Background: Intramedullary nailing is the standard of care for the definitive management of lower extremity long bone fractures. Occasionally, temporary external fixation is used in fractures with severe open wounds or vascular injury before definitive intramedullary nailing. Secondary intramedullary nailing following external fixation is somewhat controversial, especially with respect to the duration of external fixation that is allowable before the risk of infection following later nailing becomes too great. Several recent studies have provided further insight into this issue. Objective: The primary objective is to evaluate infection and non-union rates in patients treated with temporary external fixation and secondary intramedullary nailing for lower extremity long bone fractures. The secondary objective is to evaluate whether the duration of external fixation and the interval time (defined as the time from external fixator removal to intramedullary nailing) influence the risk of infection after intramedullary nailing.