title: Bone penetration of intravenous flucloxacillin and gentamicin as antibiotic prophylaxis during total hip and knee arthroplasty.
abstract: OBJECTIVE
  To investigate the bone penetration of intravenous antibiotic prophylaxis with flucloxacillin and gentamicin during hip and knee arthroplasty, and their efficacy againstStaphylococcus(S.)aureusandS. epidermidis.
  
  
  METHODS
  Bone samples from the femoral head, neck and acetabulum were collected from 18 patients undergoing total hip arthroplasty (THA) and from the femur and tibia in 21 patients during total knee arthroplasty (TKA). The concentration of both antibiotics in the samples was analysed using high performance liquid chromatography. Penetration was expressed as a percentage of venous blood concentration. The efficacy against common infecting organisms was measured against both the minimum inhibitory concentration 50, and the more stringent epidemiological cutoff value for resistance (ECOFF).
  
  
  RESULTS
  The bone penetration of gentamicin was higher than flucloxacillin. Relative to ECOFF, flucloxacillin concentrations were effective againstS. aureusandS. epidermidisin all THAs and 20 (95%) TKAs. Gentamicin concentrations were effective againstS. epidermidisin all bone samples. Gentamicin was effective againstS. aureusin 11 (61.1%) femoral neck samples in THA. Effective concentrations of gentamicin againstS. aureuswere only achieved in four (19%) femoral and six (29%) tibial samples in TKA.
  
  
  CONCLUSIONS
  Flucloxacillin and gentamicin were found to penetrate bone during THA and TKA. Gentamicin was effective againstS. epidermidisin both THA and TKA, while levels were subtherapeutic againstS. aureusin most TKAs. Bone penetration of both antibiotics was less in TKA than THA, and may relate to the use of a tourniquet. Using this antibiotic combination, effective cover against the two common infective organisms was achieved in all THAs and all but one TKA. Cite this article:Bone Joint J2017;99-B:358-64.
authors.affiliation: Glasgow Royal Infirmary, 84 Castle Street, Glasgow, G4 0SF, UK.
authors.forename: M S
authors.initials: MS
authors.lastname: Torkington
authors.affiliation: Glasgow Royal Infirmary, 84 Castle Street, Glasgow, G4 0SF, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: Davison
authors.affiliation: Glasgow Royal Infirmary, 84 Castle Street, Glasgow, G4 0SF, UK.
authors.forename: E F
authors.initials: EF
authors.lastname: Wheelwright
authors.affiliation: Glasgow Royal Infirmary, 84 Castle Street, Glasgow, G4 0SF, UK.
authors.forename: P J
authors.initials: PJ
authors.lastname: Jenkins
authors.affiliation: Glasgow Royal Infirmary, 84 Castle Street, Glasgow, G4 0SF, UK.
authors.forename: I
authors.initials: I
authors.lastname: Anthony
authors.affiliation: Southmead Hospital, Westbury-on-Trym, Bristol, BS10 5NB, UK.
authors.forename: A M
authors.initials: AM
authors.lastname: Lovering
authors.affiliation: Glasgow Royal Infirmary, 84 Castle Street, Glasgow, G4 0SF, UK.
authors.forename: M
authors.initials: M
authors.lastname: Blyth
authors.affiliation: Glasgow Royal Infirmary, 84 Castle Street, Glasgow, G4 0SF, UK.
authors.forename: B
authors.initials: B
authors.lastname: Jones
mesh_terms: D000077:Acetabulum / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D019072:Antibiotic Prophylaxis / Q000379:methods; D019644:Arthroplasty, Replacement, Hip; D019645:Arthroplasty, Replacement, Knee; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005260:Female; D005269:Femur / Q000378:metabolism; D005436:Floxacillin / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005839:Gentamicins / Q000008:administration & dosage / Q000493:pharmacokinetics*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D007720:Knee Prosthesis / Q000009:adverse effects*; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D016459:Prosthesis-Related Infections / Q000517:prevention & control*; D013203:Staphylococcal Infections / Q000517:prevention & control; D013211:Staphylococcus aureus; D013212:Staphylococcus epidermidis / Q000187:drug effects; D013977:Tibia / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins; D005436:Floxacillin
keywords: Antibiotic; Arthroplasty; Flucloxacillin; Gentamicin; Prophylaxis