After total hip and knee replacement arthoplasty, patients may become anaemic and may be prescribed oral iron. There is, however, no published evidence that this is of benefit when used postoperatively. We treated 72 patients who were anaemic after primary total hip and knee arthroplasty by randomly allocating them to receive six weeks of either oral ferrous sulphate (35 patients) or a placebo (37 patients). Both groups of patients were similar in all aspects except for the treatment given. There was no statistically significant difference in the change of haemoglobin levels between the two groups. We therefore believe that the prescription of iron to all anaemic patients postoperatively should be avoided. The level of serum ferritin should be monitored at preoperative assessment.

Aim: To estimate the prevalence of iron deficiency in patients undergoing primary total hip (THR) or knee (TKR) replacement surgery and to test the clinical effectiveness of routinely prescribing iron supplements to all anæmic patients after THR and TKR.

Method: This was designed as a randomised, doubleblind, placebo-controlled trial. Serum ferritin was measured in 230 consecutive patients admitted for primary THR or TKR. Seventy-two patients were entered into the randomised arm of the trial, 35 were randomised to the treatment group, and 37 to the placebo group. Patients meeting the inclusion criteria after primary THR or TKR were randomised to receive six week’s treatment with either ferrous sulphate (200mg) or an identical gelatin placebo, three times daily. The serum ferritin level and the change in hæmoglobin were measured between five and seven days post-operatively and each patient attended for an out-patient review at six weeks after the surgery.

Results: The study achieved a statistical power of 80%. Serum ferritin was abnormally low in 15 of 230 patients (6.5%). Hæmoglobin in the group of patients receiving ferrous sulphate increased by a mean of 0.31 g/dL more than the group receiving the placebo (95% confidence interval −0.17 −0.79 g/dL). This difference was not statistically significant (p=0.18).

Conclusions: We found that iron deficiency was uncommon in patients who had undergone primary THR or TKR. The routine prescription of oral iron salts to all anæmic patients after these procedures had no clinical benefit.