Clinical utility and potential of ultrasound in osteoarthritis.

Osteoarthritis (OA) is the most common disorder of human joints. Imaging is necessary in daily practice for OA patients, and conventional radiography remains the gold standard. However, conventional radiography is not sensitive in the early stage of OA and cannot clearly detect inflammatory condition. Recently, ultrasonography (US) is widely used in musculoskeletal field and US performs better or at least equally well for identification of osteophytes and morphologic degeneration of cartilage in OA patients. US provides relevant additional diagnostic information on pathologic changes in soft tissue (e.g., synovitis, meniscal injuries and Baker's cysts) not depicted by conventional radiography. The advantage of US is its ability to visualize even in small and hidden morphologic change even in small joints. Thus, US may be a useful imaging technique for not only knee OA but also hand OA. This review article explains relevant pathologic findings in OA and clinical usefulness in daily practice with US images.