Aims: To compare rates of blood transfusion post knee arthroplasties for patients treated with and without tranexamic acid (TA) and assess for any haemoglobin change perioperatively between the groups.

Methods: This retrospective observational study included 207 patients undergoing primary unilateral knee replacement surgery who were divided by administration of TA intraoperatively (n=120) or without (n=87). The TA group was further subdivided into patients undergoing a standardised autogenic retransfusion procedure (n= 86) and those without (n=44). Case notes and laboratory results were used to study pre and post operative haemoglobin, administration of TA and blood products. The exclusion criteria consisted of patients in ASA classes III & IV, revision surgery, and patients undergoing bilateral or unicompartmental knee replacements. Analysis of haemoglobin change was undertaken using the student t-test. Significance was concluded when p < 0.05.

Results: The average haemoglobin drop in the TA group (without auto-transfusion) was 1.96g/dL versus 1.8g/dL in the no drug group which was not significant (p= 0.459). The average drop in the TA group (with auto-transfusion) was 1.78g/dL, also not significant (p=0.922). 3 of the 44 patients (7%) from the TA group (without auto-transfusion) required blood transfusions compared against 7 of the 87 non tranexamic acid group (8%) which was not significant.

Conclusion: There was no significant difference between all three groups. This study raises questions over the efficacy of TA treatment as a means to reduce perioperative blood loss in total knee replacements. Further, TA does not reduce blood loss and transfusion requirements even when autogenic retransfusion was used.