Regardless of how the fracture is classified using the many different classification schemes, the assessment and treatment of pediatric pelvic fractures is dependent on two factors: whether the fracture is stable or unstable. A stable fracture is a single ring injury or multiple fractures with displacement of <1 cm. An unstable injury has an anterior and posterior ring fracture with displacement >1 cm.

Most pelvic fractures in children are stable injuries and have a favorable result with symptomatic treatment and weight-bearing restrictions with close follow-up. Unstable pelvic fractures with minimal displacement (<1 cm), which do not involve the acetabulum, can be managed with weight-bearing restrictions and close radiographic follow-up. There has been a trend toward a more aggressive operative approach in displaced unstable fractures. Historically, a nonoperative approach to unstable fractures has been acceptable due to the belief that the pelvis would remodel and there was minimal long-term morbidity. Recent literature suggests that residual deformity can lead to long-term morbidity of leg-length discrepancy, back pain, pelvic asymmetry, and sacroiliac arthritis (41).

The authors recommend fracture reduction of unstable fractures that are displaced >1 cm. The challenges include determining instability and reduction and stabilization in the pediatric pelvis. Anterior stabilization can be performed with external fixation or symphysis plating (Fig. 34-3). Unstable fractures may require internal fixation of posterior injury, in addition to anterior stabilization with external fixation or other means. Posterior stabilization can be achieved with a combination of
plates and screws through a posterior or an iliac fossa approach. Sacroiliac screws can be used in the immature pelvis as long as the S1 body is large enough. Careful fluoroscopy, surgeon expertise, and CT scanning can facilitate SI screw fixation (Fig. 34-3) (30, 37, 42). Traction and spica casting is an option in the patient where size may limit internal fixation. A multispecialty approach is recommended to improve outcomes. In the urgent situation, all the specialties should work together to stabilize the patient. Temporary pelvic wrapping or anterior external fixation can help the hemodynamic status and assist with patient mobilization.

Watts (40) classified acetabular fractures into four types. This classification has been used to guide
treatment (43). Precise restoration of joint congruity is recommended except for stable posterior fracture dislocations with concentric reductions (Watts type I fractures). Nondisplaced acetabular fractures are managed by closed reduction (Watts type II fractures). Multiple fragments with instability (Watts type III) are best managed by open reduction with stable internal fixation (30, 43). Early motion is also recommended (30). Comminution is often less severe in children than in adults, and the results of surgical management are generally satisfactory. Fractures with central dislocation of the hip have a poor prognosis regardless of surgical or nonsurgical management. Traction may be utilized for these fractures, or surgical management may be attempted when comminution is minimal. Poor results after anatomic reduction may still occur with all types of acetabular fractures due to the magnitude of the initial trauma (44).

Premature closure of the triradiate cartilage is a potential complication that is unique to the immature skeleton (Fig. 34-4) (45). Fractures that cause premature closure are usually nondisplaced and do not require open reduction. Children younger than 10 years are at the greatest risk for this complication. Disturbance in growth leads to the development of a shallow acetabulum because the triradiate cartilage is responsible for growth in the height and width of the acetabulum. Hip subluxation may follow, necessitating redirectional pelvic osteotomy.

Immediate management of pelvic fractures and associated injuries can be challenging, but long-term complications are rarely attributable to the bony structures. Residual morbidity is more often due to associated injuries, especially traumatic brain injury. Untreated, displaced fractures can result in a limp, back pain, rotational deformity, or limb-length discrepancy. Acetabular injuries are at risk for developing traumatic arthritis in spite of anatomic reduction. Premature closure of the triradiate cartilage can be problematic in younger children.

Treatment with closed reduction and casting is appropriate for minimally displaced fractures in children younger than 2 years (73). In children aged 2 to 12 years, stabilization of the reduced fracture may be accomplished with two smooth pins supplemented with spica casting. In older children, fixation across the physis is recommended. Open reduction is often necessary if the epiphysis is dislocated. This is performed through a posterior approach for posterior fracture dislocations. At the time of open reduction, curettage of the physeal plate has been recommended in an attempt to encourage revascularization of the femoral head (74).

If the fracture is stable and nondisplaced, and the patient is younger than 6 years, a spica cast alone can yield good results (80). Displaced fractures can usually be reduced by closed methods, but a capsulotomy may decrease the risk of avascular necrosis (62, 63, 64 and 65). Ng and Cole (64) studied the effect of early hip decompression on the frequency of avascular necrosis. It had no apparent value in type I fractures. For the type II and III fractures, 41% of 54 patients treated without hip decompression developed avascular necrosis, whereas only 8% of 39 patients with hip compression developed avascular necrosis. As previously discussed, a prompt anatomic reduction, internal fixation, and decompression are recommended by the present authors in an attempt to restore circulation in a timely manner. Fixation is achieved by the percutaneous insertion of two or three cannulated bone screws into the metaphyseal portion of the proximal fragment. If the proximal metaphyseal fragment is too small for secure fixation, smooth pins can be placed across the physis to allow subsequent growth. Stable fixation of the fracture should be given priority over preservation of the proximal femoral physis (71). Spica cast immobilization is used to augment fixation in children, especially when smooth pins have been used. In patients aged 12 years or older, threaded screws may be placed across the physis for better fixation and to avoid the use of a spica cast. Alternatively, a hip screw with a supplemental pin to control rotation may be used in older children. Caution is advised when using compression hip screws in children because dense bone may generate heat necrosis of the femoral neck during reaming. An additional smooth pin is recommended to improve rotational stability. The authors recommend an open reduction if suitable alignment is not obtained by closed means. The quality of reduction is associated with outcomes (79). An anterolateral (Watson-Jones) approach is recommended for type II fractures (Fig. 34-9).

This fracture does not require prompt stabilization except when surgical fixation improves general management. Nondisplaced fractures in this region can be managed by spica cast immobilization and close follow-up in younger children. Displaced fractures in infants and toddlers may be treated with early closed reduction and casting so long as the neck-shaft angle does not decrease to <115 degrees. Displaced fractures in older children can also be managed by skeletal traction followed by cast immobilization. However, the authors recommend surgical stabilization in children older than 6 years to reduce the risk of malunion and avoid prolonged immobilization. Interfragmentary screws may provide sufficient stability when combined with cast immobilization, but a pediatric-sized hip screw with side plate, or an angled blade plate, is preferred (Fig. 34-10). Adolescents are treated in the same manner as adults, with stable fixation across the physis using a sliding hip screw or an angled blade plate. This avoids the need for a supplemental spica cast for adolescent patients.

A wide variety of management options are currently available for femur fractures in children and adolescents. Each of these options can yield satisfactory results when used properly (93). The surgeon managing femoral fractures in children and adolescents is expected to select and perform the technique that is most appropriate under a variety of circumstances. As long as proper technique is used, there may be more than one acceptable option for treatment.

The age of the child and the fracture characteristics are the principal determinants of management. At one end of the spectrum, there are low-energy injuries in young children that are managed with closed reduction and immediate spica casting. At the other end of the spectrum, high-energy injuries in adolescents are managed with early surgical stabilization. Occasionally, however, infants with severe trauma require surgical stabilization of femoral fractures to facilitate management.

Proximal fractures in all age groups are more difficult to control, but residual deformity is better tolerated because of multidirectional hip motion. Deformity is also less obvious with proximal fractures because thick thigh muscles hide residual angulation. Proximal fragments tend to flex, abduct, and externally rotate because of the unopposed action of the iliopsoas, hip abductor, and external rotator muscles. The proximal fragment of a midshaft fracture also tends to flex, abduct, and externally rotate, but the deformity is less extreme because of adductor and hamstring attachments to the proximal fragment. More distal fragments are easier to control and produce little proximal fragment angulation, except for supracondylar fractures, which tend to hyperextend because of the posterior pull of the gastrocnemius muscle on the short distal fragment. Fractures of the distal femur require more precise alignment because the deformity is more visible and remodeling in the coronal plane is limited. Supracondylar fractures of the femur require management that is similar to that for distal femoral physeal separations (94).

Children have remarkable remodeling potential until approximately 10 years of age in girls and 12 years of age in boys. Long-term studies have demonstrated that up to 25 degrees of midshaft angulation in any plane can be expected to correct satisfactorily in children younger than 13 years (95). Remodeling continues for up to 5 years following fracture. Approximately 25% of remodeling occurs at the fracture site, whereas 75% is attributed to physeal reorientation and longitudinal growth (96, 97). Fracture translation may also contribute to realignment of the mechanical axis. Rotational remodeling may also occur, but the precise amount is unpredictable (98, 99). Clinically significant rotational deformity is uncommon, even when failure of remodeling has been documented (100, 101).

Stimulation of growth after femoral fracture occurs routinely in the 2- to 9-year age group (102, 103). Unfortunately, most authors reporting the overgrowth phenomenon do not distinguish between “catch-up growth,” which compensates for fracture overriding; and true overgrowth, which results in the fractured femur being longer than normal. Growth stimulation is greater when overriding is greater and may continue for 5 years after fracture. Average total growth stimulation is approximately 1 cm. In a prospective study of children younger than 12 years, Hougaard observed that all fractures of the femur healing with 3 cm or less discrepancy with the contralateral leg spontaneously recovered to <2 cm discrepancy (103). Therefore, any femoral fracture that heals in a shortened position should be observed for several years to determine the final outcome. True overgrowth has been reported after reduction with internal fixation, but the risk of overgrowth in this circumstance has not been clearly defined (93).

Age or weight is the first determinant of treatment choices. Age is used here with the understanding that the children are of average weight and maturity.