Spread of infection, in an animal model, after intramedullary nailing of an infected external fixator pin track

Implant sepsis, due to previous external fixator pin track infection, is th e most common complication of secondary intramedullary (IM) nailing of the tibia. We have developed an animal model, which allows different treatment methods to be studied. Using an established ovine model of a Fin track infe ction, Staphylococcus aureus was used to infect the external fixator pins, two weeks prior to reamed IM nailing. In the control group, the animals wer e killed at a mean of 10.5 days following nailing, when widespread infectio n was evident, with septic arthritis, abscess formation, and infection of t he entire length of the tibia in all six animals. In the treatment group, b efore IM nailing, the pin sites were debrided, and both local and systemic antibiotics were administered. All surgical wounds healed without evidence of infection, 4 of the 6 animals survived for 28 days, and bacteria were on ly isolated from 1 of the 6 implants. Treatment was successful at reducing, but not eliminating, infection after secondary nailing. (C) 2001 Published by Elsevier Science Ltd on behalf of Orthopaedic Research Society.