title: Reduction of the incidence of development of venous thromboembolism by ultrasound-guided femoral nerve block in total knee arthroplasty.
abstract: BACKGROUND
  Venous thromboembolism (VTE) and the subsequent development of pulmonary embolism (PE) is a major cause of post-operative mortality in total knee arthroplasty (TKA). We evaluated whether the addition of an ultrasound-guided femoral nerve block with general anesthesia affected the incidence in the development of VTE following TKA.
  
  
  METHODS
  This was a retrospective non-randomized comparative study with patients assigned to groups based on the surgery date (pre-femoral nerve block versus post-femoral nerve block periods). All anesthesia and medical records of the patients who had undergone computer-navigated TKA in our facility between January 2009 and March 2010 were retrospectively reviewed.
  
  
  RESULTS
  Forty patients were identified; 15 patients underwent computer-navigated TKA under general anesthesia alone (Group G) and 25 patients underwent surgery under general anesthesia combined with ultrasound-guided femoral nerve block (Group F). The incidence of development of VTE post-operatively was significantly lower in Group F (P = 0.037). Logistic regression analysis identified the use of a femoral nerve block as the most significant variable correlating with the incidence of post-operative development of VTE, and the odds ratio for VTE development in Group G was 3.12 (95% CI, 0.57-20.56).
  
  
  CONCLUSIONS
  We suggest the possibility that the addition of a femoral nerve block on general anesthesia may reduce the incidence of the development of VTE following TKA.
authors.affiliation: Department of Anesthesiology, Nagoya Kyoritsu Hospital, Nagoya, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Asakura
authors.forename: Hiroki
authors.initials: H
authors.lastname: Tsuchiya
authors.forename: Hisatake
authors.initials: H
authors.lastname: Mori
authors.forename: Takashi
authors.initials: T
authors.lastname: Yano
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Kanayama
authors.forename: Hideki
authors.initials: H
authors.lastname: Takagi