To investigate the bone penetration of intravenous antibiotic
prophylaxis with flucloxacillin and gentamicin during hip and knee
arthroplasty, and their efficacy against 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).Aims
Patients and Methods
Bone cement containing gentamicin may release antibiotic when fractured during revision operations. Tissue samples taken during surgery may be contaminated by gentamicin and give inaccurate microbiological assessment. We studied five patients in whom cement containing gentamicin had been used in the primary procedure. During revision hip replacement, samples of joint fluid, tissues and cement were taken both before and after disruption of the cement. With the exception of one sample of joint fluid, low concentrations of gentamicin were recorded in the samples taken before the cement was disrupted, but after disruption the specimens contained gentamicin at concentrations high enough to inhibit or prevent growth of sensitive organisms. The cement contained very high levels up to ten years after insertion. Our findings suggest that no reliance can be placed on the microbiological assessment of specimens taken once cement splitting has started and that specimens should therefore be taken as early as possible.
