[Cartilage/chondrocyte research and osteoarthritis. Current concept and future perspective for diagnosis and treatment of osteoarthritis of the knee.]

Osteoarthritis(OA)of the knee is a joint disease that is primarily affected by articular cartilage and also affected by subchondral bone and meniscus, leading to walking pain and impairing moving ability and as a result, disability. Knee OA is diagnosed by plain radiograph, however, it is not sensitive enough to detect the association between the pathophysiology and symptom of the disease. Treatment target of knee OA is to improve symptom, mainly pain. A conservative treatment is the principle of knee OA treatment, in which the combination of non-pharmacological and pharmacological treatment is primarily recommended. When the conservative treatment is ineffective, surgical treatment could be selected. It is estimated that there are 25 million people with radiographic knee OA in Japan. Recent researches using MRI and biomarkers, in addition to radiograph, have been revealed the precise mechanisms of pathophysiology of knee OA. Recently, it has been suggested that the pathophysiologies associated with pain in knee OA are altered depending upon the severity of disease. It has been expected that the pathophysiology of early stage knee OA will also be clarified.