Purpose - retrospective analysis of the causes of complications after knee replacement in tumor lesions depending on the type of implants and classification of complications by severity. Material and methods. The outcomes of operations of knee replacementin tumor lesions performed in 161 patients in the period between 1993 and 2012 were studied. All patients were divided into two groups. The first group included 68 (42.2%) patients, whom the Russian endoprostheses were implanted. The second group included 93 (57.8%) patients, who were operated using modern foreign endoprostheses. Results. 74 (45.9%) patients underwent revision surgery due to the complications in different terms after primary oncologic replacement, with 67 (90.5%) requiring a removal of the primary endoprosthesis. By severity, all complications were divided into 5 types. Infections were the most frequent complications of knee replacement resulting in revision surgery (19 cases, 25.7% of all revision operations). Conclusion. Improvement of oncological systems quality lead to the decrease in the rate of revision surgery due to mechanical reasons. However, the complication rate after knee replacement remains higher than after conventional arthroplasty.

A purpose of the study was to evaluate the immediate and medium-term outcomes of the treatment of patients with primary tumor lesions of proximal femur after the lesion resection together with total hip arthroplastyby total revision systems. Material and methods. 34 patients with primary tumors of proximal femur [chondrosarcoma - 9 (26.5%),giant cell tumor - II (32.4%),osteosarcoma - 2 (5.8%), other malignancies - 5 (14.7%),benign neoplasms - 7 (20.6%)] underwent the conserving surgery at R.R. Vreden Russian Research Institute of Traumatology and Orthopedics since 2003 through 2013. The follow-up was from one to five years. The age of patients ranged from 16 to 70 years, patients younger than 40 years accounted for 61.8%. Acetabulum was replaced by standard components. To replace post-resection defects of proximal femur, in 21 (61.8%) patents revision legs of cementless fixation Wagner Revision (Zimmer) were used, in 10 (29.4%) - “Fenix”, and in 3 (8.8%) - Solution (DePuy, J&J). Results. A technique of total hip arthroplasty with the use of revision systems demonstrated excellent and positive results in 32 (94.2%) cases. Complications leading to revision surgery occurred in 3 (8.8%) patients. Conclusion. The method allows achievement of favorable functional outcomes and early patients’ activation without worsening the oncologic component of treatment and being not inferior to expensive modular systems.