Preoperatively, to prevent infection, seventy-one patients who were to
have total hip arthroplasty were given one gram of cephalothin, cephradine,
or cefazolin intravenously. Simultaneous samples of bone and serum were
obtained after various time intervals and assayed for cephalosporin
concentration to correlate the antibiotic concentrations in these sites
with time. Of the cephalosporins tested, cefazolin achieved the highest
total peak levels in bone (thirty micrograms per gram), followed in
descending order by cephradine (twenty-three micrograms per gram) and
cephalothin (2.8 micrograms per gram). These peak levels in bone, reached
twenty-five to forty minutes after injection, were sixty, 6.7, and fifteen
times higher than the usual mean minimum inhibitory concentrations of
cefazolin, cephradine, and cephalothin, respectively, for
penicillin-resistant staphylococci. The half-lives of the antibiotics in
bone were forty-two, forty, and thirty minutes, respectively.