A pelvic fracture is a disruption of the bones of the pelvis, which consists of multiple interconnected bones that protect the lower colon and bladder in men plus the uterus in women. While the most common cause of a pelvic fracture is a fall from a standing position, there is likely to be greater injury during a fall from a height or from an automobile accident.
Pelvic fractures in motor vehicle accidents are associated with intrusion into the vehicle, age, gender, body mass index and the incidence of nearside impacts. It turns out that people with a high BMI (Body mass index) are less likely to fracture their pelvis when compared to normal weight subjects. Females were more likely to suffer from pelvic fractures and those with incursions into the door panel were likely to sustain pelvic fractures. Interior door panels that are beefed up with extra metal, adding more hardware or more armrests may protect the accident victim from getting a pelvic fracture.
The bony pelvis is made up of the iliac wings, the ischium and the pubis, which together form a ring along with the sacrum. Because the ring is relatively stable, it takes a great deal of force to fracture the bones and to injure the organs within. Pelvic fractures are usually associated with significant hemorrhage because the area has an intense blood supply.
There are two classification systems associated with pelvic fractures. There is a Tile classification system that looks like this:
• Type A injuries have an intact sacroiliac complex. There is a fracture of the ring which is stable and needs no surgical intervention.
• Type B injuries are caused by rotational forces that disrupt the sacroiliac complex. These are unstable injuries that require surgical intervention.
• Type C injuries involve complete disruption of the sacroiliac complex, which is usually the result of a motor vehicle accident. It is unstable from a vertical and rotational direction.
There is the Young Classification, which is based on the type of injury, such as lateral compression, vertical shear, anterioposterior compression or a combination of forces. These can be due to falls or motor vehicle accidents.
• Grade I injuries are associated with the sacrum being compressed on the side of impact.
• Grade II injuries are associated with fractures of the crescent of the iliac crest in a side impact
• Grade III injuries are associated with anterior-posterior compression fractures and fractures of the pelvic rami.
Incidentally, there can be fractures of the acetabulum, which is the part of the pelvis that holds the head of the femur into it. They are common fractures of a pedestrian struck by a moving vehicle at a high rate of speed. Falls of elderly persons can commonly result in fractures of the pubic rami but with an intact pubic structure.
Pelvic fractures, if severe, are associated with a high mortality rate of around 3-20 percent. Death occurs due to hemorrhage at the site of the injury or to related, often multiple, injuries.