Therefore, this prospective randomized study was performed to determine whether postoperative administration of IV FCM to patients with postoperative anemia following TKA, especially in the acute period, is effective at: (1) increasing the number of Hb responders; (2) recovering Hb and iron metabolism variable levels; (3) decreasing the transfusion rate and improving QOL. The gene discussed is GSTM1; the disease is anemia (phenotype).