Management of Pediatric Femoral Neck Fracture

Joseph T. Patterson, MD; Jennifer Tangtiphaiboontana, MD; Nirav K. Pandya, MD

Disclosures

J Am Acad Orthop Surg. 2018;26(12):411-419. 

In This Article

Management of Traumatic Injury

The American Academy of Orthopaedic Surgeons (AAOS) has not published Appropriate Use Criteria for the management of pediatric femoral neck fractures. The AAOS has published clinical practice guidelines for management of pediatric diaphyseal femoral fractures,[23] but these guidelines are not drawn from literature applicable to femoral neck fractures.

Timing of Fixation

Although early reduction of adult hip fractures improves outcomes, the effect of early versus late fracture reduction on outcomes in children remains unclear. A systematic review of 30 studies comprising 935 patients reported that the rate of osteonecrosis was 4.2 times higher in patients who had delayed treatment compared with those who underwent treatment within 24 hours of injury.[7] When fixation was delayed at least 24 hours after injury, a high incidence of complications occurred, with 64% of patients showing premature physeal arrest and 55% with osteonecrosis.[24] However, recent studies have demonstrated that shorter time to reduction (≤12 hours) did not reduce the rate of osteonecrosis in children with femoral neck fractures and may in fact be a positive predictor of osteonecrosis.[16,25] Although limited and contradicting evidence exists in the literature with regard to the timing of fixation, Spence et al[16] and Gopinathan et al[17] believe that anatomic reduction of a hip fracture should occur as soon as possible.

Closed Versus Open Reduction

Selection of closed versus open reduction depends on the amount of fracture displacement present and the surgeon's ability to achieve anatomic or near-anatomic reduction in a closed fashion. Patients are placed supine on either a radiolucent operating table or fracture table and reduction is assessed with intraoperative fluoroscopy. When closed reduction is performed with the patient on a fracture table, the hip is hyperextended with abduction and internal rotation, and slight knee flexion is maintained. Gentle longitudinal traction is applied and the hip is placed in a spica cast or percutaneous fixation is placed. We advocate for the use of open reduction when an anatomic reduction cannot be achieved.

Open reduction and internal fixation (ORIF) typically is used for severely displaced fractures or in patients in whom anatomic reduction cannot be achieved with closed reduction. In addition, when a fracture has occurred through a suspected pathologic lesion, open reduction may be necessary to confirm the lesion diagnosis and manage associated pathology (Figure 4). Evidence regarding the benefit of open reduction in reducing complications such as osteonecrosis is inconclusive. Several studies have shown that completely displaced femoral neck fractures treated with ORIF had a better reduction, higher rate of union, and fewer complications (eg, osteonecrosis) when compared with displaced femoral neck fractures treated with closed reduction with fixation.[26,27] However, other studies have shown that open reduction has been associated with higher rates of osteonecrosis.[7,28] Authors of these studies advise caution when interpreting these results because fractures that require open reduction may be substantially displaced and therefore may inherently have a high risk for osteonecrosis as a result of the injury itself.

Fractures that require ORIF may be accessed through an anterior (ie, Smith-Peterson), anterolateral (ie, Watson-Jones), or lateral (ie, Hardinge) approach to the hip. The anterior approach affords excellent visualization of the hip joint but a separate incision may be required to place fixation. Anatomic fracture reduction with stable fixation is the goal of treatment.

Aspiration and Capsulotomy

The role of capsular decompression after reduction and fixation of hip fractures has been limited to case series and systematic reviews. One case series reported a lower incidence of osteonecrosis in children who had hip capsular decompression than in those treated without capsular decompression.[27] Methods used to achieve capsular decompression include aspiration of a capsular hematoma with a large-bore needle or anterior hip approach and open capsulotomy through a small anterior incision. These procedures are relatively straightforward to perform and may theoretically decrease the risk of osteonecrosis; however, the available data fail to show a statistically significant difference in reducing the occurrence of osteonecrosis.[7,16,29]

Fixation Based on Fracture Type

The achievement of fracture stability with fixation must be weighed against the risk of potential physeal injury and premature closure. Transphyseal screws are ideally placed no less than 5 mm from the subchondral bone of the femoral head. Care must to taken to avoid posterior perforation or screw placement in the anterolateral quadrant of the epiphysis to reduce the risk of iatrogenic injury to the blood vessels. Physeal-sparing fixation methods include transphyseal fixation with smooth wires or placement of screws that do not cross the physis. Although we prefer to avoid placing screws across the physis in patients aged <10 years, both the Delbet fracture type and the skeletal maturity or age of the patient must be considered when choosing the appropriate method of fracture fixation. Stable fracture fixation should not be compromised to spare the physis.

Delbet Type I. Closed reduction may be used to manage minimally displaced type I fractures, with a spica cast applied postoperatively for immobilization in children aged <2 years. Fractures in patients aged 2 to 9 years should be stabilized with two smooth pins and immobilized with a spica cast postoperatively. Transphyseal fixation is recommended for fracture management in patients aged ≥10 years. ORIF is required to manage fractures with a dislocated epiphysis using a direct anterior, posterior, or surgical dislocation approach depending on the direction of the dislocation, location of the epiphysis, and surgeon experience (Figure 7).

Delbet Types II and III. Type II and type III fractures are the most common type of pediatric femoral neck fracture and are often displaced. Nondisplaced fractures in young children (aged <6 years) may be treated with closed reduction and spica cast immobilization. Supplemental fixation can be used in patients aged ≥2 years to prevent displacement within the cast. Because of the risk of nonunion and femoral head-neck offset from malunion, acceptable reduction in type II fractures consists of <5° of angulation and <2 mm of cortical translation. Acceptable reduction in type III fractures consists of <10° of angulation, with varus malalignment being most common. Displaced fractures that cannot be managed with closed reduction should be managed with ORIF using smooth Kirschner wires in patients aged <4 years, physeal-sparing cannulated screws in those aged 4 to 9 years, or transphyseal cannulated screws in those aged ≥10 years. Transphyseal screw fixation is recommended for fractures with a small metaphyseal fracture fragment resulting from insufficient fixation stability. Patients with an unstable fracture pattern may require alternative methods of fixation (ie, proximal femoral plates) because of the high rate of failure with screw fixation alone and the risk of posttraumatic coxa vara.[30]

Delbet Type IV. Nondisplaced or minimally displaced type IV fractures in patients aged <6 years may be managed with closed reduction and immobilization in a spica cast when <10° of angulation is obtained and maintained in the cast. Supplemental fixation can be used in patients aged ≥2 years to prevent displacement within the cast. Patients aged >6 years should undergo surgical stabilization with a pediatric sliding hip screw, blade plate, or proximal femoral locking plate. A physeal sparing screw should be considered in younger patients aged <10 years. A transphyseal hip screw should be used in adolescent patients for increased stability. An additional guidewire or screw should be placed before placement of the hip screw to prevent fracture displacement or rotation. Hip screws also should be predrilled and tapped because of the hard, dense bone in otherwise healthy children.

Postoperative Management

Patients are followed closely postoperatively, with radiographs obtained to assess for interval fracture displacement or implant failure. The need for additional spica cast immobilization after surgical stabilization depends on the fracture type, patient age, quality of the fixation, and compliance with postoperative weight-bearing and activity restrictions. Patients with stable fracture patterns who are treated with transphyseal fixation do not require spica casting and may ambulate with crutches and toe-touch weight bearing. Fracture immobilization or weight-bearing precautions continue for 6 to 8 weeks or until fracture union is achieved. Adolescents may benefit from formal physical therapy after fracture healing to assist with gait training and strengthening.

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