title: Time course of thrombosis and fibrinolysis in total knee arthroplasty with tourniquet application. Local versus systemic activations.
abstract: BACKGROUND
  Venous thrombosis is common in knee surgery, and it has been assumed that vein occlusion by tourniquet in itself may induce thrombogenic and fibrinolytic activity. Prophylactic treatment is used up to 12 h before or after surgery, and recent clinical trials suggest that the timing of initiating prophylaxis significantly influences antithrombotic effectiveness.
  
  
  METHODS
  We studied the time course of coagulation and fibrinolysis locally and systemically during total knee arthroplasty. Specific markers of thrombosis (prothrombin fragment 1.2 (F1.2)) and fibrinolysis (plasmin-antiplasmin (PAP) and D-dimer) were examined in seven female and two male patients.
  
  
  RESULTS
  There were no systemic activations of either F1.2 (P = 0.314), PAP (P = 0.314) or D-dimer (P = 0.600) during surgery or at 10 min postoperatively (P = 0.139, 0.139 and 0.128, respectively) as compared to baseline data. At 4 h postoperatively there were significant increments in levels of F1.2 (P = 0.008), PAP (P = 0.038) and D-dimer (P = 0.046). With tourniquet deflation the values of F1.2, PAP and D-dimer were significantly higher in the tourniquet limb than the in the contra lateral limb (P = 0.025, 0.012 and 0.028, respectively). At 10 min after tourniquet deflation, the differences in F1.2, PAP and D-dimer between the two limbs were not significant.
  
  
  CONCLUSIONS
  The use of tourniquet in total knee arthroplasty causes local thrombogenic and fibrinolytic activity, but without influences in the systemic circulation. Systemic activations in thrombosis and fibrinolysis start when local mediators from the injured limb are released after tourniquet deflation.
authors.affiliation: Department of Orthopaedics, Rikshospitalet University Clinic, University of Oslo, 0027, Oslo, Norway. olav.reikeras@rikshospitalet.no
authors.forename: Olav
authors.initials: O
authors.lastname: Reikerås
authors.forename: Torkil
authors.initials: T
authors.lastname: Clementsen
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D015415:Biomarkers / Q000097:blood; D005260:Female; D005342:Fibrinolysis / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000097:blood; D011183:Postoperative Complications / Q000097:blood / Q000175:diagnosis / Q000209:etiology; D011516:Prothrombin; D013927:Thrombosis / Q000097:blood* / Q000175:diagnosis / Q000209:etiology; D013997:Time Factors; D014111:Tourniquets / Q000009:adverse effects*; D054556:Venous Thromboembolism / Q000097:blood / Q000175:diagnosis / Q000209:etiology
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; C045879:prothrombin fragment 1.2; D011516:Prothrombin