Objectives: To analyze the mechanism of injury for foot and ankle fractures resulting from automobile accidents to create a basis for developing an improved design for protection.
Setting: Level I trauma center with accident research unit.
Patients: Automobile accident reports and medical records of individuals injured in the accidents.
Main outcome measurements: Technical indicators (collision type, impulse angle, deltav, and extent of vehicle deformation) and clinical data (injury location and severity [abbreviated injury scale and injury severity score] and long-term outcome).
Results: From 1973 to 1996, 15,559 car accidents were analyzed. Two hundred sixty-one front seat occupants sustained fractures of the foot and ankle (ankle, 41 percent; forefoot, 29 percent; midfoot, 20 percent; and hindfoot, 10 percent). Seventy-five percent of the fractures were classified abbreviated injury scale(foot) 2. The incidence, location, and abbreviated injury scale(foot) category of fractures were similar between driver (n = 210) and front seat passenger (n = 51). Fifty percent of the fractures occurred in head-on collisions and 34 percent occurred in accidents with multiple collisions. The deltav ranged in 82 percent of car crashes between fifteen and sixty kilometers per hour. The deltav and extent of foot compartment deformation correlated with the abbreviated injury scale. During our investigation, deltav increased; the injury severity score decreased; and the extent of deformation did not differ significantly.
Conclusions: Although overall car passenger safety has improved, the relative incidence of foot and ankle fractures has increased. Comparing drivers and front seat passengers, the foot pedals, steering wheel, or the asymmetric design of the dashboard did not influence injury incidence, mechanism, or severity. Foot fractures are mainly caused by the foot compartment deformation in head-on collisions, and therefore improvements in foot compartments are essential for fracture prevention.