The penetration of ceftriaxone and cefamandole into bone, fat and haematoma and relevance of serum protein binding to their penetration into bone

Thirteen patients undergoing total hip replacement were given ceftriaxone 1 g and cefamandole 1 g simultaneously, either immediately or 8 h before surgery. For both agents the concentrations seen in the bone and fat during the operation, and for haematoma fluid <or=24 h after the operation, exceeded the MIC for susceptible staphylococci and would be expected to provide adequate prophylaxis. Although ceftriaxone concentrations in bone and fat were significantly higher than those of cefamandole, after correction for the simultaneous blood concentrations, we were unable to detect any differences in the bone or fat penetration of the two agents. We conclude that there is no evidence that cephalosporins with a lower serum protein binding penetrate bone better than ones with higher serum protein binding.