 Patients are examined preoperative as well as 3, 6 and 12 month after operation, documenting the active range of motion and pain sensation while resting and on activity. Well established scores like the AOFAS Ankle-Hindfoot Score and the Lower Extremity Functional Scale are used to get subjective and objective informations about patients daily life and postoperative satisfaction. X-Rays are taken at the same stages. MRIs of the ankle joint with contrast agent are performed before as well as 6 and 12 months after surgery. 