The Effect of Pharmacological Thromboprophylaxis, Tourniquet and Drainage on Hemorrhagic Complications in the Early Stage after Knee Arthroplasty: Preliminary Results

Background — venous thromboembolic complications (VTC) are potential life-threatening complications following knee arthroplasty (KA). An optimal thromboprophylaxis strategy should reduce the risk of developing VTC without increasing the risk of hemorrhagic complications. The purpose of the study is to evaluate the effect of the drugs (acetylsalicylic acid, dabigatran etexilate and rivaroxaban) for the pharmacological thromboprophylaxis and the features of the surgical procedure (use of the tourniquet and drainage) on hemorrhagic complications in early periods after knee arthroplasty. Materials and Methods. 335 patients (65 men and 270 women), without additional risk factors for the development of thromboembolic complications, were included into the study. Those patients were admitted for planned primary / revision knee arthroplasty and corresponded to inclusion / non-inclusion criteria. Patients were randomized into three clinical groups, depending on the drug used thromboprophylaxis. During the inpatient treatment period, all patients recorded the development of symptomatic VTCs and the development of hemorrhagic complications. According to the clinical indications, the number of knee joint punctures was taken into account: patella balloting, restricted flexion and a smooth joint contour. Results. Symptomatic VTCs were not observed during the study period. The volume of intraoperative blood loss did not depend on the drugs used for  thromboprophylaxis, and was determined only by the surgical technique (ρs= -0.615, p = 0.0001). The use of the tourniquet during the procedure significantly reduced intraoperative blood loss (p = 0.023). No relation between surgical technique and anemia on the 5th day (ρs = 0.11, p = 0.05), as well as between surgical technique and total blood loss (ρs = 0.12, p = 0.01) was established; weak reliable correlation between the use of the tourniquet and hidden blood loss (ρs = -0.22, p = 0.01) was reported. A negative average significant correlation was observed (ρs = -0.42, p = 0.01) for the volume of total blood loss and hemoglobin level on the 5th day after the surgery. The number of postoperative punctures was comparable in the study groups. Conclusion. Sample of present size is not sufficient to make conclusions about the equal efficacy of using acetylsalicylic acid, dabigatran and rivaroxaban for thromboprophylaxis after knee arthroplasty in patients without additional risk factors for thrombosis. Data on the significant correlation of the surgical technique with the volume of intraoperative and latent blood loss, as well as total blood loss and hemoglobin level on the 5th day after the operation allow to suggest a possible effect of the drug for thromboprophylaxis on blood loss stargin from 2nd day after the procedure.