Anemia after surgery is associated with inferior outcomes post total knee arthroplasty(TKA). Traditional iron supplements were associated with serious side effects and allergic reactions. Intravenous Ferric Carboxymaltose(FCM) is a newer generation of iron preparation with a good safety profile that can be administered rapidly and does not require administration of a test dose. Previously, we reported that 500 mg of FCM on the first postoperative day hastens the recovery of haemoglobin(Hb) at 5 weeks post TKA as compared to no treatment. However, this recovery was not complete and the Hb was significantly lower than preoperative values. The maximum permissible dose of FCM is 1000 mg. Thus, we aimed to study the effect of 1000 mg of FCM on Hb recovery post TKA.
We prospectively collected data from 172 consecutive patients operated between June 2021 and May 2022 by a single surgeon. All patients received 1000 mg intravenous(iv) FCM on postoperative Day 1. We measured the Hb preoperatively (Preop-Hb), on day 3 post TKA (Day3-Hb) and at 5 weeks(+ 1 week) post TKA (Week5-Hb). This was our study group. Our control group consisted of retrospectively collecting the same data on 157 patients who received 500 mg of FCM.
Statistical analysis was performed using student paired and unpaired t -tests.
General demographics and incidence of medical diseases were comparable between the two groups.
Preop-Hb was comparable between the two groups. Week5-Hb was equal between the two groups, in spite of Day3-Hb being lower (p=0.006) in the study group.
The drop in Hb from preoperative to Day 3 was equal in both groups. The rise in Hb from Day 3 to Week 5 was significantly higher in the study group.(p<0.001) The difference between Preop-Hb and Week5-Hb was significantly lower in the study group. (p<0.05)
Additionally, 30 % of patients reached preoperative Hb values at 5 weeks in the study group as opposed to only 13 % in the control group.
1000 mg of intravenous FCM administered on the first postoperative day post TKA, further hastens the haemoglobin recovery as compared to 500 mg of FCM. More than twice the number of patients are able to achieve preoperative Hb values by 5 weeks post TKA. We recommend 1000 mg of intravenous FCM in all patients undergoing TKA to hasten the Hb recovery.