The Interaction of ‘Occupant Factors' on the Lower Extremity Fractures in Frontal Collision of Motor Vehicle Crashes Based on a Level I Trauma Center

Abstract

The interactive effect observed for height and gender on the pattern of lower extremity fracture is principally related to the body habitus and that gender may be a 'proxy' variable. The 'human factor' plays a vital role in influencing the pattern of injury in a MVC. This study strongly supports the fact that occupants with dissimilar body habitus interact differently with the interior cabin of the vehicle, thus, the performance of the active and passive safety systems.

Using multiple imputation and propensity scores to test the effect of car seats and seat belt usage on injury severity from trauma registry data

“…We did not impute the restraint usage variable. Future research might consider this analytic approach using national or regional crash data that include restraint usage, the crash energy vectors, and the presence or absence of physical injury [8]. Population density of residence zip code 34% 36%…”

Biomechanics of Musculoskeletal Injury

“…Occupant factors, such as age, gender, height and BMI also contribute to type and severity of injury. Height appears to be an important factor in pattern of injury; tall occupants (and males) sustain more knee, thigh or hip injuries while shorter (and female) occupants tend to sustain more foot and ankle injuries (Chong et al, 2007). Elderly occupants are at increased risk of injury (Moran et al, 2002;Peterson et al, 1998).…”

“…However, there is controversy regarding their effect on non-fatal injuries, particularly musculoskeletal injury. Air bag deployment without seat belt restraint is associated with increased incidence of lower extremity injury and some data suggests that air bag deployment together with seat belt restraint is also associated with increased incidence of lower extremity injury (Crandall et al, 1995;Cummins et al, 2008;Estrada et al, 2004;McGovern et al, 2000;Burgess et al, 1995;Chong et al, 2007). A possible contributing factor to the increased incidence of lower extremity injury is a "submarining" effect in which the pelvis and lower extremities are www.intechopen.com shifted under the airbag and down the seat into the knee bolster and floor of the car (Estrada et al, 2004;Crandall et al, 1998;Cummins et al, 2008).…”

“…High-heeled shoes have been shown to alter foot and ankle biomechanics leading to increased instability and injury during an MVC (Nordhoff, 2004). The effect of height on pattern of injury may be a reflection of leg position and may be related to the fact that shorter people sit closer to the steering wheel and reach for foot pedals, while taller people sit farther back with their knees closer to the level of the instrument panel (Chong et al, 2007). Many safety systems, including seat belts, air bags, and vehicle deformation, take advantage of the fact that increasing time over which decelerations are applied to the passenger compartment decreases force experienced by the occupants (Peterson et al 1998).…”

“…Initial impact points are often lower extremities, resulting in fractures of the ankle, around the knee, or fracture of the femur. There are many factors that contribute to the amount of force transferred to specific anatomical structures including change in velocity at impact, timing of impact, degree of compartment intrusion, configuration of occupant and safety devices (Siegel et al, 2001;Bansal et al, 2009;Crandall et al, 1998;Nordhoff, 2004;Chong et al, 2007) Change in velocity at time of impact is closely associated with severity of injury as well as incidence of lower extremity injury (Figure 7) (Chong et al, 2007;Dischinger et al, 1998, Rupp & Scheider, 2004. The effect of timing is illustrated in the different degree of injury sustained when knee contact with instrument panel occurs during deceleration when the instrument panel may still be moving forward causing the localized contact velocity to be lower than impacts that occur once the car has stopped moving (Mackay, 1992).…”