Blood loss following total knee replacement is a major concern of both patients and surgeons. The authors of this study are to be commended for designing a rigorous study that is clinically relevant to this topic. The objective of the study was to evaluate the efficacy of topical tranexamic acid in decreasing blood loss following total knee replacement.
This prospective, double-blinded, controlled study was performed to evaluate the relative efficacy of two different dosages of tranexamic acid, delivered topically at the end of total knee replacement, in decreasing blood loss postoperatively. The authors controlled as many variables as possible, with all patients being enrolled in a similar blood-conservation program and deep-vein thrombosis (DVT) prophylaxis protocol. Patients were randomized to one of three groups and received either 1.5 or 3 g of tranexamic acid or a placebo. All patients were evaluated with regard to blood loss, postoperative hemoglobin level, and function, and all had screening for DVT with use of ultrasound. The most important finding of the study was that patients who were given tranexamic acid had significantly lower blood loss in comparison with the control group. The authors were unable to identify any advantage of the larger dose and found no difference between the patients and the controls in terms of any of the outcomes. A novel finding of this study was that the authors systematically screened patients who were treated with the drug and found no increase in the occurrence of DVT.
Tranexamic acid is one of several antifibrinolytics that have been successfully used to decrease blood loss in patients undergoing surgery. The drug, which blocks the lysine binding site of plasminogen, has been found to be both safe and effective for decreasing blood loss in patients undergoing cardiac, oral, and spine surgery. There have been several recent studies of this drug following total knee replacement and total hip replacement1-4. Each of those studies demonstrated that use of the drug was safe and led to a decrease in the need for transfusions.
While not a major focus of the current paper, the issue of costs associated with decreasing blood loss following total knee replacement should be considered. The cost of this drug, particularly when administered topically, is substantially lower than that associated with the use of fibrin sealants5 and autologous blood donations for the treatment of postoperative anemia.
Several concerns regarding these drugs have limited their more widespread use. Issues such as a potentially increased risk of thrombosis in this already high-risk group and a potential problem related to the intravenous administration of tranexamic acid have been raised. The current study addressed both of these questions. By delivering the medication topically, at the site most needed, the investigators obviated the risks of intravenous administration. Their finding of a 20% to 25% decrease in postoperative bleeding is comparable with the findings of other studies in which the drug was administered intravenously. Their routine use of postoperative Doppler studies, which showed no increased findings of thromboembolic events following the use of this drug, is an important finding.
The authors correctly point out that further study with larger numbers of patients is needed to demonstrate the safety and efficacy of this drug. However, this well-done study adds to the growing literature supporting the use of tranexamic acid as an effective treatment for decreasing blood loss following total knee replacement.