Aims To investigate the bone penetration of intravenous antibiotic prophylaxis with flucloxacillin and gentamicin during hip and knee arthroplasty, and their efficacy against Staphylococcus (S.) aureus and S. epidermidis.
Patients and 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 against S. aureus and S. epidermidis in all THAs and 20 (95%) TKAs. Gentamicin concentrations were effective against S. epidermidis in all bone samples. Gentamicin was effective against S. aureus in 11 (61.1%) femoral neck samples in THA. Effective concentrations of gentamicin against S. aureus were only achieved in four (19%) femoral and six (29%) tibial samples in TKA.
Conclusion Flucloxacillin and gentamicin were found to penetrate bone during THA and TKA. Gentamicin was effective against S. epidermidis in both THA and TKA, while levels were subtherapeutic against S. aureus in 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 J 2017;99-B:358–64.
M. S. Torkington: Patient recruitment, Sample processing, Initial draft preparation, Revision of initial draft.
M. J. Davison: Ethics application, Patient recruitment, Sample processing, Initial draft preparation, Revision of initial draft.
E. F. Wheelwright: Patient recruitment, Sample collection, Initial draft preparation.
P. J. Jenkins: Statistical analysis, Initial draft preparation.
I. Anthony: Study design, Ethics application, Statistical analysis, Initial draft preparation.
A. M. Lovering: Study design, Sample processing, Initial draft preparation.
M. Blyth: Study design, Patient recruitment, Sample collection, Initial draft preparation.
B. Jones: Study design, Patient recruitment, Sample collection, Initial draft preparation.
No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
This article was primary edited by G. Scott.
- Received April 26, 2016.
- Accepted November 3, 2016.
- ©2017 The British Editorial Society of Bone & Joint Surgery