Long-term results of oncological endoprosthetics of the diaphyseal bone: multicenter study

Introduction. Metastatic bone lesions are the 3rd most common metastases after lung and liver metastases. In many cases, lesions in the long bones are accompanied by lesions in the femur; their incidence is 71 %. In 25 % of cases of metastases in the bone diaphysis, pathological fracture of the femur occurs. Primary bone sarcomas usually develop in the metaepiphysial areas which requires resection of both the affected bone and the intact joint located in the immediate vicinity of the tumor. According to various authors, the main problems of evaluation of the results of endoprosthesis of diaphyseal defects are long duration of data accumulation (retrospective study design) due to small number of tumors in this area requiring surgical correction, differences in follow-up duration, and heterogenous histological structure of the tumor.Aim. To analyze the results of postresection defect reconstruction in tumors of the diaphyseal parts of the bones using different endoprostheses models.Materials and methods. The study included 50 patients with primary tumors of the bones and soft tissues who underwent 59 primary and revision surgeries consisting of reconstruction of the diaphyseal and metadiaphyseal defects of the tibia, humerus and femur between 1995 and July of 2025. The primary endoprosthesis group (n = 50) included 29 men and 21 women. Mean patient age was 50.8 years (16–77 years). The group of repeat endoprosthesis (n = 9) included 6 men and 3 women. Mean patient age was 46.2 years (27–68 years). Primary tumors were observed in 30 (61.2 %) patients, metastases in 20 (38.8 %). In 22 (73.3 %) patients with primary tumors, bone sarcomas were diagnosed; in 8 (26.7 %) – soft tissue sarcomas with long bone lesions. In the 29-year period, results of 50 (84.7 %) primary endoprosthesis surgeries and 9 (15.3 %) repeat oncological endoprosthesis surgeries of the diaphyseal part of the long bones were analyzed. Surgical interventions for lesions in the femoral diaphysis were the most common: 49 % (29/59) cases. For lesions of the humeral diaphysis, surgeries were performed in 27 % (16/59) cases; for lesions of the tibial diaphysis, in 24 % (14/59).Results. During the 29-year observation period, overall rate of type I–IV complications (per the International Society of Limb Salvage classification 2013, ISOLS 2013) was 40.7 %, mean time to diagnosis of oncological and nononcological complications was 14.3 (1–58) months. Type IA complications (construction instability) were observed in 3 (4.8 %) cases, type IIА (early aseptic instability) in 9 (14.3 %), type IIВ (late aseptic instability) in 2 (3.2 %), type IIIA (destruction of endoprosthesis elements) in 5 (8 %), type IIIВ (periprosthetic bone fraction) in 1 (1.6 %), type IVA (early endoprosthesis infection) in 1 (1.6 %), type VА (soft tissue recurrence) in 6 (12 %), type VВ (bone recurrence) in 1 (2 %). Total percentage of oncological complications was 32 %. Among oncological complications, only local recurrence was diagnosed in 10 % of cases, only metastasis in 18 %, progression in the form of local recurrence and metastasis in 4 %. Total percentage of non-oncological complications (types I–IV per ISOLS 2013) was 35.6 %. In the current study, the most common adverse events after endoprosthesis of the tibial, humeral and femoral diaphyses were aseptic instability (17.5 % of cases) and tumor recurrence (14 % of cases).Conclusion. According to the study results and literature data, the most optimal are modular implants and models manufactured using 3D printing. Resection of the diaphyseal part of the bone with its reconstruction with an endoprosthesis is the method of choice for patients with primary and metastatic lesions of this part of the bone. Complication rate per the ISOLS 2013 classification corresponds to the average results after oncologic endoprosthesis presented in literature. Moreover, the patients’ functional results and quality of life were better than after surgeries with endoprosthesis of the neighboring joints.