[Ultrasonography of the hip, knee and ankle]

Hip ultrasonography (US), besides visualization of anatomic structures, provides precise puncture and aspiration of the joint content. The most often US findings in inflammatory rheumatic diseases are intra-articular effusion (pathologic finding>2 mm), hypertrophy ofsynovial membrane, cartilage damage and bone erosions. US characteristics ofosteoarthritis (OA) are small amount of effusion, lost of cartilage, osteophytes on the articular edges and possible mild hypertrophy of synovial membrane. Recently, US has been used in diagnostics of many knee disorders, including lesions of articular cartilage, tendons, ligaments, menisci, synovial joint and surrounding blood vessels and muscles. US could be used for measuring thickness of hyaline cartilage and for assessment of its integrity at the area of femoral condyles and intercondylar notch, but only if patients are enable to bend their knees. Numerous arthropathies that affect the knee could be evaluated by US too, so it is possible to document the presence of effusion, hypertrophy ofsynovial membrane, formation ofpannus, popliteal cysts, loose bodies, cartilage thinness and synovial plica. New technologic development of US diagnostics provides high-quality presentation of some smaller structures like ankle joint, calcaneal insertion of Achilles tendon and surrounding soft tissues. The most important achievement is demonstration ofpathologic changes of Achilles tendon within inflammatory and degenerative diseases.