Risk factors for deep infection in secondary intramedullary nailing after external fixation for open tibial fractures

BACKGROUND: Risk factors for deep infection in secondary intramedullary nailing (IMN) after external fixation (EF) for open tibial fractures were investigated by multivariate analysis following univariate analyses. METHODS: Forty-two open tibial fractures were treated with secondary IMN after EF. The open tibial fractures were classified according to the criteria proposed by Gustilo et al.: type II, 11; type IIIA, 8; type IIIB, 22 and type IIIC, 1. Locked IMNs with limited reaming were performed in 27 patients, and locked IMNs without reaming in 15 patients. The following factors contributing to deep infection were selected for analysis: age, gender, Gustilo type (II or III), fracture grade by AO type (A or B+C), fracture site, existence of multiple trauma (Injury Severity Score, ISS<18 or ISS> or = 18), existence of floating knee injury, debridement time (< or = 6 h or > 6 h), reamed (R) versus unreamed (UR) nailing, duration of external fixation (< or = 3 weeks or >3 weeks), interval between removal of EF and IMN (< or = 2 weeks or >2 weeks), skin closure time (< or = 1 week or >1 week), existence of superficial infection (+ or -) and existence of pin tract infection (+ or -). The relationship between deep infection and the above factors was evaluated by univariate analyses. RESULTS: Seven (16.7%) of the 42 open tibia fractures developed deep infections. All deep infections occurred in Gustilo type III (22.6%, 7/31). Only the skin closure time was a significant factor affecting the occurrence of deep infection on the present analysis (p = 0.006). CONCLUSION: The present evaluation showed that early skin closure within 1 week is the most important factor in preventing deep infections when treating open tibial fractures with secondary IMN after EF.