Bilateral lower extremity injuries in pedestrian versus motor vehicle collisions

Background Lower extremity (LE) injuries following pedestrian versus motor vehicle collision (PMVC) are a common cause of morbidity and mortality in orthopedic trauma. There is currently no evidence illustrating the presentation of orthopedic bilateral LE injuries (BLEI). This study aimed to evaluate the patterns of BLEI on postoperative outcomes and hospital utilization following PMVC.Methods This retrospective cohort analysis included 532 consecutive patients presenting to a single level I trauma center with LE injuries following PMVC from January 1, 2017 to May 31, 2021. Injury location was categorized by extremity region (hip/femur, knee, leg, ankle, midfoot). Outcome measures included 30-day postoperative complications (infection, compartment syndrome, myocardial infarction, pneumonia, pulmonary embolism, sepsis, stroke) and hospital utilization (length of stay, ICU admission, prolonged ventilation [=48 h], readmission). Mann-Whitney U, chi-square, and logistic regressions were performed calculating odds ratio (OR) with 95% confidence intervals.Results A total of 142 (26.7%) patients sustained BLEI. The most common BLEI complexes (212 total) were bilateral leg (25.0%), hip/femur and leg (17.0%), leg and knee (12.3%), and hip/femur and knee (8.0%). Bilateral and unilateral injuries showed no difference for postoperative complications (11.3% vs. 6.2%; p = 0.062). However, BLEI had higher odds of ICU admission (OR:2.97, CI:1.68-5.26), prolonged ventilation (OR:2.38, CI:1.24-4.59), and patients remained hospitalized 10.87 days longer (p < 0.001).Conclusion Our findings indicate that more than a quarter of PMVCs with LE injuries present with BLEI and require significantly more hospital resources. This is the first study to characterize BLEI in PMVCs, highlighting associated patterns to encourage heightened awareness in trauma evaluation.