Risk factors for bacterial infection following replantation of zone 1 amputation

Purpose: Bacterial infection is a critical complication influencing the survival of a replanted digit. This study aimed to identify risk factors for bacterial infection following zone 1 replantation. Methods: A retrospective chart review was conducted on patients who underwent zone 1 replantation from January 2016 to November 2022. The factors included in the comparative analysis were patient demographics (age, sex), past medical history (hypertension, diabetes mellitus), smoking, types of injury, degree of contamination, source of trauma, fractures, number of vascular anastomoses, use of salvage therapies, and the use of vein grafts. A bacterial infection was diagnosed based on observation of visible inflammatory signs with the results of culture studies. Results: In total, 313 patients were selected. Thirty-eight cases of bacterial infection were identified, which accounted for 12.1% of total patients. Methicillin-resistant Staphylococcus epidermidis (MRSE) was the most prevalent bacterium (63.2%, 24 of 38 cases). The patient and injury-related factors showed no significant differences, but the number of vein anastomoses and use of salvage therapy were significantly correlated with the occurrence of bacterial infection. Conclusion: Performing fewer vein anastomoses appears to increase the likelihood of a salvage procedure, and subsequently increases the risk of bacterial infection by an increased need for direct wound manipulation after zone 1 replantation. Infections caused by MRSE were more commonly identified than those by Aeromonas hydrophilia, which is a commonly known pathogen in medicinal leeches.