Traumatic Dens Fracture Patients Comprise Distinct Subpopulations Distinguished by Differences in Age, Sex, Injury Mechanism and Severity, and Outcome

Abstract

Dens fractures are an increasingly common injury, yet their epidemiology and its implications remain underexamined. We retrospectively analyzed all traumatic dens fracture patients managed at our institution over a 10-year period, examining demographic, clinical, and outcomes data. Patient subsets were compared across these parameters. Among 303 traumatic dens fracture patients, we observed a bimodal age distribution with a strong goodness of fit centered at age 22.3 ± 5.7 (R= 0.8781) and at 77.7 ± 13.9 (R= 0.9686). A population pyramid demonstrated a bimodal distribution among male patients, but not female patients, which was confirmed with a strong goodness of fit for male patient subpopulations age <35 (R= 0.9791) and age ≥35 (R= 0.8843), but a weaker fit for a second female subpopulation age <35. Both age groups were equally likely to undergo surgery. Patients younger than age 35 were more likely to be male (82.4% vs. 46.9%, odds ratio [OR]= 5.29 [1.54, 17.57], P= 0.0052), have motor vehicle collision as their mechanism of injury (64.7% vs. 14.1%, OR= 11.18 [3.77, 31.77], P < 0.0001), and to have a severe trauma injury severity score (17.6% vs. 2.9%, OR= 7.23 [1.88, 28.88], P= 0.0198). Nevertheless, patients age <35 were less likely to have fracture nonunion at follow (18.2% vs. 53.7%, OR= 0.19 [0.041, 0.76], P= 0.0288). The dens fracture patient population comprises 2 subpopulations, distinguished by differences in age, sex, injury mechanism and severity, and outcome, with male dens fracture patients demonstrating a bimodal age distribution. Young, male patients were more likely to have high-energy injury mechanisms leading to severe trauma, yet were less likely to have fracture nonunion at follow-up.