The aim of the investigation was to work out a concept of modern arthrodesis of the ankle joint in posttraumatic crusarthrosis, grade III-IV, using innovative fixing implants.Materials and Methods. The results of treating 53 patients covering the period from 1 to 15 years after 56 operations of arthrodesis, performed for posttraumatic crusarthrosis, grade III-IV (according to Kellgren and Lawrence classification), have been analyzes. The conclusions were based on the data of radiographic, clinical examination and the scoring according to the international rating scale AOFAS. Arthrodesis was performed using state-of-the-art fixing implants: with the help of the screws, retrograde intramedullary HAN rod, Ilizarov apparatus for external fixation, wires.Results. In the majority of patients (41%) the main cause of developing posttraumatic crusarthrosis of grade III-IV was unrepaired intraarticular dislocation of the ankle fragments and a large fragment (more than 1/3) of the posterior tibia margin. The best results, i.e. fewer ligamentous ankylosis (32%) and the greatest number of good (39%) and satisfied (54%) results according to AOFAS scale were obtained when crossed screws were used in arthrodesis. It was estimated, that the assessment of clinical and functional signs according to the international scale AOFAS does not reflects the most vital spectrum of life activity indices of patients, therefore, it has been suggested to use additionally individualized indices characterizing the quality of life of patients of various professions, levels of every-day activity and psychological motivation to adequate rehabilitation. Unsatisfied radiographic findings did not always corresponded to the poor clinical results. In 56% of patients with ligamentous ankylosis the result according to AOFAS was good or satisfactory (slight pains in prolonged walking, moving without additional supporting means, absence of evident limping).Conclusion. The worked out concept of modern arthrodesis is as follows: 1) the choice of ankle arthrodesis method and the type of a fixing implant must depend not only on the type of deformation, but on the patient's age, gender traits, diseases contributing to the development of unfavorable treatment results; 2) the best clinical and functional results are connected with the method of fixation providing primary stability, and with regenerative and adaptive capabilities of patients in diverse age groups; 3) the most optimal state-of-the-art implants for arthrodesis are crossed screws for fixation, providing the greatest strength and good primary compression, if there is no marked disorder of blood supply of the articular bones and radical removal of the cartilaginous tissue.