Purpose: The current study is intended to provide clinical evidence for the safety of conversion from external fixation to internal fixation for the treatment of previously open tibial fractures on the basis of normal Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level and leucocyte count/ratio.Methods: A monocentric retrospective cohort study was conducted From January 2010 to December 2014.All patients suffering open tibial shaft fractures treated with external fixators at the first stage at our trauma center were included.Patients were divided into exposed group, that underwent conversion to internal fixation, and control group, that did not, according to the therapeutic strategy.Demographic data, treatment details and infection rates of the included patients were collected.The overall infection rate for each group was calculated and a comparison between the two groups was performed using 2×2 x2 test or Fishers exact test.