title: Prophylaxis against fat and bone-marrow embolism during total hip arthroplasty reduces the incidence of postoperative deep-vein thrombosis: a controlled, randomized clinical trial.
abstract: BACKGROUND
  Clinical and experimental studies have suggested that the maximum risk of thrombogenesis occurs during, rather than after, total hip arthroplasty. With use of conventional cementing techniques, insertion of a femoral component results in marrow embolization of tissue thromboplastin into the veins of the proximal part of the femur, leading to activation of the clotting cascade and thrombogenesis. We hypothesized that an operative technique designed for the prevention of fat and bone-marrow embolism can also reduce the incidence of postoperative deep-vein thrombosis and pulmonary embolism.
  
  
  METHODS
  A total of 130 consecutive patients with osteoarthritis who were to have a primary total hip arthroplasty were randomly assigned to one of two groups. One group consisted of sixty-five patients (sixty-five hips) who had the femoral component inserted with our standard cementing technique without use of a bone vacuum, and the other group included sixty-five patients (sixty-five hips) who had the femoral component cemented with use of a bone-vacuum technique. In the hips managed with the bone vacuum, suction (-800 mbar) was applied to a drainage cannula placed along the linea aspera of the femur in order to prevent an increase in intramedullary pressure during the insertion of the stem. We measured the incidence of intraoperative fat and bone-marrow embolism with use of echocardiography and a transesophageal probe and the incidence of deep-vein thrombosis with use of serial duplex ultrasonography on the day before the operation and on postoperative days 4, 14, and 45. All patients were managed with prolonged pharmacological prophylaxis (low-molecular-weight heparin) against deep-vein thrombosis.
  
  
  RESULTS
  The control group had significantly more severe and prolonged echocardiographic embolic events than did the group managed with the bone-vacuum technique (p < 0.05). A cascade of fine echogenic particles or embolic masses with a diameter of < or =5 mm was observed during the insertion of the stem in fifty-nine hips (91%) in which our standard cementing technique was used and in ten hips (15%) in which the bone-vacuum cementing technique was used. Deep-vein thrombosis was detected on postoperative day 4 in twelve patients (18%) in the control group and in two patients (3%) in the group managed with the bone-vacuum technique; the difference was significant (p < 0.05).
  
  
  CONCLUSIONS
  Intraoperative prophylaxis against fat and bone-marrow embolism during total hip arthroplasty with cement can reduce the incidence of postoperative deep-vein thrombosis. We now use the bone-vacuum technique routinely in all total hip arthroplasties performed with cement.
authors.affiliation: Department of Orthopaedic Surgery, University of Auckland, Middlemore Hospital, Otahuhu, Auckland, New Zealand. rpitto@middlemore.co.nz
authors.forename: Rocco Paolo
authors.initials: RP
authors.lastname: Pitto
authors.forename: Hendrik
authors.initials: H
authors.lastname: Hamer
authors.forename: Renato
authors.initials: R
authors.lastname: Fabiani
authors.forename: Martin
authors.initials: M
authors.lastname: Radespiel-Troeger
authors.forename: Matthias
authors.initials: M
authors.lastname: Koessler
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D001853:Bone Marrow; D004617:Embolism / Q000517:prevention & control*; D004620:Embolism, Fat / Q000517:prevention & control*; D006801:Humans; D010003:Osteoarthritis / Q000601:surgery; D011183:Postoperative Complications / Q000517:prevention & control; D020246:Venous Thrombosis / Q000517:prevention & control*