This study aims to assess postoperative blood loss and transfusion rates in total knee replacement after one-time administration of topical tranexamic acid.

Autologous (donor) blood transfusion is an expensive and common occurrence after total knee replacement. Published data puts this rate between 9 and 40% after primary unilateral total knee arthroplasty. There have been many proposed adjunctive measures to decrease intraoperative and postoperative blood loss during such surgery. Most of these include thrombin inhibition, so-called "minimally- invasive" techniques or instrumentation, or other adjunctive drugs. Hitherto, tranexamic acid, a specific drug that promotes part of the clotting cascade, has been used extensively in multiple areas of surgery with multiple studies evaluating its efficacy in cardiac surgery, spinal procedures, and as a dental swishing solution after tooth extraction. There have been small studies evaluating intravenous tranexamic acid and its effect on total knee replacement, with some promising results. The topical form of TA has been evaluated in only one prospective, randomized clinical trial with a significant decrease in postoperative blood loss and a trend towards decreased autologous blood transfusion rates. This study proposes to further evaluate tranexamic acid as an inexpensive and viable option for use in total knee arthroplasty. The topical form of the drug has been shown to achieve these hemostatic effects without increasing the risk of blood clots after surgery. Furthermore, the one aforementioned randomized clinical trial used a variety of postoperative deep vein thrombosis prophylaxis after surgery and introduced a potential confounding variable. A rigorous analysis of the effects of tranexamic acid demand a more standardized approach. Such a regimen is practiced at Henry Ford Hospital as all patients on the Adult Reconstruction service are placed on an identical dose of enoxaparin (a subcutaneous blood thinner) postoperatively for two weeks.

Inclusion Criteria:

• All adult patients over age eighteen
• Primary unilateral total knee arthroplasty at Henry Ford Hospital (Detroit, Michigan, United States) and Henry Ford West Bloomfield Hospital (West Bloomfield, Michigan, United States)

Exclusion Criteria:

• patient history of venous thromboembolic disease or coagulopathy
• use of anticoagulant medications within 7 days of surgery
• history of arterial embolic disease
• history of Class III or IV heart failure
• renal failure
• intraoperative cardiovascular, pulmonary, orthopaedic, or anesthetic complication (MI, intraoperative fracture, vasopressor support, emergent intubation).