Osteoarthritis (OA) is a multifactorial process affecting cartilage and subchondral bone. Conventional radiographs are inexpensive and readily available. The increased knowledge with regard to interpreting weightbearing radiographs of the tibiofemoral joint and axial radiographs of the patellofemoral joint will enable these examinations to remain competitive techniques compared with more expensive and sophisticated methods, such as MR imaging, when investigating knee pain to establish the diagnosis and the severity of OA.