Lateral compression (LC) fractures involve transverse fractures of the pubic rami, either ipsilateral or contralateral to a posterior injury. Grade I – Associated sacral compression on side of impact
Grade II – Associated posterior iliac ("crescent") fracture on side of impact
Grade III – Associated contralateral sacroiliac joint injuryThe most common force type, lateral compression (LC) forces, from side-impact automobile accidents and pedestrian injuries, can result in an internal rotation. The superior and inferior pubic rami may fracture anteriorly, for example. Injuries from shear forces, like falls from above, can result in disruption of ligaments or bones. When multiple forces occur, it is called combined mechanical injury (CMI). The best imaging modality to use for this classification is probably a pelvic CT scan. Open book fracture
One specific kind of pelvic fracture is known as an open book fracture. This is often the result of a heavy impact to the groin (pubis), a common motorcycling accident injury. In this kind of injury, the left and right halves of the pelvis are separated at front and rear, the front opening more than the rear, i.e. like an open book that falls to the ground and splits in the middle. Depending on the severity, this may require surgical reconstruction before rehabilitation. Forces from an anterior or posterior direction, like head-on car accidents, usually cause external rotation of the hemipelvis, an “open-book” injury. Open fractures have an increased risk of infection and hemorrhaging from vessel injury, leading to higher mortality.
Complications
Complications are likely to result in cases of excess blood loss or puncture to certain organs, possibly leading to shock. Swelling and bruising may result, more so in high-impact injuries. Pain in the affected areas may differ where severity of impact increases its likelihood and may radiate if symptoms are aggravated when one moves around. Causes
Common causes include falls, motor vehicle collisions, a vehicle hitting a pedestrian, or a direct crush injury. In younger people significant trauma is typically required while in older people less significant trauma can result in a fracture. Pathophysiology
The bony pelvis consists of the ilium (i.e., iliac wings), ischium, and pubis, which form an anatomic ring with the sacrum. Disruption of this ring requires significant energy. When it comes to the stability and the structure of the pelvis, or pelvic girdle, understanding its function as support for the trunk and legs helps to recognize the effect a pelvic fracture has on someone. The pubic bone, the ischium and the ilium make up the pelvic girdle, fused together as one unit. They attach to both sides of the spine and circle around to create a ring and sockets to place hip joints. Attachment to the spine is important to direct force into the trunk from the legs as movement occurs, extending to ones back. This requires the pelvis to be strong enough to withstand pressure and energy. Various muscles play important roles in pelvic stability. Because of the forces involved, pelvic fractures frequently involve injury to organs contained within the bony pelvis.