[Chronic diseases of the ankle joint]

The etiology of chronic diseases of the ankle joint comprises a wide spectrum including chronic inflammatory processes and chronic degenerative, tumorous 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 disease, psoriasis or chronic monoarthritid diseases such as gout, as well as granulomatous diseases (tuberculosis, sarcoidosis) and fungal infections, may affect the ankle joint in a chronic course. Chronic degenerative changes are usually secondary due to abnormal positioning of the joint constituents or repetitive trauma. Neuropathic changes, as frequently seen in the course of diabetes, present with massive osseous destruction and malposition of the articular constituents. Chronic osseous as well as cartilaginous and synovial changes are seen in hemophilic patients. Chronic traumatic changes are represented by pigmented villonodular synovitis (PVNS), and chondromatosis, both with a predilection for the ankle joint. Due to the possibilities of magnetic resonance imaging (MRI), diagnosis of chronic ankle changes includes chronic ligamentous, tendinous and soft tissue changes. With the use of MRI, specific syndromes can be defined which particularly affect the ankle joint in a chronic way, such as the os trigonum syndrome, the anterolateral impingement syndrome and the sinus tarsi syndrome. Nevertheless, plain film radiographs are still the basic element of any investigation. MRI, however, can be potentially used as a second investigation, saving an unnecessary cascade of investigations with ultrasound and CT. The latter investigations are used only with very specific indications, for instance CT for subtle bone structures and sonography for a limited investigation of tendons or evaluation of fluid. Particularly due to the possibilities of MRI and the development of special gradient-echo imaging or high-resolution coils, the investigation of the ankle joint still offers a wide spectrum of innovation for the next years, which is particularly enforced by the increasing demand for specific diagnosis of chronic diseases in orthopedic medicine.