What are the most common reasons that patients need THA? Pain and progressively limited function are the main reasons patients seek orthopedic surgeons. Regarding the etiology of arthritic disease, all over the world, THA is most frequently performed for primary osteoarthritis, but local factors play an important role. For instance, in Anglo-Saxon countries, rheumatoid arthritis is common, whereas in Mediterranean countries, it is rare. Conversely, congenital hip disease is more frequent along the Mediterranean coast than in Northern Europe. What is the role of imaging in diagnosing THA? Imaging is certainly important for diagnosis and treatment, but direct, accurate examination of each patient is more important. We have to keep in mind that we treat patients, not radiographs.