title: Intraosseous concentration and inhibitory effect of different intravenous cefazolin doses used in preoperative prophylaxis of total knee arthroplasty.
abstract: BACKGROUND
  The aim of this study was to compare the intraosseous concentrations and the inhibitory effects on the growth of Staphylococcus aureus of 1 g versus 2 g of intravenous (IV) prophylactic cefazolin in total knee arthroplasty (TKA).
  
  
  METHODS
  Eighteen patients (21 knees) with primary knee osteoarthritis were divided into two groups receiving 1 g (12 patients: 14 knees) versus 2 g (six patients: seven knees) IV prophylactic cefazolin prior to the incision in TKA. Subchondral bone samples (proximal tibia, distal femur) were taken during the operation. These samples were analyzed for intraosseous concentration of cefazolin and their inhibitory effects on the growth of S. aureus, using high-performance liquid chromatography (HPLC) and agar disc diffusion bioassays.
  
  
  RESULTS
  The mean intraosseous concentration in the 2 g dose group was significantly higher than in the 1 g dose group in the proximal tibia (p = 0.007) and distal femur (p = 0.016). There were no significant differences between the two groups in terms of mean inhibitory effects in the proximal tibia or distal femur (p > 0.05). No significant correlations were found between the intraosseous concentrations and inhibitory effects in the proximal tibia (r = 0.18, p = 0.52) and distal femur (r = -0.29, p = 0.30).
  
  
  CONCLUSIONS
  IV cefazolin at a dose of 2 g produced greater intraosseous concentrations overall than a dose of 1 g. However, the higher intraosseous concentrations did not correlate with higher inhibitory effects.
authors.affiliation: Department of Orthopaedics, Faculty of Medicine, Thammasat University, Pathum Thani, 12120, Thailand. chatthara@yahoo.com.
authors.forename: Chayanin
authors.initials: C
authors.lastname: Angthong
authors.affiliation: Department of Orthopaedics, Faculty of Medicine, Thammasat University, Pathum Thani, 12120, Thailand.
authors.forename: Pongpaibool
authors.initials: P
authors.lastname: Krajubngern
authors.affiliation: Department of Chemistry, Faculty of Science and Technology, Thammasat University, Pathum Thani, Thailand.
authors.forename: Warawut
authors.initials: W
authors.lastname: Tiyapongpattana
authors.affiliation: Department of Orthopaedics, Faculty of Medicine, Thammasat University, Pathum Thani, 12120, Thailand.
authors.forename: Boonchana
authors.initials: B
authors.lastname: Pongcharoen
authors.affiliation: Department of Orthopaedics, Faculty of Medicine, Thammasat University, Pathum Thani, 12120, Thailand.
authors.forename: Piya
authors.initials: P
authors.lastname: Pinsornsak
authors.affiliation: Department of Orthopaedics, Faculty of Medicine, Thammasat University, Pathum Thani, 12120, Thailand.
authors.forename: Nattapol
authors.initials: N
authors.lastname: Tammachote
authors.affiliation: The Surgical Unit, Thammasat University Hospital, Pathum Thani, Thailand.
authors.forename: Wanna
authors.initials: W
authors.lastname: Kittisupaluck
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D019072:Antibiotic Prophylaxis; D019645:Arthroplasty, Replacement, Knee; D002437:Cefazolin / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D013211:Staphylococcus aureus / Q000187:drug effects; D013530:Surgical Wound Infection / Q000517:prevention & control*; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D002437:Cefazolin
keywords: Cefazolin; Effect; Inhibitory; Intraosseous concentration; Knee arthroplasty; Prophylaxis