The problem of thromboembolic complications concerns nearly all orthopaedic and trauma patients. However, risk factors are different and prophylaxis slightly varies depending on the complication. The presence of thrombosis of complex and insidious clinical picture, which is presented in this case report, is alarming. The article reports a case of a 64-year-old male patient with risk factors of thromboembolism. The patient underwent high tibial osteotomy for varus deformity correction due to gonarthrosis. Venus thrombosis and pulmonary embolism developed in the postoperative period. Additionally, symptoms of infection appeared during the treatment in the form of inappropriate wound healing, which was an indication for surgical revision of the wound. The authors present the manner of safe perioperative management of a patient, which is consistent with the standards, taking into account the risk of recurrence of thromboembolism.