 Total hip replacement provides pain relief and improves physical function and quality of life in patients with end-stage hip osteoarthritis. The incidence of hip replacement operations is expected to increase due to the growing elderly population. Overall, the posterior approach and lateral approach are the two most commonly used approaches for hip replacement operations. The posterior approach is associated with an increased risk of revision due to dislocations, and some studies have shown that the lateral approach is associated with reduced patient-reported outcomes, including physical function and pain; however, this has not been investigated in a randomised controlled trial with a twelve-month follow-up. We hypothesized that the lateral approach has an inferior outcome in patient-reported outcome compared with the posterior approach after one year.