title: The influence of tourniquet use and operative time on the incidence of deep vein thrombosis in total knee arthroplasty.
abstract: OBJECTIVE
  To evaluate the association between tourniquet and total operative time during total knee arthroplasty and the occurrence of deep vein thrombosis.
  
  
  METHODS
  Seventy-eight consecutive patients from our institution underwent cemented total knee arthroplasty for degenerative knee disorders. The pneumatic tourniquet time and total operative time were recorded in minutes. Four categories were established for total tourniquet time: <60, 61 to 90, 91 to 120, and >120 minutes. Three categories were defined for operative time: <120, 121 to 150, and >150 minutes. Between 7 and 12 days after surgery, the patients underwent ascending venography to evaluate the presence of distal or proximal deep vein thrombosis. We evaluated the association between the tourniquet time and total operative time and the occurrence of deep vein thrombosis after total knee arthroplasty.
  
  
  RESULTS
  In total, 33 cases (42.3%) were positive for deep vein thrombosis; 13 (16.7%) cases involved the proximal type. We found no statistically significant difference in tourniquet time or operative time between patients with or without deep vein thrombosis. We did observe a higher frequency of proximal deep vein thrombosis in patients who underwent surgery lasting longer than 120 minutes. The mean total operative time was also higher in patients with proximal deep vein thrombosis. The tourniquet time did not significantly differ in these patients.
  
  
  CONCLUSIONS
  We concluded that surgery lasting longer than 120 minutes increases the risk of proximal deep vein thrombosis.
authors.affiliation: Department of Orthopedics and Traumatology, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Arnaldo José
authors.initials: AJ
authors.lastname: Hernandez
authors.forename: Adriano Marques de
authors.initials: AM
authors.lastname: Almeida
authors.forename: Edmar
authors.initials: E
authors.lastname: Fávaro
authors.forename: Guilherme Turola
authors.initials: GT
authors.lastname: Sguizzato
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061646:Operative Time; D011859:Radiography; D015203:Reproducibility of Results; D012307:Risk Factors; D018709:Statistics, Nonparametric; D013997:Time Factors; D014111:Tourniquets / Q000009:adverse effects*; D020246:Venous Thrombosis / Q000000981:diagnostic imaging / Q000209:etiology*