This study examines the formation of bacterial biofilms on percutaneous wires used for fracturefixation. Twelve control (clinically uninfected) wires and ten infected wires were collected andexamined using broth culture and scanning electron microscopy. Three of the 12 control wires grewStaphylococcus spp. with very low bacterial counts in their percutaneous portions. In theclinically infected wires, six wires in four subjects had positive cultures in their percutaneous portions and four of these also had positive cultures in their deep portions with much higherbacterial counts than the controls. In two patients (four wires) treated with antibiotics, cultureswere negative except for the percutaneous portion of one wire. Scanning electron microscopy didnot reveal bacterial biofilm formation, but biological deposit without bacteria was noted on mostwires. During the 6 weeks of fracture fixation, some bacterial colonization of wires occurred, butbacteria did not form biofilms which may increase bacterial resistance to systemic antibiotics, causeimplant loosening and act as a source of late infection.