Postoperative anaemia are common in patients undergoing major orthopaedic surgery. The main consequence of perioperative anaemia is an increased risk of red blood cell (RBC) transfusions. Allogeneic RBC transfusion and anaemia are associated with higher postoperative mortality and morbidity.

The aim of this study was to compare the efficacy of postoperative i.v. ferric carboxymaltose (FCM) and oral ferrous glycine sulphate (FS) for early improvement of postoperative anaemia after total knee arthroplasty and whether iron treatment could facilitate recovery from surgery.

Both pre- and postoperative anaemia are common in patients undergoing major orthopaedic surgery. The main consequence of perioperative anaemia is an increased risk of red blood cell (RBC) transfusions. Allogeneic RBC transfusion and anaemia are associated with higher postoperative mortality and morbidity. Since blood transfusions increase Hb levels only transiently but come at the price of higher mortality and morbidity (e.g. postoperative infections), the three-pillar concept of patient blood management (PBM) has been developed to reduce the risk of blood transfusions and improve patient outcomes. Among its three pillars, the treatment or prevention of preoperative anaemia is the mainstay of PBM. Also the second pillar, minimisation of intraoperative blood loss,15 targets at least indirectly the patient's haemoglobin (Hb) levels.

The third PBM pillar, use of low Hb cut-off levels triggering transfusion, means that a certain degree of postoperative anaemia is taken into account. However, it remains unclear whether a lowered transfusion threshold allows optimal functional recovery and quality of life. Since patients undergoing total knee arthroplasty (TKA) are often elderly and have several comorbidities, prolonged exposure to low Hb levels is not a good option for this population. Furthermore, TKA patients should be mobilised as soon as possible after surgery which increases the metabolic demand.

Although, depending on the timescale before surgery, oral iron is suggested for preoperatively anaemic patients with absolute iron deficiency, oral iron showed no benefit over placebo in anaemic patients after lower limb arthroplasty. In patients at risk of functional iron deficiency due to chronic inflammation of different aetiologies, intravenous (i.v.) iron administration has proven its superiority over oral iron. Even in iron-deficient patients without established anaemia, i.v. iron improved physical performance and cardiac functional class. Thus, postoperative anaemia treatment with i.v. iron might not only reduce RBC requirements but also improve performance, rehabilitation and outcomes.

The aim of this study was to compare the efficacy of postoperative i.v. ferric carboxymaltose (FCM) and oral ferrous glycine sulphate (FS) for early improvement of postoperative anaemia after total knee arthroplasty and whether iron treatment could facilitate recovery from surgery.

Inclusion Criteria:

• Adult patients (≥18 years of age) were recruited at the scheduled preoperative visit (21 to 30 days prior surgery knee replacement). Anaemia (Hb <12 g/dL) and/or iron deficiency (TSAT <20%) the day after surgery

Exclusion Criteria:

• Patients with known hypersensitivity or contraindications to iron, liver insufficiency (aspartate aminotransferase or alanine aminotransferase >60 IU/L), bronchial asthma, presence of acute or chronic infection, severe heart disease, significant history of allergies (rash, etc.) or anti-anaemia treatment within 15 days prior to surgery were excluded from participation. Also pregnant or nursing women were excluded (negative pregnancy urine test within 7 days prior first study treatment or amenorrhoea for at least 12 months).