[Sonography of the foot in rheumatology : Ultrasound diagnostics of the ankle joint and foot in the rheumatological routine].

Ultrasound examination of the joints is an essential component of diagnostics in rheumatology. Due to its easy accessibility, excellent image definition of soft tissue and bone surfaces with standardized scan sections and scoring systems, ultrasound examination of the joints enables decisions to be made on early and differential diagnostics, treatment monitoring and prognosis. Involvement of the ankle and foot is a common problem in both inflammatory and degenerative rheumatological diseases. Persisting inflammatory processes and bone destruction increase the burden of disease by causing a loss of mobility due to pain. As treatment is often prolonged it is an important issue for both the quality of life of affected patients and a burden on the resources of the healthcare system. The anatomical characteristics of the foot make it difficult to draw diagnostic conclusions by physical examination only. These diagnostic gaps in the remaining rheumatological questions can often be answered by ultrasound examination of the joint.