Effect of irrigation and tourniquet application on aminoglycoside antibiotic concentrations in bone

Preoperative antibiotics are an important measure taken to prevent infection in joint replacement surgery. The local availability of these antibiotics in the operative site is absolutely necessary to ensure adequate prophylaxis against contaminant bacteria. Because pulsatile-lavage rapid-recovery systems have become a routine technique of bone preparation in joint reconstruction, we chose to study the effect of these systems on local antibiotic concentrations. We further investigated the effect of irrigation with and without use of a limb tourniquet. For our study, we obtained 23 bone specimens in 16 patients undergoing joint reconstruction (14) or amputation (2). The patients were classified into one of four groups based on whether a tourniquet was applied during the procedure and whether the bone specimens were irrigated. In addition, matched blood samples were obtained to establish that therapeutic serum levels were achieved. Nine patients contributed 13 bone specimens, which underwent vigorous irrigation in vitro. None of these specimens had detectable levels of antibiotics, regardless of whether a tourniquet was used. Seven patients yielded 10 bone specimens, which were not irrigated. Five of these seven patients had detectable levels of antibiotics. In addition, the specimens from limbs without tourniquets had levels that averaged 0.51 microgram/ml while those with tourniquets averaged below 0.2 microgram/ml. Therefore, the use of vigorous irrigation in bone preparation has a significant deleterious effect on the local presence of previously administered systemic antibiotics. This effect is compounded if the operative site is isolated from continuous blood flow by use of a tourniquet. We therefore recommend that additional measures be taken to ensure that adequate antibiotic levels are present.(ABSTRACT TRUNCATED AT 250 WORDS)