In a prospective randomised controlled trial, 51 patients who did not receive a bone plug during total knee replacement surgery were compared to 49 patients who received a bone plug. The primary outcome measure was the need for allogenic blood transfusion requirement and the secondary outcome was the post-operative blood loss and decline in haemoglobin levels. The patients had autologous re-transfusion from their closed drainage system. The two groups did not differ in the demographics. The mean intra-operative blood loss was slightly more in the no plug group (difference of 41.25 millilitres), which was not statistically significant. There was no statistically significant difference in total post-operative blood loss and drop in haemoglobin levels. Only one patient had two units of allogenic blood transfusion in the no bone plug group while none required allogenic blood in the bone plug group. There was no statistically significant difference in the amount of blood re-transfused from the drain between the two groups. Our findings did not show any statistically significant difference in post-operative blood loss, decline in haemoglobin levels and the need for allogenic blood transfusion in total knee replacement surgery.