Clinical Research Directory

Inclusion Criteria: 1. Age 18 years or older at the time of enrolment. 2. Scheduled to undergo primary, elective THA for a diagnosis of primary osteoarthritis. 3. Considered by the treating surgeon to be clinically suitable for either RA-THA or CO-THA. 4. Willing and able to provide written informed consent and complete protocol-defined study assessments. Exclusion Criteria: 1. THA indicated for a diagnosis other than primary osteoarthritis, including inflammatory arthritis, post-traumatic arthritis, avascular necrosis, hip dysplasia, or femoral neck fracture. 2. History of any prior surgery of the index hip joint. 3. Complex primary THA, including anatomical or reconstructive considerations that, in the opinion of the treating surgeon, would render the participant unsuitable for either randomized intervention. 4. Active or prior infection involving the index hip that, in the opinion of the treating surgeon, would affect suitability for primary elective THA. 5. Simultaneous bilateral THA or a planned staged contralateral THA before completion of the 6-month primary outcome assessment. 6. Previous randomization in the present trial. 7. Current participation in another study that does not permit co-enrolment or that, in the opinion of the Investigator, would interfere with participation in this trial. 8. Any medical condition, cognitive impairment, or other circumstance that, in the opinion of the Investigator, would interfere with the participant's ability to complete protocol-defined assessments or follow-up. 9. Unable to complete the required study questionnaires in English or unable to provide informed consent.