The young pelvis has a great amount of cartilage and pliability and can absorb tremendous amounts of energy without resulting in a fracture. Pelvic fractures in children usually require high-energy trauma mechanisms such as automobile versus pedestrian, motor vehicle crashes, or significant falls. The violent forces required to cause pelvic fractures often result in multisystem trauma accompanied by visceral organ damage, limb fractures, and/or urogenital injuries. Morbidity and mortality rates following pelvic fractures in children are much lower than those seen in adults. Obese youth are more likely to suffer pelvic injuries if their BMI ≥95%.¹

The recognition and stabilization of any accompanying injuries is the most pressing issue surrounding pelvic injuries in the emergency department (ED). Traumatic, high-energy pelvic fractures are classified depending upon their involvement of either the pelvic ring or the acetabulum. Pelvic ring fractures can be classified as either stable or unstable. Stable injuries include single breaks in the pelvic ring, diastasis of the pubic symphysis, and fractures of the iliac wings. Stable fractures may be successfully managed nonoperatively with protected weight bearing. Unstable injuries include those with two breaks of the pelvic ring (Fig. 32-1) or those having a sacroiliac dislocation/fracture along with an associated rami or pubic symphysis fracture. Unstable fracture patterns often require external fixation or open reduction/internal fixation to stabilize the bony injury while allowing for better management of associated injuries.

Fractures of the acetabulum are rare in children and result from forces transmitted through the femoral head. The acetabulum will usually fracture where the triradiate cartilage meets the pelvis (Fig. 32-2). Like pelvic ring fractures, these injuries are usually associated with high-energy trauma. Any acetabular fracture associated with a pelvic ring fracture is considered unstable. Many acetabular fractures are associated with hip dislocations. Dislocations of the hip may be evident in the ED or may spontaneously reduce before presentation. Occasionally, acetabular fractures can occur following lower-energy trauma, such as a sports-related hip dislocation.

Evaluate any pelvic injury beginning with a history followed by a close inspection for any asymmetry, ecchymosis, or abrasions to the pelvis. Pain or crepitus elicited by compressing the iliac crests or by putting direct pressure on the pubic symphysis suggests a possible pelvic ring or acetabular fracture. Because of the association with multisystem trauma, perform a thorough physical examination of the head, chest, abdomen, urogenitals, and rectum. AP radiographs of the pelvis used to be part of many trauma protocols, but may be unnecessary unless there is a high-risk mechanism of injury, hematuria, or findings such as pain, ecchymosis, or abrasions on pelvic/genital/abdominal examination.² If you desire a lateral view, obtain the cross-table lateral view over the frog-leg view in acute trauma due to risk of further displacement. CT scans are more sensitive than radiographs for detecting pelvic fractures, so omit radiographs whenever abdominopelvicscans are indicated.

Pelvic fractures in children may have good outcomes with conservative, nonsurgical management. Morbidity is closely related to the number and severity of associated multisystem injuries. Focus ED management on stabilization of the associated injuries and controlling any signs of hemorrhage. Obtain emergent orthopedics consult if the fracture is open, unstable, or the hemorrhage is difficult to control. Orthopedists may elect to place an external fixator for temporary stabilization. Younger children with unstable fractures may be admitted for bed rest, but adolescents often require open reduction and internal fixation. Treat stable fractures of the pelvis with protected weight bearing for 4 to 6 weeks.

Avulsion fractures of the pelvis are very common in adolescents and occur at the site of pelvic apophyses where muscle attaches to immature bone. Avulsions frequently occur with adolescents playing sports (Fig. 32-3), and usually involve a sudden, explosive activity. Frequent avulsions and their associated attachments are the iliac crest (tensor fascia), anterior inferior iliac spine (rectus femoris), anterior superior iliac spine (sartorius), and the ischium (hamstrings). Suspect avulsion injuries with appropriate history and point tenderness over specific landmarks such as the iliac crest, iliac spine, or ischium. Avulsion fractures typically heal very well and require only protected weight bearing for 2 to 4 weeks with a gradual progression back to ambulation and activities. It is rare for avulsions to develop nonunion and require surgical fixation.³

Dislocations of the hip are rare events in pediatrics and account for less than 5% of dislocations. Unlike in adults, the forces required for dislocation in young children are less violent because of the increased joint laxity and shallow nonossified acetabulum. The mechanism in younger children may even be trivial falls or sporting injuries, so a high index of suspicion is warranted.⁴ Once the acetabulum deepens and ossifies during adolescence, much stronger forces are required to dislocate the hip. Hip dislocations are described based on where the femoral head lies in relation to the pelvis; more than 90% of the time, hip dislocations are posterior in nature. Fracture-dislocations of the hip involving the proximal femur or acetabulum occur less commonly than in adults.⁵

Most hip dislocations present to the ED in severe discomfort with a shortened leg, flexed hip, and internal rotation. Dislocations that reduce spontaneously before ED presentation are diagnostically challenging, but should always be considered with an acute hip injury. After thoroughly palpating the pulses and assessing neurologic function, begin with imaging (AP radiograph of the pelvis). Review radiographs for asymmetric joint spacing or possible acetabular and femoral neck fractures. Any suspicious findings warrant further radiographs or a CT scan to determine the extent of injury. Closed reduction may be performed in the ED or operating suite using procedural sedation and muscle relaxants. One technique for reducing a posterior dislocation involves flexing the hip and knee to 90° before applying axial traction to the thigh with gentle external rotation. A postreduction MRI of the hip is recommended to look for any intra-articular fractures or fragments along with judging the adequacy of the reduction. If the dislocation cannot be easily reduced or is accompanied by a proximal femur or acetabular fracture, then open reduction and fixation is preferred. Perform reductions within 6 hours of the injury to decrease the risk of avascular necrosis (AVN) and osteoarthritis; delays in reduction make the procedure much more difficult. Spica cast for young children and protected weight bearing for adolescents with close follow-up are recommended.⁶

Proximal femur fractures are very rare in pediatrics and account for less than 1% of fractures around the hip. Proximal femur fractures can occur at the physis, neck, or trochanteric region depending upon the forces involved. These fractures are complicated by a high risk of premature physeal closure or AVN of the femoral head (up to 50%). The risk is greatest with displaced transphyseal fractures, which must be differentiated from slipped capital femoral epiphysis (SCFE) as they are similar in appearance on radiographs (Chapter 109); however, their presentations are distinctly different. Transphyseal fractures present in younger children following a significant trauma, and SCFEs traditionally present subacutely in obese teenagers without a major traumatic event. Obtain orthopedic consultation in the ED for any proximal femur fracture due to the risk of complications and likely need for surgical fixation.⁶

Similar to the pelvis, the proximal femur may also have avulsion fractures of the apophyses where large muscle groups attach to the greater or lesser trochanter. Adolescents during sporting activities may violently contract the iliopsoas, avulsing the lesser trochanter, or contract the hip abductors and avulse the greater trochanter. Like pelvic avulsions, these injuries usually do well with conservative management and progressive weight bearing over 4 weeks. In rare instances, the avulsed fragment may be significantly displaced, requiring open reduction and fixation.

Most pediatric femur fractures involve the femoral shaft. Femoral shaft fractures are classified and managed based upon the patient’s age. The most common site of fracture along the shaft is the middle third, but the proximal (subtrochanteric) and distal third also occur regularly. Unlike adult femur fractures, the pediatric patient rarely experiences hypotension or shock due to an isolated femur fracture. If shock-like symptoms are present, look for an accompanying injury. In adolescents, where high-energy trauma is usually the mechanism, evaluate for injuries to the visceral organs.

If a femur fracture is suspected, splint the leg immediately following any necessary resuscitation, assess the distal pulses, and test the distal nerves. Splinting and pain control are often very helpful before radiographs are taken. Obtain radiographs of the entire femur, along with hip and knee radiographs to look for accompanying dislocations or injuries. Because of the intense amount of pain with femur fractures, patients may not localize pain as well as with other extremity fractures. Closely monitor distal pulses and distal nerve function during observation, and consult orthopedics. Hospital admission for pain control, observation, and definitive management is typical.

The nonambulatory infant with a femur fracture should raise concerns of nonaccidental trauma, although no particular fracture pattern is pathognomonic, spiral, or transverse in nature. Most experts also recommend a skeletal survey as part of the evaluation in infants with a femur fracture. The young patient with a femur fracture has a tremendous ability to remodel and heal well without surgical intervention, so most do well in either a hip spica cast or Pavlik harness.

Older toddlers and preschool children increasingly suffer femur fractures from automobile versus pedestrian accidents, but they may also sustain femur fractures from falls during normal childhood activity.⁷ If high-energy forces are involved, look for any concomitant, life-threatening injuries. Once stabilized in the ED, management is usually closed reduction with spica casting. Surgical fixation is rarely necessary in this age group. Recent studies also suggest a single-leg hip spica cast may offer benefits over double-leg spica casts without differences in outcomes.⁸

School-aged children and adolescents typically present with femur fractures following high-energy trauma such as automobile accidents. The larger, stronger muscle groups in these patients and decreased remodeling increase the risk for limb shortening and malunion after reduction, so these injuries are now managed with surgical placement of either an intramedullary rod or flexible “Nancy” nail. Historically, this older age group was managed with weeks of prolonged traction, but most are now managed surgically soon after the time of injury.⁹