Post-operative blood loss in total knee arthroplasty: knee flexion versus pharmacological techniques.

Purpose To compare the blood loss and the blood transfusion between a control group and a group of patients following either a local administration of tranexamic acid or a mechanical post-operative knee flexion, a controlled randomized study was performed. Methods Sixty patients affected by primary knee osteoarthritis and candidates to receive a primary unilateral total knee arthroplasty were enrolled in a prospective, randomized, controlled study. Exclusion criteria were the following: tranexamic acid allergy, the use of pharmacological anticoagulant therapy, previous knee surgery and renal failure. For each patient, the following parameters were investigated: the blood loss volume, the haemoglobin and haematocrit concentrations and the blood transfusion needs. Results Compared to the control group, the administration of systemic tranexamic acid significantly reduces (p\0.05) both the blood loss (average reduction 39.8 %) and the blood transfusion needs (64 %). Furthermore, the tranexamic acid group shows a significant reduction (p\0.05) compared to the knee flexion group of the blood loss (average reduction 31.8 %) and the transfusion needs (65 %). However, even if the knee flexion technique slightly reduces the blood loss (average reduction 11.6 %) compared to the control group, this difference is not statistically significant (n.s.). Moreover, this treatment did not reduce the transfusion needs compared to the control group (n.s.). Incidence of complications was not influenced by any of the treatments. Conclusions The use of tranexamic acid compared to knee flexion and to control group significantly reduces blood loss and transfusion needs, without wound complications or symptomatic deep vein thrombosis. Level of evidence Prospective therapeutic study, Level I.