Lower limb response and injury in frontal crashes.

This article examines two observational and two experimental data sets that emphasize lower limb injuries in passenger car crashes. Statistics show that 60% of moderate-to-severe below-knee injuries sustained by front seat occupants in head-on crashes occur with > 3 cm of footwell intrusion. Moreover, crash tests and computer simulations of car-to-car frontal offset collisions show no causal relationship between the magnitude of footwell intrusion and the axial load measured in the dummy leg. This article correlates below-knee injuries with several factors that influence their frequency and severity, such as the vehicle change in velocity, the magnitude of footwell intrusion, the rate and timing of the intrusion and the size of the vehicle. The vehicle change in velocity and the intrusion rate and timing had the greatest influence on the risk of lower limb injury, while the other factors had much less of an effect.

Airbag protection versus compartment intrusion effect determines the pattern of injuries in multiple trauma motor vehicle crashes.

OBJECTIVE: A prospective study of the interaction between airbag (AB) and seat-belt (Bt) protection versus vehicular compartment (VC) intrusion effects on injury patterns in motor vehicle crash (MVC) trauma patients. METHODS: Two hundred MVC patients, nonejected drivers or front seat passengers with multiple trauma or severe lower extremity (LE) trauma admitted to two Level I trauma centers. RESULTS: In frontal crashes, airbags (AB) more than Bt reduced Glasgow Coma Scale severity in brain injury, face fracture, shock, and the need for MVC extrication (all p < 0.05). Frontal AB also had a protective effect on LE fractures (41% vs. 66%, p < 0.01), but had no significant protective effect on pelvic fractures. When AB protection was present, it prevented brain and face fracture injuries caused by impact contacts and reduced the incidence of these injuries resulting from VC intrusions (p < 0.05). Thoracoabdominal injuries resulting from steering wheel intrusion showed AB protection against intrusions of twice the magnitude of those seen in non-AB vehicles (p < 0.05). In frontal MVCs, AB reduced LE fracture contact injuries but did not prevent LE fractures resulting from intrusions of instrument panel, toepan, or floor pedal structures. In lateral MVCs, Bt did not protect against brain, face, thorax, or pelvic injuries. CONCLUSIONS: Safety measures beyond frontal airbags must address frontal crash LE injuries induced by steering wheel, instrument panel, and toepan passenger compartment structure intrusions. Lateral crash injuries may profit from side AB supplemental restraint protection.

Lower extremity injuries in drivers of airbag-equipped automobiles: clinical and crash reconstruction correlations.

OBJECTIVE AND DESIGN: To determine the relationship between airbags and lower extremity injuries, 10 drivers admitted to a level-I trauma center with substantial lower extremity trauma incurred in crashes involving airbag-equipped vehicles were studied in depth with regard to their injuries, the circumstances of the crashes, and the medical charges for the acute management of those injuries. MATERIALS AND METHODS: During the clinical investigation portion of this study, we photographed lower extremity injuries, both soft tissue and radiographs, and performed a detailed surgical exploration during the debridement of open wounds or fracture fixation to treat them appropriately and to define the mechanism of injury, the fracture pattern, the pattern of soft-tissue insult, and the extent of periosteal stripping. We recorded the hospital and professional charges associated with the acute management not only of these injuries, but of the other injuries as well. The analysis performed for each case included a detailed crash reconstruction, including force, contact point, and vehicle intrusion data. Particular attention was paid to the dashboard and toe pan areas to determine deformation and intrusion and their association with thigh, leg, and foot injuries. Pertinent deformation and trajectory information was entered into the Calspan Reconstruction of Accident Speeds on the Highway (CRASH) computer program to generate a delta V or change in velocity measurement used as a measure of collision severity. When field data were incompatible with the limitations of the CRASH program, manual calculations such as "slide to stop" and conservation of momentum formulas were used. RESULTS: The seven male and three female drivers had a mean age of 39.4 years. Only four used seatbelt restraints. The mean delta V was 28.3 mph and the mean maximum crush was 32.4 inches. The mean Injury Severity Score of 13.2. Musculoskeletal injuries included 11 foot/ankle fractures, 6 tibial fractures, 2 patellar fractures, 6 femoral fractures, and two acetabular/pelvic fractures. Other trauma included abdominal, thoracic, head and upper torso injuries, it seems that these safety devices do not prevent injuries to the lower extremity.