RESUMEN
A 22 year old male with hemophilia B was scheduled for the correction of a right subtrochanteric femur fracture. Plasma concentration of coagulation factor IX in this patient was 50% of the normal level and the partial thromboplastin time was 57 seconds on the first day of hospital administration. We started the intravenous administration of facnyne injection (factor IX) 11 days before the operation when his plasma concentration was 20%. His plasma concentration was 40% on the operation day. The operation and general anesthesia were accomplished safely without severe hemorrhage or major complication. He received facnyne injection continuously until the 5th postoperative day: 25-43% of his plasma concentrations of factor IX was maintained. He had no problem with postoperative care.