Association between tourniquet use and postoperative D-dimer elevation in total knee arthroplasty: a retrospective case-control study

Background: Whether the use of tourniquets during total knee arthroplasty increases postoperative D-dimer levels in patients is still under debate. Objectives: This study aimed to control factors that could influence D-dimer levels, including demographics and living habits, medical history, preoperative platelet count, preoperative and postoperative hemoglobin, and the amount of blood loss during surgery, to investigate the effects of tourniquet use on postoperative D-dimer levels in patients. Methods: A retrospective case-control study was conducted using hospitalization records of patients who had undergone unilateral total knee arthroplasty between 01/09/2015 and 31/01/2022. Patients were age- and gender-matched (3:1), yielding 402 in the tourniquet group and 134 in the non-tourniquet group. The primary endpoint was postoperative D-dimer level, with tourniquet use as the main variable. Changes in D-dimer levels were compared between the two groups to examine the association between tourniquet use and changes in postoperative D-dimer levels. Results: Differences were found between the no tourniquet group and the tourniquet group in amount of blood loss during surgery (p < .001) and D-dimer levels on the day after surgery (p = < .001). Multiple linear regression analysis with D-dimer levels as the dependent variable revealed that the regression coefficients of tourniquet usage (β = .18, p = .001), age (β = .18, p < .001), the regular use of antiplatelet agents or anticoagulants for more than three consecutive months prior to surgery (β = .11, p = .024), and the difference between preoperative and postoperative hemoglobin (β = .14, p = .001) were positive. Conclusion: This study demonstrates that the use of a tourniquet during unilateral total knee arthroplasty was independently associated with elevated postoperative D-dimer levels. These findings highlight the importance of carefully evaluating the use of tourniquets in clinical practice, given their potential implications for postoperative thrombotic risk.