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, and facial injuries. All drivers survived. The mean total acute care cost was $54,578. Conclusions: Although airbags have been shown to reduce head and upper torso injuries, it seems that these safety devices do not prevent injuries to the lower extremity.