eMedicine Specialties > Radiology > Musculoskeletal

Pelvic Ring Fractures

D Dean Thornton, MD, Clinical Associate Professor, Department of Radiology, University of Alabama at Birmingham; Musculoskeletal Radiologist, Radiology Associates of Birmingham, PC

Updated: Feb 11, 2009

Introduction

Background

Pelvic ring fractures occur as the result of high-energy blunt trauma, as may result from motor vehicle collisions and falls. These injuries are associated with significant morbidity and mortality, both from the complications of pelvic ring fractures and from commonly associated injuries. Recognition of the pattern of injury to the bony pelvis directs the search for associated soft tissue injuries and allows implementation of the appropriate therapy.^1,2,3,4,5

Anteroposterior compression injury as seen on an anteroposterior radiograph of the pelvis. The symphysis pubis is wider than 2.5 cm (double arrow). The right sacroiliac joint is diastatic (single arrow). This is a type II or type III injury, depending on the status of the posterior sacroiliac ligaments.

Anteroposterior (AP) compression injury as seen on a pelvic CT scan. The location and degree of sacroiliac disruption is better seen on CT scans than on radiographs. The external rotation of the right hemipelvis is a characteristic finding in AP compression. A slight posterior displacement of the right, iliac side of the sacroiliac joint suggests ligamentous disruption (arrow). This represents a type III AP compression injury.

Pathophysiology

Three primary loading vectors result in pelvic ring fractures: anteroposterior (AP) compression, lateral compression, and vertical shear. Each of the forces leaves its mark in a characteristic pattern. The identification of 1 element of the pattern prompts a search for the remaining elements, allowing identification of all osseous and soft tissue injuries.^6,7

AP compression injuries most often result from head-on motor vehicle collisions in which the patient is a passenger. The injuries also result when a motorcycle accident occurs or when a pedestrian is struck by a vehicle. The force may be directed either from anterior to posterior or from posterior to anterior (see Image 1).

Anteroposterior (AP) compression injury as seen on an AP radiograph of the pelvis. Characteristic features of an AP compression injury include symphyseal and sacroiliac joint diastasis. In this patient, the pubic symphysis and right sacroiliac joint are widened.

Windswept pelvis (lateral compression injury) as seen on a pelvic CT scan. The patient sustained a left lateral compression injury with internal rotation of the left hemipelvis and a characteristic sacral buckle fracture. Note the concomitant left sacroiliac joint diastasis. The lateral force vector continued across the pelvis to produce external rotation of the right hemipelvis and diastasis of the right sacroiliac joint. The combination of injuries resulted in a windswept pelvis.

Vertical shear injury as seen on an anteroposterior radiograph of the pelvis. The left hemipelvis is displaced in a cranial direction, with associated sacroiliac joint diastasis. The vertically oriented fractures of the pubic rami usually are ipsilateral; however, in this patient, the rami fractures are contralateral.

Frequency

United States

Table 1. Incidences of Pelvic Ring Fractures

Mortality/Morbidity

With improvement in emergency management techniques, the morbidity and mortality rates of pelvic fracture have decreased in recent decades.

• The overall mortality rate in pelvic ring fractures is approximately 6%. Uncontrolled pelvic hemorrhage accounts for 39% of related deaths; head injury, 31%; and multiple organ failure, 30%. AP compression and vertical shear injuries are associated with a higher incidence of pelvic vascular injury and hemorrhage.
• Associated injuries are commonly found as a result of the powerful forces necessary to fracture the pelvic ring. Injuries to the peripheral nerve, urethra, and bladder are directly attributable to pelvic ring fractures. The frequencies of associated injuries are as follows:
  • Closed head injury — 51%
  • Long bone fracture — 48%
  • Peripheral nerve injury — 26%
  • Thoracic injury — 20%
  • Urethra (male) — 15%
  • Bladder — 10%
  • Spleen — 10%
  • Liver — 7%
  • GI tract — 7%
  • Kidney — 7%
  • Urethra (female) — 6%
  • Mesentery — 4%
  • Diaphragm — 2%
• Immediate complications may be observed.
  • Pelvic hemorrhage is the most serious immediate complication of a pelvic ring fracture. Disruption of the osseous pelvic ring leads to disruption of pelvic veins and/or arteries in as many as 75% of patients.
    • Venous bleeding may arise from the posterior pelvic veins (usually in the setting of sacral injury) or from the marrow space of broken pelvic bones.
    • Arterial bleeding occurs as the result of direct injury to a vessel close to an osseous injury. The injured vessels are typically branches of the internal iliac artery.
    • Posterior fractures, especially those through the greater sciatic notch, may injure the superior gluteal artery.
    • Anterior fractures or disruptions may injure the internal pudendal artery.
    • Pelvic hemorrhage is immediately treated by means of pelvic stabilization, either with sheets wrapped around the pelvis or with external fixator devices. In either case, the goal is to restore the normal anatomic relationships in the pelvis; this restoration serves to reduce the pelvic volume. The larger the pelvic volume, the greater the amount of bleeding that may occur. Uncontrollable hemorrhage requires angiographic evaluation and embolization of the bleeding vessels.
  • Bladder injury occurs as either an associated injury or a complication of a pelvic ring fracture.¹⁰
    • Extraperitoneal bladder rupture occurs more commonly (in approximately 80% of patients) than intraperitoneal rupture (20%). Extraperitoneal rupture results either from direct bladder injury caused by pelvic fracture fragments or from shearing forces near the base of the bladder.
    • Intraperitoneal rupture is usually the result of blunt trauma to a distended bladder.
    • Pelvic fractures need not be present in either type of bladder rupture; they are more often associated with extraperitoneal injuries. Traditionally, the diagnosis of bladder injury was made by use of conventional cystography; however, with the increased use of computed tomography (CT), CT cystography is now more routinely performed.
  • Urethral injury results from the same shearing forces that lead to extraperitoneal bladder rupture. Distraction of the anterior pelvic osseous support structures leads to stretching of the urogenital diaphragm, the most common location for urethral injury. The male urethra is longer and more mobile than the female urethra; therefore, it is more prone to injury.
    • In a type I urethral injury, the membranous urethra (above the urogenital diaphragm) is stretched and narrowed.
    • In a type II injury, disruption of the membranous urethra occurs near the base of the bladder.
    • In a type III injury, the disruption of the membranous urethra extends below the level of the urogenital diaphragm to involve the bulbous urethra.
  • Nerve injury occurs as both an immediate and a late complication of pelvic ring fracture. With fractures of the sacrum or sacroiliac (SI) joints, injury to the adjacent sacral plexus or sacral nerve roots may occur. With fractures extending into the region of the greater sciatic notch, injury to the sciatic nerve may occur. Posterior acetabular fractures also are associated with sciatic nerve injury. Nerve dysfunction may persist even after reduction and fixation of the pelvic fracture.
• Early complications may occur.
  • Blood loss in the preoperative and immediate postoperative period results in morbidity in several ways. Uncontrolled hemorrhage may result in exsanguination. Continued blood loss or inadequate volume repletion may result in shock and its clinical ramifications, such as coagulopathy and renal failure.
  • Infection may occur in a number of settings. The pelvic hematoma that accompanies most significant pelvic fractures may transform into an abscess. Open drainage or, if possible, percutaneous drainage is required. Patients undergoing open surgical fixation of a pelvic fracture are at risk for wound infection. Of course, all postsurgical patients are susceptible to a variety of infections, most notably those of the pulmonary system and urinary tract. Fixation devices, either external or internal, may become infected and require removal.
  • Thromboembolic disease is frequently encountered in the setting of pelvic fracture. The potential for coagulopathy coupled with inevitable temporary immobility of the patient serves to increase the risk. Deep venous thrombosis (DVT) in the lower extremities is readily visualized by using Doppler ultrasonography (US). However, most clinically significant and potentially deadly thrombi occur in the veins of the pelvis, an area not easily accessible to US. Magnetic resonance venography (MRV) is potentially useful in assessing the pelvic venous system.
• Late complications are possible.
  • Pain is the most common long-term complaint of patients with pelvic fractures. Pain most often is associated with abnormalities of the SI joint. Osteoarthrosis, malunion, and nonunion are potential etiologies of the pain.
  • Malunion of the fracture most often occurs in the setting of unreduced pelvic fractures. Leg-length discrepancies may result, resulting in gait abnormalities and pain.
  • Nonunion of the fracture develops in the setting of vertically unstable pelvic fractures. Treatment for this uncommon complication requires stable fixation of the pelvic disruption and correction of any malpositioning.

Race

Race is not a contributing factor in the incidence or pattern of pelvic ring fractures.

Sex

The incidence of motor vehicle collisions is higher in males, particularly young men, than in females. No difference is noted in the pattern of pelvic ring injuries between males and females. The incidence of urethral injury is higher in males (15%) than in females (6%).

Age

Compared with others, young adults are more likely to be involved in serious motor vehicle collisions. No difference is noted in the pattern of pelvic ring injuries between age groups. Elderly patients are more likely to have isolated pubic rami fractures secondary to osteoporosis.

Anatomy

The osseous pelvis is the bridge between the spine and the lower extremities. The pelvis comprises 3 bones: the sacrum and the 2 innominate bones. The innominate bones are formed by joining 3 ossification centers at the triradiate cartilage of the acetabulum: the ilium, the ischium, and the pubis. The sacrum posteriorly articulates with the 2 innominate bones at the SI joint, with the innominate bones joining anteriorly at the pubic symphysis. The posterior pelvic arch (sacrum, SI joints, and iliac bones) transmits the weight-bearing force from the lower lumbar spine to the acetabula (when a person is standing) or to the ischial tuberosities (when a person is sitting). During weight bearing, the anterior pelvic arch (pubic rami and symphysis) functions as a strut to maintain the shape of the pelvic ring.

Pelvic ligaments as seen on an anterior view of the pelvis. The horizontally oriented anterior sacroiliac and sacrospinous ligaments resist rotation. The vertically oriented sacrotuberous ligaments resist vertical displacement.

Pelvic ligaments as seen on a superior view of the pelvis. The posterior sacroiliac ligaments are the most important structures for pelvic stability.

Pelvic ligaments as seen on a posterior view of the pelvis. The short and long posterior sacroiliac ligaments are the most vital structures for the preservation of pelvic ring stability. Note the iliolumbar ligament attachment to the L5 transverse process. An avulsion fracture at this site may be a sign of posterior ligamentous disruption.

Vertically oriented ligaments—that is, the long posterior SI, sacrotuberous, and lateral lumbosacral ligaments—oppose vertical displacement of the pelvis (see Image 6). The strongest of these ligaments, as well as the most important with regard to pelvic stability (especially vertical stability), are the short and long posterior SI ligaments. Interosseous SI ligaments provide an added level of support to the SI joints.

Presentation

The Young-Burgess^2,11,12,13 and the Tile^9,13 systems are 2 major classification schemes that have been developed for describing pelvic ring fractures. With both systems, injuries are classified on the basis of the direction of the injuring force. The Young-Burgess classification system focuses on the degree of injury (see Table 2).^2,11,12 The Tile classification system focuses on pelvic stability (see Table 3).⁹

Lateral compression injury as seen on an anteroposterior radiograph of the pelvis. Note the characteristic left sacral buckle fracture (long arrow) and the minimally overlapping left pubic rami fractures (short arrow). The sacral fractures may be subtle on radiographs.

Lateral compression injury as seen on a pelvic CT scan. The left sacral buckle (anterior crush) fracture is more readily apparent on the CT scan than on other images.

Windswept pelvis (lateral compression injury) as seen on a pelvic CT scan. The features of each component of the injury are seen to better advantage with CT. Note the internal rotation of the left hemipelvis and external rotation of the right hemipelvis (long arrows). Note also the left sacral buckle fracture (short white arrow) and the right sacroiliac joint diastasis (short black arrow). The left sacroiliac joint also is disrupted.

Anteroposterior compression injury as seen on an anteroposterior radiograph of the pelvis. The symphysis pubis is wider than 2.5 cm (double arrow). The right sacroiliac joint is diastatic (single arrow). This is a type II or type III injury, depending on the status of the posterior sacroiliac ligaments.

Anteroposterior (AP) compression injury as seen on a pelvic CT scan. The location and degree of sacroiliac disruption is better seen on CT scans than on radiographs. The external rotation of the right hemipelvis is a characteristic finding in AP compression. A slight posterior displacement of the right, iliac side of the sacroiliac joint suggests ligamentous disruption (arrow). This represents a type III AP compression injury.

• AP compression injury
  • The hallmark of the AP compression injury is pubic diastasis with or without disruption of the SI joints. The location and degree of diastasis is correlated with the magnitude of force imparted to the pelvis and with the amount of resulting instability. The AP compression causes the pelvis to open: one or both hemipelves undergo external rotation. According to the Young-Burgess classification system, 3 degrees of AP compression injury are identified.
    • Type I injuries: Less than 2.5 cm of the pubic diastasis is noted, either at the symphysis or through vertically oriented rami fractures. The SI joints and posterior ligaments remain intact, and stability is maintained.
    • Type II injuries: The amount of anterior diastasis exceeds 2.5 cm. In addition, diastasis occurs in 1 or both of the SI joints. This incomplete posterior arch disruption results in rotational instability. The posterior ligaments are not injured; therefore, vertical stability is preserved.
    • Type III injuries: These injuries extend to the posterior SI ligaments, which are disrupted. Consequently, the pelvis is vertically and rotationally unstable (see Images 7-8).
  • External rotation of the hemipelvis results in an increase in the volume of the pelvic cavity. This increased pelvic volume allows more pelvic hemorrhage to occur before the osseous and soft tissue structures cause tamponade. Exsanguination from a pelvic hemorrhage is a primary potential complication. Reduction of the increased pelvic volume is a primary goal in resuscitating a patient with an AP compression injury. Immediate reduction may be achieved by tightly wrapping the pelvis in sheets or a pneumatic antishock garment. The application of an external pelvic fixation device results in more definitive reduction. AP compression injuries are also strongly associated with brain and intra-abdominal injuries.

• Lateral compression injury
  • Lateral compression injury results in internal rotation of the affected hemipelvis. This internal rotation decreases rather than increases the pelvic volume. Consequently, pelvic vascular injuries and resulting hemorrhage are less common with this injury than with other injuries. Lateral compression injuries are associated with brain and intra-abdominal injuries.
  • The hallmarks of a lateral compression injury include sacral buckle fractures and horizontal pubic rami fractures. The Young-Burgess classification system describes 3 types of injuries.
    • Type I injuries: These involve a force directed posteriorly to the lateral aspect of the hemipelvis, which results in an ipsilateral sacral buckle fractures; ipsilateral horizontal pubic rami fractures; or, less commonly, disruption of the pubic symphysis with overlap of the pubic bones (see Images 9-11). The posterior ligaments remain intact; therefore, the pelvis is stable. Lateral forces directed anteriorly to the hemipelvis produce type II and type III injuries.
    • Type II injuries: These involve more internal rotation of the hemipelvis. As in type I injuries, ipsilateral sacral buckle fractures and horizontal pubic rami fractures are associated with fracture of the ipsilateral iliac wing or disruption of the ipsilateral posterior SI joint. The pelvis is rotationally unstable, but its vertical stability is maintained.
    • Type III injuries: The force continues from the ipsilateral side across the midline to affect the contralateral hemipelvis. The ipsilateral hemipelvis sustains either a type I or type II injury with associated internal rotation. The contralateral pelvis undergoes external rotation. This pattern has been described as a windswept pelvis (see Images 12-13). Contralateral vertical pubic rami fractures or disruption of the sacrotuberous and/or sacrospinous ligaments may occur. As in type II injuries, the pelvis is rotationally unstable but vertically stable.
• Vertical shear injury
  • A vertically oriented force applied to a hemipelvis, usually by the femur, results in a vertical shear injury. At the anterior aspect, vertically oriented fractures of the pubic rami occur. Posteriorly, the ipsilateral SI joint (or occasionally the contralateral SI joint) and its associated ligaments are disrupted (see Images 14-18).
  • The affected hemipelvis is displaced in a cranial direction. Complete disruption of the posterior ligaments yields a rotationally and vertically unstable pelvis.
  • Associated injuries seen in the vertical shear pattern are similar to those encountered in type III AP compression injuries.
• Complex injury
  • The forces applied to the pelvis may not conform to the primary vectors described for other types of injuries.
  • Complex injuries involve more than 1 pattern of injury. The specific findings of each pattern are still present.
  • Pelvic stability may be determined by use of the criteria outlined above.
• Ring-sparing injury
  • The Tile classification system includes fractures of the pelvis that do not significantly disrupt the pelvic ring (Tile type A). These injuries include avulsion fractures of the anterior iliac spine, iliac crests, and ischial tuberosities (see Image 19).
  • Also included are iliac wing fractures (see Image 20) and sacrococcygeal fractures that do not involve the SI joints. Minimally or nondisplaced pubic rami fractures resulting from a direct blow or straddle injury do not affect pelvic ring stability.

Preferred Examination

Radiography^{1,10,12,14,15,16,17}

The anteroposterior image of the pelvis is routinely acquired as part of the initial radiographic examination of the pelvis.

Compared with the anteroposterior view, the inlet perspective of the pelvis better demonstrates internal or external rotation and anteroposterior displacement of the hemipelvis.

Cranial displacement of the hemipelvis is demonstrated better on this outlet view of the pelvis than on other images. In addition, the sacral neural foramina are better profiled.

• AP radiography of the pelvis (see Image 21)
  • AP radiographs of the pelvis and chest and lateral radiographs of the cervical spine are included in the initial radiographic assessment of a patient with major traumatic injuries.
  • Radiographs are obtained with the patient in the supine position, with the x-ray beam passing in an AP direction.
  • Abnormalities depicted on the AP pelvis radiograph direct the need for the next set of radiographs, which include oblique (Judet) views of the pelvis in acetabular fractures,^18,19 and inlet and outlet radiographs of the pelvis in patients with pelvic ring fractures.
• Inlet and outlet radiography of the pelvis
  • Inlet radiographs of the pelvis are obtained with the patient in the supine position, with the x-ray tube positioned at the patient's head and angled 45° toward the feet (see Image 22). The x-ray beam is perpendicular to the pelvic brim (or inlet). This view allows the evaluation of pelvic brim integrity, AP displacement of the hemipelvis, internal/external rotation of the hemipelvis, and sacral impaction.
  • Outlet radiographs of the pelvis are obtained with the patient in the supine position, with the x-ray tube positioned at the patient's feet and angled 45° toward the head (see Image 23). The x-ray beam is perpendicular to the sacrum. This view allows confirmation of vertical (cranial) displacement of the hemipelvis and evaluation of the sacral neural foramina.
• Pelvic CT²⁰
  • During the initial trauma evaluation, CT images may be obtained of the pelvis in isolation, or CT scans of the pelvis may be obtained at the same time that scans of the abdomen are obtained.
  • Axial CT scans may be obtained, but helical CT scans (especially with multidetector CT) yield better 2-dimensional (2D) and 3-dimensional (3D) images.
  • CT allows the detection of subtle fractures and displacements not appreciated on radiographs.

Limitations of Techniques

Radiographs of the pelvis may not demonstrate subtle fractures that do not affect classification of the injury. Spatial orientation of fracture fragments and joints is visualized better on pelvic CT scans.

Pelvic CT scans require transport of the patient to the CT scanner; most patients need to undergo abdominal and pelvic CT for an assessment of visceral injury.

Differential Diagnoses

Acetabulum, Fractures
Pelvis, Insufficiency Fractures

Radiography

Anteroposterior (AP) compression injury as seen on an AP radiograph of the pelvis. Characteristic features of an AP compression injury include symphyseal and sacroiliac joint diastasis. In this patient, the pubic symphysis and right sacroiliac joint are widened.

Vertical shear injury as seen on an anteroposterior radiograph of the pelvis. The left hemipelvis is displaced in a cranial direction, with associated sacroiliac joint diastasis. The vertically oriented fractures of the pubic rami usually are ipsilateral; however, in this patient, the rami fractures are contralateral.

Anteroposterior compression injury as seen on an anteroposterior radiograph of the pelvis. The symphysis pubis is wider than 2.5 cm (double arrow). The right sacroiliac joint is diastatic (single arrow). This is a type II or type III injury, depending on the status of the posterior sacroiliac ligaments.

Lateral compression injury as seen on an anteroposterior radiograph of the pelvis. Note the characteristic left sacral buckle fracture (long arrow) and the minimally overlapping left pubic rami fractures (short arrow). The sacral fractures may be subtle on radiographs.

Lateral compression injury as seen on an inlet radiograph of the pelvis. The internal rotation of the left hemipelvis is better visualized by using the inlet view. The fractures of the left sacrum (long arrow) and left pubic rami (short arrows) are shown.

Windswept pelvis (lateral compression injury) as seen on an anteroposterior radiograph of the pelvis. The patient had a left lateral compression injury. Note the internal rotation of the left hemipelvis and the overlapping left pubic rami fractures (double arrow). The pubic symphysis diastasis, rightward displacement of the pubic symphysis with external rotation of the right hemipelvis, and right sacroiliac joint diastasis (single arrow) are features of anteroposterior compression. The combination results in the characteristic appearance of the windswept pelvis.

Vertical shear injury as seen on an anteroposterior radiograph of the pelvis. The left hemipelvis is displaced in a cranial direction with associated sacroiliac joint diastasis (long arrow). The vertically oriented fractures of the pubic rami usually are ipsilateral; however, in this patient, the rami fractures are contralateral (short arrow).

Iliac wing fracture as seen on an anteroposterior radiograph of the pelvis. A fracture of the left iliac wing occurred secondary to a direct blow to the left hemipelvis. The fracture does not involve the pelvic ring; therefore, the pelvis is stable.

Findings

AP radiographs of the pelvis

Usually, the pubic symphysis is approximately 5 mm wide; it should not be more than 1 cm wide. Pubic symphysis diastasis occurs when the fibrocartilage connecting the 2 pubic bones is disrupted. Diastasis of the pubic symphysis indicates an AP compression injury. If overlap of the pubic bones at the symphysis is noted, a lateral compression injury is suggested. The superior pubic rami should be at the same level as they join at the symphysis. In a vertical shear injury, 1 side is displaced in a cranial direction. The lower margins of the rami are a better guide because nonalignment of the upper margins may be a normal variation (see Image 25).

The combination of a sacral buckle fracture and ipsilateral overlapping pubic rami fractures is characteristic of a lateral compression injury.

The direction of hemipelvic displacement indicates the mechanism of injury. External rotation of the hemipelvis (open-book pelvis) occurs with AP compression. Internal rotation is seen in lateral compression. Vertical shear injuries result in vertical (cranial) displacement of the hemipelvis. Iliac wing fractures with extension to the vicinity of the SI joint are found in the more severe lateral compression injuries. Avulsion of the ischial spine occurs in external rotation or vertical displacement of the hemipelvis. Isolated iliac wing fractures may occur as a result of a direct blow without disruption of the pelvic ring. With iliac crest, anterior iliac spine, and ischial tuberosity avulsion fractures, the integrity of the pelvic ring is also maintained.

The normal SI joint space is approximately 2-4 mm in width. When the SI joint is analyzed for diastasis, the anterior and posterior aspects should be examined. Disruption of the SI joint with external rotation of the ipsilateral hemipelvis is characteristic of AP compression. If only the anterior SI joint is widened, the posterior ligaments are intact and preserving vertical stability. If the SI joint is anteriorly and posteriorly diastatic, the pelvis is completely unstable. Usually, the SI joint is completely disrupted in vertical shear injuries. Displaced vertical fractures through the sacrum or the iliac wing adjacent to the SI joint have the same implication as SI joint diastasis.

Buckle (anterior crush) fractures of the sacrum are the hallmark of lateral compression injuries. The fractures are usually oriented vertically. They may be isolated to the sacral ala, pass through the neural foramina, or extend centrally into the sacral spinal canal. Radiographic findings of the fractures may be subtle. The sacral promontory and arcuate foramina should be carefully examined for cortical disruption. Displaced vertical fractures through the sacrum may be seen in lieu of SI joint disruption in AP compression and vertical shear injuries. Horizontal fractures of the sacrum below the level of the S2 do not affect the integrity of the pelvic ring.

The iliolumbar ligament is inserted at the tip of the L5 transverse process. An avulsion fracture at this site is associated with disruption of the posterior SI ligament complex, as seen in severe AP compression and vertical shear injuries. Hence, an L5 transverse-process avulsion fracture may indicate complete pelvic instability.

Inlet radiographs of the pelvis

The inlet view of the pelvis permits more accurate determination of the following: the degree of posterior displacement at the SI joint, the degree of internal or external rotation of the hemipelvis, the degree of pubic diastasis or overlap, and the presence of subtle sacral fractures.

Outlet radiographs of the pelvis

The primary purpose of the outlet view of the pelvis is to demonstrate the magnitude of vertical (cranial) displacement of the hemipelvis. Additionally, some sacral and pubic rami fractures are better visualized with the outlet view than with other views. The sacral neural foramina are especially well depicted by using the outlet view.

Degree of Confidence

In most patients, an analysis of the AP radiographs of the pelvis results in the correct determination of the mechanism of pelvic ring injury. Appropriate therapeutic maneuvers may be initiated immediately. Additional radiographic views (eg, inlet and outlet views) and pelvic CT scans allow more precise classification when definitive treatment is considered.

Multidetector CT is now routinely used to evaluate trauma patients; some authors have questioned whether pelvic radiographs should be routinely used for patients who are destined to undergo a CT scan.^1,14

False Positives/Negatives

True pelvic ring fractures must be distinguished from pelvic fractures that do not affect pelvic stability (eg, Tile type A injury).

Pelvic ring fractures should be distinguished from acetabular fractures, which may also occur with pubic rami and iliac wing fractures. The sites that are important for pelvic stability (eg, pubic symphysis, SI joints, sacrum) should be examined to exclude a pelvic ring fracture.

An acetabular fracture may be present in addition to a pelvic ring fracture. With both types, fractures should be analyzed individually.

Computed Tomography

Windswept pelvis (lateral compression injury) as seen on a pelvic CT scan. The patient sustained a left lateral compression injury with internal rotation of the left hemipelvis and a characteristic sacral buckle fracture. Note the concomitant left sacroiliac joint diastasis. The lateral force vector continued across the pelvis to produce external rotation of the right hemipelvis and diastasis of the right sacroiliac joint. The combination of injuries resulted in a windswept pelvis.

Anteroposterior (AP) compression injury as seen on a pelvic CT scan. The location and degree of sacroiliac disruption is better seen on CT scans than on radiographs. The external rotation of the right hemipelvis is a characteristic finding in AP compression. A slight posterior displacement of the right, iliac side of the sacroiliac joint suggests ligamentous disruption (arrow). This represents a type III AP compression injury.

Lateral compression injury as seen on a pelvic CT scan. The left sacral buckle (anterior crush) fracture is more readily apparent on the CT scan than on other images.

Windswept pelvis (lateral compression injury) as seen on a pelvic CT scan. The features of each component of the injury are seen to better advantage with CT. Note the internal rotation of the left hemipelvis and external rotation of the right hemipelvis (long arrows). Note also the left sacral buckle fracture (short white arrow) and the right sacroiliac joint diastasis (short black arrow). The left sacroiliac joint also is disrupted.

Vertical shear injury as seen on a pelvic CT scan. A displaced vertically oriented fracture of the ilium extends to the left sacroiliac joint.

Findings

All radiographic findings should be further assessed on pelvic CT scans (see Radiograph) because subtle fractures and disruptions may be more apparent on CT scans. In particular, sacral fractures may be difficult to detect on radiographs (see Images 24, 26).^16,20,21

Diastasis of the symphysis pubis, which most commonly indicates an anteroposterior compression injury.

Avulsion fractures of the pelvis (eg, from the anterior inferior aspect of the iliac spine) do not affect the integrity of the pelvic ring. Isolated iliac wing fractures may occur as a result of a direct blow without disruption of the pelvic ring. With iliac crest, anterior iliac spine, and ischial tuberosity avulsion fractures, the integrity of the pelvic ring is also maintained.

In addition to the osseous structures, the soft tissues of the pelvis should be examined. The size of a pelvic hematoma secondary to a pelvic ring fracture may be determined. If contrast material is intravenously administered for pelvic CT, active arterial bleeding may be demonstrated, and the information may be used to guide the clinical decision to incorporate angiography into the patient's treatment plan.²⁰

Degree of Confidence

The combination of the pelvic CT scans and the AP radiographs with inlet and/or outlet views permits accurate classification of pelvic ring fractures in virtually every patient.

Magnetic Resonance Imaging

Findings

Magnetic resonance imaging (MRI) is not used to evaluate pelvic ring fractures. Research is currently underway to evaluate the use of MRI in the evaluation of deep venous thrombosis in orthopedic patients. MR venography may prove useful in depicting lower extremity and pelvic venous thrombosis.²²

Ultrasonography

Findings

Ultrasound (US) is not used to evaluate pelvic ring fractures. Lower-extremity Doppler US is used to assess for the presence of lower-extremity DVT.

Nuclear Imaging

Findings

Nuclear medicine studies are not used to evaluate acute pelvic ring fractures.

Angiography

Findings

Angiography is used to diagnose and treat potentially life-threatening hemorrhage secondary to pelvic ring injury. Pelvic arteriography demonstrates the injured vessels responsible for the hemorrhage. The vessels may then be embolized to control or stop the bleeding.

Intervention

Pelvic angiography with transcatheter embolization of injured arteries may be required in the treatment of severe pelvic hemorrhage associated with pelvic ring fractures. The first priority in patients with pelvic hemorrhage associated with pelvic ring fracture is pelvic stabilization. This may be immediately accomplished by using a pneumatic antishock garment or by tightly wrapping sheets around the pelvis until more definitive measures, such as a pelvic external fixator, may be used. Pelvic angiography with transcatheter embolization is faster, less invasive, and more successful than open surgical procedures for controlling pelvic hemorrhage.^3,9,23

Multimedia

Media file 1: Anteroposterior (AP) compression injury as seen on an AP radiograph of the pelvis. Characteristic features of an AP compression injury include symphyseal and sacroiliac joint diastasis. In this patient, the pubic symphysis and right sacroiliac joint are widened.

Media file 2: Windswept pelvis (lateral compression injury) as seen on a pelvic CT scan. The patient sustained a left lateral compression injury with internal rotation of the left hemipelvis and a characteristic sacral buckle fracture. Note the concomitant left sacroiliac joint diastasis. The lateral force vector continued across the pelvis to produce external rotation of the right hemipelvis and diastasis of the right sacroiliac joint. The combination of injuries resulted in a windswept pelvis.

Media file 3: Vertical shear injury as seen on an anteroposterior radiograph of the pelvis. The left hemipelvis is displaced in a cranial direction, with associated sacroiliac joint diastasis. The vertically oriented fractures of the pubic rami usually are ipsilateral; however, in this patient, the rami fractures are contralateral.

Media file 4: Pelvic ligaments as seen on an anterior view of the pelvis. The horizontally oriented anterior sacroiliac and sacrospinous ligaments resist rotation. The vertically oriented sacrotuberous ligaments resist vertical displacement.

Media file 5: Pelvic ligaments as seen on a superior view of the pelvis. The posterior sacroiliac ligaments are the most important structures for pelvic stability.

Media file 6: Pelvic ligaments as seen on a posterior view of the pelvis. The short and long posterior sacroiliac ligaments are the most vital structures for the preservation of pelvic ring stability. Note the iliolumbar ligament attachment to the L5 transverse process. An avulsion fracture at this site may be a sign of posterior ligamentous disruption.

Media file 7: Anteroposterior compression injury as seen on an anteroposterior radiograph of the pelvis. The symphysis pubis is wider than 2.5 cm (double arrow). The right sacroiliac joint is diastatic (single arrow). This is a type II or type III injury, depending on the status of the posterior sacroiliac ligaments.

Media file 8: Anteroposterior (AP) compression injury as seen on a pelvic CT scan. The location and degree of sacroiliac disruption is better seen on CT scans than on radiographs. The external rotation of the right hemipelvis is a characteristic finding in AP compression. A slight posterior displacement of the right, iliac side of the sacroiliac joint suggests ligamentous disruption (arrow). This represents a type III AP compression injury.

Media file 9: Lateral compression injury as seen on an anteroposterior radiograph of the pelvis. Note the characteristic left sacral buckle fracture (long arrow) and the minimally overlapping left pubic rami fractures (short arrow). The sacral fractures may be subtle on radiographs.

Media file 10: Lateral compression injury as seen on an inlet radiograph of the pelvis. The internal rotation of the left hemipelvis is better visualized by using the inlet view. The fractures of the left sacrum (long arrow) and left pubic rami (short arrows) are shown.

Media file 11: Lateral compression injury as seen on a pelvic CT scan. The left sacral buckle (anterior crush) fracture is more readily apparent on the CT scan than on other images.

Media file 12: Windswept pelvis (lateral compression injury) as seen on an anteroposterior radiograph of the pelvis. The patient had a left lateral compression injury. Note the internal rotation of the left hemipelvis and the overlapping left pubic rami fractures (double arrow). The pubic symphysis diastasis, rightward displacement of the pubic symphysis with external rotation of the right hemipelvis, and right sacroiliac joint diastasis (single arrow) are features of anteroposterior compression. The combination results in the characteristic appearance of the windswept pelvis.

Media file 13: Windswept pelvis (lateral compression injury) as seen on a pelvic CT scan. The features of each component of the injury are seen to better advantage with CT. Note the internal rotation of the left hemipelvis and external rotation of the right hemipelvis (long arrows). Note also the left sacral buckle fracture (short white arrow) and the right sacroiliac joint diastasis (short black arrow). The left sacroiliac joint also is disrupted.

Media file 14: Vertical shear injury as seen on an anteroposterior radiograph of the pelvis. The left hemipelvis is displaced in a cranial direction with associated sacroiliac joint diastasis (long arrow). The vertically oriented fractures of the pubic rami usually are ipsilateral; however, in this patient, the rami fractures are contralateral (short arrow).

Media file 15: Vertical shear injury as seen on an outlet radiograph of the pelvis. The vertical (cranial) displacement of the left hemipelvis and pubic symphysis is better visualized by using the outlet view. In addition, a left iliac fracture is more readily apparent (large arrows). Left sacroiliac joint diastasis is seen (small arrow).

Media file 16: Vertical shear injury as seen on a pelvic CT scan. A displaced vertically oriented fracture of the ilium extends to the left sacroiliac joint.

Media file 17: Vertical shear injury as seen on a pelvic CT scan. A slightly more inferior image demonstrates anterior and posterior disruption of the left sacroiliac joint. The left hemipelvis is rotationally and vertically unstable.

Media file 18: Vertical shear injury as seen on a pelvic CT scan. As also shown on the radiograph of this injury (see Image 14), a vertically oriented fracture of the right superior pubic ramus is depicted with cranial displacement of the pubic symphysis and left hemipelvis.

Media file 19: Bilateral anterior inferior iliac spine avulsion fracture as seen on an anteroposterior radiograph of the pelvis. Hyperextension of the hip occurred in this patient during a motor vehicle collision. The injury resulted in avulsion fractures at the origins of both rectus femoris muscles. Note that the integrity of the pelvic ring is preserved.

Media file 20: Iliac wing fracture as seen on an anteroposterior radiograph of the pelvis. A fracture of the left iliac wing occurred secondary to a direct blow to the left hemipelvis. The fracture does not involve the pelvic ring; therefore, the pelvis is stable.

Media file 21: The anteroposterior image of the pelvis is routinely acquired as part of the initial radiographic examination of the pelvis.

Media file 22: Compared with the anteroposterior view, the inlet perspective of the pelvis better demonstrates internal or external rotation and anteroposterior displacement of the hemipelvis.

Media file 23: Cranial displacement of the hemipelvis is demonstrated better on this outlet view of the pelvis than on other images. In addition, the sacral neural foramina are better profiled.

Media file 24: Diastasis of the symphysis pubis, which most commonly indicates an anteroposterior compression injury.

Media file 25: The combination of a sacral buckle fracture and ipsilateral overlapping pubic rami fractures is characteristic of a lateral compression injury.

Media file 26: Avulsion fractures of the pelvis (eg, from the anterior inferior aspect of the iliac spine) do not affect the integrity of the pelvic ring. Isolated iliac wing fractures may occur as a result of a direct blow without disruption of the pelvic ring. With iliac crest, anterior iliac spine, and ischial tuberosity avulsion fractures, the integrity of the pelvic ring is also maintained.

References

1. Kessel B, Sevi R, Jeroukhimov I, Kalganov A, Khashan T, Ashkenazi I. Is routine portable pelvic X-ray in stable multiple trauma patients always justified in a high technology era?. Injury. May 2007;38(5):559-63. [Medline].

2. Burgess AR, Jones AL. Fractures of the pelvic ring. In: Rockwood CA, Green DP, Bucholz RW, Heckman JD, eds. Rockwood and Green's Fractures in Adults. 4th ed. Lippincott-Raven;1996:1575-615.

3. Kellam JF, Browner BD. Fractures of the pelvic ring. In: Skeletal Trauma: Fractures, Dislocations, Ligamentous Injuries. 2nd ed. Philadelphia: WB Saunders Co;1998:1117-79.

4. Scalea TM, Burgess AR. Pelvic fractures. In: Mattox KL, Feliciano DV, Moore EE, eds. Trauma. New York: McGraw-Hill Pub;2000:807-37.

5. Young JW. Pelvic injuries. Semin Musculoskelet Radiol. 1998;2(1):83-104. [Medline].

6. Balogh Z, King KL, Mackay P, McDougall D, Mackenzie S, Evans JA. The epidemiology of pelvic ring fractures: a population-based study. J Trauma. Nov 2007;63(5):1066-73; discussion 1072-3. [Medline].

7. Mackay P, King K, Mackenzie S, McDougall D, Evans J, Balogh Z. Ts04 the epidemiology of pelvic fractures: the whole picture. ANZ J Surg. May 2007;77 Suppl 1:A93. [Medline].

8. McCort JJ, Mindelzun RE. Bladder injury and pelvic fractures. Emerg Radiol. 1994;1:47-51.

9. Tile M. Pelvic ring fractures: should they be fixed?. J Bone Joint Surg Br. Jan 1988;70(1):1-12. [Medline].

10. Avey G, Blackmore CC, Wessells H, Wright JL, Talner LB. Radiographic and clinical predictors of bladder rupture in blunt trauma patients with pelvic fracture. Acad Radiol. May 2006;13(5):573-9. [Medline].

11. Burgess AR, Eastridge BJ, Young JW, et al. Pelvic ring disruptions: effective classification system and treatment protocols. J Trauma. Jul 1990;30(7):848-56. [Medline].

12. Young JW, Burgess AR, Brumback RJ, Poka A. Pelvic fractures: value of plain radiography in early assessment and management. Radiology. Aug 1986;160(2):445-51. [Medline].

13. Koo H, Leveridge M, Thompson C, Zdero R, Bhandari M, Kreder HJ, et al. Interobserver reliability of the young-burgess and tile classification systems for fractures of the pelvic ring. J Orthop Trauma. Jul 2008;22(6):379-84. [Medline].

14. Obaid AK, Barleben A, Porral D, Lush S, Cinat M. Utility of plain film pelvic radiographs in blunt trauma patients in the emergency department. Am Surg. Oct 2006;72(10):951-4. [Medline].

15. Resnik CS, Stackhouse DJ, Shanmuganathan K, Young JW. Diagnosis of pelvic fractures in patients with acute pelvic trauma: efficacy of plain radiographs. AJR Am J Roentgenol. Jan 1992;158(1):109-12. [Medline].

16. Kuklo TR, Potter BK, Ludwig SC, Anderson PA, Lindsey RW, Vaccaro AR. Radiographic measurement techniques for sacral fractures consensus statement of the Spine Trauma Study Group. Spine. Apr 20 2006;31(9):1047-55. [Medline].

17. Chmelová J, Dzupa V, Pleva L. [Pelvic fractures: role of imaging methods in the diagnosis of isolated pelvic fractures and multi-trauma]. Acta Chir Orthop Traumatol Cech. Apr 2008;75(2):93-8. [Medline].

18. Hunter JC, Brandser EA, Tran KA. Pelvic and acetabular trauma. Radiol Clin North Am. May 1997;35(3):559-90. [Medline].

19. Pitt MJ, Ruth JT, Benjamin JB. Trauma to the pelvic ring and acetabulum. Semin Roentgenol. Oct 1992;27(4):299-318. [Medline].

20. Pereira SJ, O'Brien DP, Luchette FA, Choe KA, Lim E, Davis Jr K. Dynamic helical computed tomography scan accurately detects hemorrhage in patients with pelvic fracture. Surgery. Oct 2000;128(4):678-85. [Medline].

21. Bale RJ, Kovacs P, Dolati B, Hinterleithner C, Rosenberger RE. Stereotactic CT-guided percutaneous stabilization of posterior pelvic ring fractures: a preclinical cadaver study. J Vasc Interv Radiol. Jul 2008;19(7):1093-8. [Medline].

22. Zajick DC, Zoga AC, Omar IM, Meyers WC. Spectrum of MRI findings in clinical athletic pubalgia. Semin Musculoskelet Radiol. Mar 2008;12(1):3-12. [Medline].

23. Clements JP, Moriaty N, Chesser TJ, Ward AJ, Cunningham JL. Determination of pelvic ring stability: a new technique using a composite hemi-pelvis. Proc Inst Mech Eng [H]. Jul 2008;222(5):611-6. [Medline].

Keywords

pelvic ring fracture, pelvis fracture, blunt trauma, bladder rupture, vertical shear injury, anteroposterior compression injury, AP compression injury, lateral compression injury, pelvic hemorrhage, osseous pelvis, Young-Burgess classification, Tile classification, pubic diastasis, sacral buckle fracture, pubic rami fracture, iliac wing fracture

Contributor Information and Disclosures

Author

D Dean Thornton, MD, Clinical Associate Professor, Department of Radiology, University of Alabama at Birmingham; Musculoskeletal Radiologist, Radiology Associates of Birmingham, PC
D Dean Thornton, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Radiology, American Roentgen Ray Society, Medical Association of the State of Alabama, Radiological Society of North America, and Society of Skeletal Radiology
Disclosure: Nothing to disclose.

Medical Editor

Amilcare Gentili, MD, Clinical Professor of Radiology, University of California at San Diego; Consulting Staff, Department of Radiology, Thornton Hospital
Amilcare Gentili, MD is a member of the following medical societies: American Roentgen Ray Society, Radiological Society of North America, and Society of Skeletal Radiology
Disclosure: Nothing to disclose.

Pharmacy Editor

Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand
Disclosure: Nothing to disclose.

Managing Editor

Theodore E Keats, MD, Professor, Departments of Radiology and Orthopedics, University of Virginia School of Medicine
Disclosure: Nothing to disclose.

CME Editor

Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute
Robert M Krasny, MD is a member of the following medical societies: American Roentgen Ray Society and Radiological Society of North America
Disclosure: Nothing to disclose.

Chief Editor

Felix S Chew, MD, MBA, EdM, Professor, Department of Radiology, Vice Chairman for Radiology Informatics, Section Head of Musculoskeletal Radiology, University of Washington
Felix S Chew, MD, MBA, EdM is a member of the following medical societies: American Roentgen Ray Society, Association of University Radiologists, and Radiological Society of North America
Disclosure: Nothing to disclose.

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