Artificially contaminated open tibial fractures: Therapy with cloxacillin sodium

Three methods of treatment by Cloxacillin were applied for the prevention of deep infection of bones after artificial contamination of fractured rat tibia, with Staphylococcus aureus. Thus, combined intramedullary and parenteral therapy was compared with intramedullary administration only and parenteral therapy only. Intramedullary injection of 15 mg Cloxacillin (dissolved in water) during surgical management of the fracture and postoperative parenteral treatment with the same antibiotic in a dose of 50 mg/kg/day over 14 days prevented the development of staphylococcal infection in all animals (n=21). Cloxacillin parenteral treatment only achieved a therapeutical effect after 42 days of application in a dose of 50 mg/kg. A single, intramedullary injection of 15 mg aqueous solution of Cloxacillin failed to prevent completely the staphylococcal infection. This therapy was relatively successful till postoperative day 28, namely, there were only 16.6% of positive results for S.aureus in relation to 40% on day 42 after the surgery. Gross, radiological and histological changes of the operated tibia of rats were correlated to the effects of the therapy applied. The results of our studies suggest that, in open tibial fractures, parenteral therapy together with intramedullary administration of antibiotics may prevent the development of infection and shorten the parenteral therapy by a direct effect on the contaminated injury during the first few postoperative days.