[Quantitative trauma mechanics in pelvic fracture]

Quasistatic loading of the isolated pelvis and of the pelvis in situ is reported; dynamic loading with an impactor and on 90 degrees car/car side impact are then considered. The isolated pelvis was loaded laterally at the ala of the ilium and the pelvis in situ in the anterior-posterior direction in the area of the symphysis with universal dynamometer; the loading profile was a rigid disk 150 mm in diameter. Some dynamic tests were performed with an impactor with rigid disk 80 mm in diameter as impact surface; the impact was applied against the trochanter major area at a velocity of 30-35 km/h. Otherwise, the pelvic area was stressed by impact through the intrusion of the car side or by impaction of the pelvis against a rigid wall. In the tests conducted with isolated pelves, forces of 850-4850 N were measured; pelvic fractures were observed, specifically fractures of the acetabular margin, pubic bone, and ischium, and comminuted fractures of the symphysis and the iliosacral. In the impactor tests, forces of 6.5-11 kN were enough to cause, pelvic fracture except in one case, and fractures of the femoral neck were found in some cases in addition. With quasistatic anterior-posterior loading of the pelvis in situ, forces of 4,700-10,000 N were measured in cases in which fractures were found.