When it comes to auto accidents, pedestrian injury accidents account for about 14 percent of all auto-related mortality. In one study, a thousand injured pedestrians were looked at over a five year period of time to see what kinds of injuries these patients had. In particular, pelvic injuries were examined to see the degree of morbidity and mortality in those who had fractures of the pelvis.
Pelvic fractures happen only when extreme forces happen across the lower half of the body. The pelvis is actually a ring of nine bones, including the ilium, the ischium and the pubis, which are fused together and paired, and the sacrum, which is jointed to the other three bones. The ring is generally very strong and resists minor forces. Pedestrian auto accidents, however, involve major forces and the ring fractures. There are several areas of vulnerability of the pelvis, including the sacroiliac joints and the pubic rami.
People who have pelvic fractures tend to have other injuries as well because of the severity of the accident. In the above study, about 11 percent of all patients suffered from high force disruptions of the pelvic ring. The average age of these patients was almost 40 years of age. These people had high injury severity scores and moderate Glasgow Coma Scale values. The injuries sustained were sustained due to lateral compression forces, anteroposterior forces (front to back) and vertical shear forces.
In the study, there were numerous other injuries besides the pelvic injury. They included head injuries or other neurological injury in 27 percent of cases, thoracic injury (such as rib fractures or sternum fractures) in 26 percent and abdominal injuries in 14 percent of patients. These patients needed a fair amount of blood–a total of 4 units on average within the first day. The total mortality rate of all pelvic injured patients was 23 percent.
A total of 71 percent of fractures were from lateral compression of the pelvis (a side to side force). A total of 20 percent had front to back forces play into their fracture. It turned out that the worse the pelvic fracture, the worse was the severity of the other injuries as well. More blood was needed in severe fractures and the highest mortality rate was associated with the most severe injuries to the pelvis. In fact half the patients with Grade III pelvic fractures died.
The study concluded by saying that the presence of a pelvic fracture was a major factor in the morbidity and mortality of pedestrians who get involved in auto accidents. While the pelvic fracture alone may not kill them, it is the presence of multiple other injuries that leads to ultimate death or disability. In a sense, the presence of a pelvic fracture means that great forces were at work within the body at the time of the collision and therefore there is a great chance that other severe injuries have also come into play at the time of the injury and the combination of injuries lead to the morbidity and mortality found in these kinds of accidents.