A Randomised Multi-centre Study to Compare the Long-term Performance of the Future Hip to 3 Other Implants in Primary Total Hip Replacement

Inclusion Criteria: i) Administrative - The subject is able to understand the study, is willing to give voluntary, written, informed consent, will co-operate with assessment procedures and is geographically able to comply with the post-operative follow-up regime. ii) Age - The subject's age is between 18 and 75 years inclusive. iii) Sex - Male or female subjects may be recruited to the study. iv) Diagnosis -Subjects must be undergoing primary THR surgery for non-inflammatory degenerative joint disease including osteoarthritis, avascular necrosis, post-traumatic arthritis, fractured neck of femur and non-union of fractured neck of femur, SUFE or Perthes disease. v) Suitability - Subjects who in the opinion of the Investigator are considered to be suitable for treatment with the devices involved in the study. Exclusion Criteria: i) Subjects undergoing revision procedure to the operative hip. ii) Subjects who have had a previous femoral osteotomy to the operative hip. iii) Subjects who have a history of active sepsis in the joint. iv) Subjects who have been diagnosed with primary or secondary carcinomas in the last five years (excluding basal cell carcinoma or cervical carcinoma). v) Subjects with any condition which may, in the opinion of the Investigator, interfere with the total hip replacement's survival or outcome, e.g. Paget's disease, Charcot's disease. vi) Subjects with psycho-social disorders which, in the opinion of the Investigator would limit rehabilitation. vii) Subject's whose weight is > 100kg. viii) Subjects with femoral head necrosis on the non-operated side (RSA and DEXA subjects only). ix) Subjects who have a fracture of the femur > 6 months old (RSA and DEXA subjects only). x) Subjects diagnosed as having ankylosing spondylitis (RSA and DEXA subjects only) xi) Subjects with a known history of poor compliance to medical treatment.