The Common Vein Copyright 2011
Definition
Fractures of the pelvis are usually caused by ow-energy injuries that lead to individual bone fractures or high-energy fractures that may disrupt the pelvic ring. Crush injuries may cause a variety of fracture types. Involvement may include ilium ischium and or pubic bone
The fracture may be stable or an unstable. Stable injuriesdo not deform with normal physiologic forces. Unstable injuries may reveal either a rotational or vertical displacement.
The Young and Burgess Classification System is based on the mechanism of injury and is most commonly used to classify pelvic fractures.
Lateral compression (LC) injuries have a transverse fracture of the pubic rami, ipsilateral or contralateral to the posterior injury due to an implosion of the pelvis. The mechanism is from a lateral force. A type 1 LC injury has sacral impaction on the side of the impact with stable transverse fractures of the pubic rami. A type 2 LC injury is a posterior iliac wing fracture on the side of the impact. There can be disruptions of the posterior ligamentous structures leading to mobility of the bone fragments. A type 3 LC injury occurs with either a type 1 or 2 LC injury with the addition of a “windswept pelvis” due to sacroiliac, sacrotuberous, and sacrospinous ligament disruption. These type 3 LC injuries can be associated with significant hemorrhage and neurologic injury.
Anterior-posterior compression (APC) injuries are symphyseal diastasis, external rotation injuries, or longitudinal rami fractures that result from an anterior force. A type 1 APC injury is less than 2.5 cm of symphyseal diastatsis and vertical fractures or one or both pubic rami. The posterior ligaments remain intact. A type 2 APC injury is more than 2.5cm of symphyseal diastasis with widening of the SI joints due to disruption of the anterior SI ligaments. An “open book injury” occurs when there is disruption of the sacrotuberous, sacrospinous, and symphyseal ligaments. The “open book “injury has internal and external rotation instability with vertical stability maintained. A type 3 APC is complete disruption of the symphysis, sacrotuberous, sacrospinous, and sacroiliac ligaments leading to extreme rotational instability and lateral displacement. There is no cephaloposterior displacement. The fractures are very unstable and have the highest rate of vascular injury and hemorrhage.
Vertical shear (VS) injuries are a complete disruption of the symphysis, sacrotuberous, sacrospinous, and sacroiliac ligaments with cephaloposterior instability. This type of injury occurs when there are vertical or longitudinal forces from a fall onto an extended lower extremity or with motor vehicle accidents where the lower extremity hits the dashboard. The fractures are unstable and have a high incidence of neurovascular injury and hemorrhage.
Combined mechanical (CM) refers to a combination of different injuries that result from crush mechanisms of injury. It is most common to have a combined vertical shear and lateral compression type of injury.
The fracture may be complicated in the acute phase by hemorrhage, neurovascular injury, or in the subacute or chronic phases by nonunion, malunion, infection, osteonecrosis, and osteoarthritis. Complications specific to fractures of the pelvis include genitourinary injury, and gastrointestinal injury.
The diagnosis of this injury is usually made by a combination of physical examination and x-ray imaging.
Imaging includes the use of plain x-rays, and if indicated CT-scan, or MRI.
Nonoperative treatment is reserved from fractures with minimal displacement. Patients may be initially non-weightbearing or partial weightbearing with the use of crutches to protect the healing fracture. For unstable fractures and those with other associated injuries the operative measures can be placement of an external fixation device or by an open reduction internal rotation (ORIF) procedure.
External fixation involves the placement of two to three pins spaced 1 cm apart along the anterior iliac crest on each side. An alternative method is the Hanover frame which involves the use of single pins in the supra-acetabular area. External fixation is not a definitive procedure for posterior pelvic fractures, but rather only definitive for anterior pelvic fractures.
ORIF procedures depend upon what part of the pelvis is fractured. An iliac wing fracture is treated with lag screws and neutralization plates. A pubic symphysis diastasis injury is repaired by plate fixation if there is not an open fracture or urologic injury. Sacral fractures can be treated with plate or sacroiliac screw fixation. Posterior screw fixation can be used to treat a bilateral posterior unstable disruption.
Complications of pelvic fracture surgery include infection, thromboembolism, malunion, and nonunion.
Normal Pelvis |
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Courtesy Ashley Davidoff MD 71198b01 |
References
Davis MF, Davis PF, Ross DS. Expert Guide to Sports Medicine. ACP Series, 2005.
Elstrom J, Virkus W, Pankovich (eds), Handbook of Fractures (3rd edition), McGraw Hill, New York, NY, 2006.
Koval K, Zuckerman J (eds), Handbook of Fractures (3rd edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.
Lieberman J (ed), AAOS Comprehensive Orthopaedic Review, American Academy of Orthopaedic Surgeons, 2008.
Moore K, Dalley A (eds), Clinically Oriented Anatomy (5th edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.