Although pelvic fractures are rare in children (<0.2%), they are associated with injury to numerous other organ systems because they are typically the result of high-energy mechanisms.

A pelvic fracture should be appreciated as a sign of severe whole-body injury. Patient mortality is not usually related to the pelvic fracture itself but to the associated injuries.

Older notions of good functional outcome from nonoperative treatment of pediatric pelvic fractures are not supported by more recent data, and more recent emphasis is on operative treatment of unstable fractures or fractures that involve the acetabular growth plates.

Acetabular fractures are an even rarer fracture type, constituting 6% to 17% of pediatric pelvic fractures. The impact of such fractures on the triradiate cartilage, the growth center of the acetabulum, is the central difference between pediatric and adult acetabular injury.

Important differences exist between the pelvis of a child and an adult.

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  A child’s pelvis has greater elasticity secondary to the elasticity of the joints and the bone. The child’s pelvis can absorb greater energies before fracture.

  
  
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  A child’s pelvis may fracture in only one location as a result of its elasticity, whereas the adult pelvic ring, because of its rigid nature, must necessarily fracture in two locations.

  
  
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  Avulsion fractures and fractures of the acetabulum through the triradiate cartilage are more frequent because the apophyseal or physeal cartilage presents a relative weak point in the pelvis.

  
  
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  Growth plate fractures can result in late deformity.

A primary ossification center exists in each of the three bones of the pelvis: the ilium, the ischium, and the pubis. The three centers meet at the triradiate cartilage and fuse at 16 to 18 years of age ( Fig. 26-1 ).

Lateral (A) and anteroposterior (B) views of the pelvis, showing the junction of the ilium, ischium, and pubis at the triradiate cartilage. The ischiopubic synchondrosis between the ischium and the pubis is apparent. The secondary ossification centers for the iliac crest, ischial apophysis, anterior inferior iliac spine, pubic tubercle, ischial spine, and lateral wing of the sacrum are illustrated.

(Adapted from Herring J: Tachdjian’s pediatric orthopaedics, ed 4, Philadelphia, 2007, Saunders.)

The ischiopubic synchondrosis, a persistent lucent area in the bilateral inferior pubic rami, is present through late adolescence and can often be confused for a fracture.

Secondary ossification centers are found throughout the pelvis and may be confused for fracture.

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  The iliac crest appears at 13 to 15 years and fuses at 15 to 17 years.

  
  
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  The ischial apophysis appears at 15 to 17 years and fuses by 25 years.

  
  
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  The anterior inferior iliac spine appears at 14 years and fuses at 16 years.

  
  
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  The pubic tubercle, ischial spine, and lateral wing of the sacrum all have secondary ossification centers.

The cuplike acetabulum grows in depth through the triradiate cartilage, and its periphery enlarges through appositional growth from cartilage and periosteal new bone formation at the acetabular margin.

At puberty, two main secondary centers of ossification appear in the cartilage surrounding the acetabulum.

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  The os acetabuli, the epiphysis of the pubis bone, appears at 8 years of age and expands to form most of the anterior acetabular wall, fusing with the pubis by 18 years.

  
  
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  The acetabular epiphysis, or the epiphysis of the ilium, follows a similar time-line for appearance and fusion and constitutes a large portion to the roof of the acetabulum.

Most pelvic fractures in children result from motor vehicle accidents, either as a pedestrian struck by a motor vehicle (60%) or as a passenger in a motor vehicle (22%).

Avulsion injuries from the pelvis are generally sports injuries.

Isolated fractures of the pelvis in an infant or toddler may be the only indication of child abuse. Pelvic radiographs are necessary for any skeletal survey.

Pelvic fractures in pediatric patients are associated with multiple organ system injury.

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  Associated head injury occurs in 9% to 48% of fractures and is the leading cause of death and the major cause of long-term disability in patients with pelvic fractures.

  
  
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  Life-threatening hemorrhage from an arterial interruption is rare in pediatric patients and differs in this respect from adults ; bleeding is typically venous, and acute interventions to reduce pelvic volume, such as a simple pelvic wrapping, usually suffice.

  
  
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  Urogenital injury occurs in 4% to 15% of patients, although the incidence of hematuria is notably greater and can occur in 52% of patients.

  
  
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  Vaginal and rectal lacerations may be present in 2% to 18% of patients and should be sought if a fracture has significant displacement, or perineal ecchymosis or bleeding exists. This injury suggests an open pelvic fracture.

  
  
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  Abdominal and hollow viscera injuries range from 14% to 21%.

  
  
  
  
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    Computed tomography (CT) scan best shows injuries to the abdomen.

    
    
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    Ultrasound and diagnostic peritoneal lavage may be useful adjuncts.

  
  
  
  
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  Long bone fractures are present in 40% to 50% of children with pelvic fractures.

  
  
  
  
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    Long bone fractures in patients with pelvic fractures are associated with twice the frequency of death, thoracic injury, laparotomy, and nonorthopedic procedures.

    
    
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    Long bone fracture is strongly associated with additional abdominal or head injury.

  
  
  
  
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  Lumbosacral plexus injury is rare and may occur in 1% to 3% of patients. This injury is found in pelvic ring fractures with significant posterior displacement.

  
  
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  Acetabular fractures may result from high-energy or low-energy mechanisms.

  
  
  
  
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    The fracture pattern is determined by the position of the femur at the time of impact.

    
    
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    Acetabular fractures are often seen in association with pelvic fractures. Pelvic fractures, such as ramus fractures, may often propagate into the triradiate cartilage.

  
  

Initial management of a child with a pelvic or acetabular fracture consists of board transport and immobilization of the lower extremities.

Cervical spine stabilization should also be performed because pelvic fractures most often result from high-energy mechanisms, and additional associated injuries may be present.

Fractures with gross bleeding should be covered with a moist saline dressing for transport. No attempts at reduction should be made before transport to the emergency department.

Life-threatening associated injuries to the head, chest, and abdomen should be evaluated and managed before a thorough physical examination of the pelvis.

Areas of contusion, abrasion, laceration, ecchymosis, or hematoma, especially in the perineal region ( Fig. 26-2 ), should be inspected and documented.

An 8-year-old boy was struck by a car. The pattern of ecchymosis (arrowhead) across the lower abdomen and pelvis suggests significant injury.

Palpation should be performed only once, especially in the setting of a potentially unstable pelvic ring injury, because repeated examination can disrupt a tenuous intrinsic hemostasis process.

Posterior pressure along the anterior superior iliac spines and medially directed compression of the iliac wings may yield crepitus, suggesting gross fracture and instability.

Posterior pressure on the symphysis pubis may cause motion and suggest instability.

The hip should be put through range of motion; any discomfort may suggest a proximal femur or acetabular fracture.

A complete neurovascular examination is necessary to rule out peripheral nerve injury.

As with any high-energy trauma, a complete spine examination is required.

Inspection of the genitourinary system is indicated, especially if there is associated ecchymosis or hematoma along the perineum.

Rectal examination should not be done routinely in pediatric patients but is indicated in significantly displaced fractures or with evidence of ecchymosis in the perineum to exclude a communication with the fracture site.

X-ray

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  Evaluation and stabilization of a child with a potential pelvic ring injury precedes diagnostic studies.

  
  
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  The initial evaluation begins with a single anteroposterior projection of the pelvis.

  
  
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  Any suggestion of pelvic ring instability on plain radiographs should prompt additional imaging.

CT

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  CT scan has largely supplanted radiographs for further clarification of bony anatomy if an injury is suspected.

  
  
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  CT scan has numerous advantages over plain radiographs, including rapid acquisition, ability to reconstruct the pelvis in multiple planes, and superior sensitivity.

  
  
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  Although plain radiographs can reliably predict the need for operative intervention, the information from a CT scan can change the specific operative management.

  
  
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  Most centers routinely obtain CT scan images through the abdomen in trauma patients; the addition of cuts through the pelvis may obviate screening plain radiographs.

Magnetic Resonance Imaging (MRI)

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  In young patients, MRI examination is necessary to decipher completely any fracture lines through the triradiate cartilage or posterior wall of the acetabulum.

  
  
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  Minimally displaced fractures may be better visualized.