Both chief surgeons will not know about the study until the end of it. At the end of the study, a comparison of both groups' acetabular cup angles will be done. The angles will be measured twice. The first measurement will be done by a senior orthopedic surgeon specializing in joint replacement operations. The second one will be done by a senior radiologist specialized in skeletal radiology. If a difference of 5 degrees or more is found between the two measurements, a third measurement will be done by a third examiner.