Long-term results of oncological endoprosthetics of the ankle joint: multicenter study

Introduction. The distal tibia and fibula are rare sites of involvement by primary and metastatic tumors. For a long time, amputation remained the standard surgical intervention for this location. Oncological ankle replacement is associated with a number of difficulties, including a lack of soft tissue necessary to cover the implant, close proximity of anatomical structures, a high probability of vascular and infectious complications, and difficulties in restoring the biomechanics of the lost joint. Currently, due to the small number of analyzed groups and short-term observations, there is no generalized data on primary and revision oncological ankle replacement, and there is no developed approach to treatment and prevention of complications.Aim. To generalize the analysis of long-term results, the structure of complications, and functional results in a group of patients after primary and revision oncological ankle replacement in a statistically significant group of patients.Materials and methods. The study included 40 patients with benign bone tumors, primary localized sarcomas of bone and soft tissue, and metastatic lesions, which, since 2008, until 2023 56 primary and revision endoprosthetics of postresection defect of the distal tibia were performed. Over a period of 15 years, the study group included 40 (71.4 %) surgeries in the scope of primary endoprosthetics and 16 (28.6 %) surgeries in the scope of revision oncological endoprosthetics of the ankle joint.Results. Over a 15-year follow-up period, the overall incidence of complications, structured according to the International Society of limb Salvage (ISOLS) 2013 classification, after primary and revision arthroplasty was 50 %. The average time until detection of oncological and non-oncological complications was 16.1 months. The leading complication after endoprosthetics was aseptic instability (Type II; 21.4 %) and tumor recurrence (Type V) – 20 %. The average functional outcome after primary and revision ankle replacement was assessed using the MSTS scale and was 72 % after 6 months and ranged from 43 to 97 %. After 12 months, this figure was 78 % and ranged from 49 to 97 %.Conclusion. An objective assessment and increase in the statistical reliability of the results of oncological ankle replacement requires a larger number of surgeries, a longer observation period and joint consolidation of data from various clinics. Development of indications for such reconstructive operations, careful selection of patients taking into account the effect of conservative treatment allows to reduce the total number of complications, the number of local relapses and achieve a good functional result.