title: Preoperative low molecular weight heparin as venous thromboembolism prophylaxis in patients at risk for prosthetic infection after knee arthroplasty.
abstract: OBJECTIVE
  To investigate the effect of preoperative initiation of low molecular weight heparin as prophylaxis for deep venous thrombosis in patients at risk of developing surgical-site infections after knee arthroplasty.
  
  
  METHODS
  Case-control study nested in a cohort. The incidence of surgical-site infection in the cohort was calculated. With the use of data extracted from medical histories and after adjustment for other risk factors, the effect of preoperative heparinization on the risk of incisional and prosthetic infection among case-patients and control-patients (1:3 ratio) was assessed.
  
  
  METHODS
  Orthopedic department in a tertiary-care referral hospital.
  
  
  METHODS
  A cohort of 160 consecutive patients who had received prosthetic knee implants between October 1, 2001, and November 30, 2003.
  
  
  RESULTS
  Eighteen patients with surgical-site infections were identified, yielding an incidence of incisional and prosthetic infection of 6.9 (95% confidence interval [CI95], 3.5 to 12.0) and 4.4 (CI95, 1.8 to 8.8) cases per 100 patients undergoing surgery, respectively. Surgical-site infection was associated with preoperative use of low molecular weight heparin (odds ratio [OR], 6.2 after adjustment for medical and surgical factors; CI95 1.5 to 23). Prosthetic infection was strongly associated with preoperative use of prophylaxis (OR, undetermined [100% exposure in case-patients vs 35% exposure in control-patients]; P = .002), but incisional surgical-site infection was not.
  
  
  CONCLUSIONS
  The use of low molecular weight heparins immediately before knee arthroplasty as prophylaxis for deep venous thrombosis should be questioned because of probable increased risk of prosthetic infection.
authors.affiliation: Servicio de Medicina Preventiva, Hospital Universitario Puerta de Hierro, Madrid, Spain. aasensio.hpth@salud.madrid.org
authors.forename: Angel
authors.initials: A
authors.lastname: Asensio
authors.forename: Antonio
authors.initials: A
authors.lastname: Ramos
authors.forename: Elena
authors.initials: E
authors.lastname: Múñez
authors.forename: José L
authors.initials: JL
authors.lastname: Vilanova
authors.forename: Pedro
authors.initials: P
authors.lastname: Torrijos
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: García
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000009:adverse effects* / Q000627:therapeutic use; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D016022:Case-Control Studies; D018890:Chemoprevention; D015331:Cohort Studies; D005260:Female; D006495:Heparin, Low-Molecular-Weight / Q000009:adverse effects* / Q000627:therapeutic use; D006801:Humans; D007720:Knee Prosthesis / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D016459:Prosthesis-Related Infections / Q000209:etiology*; D013530:Surgical Wound Infection / Q000209:etiology; D020246:Venous Thrombosis / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight