RESUMO
OBJECTIVE: To determine the effect of cefazolin and cefuroxime (the two most commonly used beta lactam antibiotics) at therapeutic doses in fracture healing in an animal model. MATERIAL AND METHODS: 75 adult male wistar rats (3months old) were selected. They were divided into three groups of 25 animals each (placebo, cefazolin and cefuroxime). A closed fracture was made in the middle third of the right femur of each rat and fixed with a Kirschner wire. Each group was treated with either saline (placebo), cefazolin or cefuroxime at therapeutic doses during fracture healing. Four weeks after fracture rats were killed and femora analysed through mechanical and histological testing. RESULTS: The group treated with cefuroxime showed a lower mechanical resistance of the healing callus and a lower histological grade than placebo. The group treated with cefazoline showed a similar mechanical resistance and histological grade of callus to placebo. CONCLUSION: Cefuroxime appear to disturb fracture healing more than cefazolin or placebo in Wistar rats. If those results are similar to human, the use of cefuroxime during fracture healing should be avoided in the clinical setting, if possible.
