Primary Suture Closure of External Fixation Pin Sites After Removal Has a Lower Risk of Infection Compared to Pin Sites Left Open

To compare infection rates after external fixation removal, comparing pin sites that were primary closed compared to those left open to heal by secondary intention. Design: Retrospective review. Multi-center study. All adult patients (18 years and older) who underwent removal of external fixator that was utilized for extremity fractures from 2007 to 2023 with at least 30 days follow up. Patients were stratified into two cohorts: 1) external fixator pin sites primarily closed after external fixator removal and 2) pin sites left open to heal with secondary intention after external fixator removal. Patient characteristics, fracture characteristics, and details of the external fixator removal surgery were recorded. Comparison of the rate of surgical site infection (SSI) of pin site after external fixation removal were performed between the two groups (pin sites that were closed primarily and those left open after external fixator removal). A total of 412 patients were included, with a mean follow-up of 259 days. There were 254 patients in the closed pin site after pin removal group (mean age 53 years, range 18-95, 39% female) and 158 in the pin sites left open after pin removal group (mean age 54, range 18-93, 49.4% female). Median duration of external fixator in the closed group was 11 days, and 19 days in the open group (p<0.05). Multivariate analysis demonstrated increased odds of SSI of pin site after pin removal if the pin site was left open (OR=3.2; 95% CI: 1.44-7.19, p<0.01) and with tibial plateau fractures (OR=4.45; 95% CI: 1.92-10.32, p<0.001). After external fixation removal, closure of pin sites was associated with lower risk of pin site SSI after pin removal compared to leaving them open when external fixation duration was less than 2 weeks. External fixation is a common procedure, and this study can help change practice and decrease the risk of SSI of pin site after pin removal. III.