title: Short versus extended thromboprophylaxis after total knee arthroplasty: a randomized comparison.
abstract: BACKGROUND
  The optimal duration of thromboprophylaxis after total knee arthroplasty remains uncertain.
  
  
  METHODS
  We performed a randomized, open trial to determine whether to stop thromboprophylactic therapy at Day 10±2 ('short thromboprophylaxis') was non-inferior to continue thromboprophylactic therapy up to Day 35±5 ('extended thromboprophylaxis') after total knee arthroplasty. At Day 7±2, subjects were screened by ultrasonography for asymptomatic deep-vein thrombosis and randomized. The primary outcome was a composite of proximal deep-vein thrombosis, any symptomatic deep-vein thrombosis, non-fatal symptomatic pulmonary embolism, major bleeding, heparin-induced thrombocytopenia, or all-cause death up to Day 35±5. The secondary outcome was ultrasonographic (extension or new onset) distal deep-vein thrombosis at Day 35±5.
  
  
  RESULTS
  Twenty-one patients (2.4%) were not randomized, because of asymptomatic proximal deep-vein thrombosis on systematic ultrasonography at Day 7±2. Among the 857 randomized patients, mean (SD) duration of anticoagulant treatment was 11.2 (6.7) and 33.9 (3.7) days in the short and extended thromboprophylaxis groups, respectively. The respective rates of the primary outcome were 4.0% (17/420) and 2.4% (10/422), with an absolute difference of 1.7% (90% confidence interval, -0.3 to 3.7). In 285 patients with asymptomatic distal deep-vein thrombosis at Day 7±2, the respective rates of the primary outcome were 7.8% and 2.8% (p=0.067). The rates of the secondary outcome were 14.8% (62/420) and 4.5% (19/422), respectively (p<0.001).
  
  
  CONCLUSIONS
  Short thromboprophylaxis was not non-inferior to extended thromboprophylaxis after total knee arthroplasty. In this setting, the thromboembolic risk persisted longer than seven days, notably in patients with asymptomatic distal deep-vein thrombosis at discharge. ClinicalTrials.gov number: NCT00362492.
authors.affiliation: University Hospital, Caen, France.
authors.forename: Marie-Thérèse
authors.initials: MT
authors.lastname: Barrellier
authors.forename: Benoît
authors.initials: B
authors.lastname: Lebel
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Parienti
authors.forename: Patrick
authors.initials: P
authors.lastname: Mismetti
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Dutheil
authors.forename: Claude
authors.initials: C
authors.lastname: Vielpeau
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007866:Leg / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008875:Middle Aged; D015912:Thrombolytic Therapy / Q000379:methods*; D013997:Time Factors; D014463:Ultrasonography; D020246:Venous Thrombosis / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000209:etiology
chemical_list: D000925:Anticoagulants