Motor vehicle crashes are a major cause of lower extremity injuries (LEI). Lower extremity injuries, especially leg/foot injuries, are frequent and costly, often resulting in lifetime disabilities. The goal of this research is to develop a data collection instrument, for future use, which will capture more detailed injury and crash information and will allow for better understanding of the interrelationship of the biomechanical, engineering, and medical aspects of lower extremity injuries.
Orthopaedic and other injury data were collected on 50 front seat occupants admitted to the R Adams Cowley Shock Trauma Center with LEI. Crash reconstructions were conducted with special emphasis on the toepans and instrument panels of the vehicles. Based on these findings and the clinical insights gained from treatment (often operative) of the patients, mechanisms of injury were postulated. These mechanisms include such forces as axial loading, translation (direct contact), inversion, eversion, and dorsiflexion; possible sources of the stresses were evaluated and discussed. Preliminary analyses for these cases have been completed.
Epidemiologic analyses of lower extremity injuries are also being conducted based on a linked trauma registry/police crash report database. This database will be used to ascertain the representativeness of the selected study cases; furthermore, these data will be used to examine the importance of other factors such as vehicle size or seatbclt use as they may relate to LE1.
Postulated mechanisms of injury from the patient data are being tested at the University of Virginia Automobile Safety Laboratory using cadaver and human surrogate testing and computer simulation work. Since axial loading was determined to be a significant cause of lower extremity injury, pendulum tests will be conducted on lower limbs. The impact conditions will represent an offset frontal collision in which there is 6.0“ of longitudinal intrusion occurring at a peak rate of 14 mph. Ankle moments and forces will be measured with a five axis in situ tibial load cell. Kinematics of the ankle will be determined from high speed film analysis and angular rate sensor time histories.
Based on the findings from the clinical, epidemiologic, and experimental work, a final data collection instrument will be developed. In addition, possible countermeasure options will be discussed in light of study findings.