Study involved 112 patients with implanted total endoprothesis (TEP) of hip or knee. Thromboembolism is a threat for patients and surgeon during complicated operations in orthopedic and traumatology and could destroy even the most successful procedures. Clinic for bone surgery pays special attention to this problem. Original protocol has developed. In study, original statistic paper and software support were used. We described complications of TE we were faced on our Clinic and explained in details prevention protocol. Protocol was confronted to similar protocols in countries of Western Europe and USA. First results are promising.