Is It Safe to Prep the External Fixator in Situ During Staged ORIF of Pilon Fractures? A Retrospective Comparative Cohort Study

CATEGORY: Trauma; Ankle INTRODUCTION/PURPOSE: Pilon fractures usually result from high energy mechanisms and are associated with signifcant soft tissue injuries in addition to complex fracture patterns. Treatment typically involves staged management with initial placement of an external fixator and subsequent definitive internal fixation once soft tissues are amenable. The purpose of this study was to compare the risk of fracture-related infection (FRI) and unplanned re-operation after staged open reduction and internal fixation (ORIF) of pilon fractures between cases in which elements of the temporizing external fixator (ex-fix) were prepped into the surgical field and cases in which it was completely removed prior to definitive fixation. METHODS: This was a multi-surgeon retrospective comparative cohort study on patients 18 years and older with pilon fractures who underwent operative treatment over a ten-year period between January 1, 2010 to January 1, 2020 at an academic-level 1 trauma center. Medical records and radiographic images were reviewed for each patient to assess demographics, clinical characteristics and surgical outcomes. The primary outcome measures were FRI and unplanned re-operation, including arthrodesis and amputation. All analyses were completed using JMP Software (Version 15.0, SAS Institute Inc., Cary, NC), and an alpha of 0.05 was used for statistical significance. RESULTS: 133 patients underwent staged ORIF, 47 with retained elements of the ex-fix prepped in situ for definitive ORIF and 86 with the ex-fix entirely removed. The overall rate of FRI was 23.3% while the overall rate of unplanned re-operation was 11.3% (4.5% rate of arthrodesis and 6.8% rate of amputation). There was no difference in FRI between the group in which ex-fix was prepped in versus the group in which it was completely removed (23.4% vs 23.3%, p=0.985) and no difference in overall rate of unplanned re-operation (10.6% vs 11.6%, p=0.863). Assessing the subset of patients with FRI, those with ex-fix prepped in had a higher prevalence of infection with MRSA and MSSA (81.8% vs 40%, p=0.021). Using alpha=0.05, and power=0.8, a sample size of 42 patients with FRI post-ORIF (27 with ex-fix prepped in, and 15 with ex-fix removed) would be needed to detect a difference in MRSA/MSSA bacteriology. CONCLUSION: Although there were relatively high complication rates in this cohort of pilon fractures treated with staged ORIF, prepping in elements of the external fixator did not lead to a significant increase in rates of fracture-related infection nor unplanned re-operation, including arthrodesis and amputation. This study offers clinical support regarding a common practice used to assist in reduction and definitive fixation of distal tibial pilon fractures.