Determination of serum and bone concentrations of cephradine and cefuroxime by HPLC in patients undergoing hip and knee joint replacement surgery.

Bone and serum concentrations of cephradine and cefuroxime were measured by HPLC in 21 patients undergoing hip and knee joint replacement surgery. An intravenous dose of 750 mg of each cephalosporin was given to patients at induction of anaesthesia. The serum and bone concentrations of both compounds were similar in individual patients although there was considerable interpatient variation. The mean concentrations in the femoral head bone supernatant in hip replacements were 7.2 mg/kg of cephradine and 8.0 mg/kg of cefuroxime. In knee replacement the femoral condyle bone concentrations were 5.1 mg/kg of cephradine and 4.2 mg/kg of cefuroxime, and for tibial bone 5.6 and 4.6 mg/kg respectively. Both cephradine and cefuroxime diffuse well into bone giving bone concentrations effective against common pathogens such as Staphylococcus aureus and S. epidermidis.