patients where obesity is severe enough to affect subject's ability to perform activities of daily living (body mass index, kg/m2: BMI ≥ 35). 9. Patients with active or suspected infection. 10. Patients with malignancy - active malignancy. 11. Patients with severe osteoporosis, rheumatoid arthritis (RA), Paget's disease or renal osteodystrophy. 12. Patients immunologically suppressed, or receiving steroids in excess of physiologic dose requirements. 13. The patient has a neuromuscular or neurosensory deficit which would limit the ability to assess the performance of the device or the patient has a neurological deficit which interferes with the patient's ability to limit weight bearing or places an extreme load on the implant during the healing period. 14. Female patients planning a pregnancy during the course of the study. 15. Patients with systemic or metabolic disorders leading to progressive bone deterioration. 16. Patients, who as judged by the surgeon, are mentally incompetent or are unlikely to be compliant with the prescribed post-operative routine and follow-up evaluation schedule. 17. Patients with other severe concurrent joint involvements, which can affect their outcome. 18. Patients with other concurrent illnesses, which are likely to affect their outcome such as sickle cell anaemia, systemic lupus erythematosus or renal disease requiring dialysis. 19. Patient with a known sensitivity to device materials. 20. Patients under the protection of law (e.g. guardianship).