Background: Ecchymosis is a common complication after total knee arthroplasty (TKA). However, only a few studies have been conducted to determine the coagulation status of these patients. Using thromboelastography (TEG), a new technique recording the viscoelastic changes of a whole-blood sample, this study was performed to understand the ecchymosis-related coagulation status and its risk factors.
Methods: Seventy-five patients receiving unilateral TKA were recruited in this observational study. Oral rivaroxaban was applied as prophylaxis treatment after surgery. TEG was performed 1 day before surgery and 4 days after surgery. Total blood loss and hidden blood loss were recorded and calculated. Univariate and multivariate analyses were conducted to determine risk factors.
Results: Twenty-five patients (33.3%) developed ecchymosis within 2-3 days after TKA. Compared with the baseline before TKA, the α-angle (P = .032) and calculated coagulation index (CI; P = .012) were increased in non-ecchymosis group, whereas in the ecchymosis group, there was no significant difference regarding any variable of postoperative TEG evaluation. The ecchymosis group exhibited more hidden blood loss (P = .007) and total blood loss (P = .011). Value change of CI (OR = 0.666, 95% confidence interval = [0.496, 0.895], P = .007) and hidden blood loss (OR = 1.008, 95% confidence interval = [1.002, 1.013], P = .004) were recognized as the independent risk factors for postoperative ecchymosis.
Conclusion: In TEG evaluation, the value change of CI and hidden blood loss are independent risk factors of ecchymosis. In view of the relative hypocoagulation status, it is reasonable to stop anticoagulation therapy in patients with excessive ecchymosis. Personalized anticoagulation therapy may be helpful for managing ecchymosis after TKA.
Keywords: Thromboelastography; ecchymosis; total knee arthroplasty.
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