Radiology of chronic diseases of the ankle joint

The etiology of chronic diseases of the ankle joint comprises a wide spectr um including chronic inflammatory processes and chronic degenerative, tumor ous and neuropathic processes, as well as some specific syndromes based on chronic changes of the ankle joint. Of the inflammatory processes, chronic juvenile arthritis (JVC) is the most common disease. However, also Reiter d isease, psoriasis or chronic monoarthritid diseases such as gout,as well as granulomatous diseases (tuberculosis,sarcoidosis) and fungal infections, m ay affect the ankle joint in a chronic course. Chronic degenerative changes are usually secondary due to abnormal positioning of the joint constituent s or repetitive trauma. Neuropathic changes, as frequently seen in the cour se of diabetes, present with massive osseous destruction and malposition of the articular constituents. Chronic osseous as well as cartilaginous and s ynovial changes are seen in hemophilic patients. Chronic traumatic changes are represented by pigmented villonodular synovitis (PVNS), and chondromato sis, both with a predilection for the ankle joint. Due to the possibilities of magnetic resonance imaging (MRI), diagnosis of chronic ankle changes in cludes chronic ligamentous,tendinous and soft tissue changes. With the use of MRI, specific syndromes can be defined which particularly affect the ank le joint in a chronic way, such as the os trigonum syndrome,the anterolater al impingement syndrome and the sinus tarsi syndrome. Nevertheless, plain f ilm radiographs are still the basic element of any investigation. MRI, howe ver, can be potentially used as a second investigation, saving an unnecessa ry cascade of investigations with ultrasound and CT. The latter investigati ons are used only with very specific indications,for instance CT for subtle bone structures and sonography for a limited investigation of tendons or e valuation of fluid. Particularly due to the possibilities of MRI and the de velopment of special gradient-echo imaging or high-resolution coils, the in vestigation of the ankle joint still offers a wide spectrum of innovation f or the next yea rs, which is particularly enforced by the increasing demand for specific diagnosis of chronic diseases in orthopedic medicine.