Aging is not a risk factor for femoral and tibial fractures in motor vehicle crashes.

Objective: To determine the effect of aging on the occurrence of femoral and tibial fractures during vehicular crashes.

Methods: The Crash Injury Research and Engineering Network (CIREN), which includes occupants of a vehicle < 8 years old with at least one AIS > or = 3 or two AIS > or = 2 injuries in different body regions, comprised the study population. The occurrence of femoral and tibial fractures during vehicular crashes was analyzed in relation to age and other confounders [gender, BMI, stature, change in velocity (Deltav), restraint use, occupant position (driver vs. passenger) and principal direction of force (PDOF)] using chi2, Mantel-Haenszel chi2 and student t test. Multiple logistic regression (MLR) models were built for the prediction of femoral and tibial fractures with age as the independent variable and possible confounders as co-variates. An alpha = 0.05 was used for all statistics.

Results: The incidence of femoral and tibial fractures in the study population (N=1,418) was 23% and 27%, respectively. Univariate analyses revealed a negative association between increasing age and femoral fractures and no association between age and tibial fractures. MLR models revealed no clear effect of increasing age on the occurrence of either femoral or tibial fractures. Obesity, frontal PDOF, and high Deltav affected the occurrence of femoral fractures. Tibial fractures were influenced by occupant position (driver), frontal PDOF, high Deltav and shorter stature.

Conclusion: Despite the known changes in bone composition and strength with aging, elderly vehicular occupants do not experience higher odds of incurring femoral and tibial fractures during crashes.