Matthew R. Garner and John M. Flynn
DEFINITION
Femoral shaft fractures in children occur with an incidence of 20 per 100,000.2,5,10 They constitute 2% of all pediatric fractures.1,7
In the very young child who presents with a femoral shaft fracture, child abuse must be considered, especially if the child is not yet walking.
In the child who has a history of multiple fractures, osteogenesis imperfecta might be the underlying cause and is often mistaken for child abuse in the young child.
In children who sustain multiple traumatic injuries, the nature and severity of each injury must be considered to optimize treatment.
ANATOMY
The limb bud develops at about 4 weeks age of gestation, the femoral shaft serving as the primary ossification center. The proximal ossification center is seen by 6 months and the distal femoral ossification center appears at 7 months.
The femur is initially composed of weaker woven bone, which is gradually replaced with lamellar bone during childhood.
Both the endosteal circulation and the periosteal circulation supply the femur. The profunda femoris artery gives rise to four perforating arteries, which enter the femur posteromedially. The majority of the blood is supplied by the endosteal circulation. During fracture healing, however, the majority of the blood is supplied by the periosteal circulation.
The femoral shaft flares distally, forming the supracondylar area of the femur.
PATHOGENESIS
Age is an important factor to consider in terms of the pathogenesis of the injury. The degree of trauma required to cause injury increases exponentially as the character of the bone changes and gradually becomes stronger and larger from infancy to adolescence. Low-energy injuries resulting in fractures may point to a pathologic nature of the condition, except in toddlers, in whom low-energy femur fractures are common.
The radiographic appearance of the fracture usually reflects the mechanism of injury and the force applied. Highvelocity injuries usually present with more complex, comminuted patterns.
The position of the fracture fragments after the injury depends on the level of the fracture and reflects the soft tissue and muscle forces acting on the femur.
PATIENT HISTORY AND PHYSICAL FINDINGS
In most cases, there is a history of a traumatic event.
The clinician inspects the lower extremity and looks for open wounds, bruising, or obvious deformity.
In the setting of an isolated femur fracture, the thigh appears swollen with minor bruises and abrasions. Shortening may also be present.
Open wounds may change the management of this injury; obvious deformity helps in the initial diagnosis.
The clinician palpates the length of the lower extremity, feeling for bony deformity and checking compartments carefully for tension. Tense compartments may indicate current or developing compartment syndrome.
The affected extremity should be checked to ensure that there is no vascular or neurologic injury.
The clinicians should check carefully for femoral, popliteal, dorsalis pedis, and posterior tibial pulses. Diminished pulses may indicate vascular compromise or compartment syndrome. If diminished, they should be rechecked with Doppler.
Sensation to light touch is tested along the length of the entire lower extremity. Decreased sensation in the lower extremity may indicate nerve damage.
Motor examination may be difficult because of injury. Ankle dorsiflexion and plantarflexion are tested. Diminished strength may indicate nerve damage or compartment syndrome or may also be secondary to pain.
Examining reflexes may also be difficult. The clinician strikes the patellar and Achilles tendons with a reflex hammer and looks for contraction of the quadriceps and gastrocnemius, respectively. Diminished knee or ankle reflexes may indicate femoral or sciatic nerve injury or may also be secondary to guarding.
In cases of high-energy trauma, concomitant injuries to the skin and soft tissue as well as other organ systems are usually present.
The knee is examined to ensure that no ligamentous injury is present. This examination may be performed under anesthesia.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Standard high-quality anteroposterior (AP) and lateral radiographs of the femur are usually all that is needed to define the extent and severity of the injury (FIG 1).
Radiographs should include the joints above and below the fracture site to avoid missing any concomitant injuries.
Rarely, a CT scan may be helpful in assessing more complex injury patterns. It also helps in revealing subtle injuries that may not be apparent on radiographs, such as stress fractures, and aids in characterizing intra-articular injuries.
DIFFERENTIAL DIAGNOSIS
Soft tissue trauma
Stress fracture
Tumor
Metabolic conditions
FIG 1 • AP and lateral radiographs of an oblique diaphyseal femur fracture in a child 4 years and 2 months of age.
NONOPERATIVE MANAGEMENT
Management of femoral shaft fractures depends on the age of the patient.
In infants, stable femoral shaft fractures can be treated in a Pavlik harness or a splint.
In children younger than 6 years, closed reduction and casting is used in the vast majority of cases.
Immediate spica casting in the emergency department without the use of general anesthesia has been shown to be effective, provided there are no other indications for hospital admission.3
SURGICAL MANAGEMENT
In children younger than 6 years, closed reduction and casting is successful for most femoral shaft fractures.
For older children and adolescents, 3 weeks of skeletal traction followed by spica casting was once common but has been replaced by internal or external fixation in most cases.
Preoperative Planning
A detailed review of the clinical findings and all appropriate imaging studies is performed before the procedure.
Shortening should be determined to be less than 2 cm using a lateral radiograph, although some suggest spica casting can be accomplished regardless of shortening.6
If the mechanism of injury is considered low energy, a singleleg “walking spica” can be considered, as it has been shown to be as effective as traditional spica casting and may also decrease the burden of care on the family.4
The presence of concomitant injuries should be considered as well as factors that may hinder or complicate treatment.
Positioning
The child is taken to the operating room or sedation unit and placed in the supine position on the table.
The injured extremity is casted first, and then the patient is transferred to a spica table.
TECHNIQUES
TRADITIONAL SPICA CASTING
A long-leg cast is placed with the knee and ankle flexed at 90 degrees (TECH FIG 1A). Because of recent reports of compartment syndrome of the leg after spica casting for pediatric femur fractures,8,9many centers (ours included) have been using less hip and knee flexion and not including the foot for the cast of the injured leg.
Extra padding in the popliteal fossa is applied. To avoid vascular compromise, care must be taken not to flex the knee once the padding is in place.
A valgus mold at the fracture site is used to prevent varus deformity (TECH FIG 1B).
The patient is transferred to a spica table, where the weight of the legs is supported with manual traction.
The hip is placed at 90 degrees of flexion and 30 degrees of abduction. Fifteen degrees of external rotation at the hip is used to allow alignment of the proximal and distal fragments (TECH FIG 1C,D).
The remainder of the spica cast is placed while holding the fracture out to length.
Care should be taken to avoid excessive traction, which increases the risk of compartment syndrome and skin sloughing.
New AP and lateral radiographs are taken to ensure acceptable anatomic alignment.
Gore-Tex liners are used at some institutions to prevent diaper rash and superficial infections.
TECH FIG 1 • A. Cylinder cast with 90 degrees of knee flexion for traditional spica casting. B. Valgus molding technique to prevent varus deformity in early postcasting period. (continued)
TECH FIG 1 • (continued) C,D. Traditional spica casting with 90 degrees of hip flexion, 30 degrees of abduction, and 15 degrees of external rotation.
WALKING SPICA CASTING
A walking spica is becoming a popular choice for lowenergy femur fractures.
The cylinder cast should be applied with about 50 degrees of knee flexion.
The foot remains uncovered with the cast stopping in the supramalleolar area, which is protected with extra padding.
Before the remainder of the cast is applied, the hip is flexed to 45 degrees and remains abducted to 30 degrees with 15 degrees of external rotation (TECH FIG 2A,B).
The pelvic band is applied with multiple layers of stockinette folded on the abdomen to prevent abdominal compression from the casting. These folded layers of stockinette are removed after the pelvic band is placed (TECH FIG 2C).
It is important to reinforce the cast on the injured side anteriorly at the hip. Seven or eight layers of folded fiberglass are placed in the inter-hip crease to decrease the risk of the cast breaking, while a wide pelvic band is needed to immobilize the hip as well as possible.
TECH FIG 2 • A. Cylinder cast with 50 degrees of knee flexion and 45 degrees of hip flexion for walking spica cast. B. Walking spica casting position with 30 degrees of abduction and 15 degrees of external rotation. C.Wide pelvic band and anterior reinforcement for additional support in a final walking spica cast.
POSTOPERATIVE CARE
A significant burden of care is placed on the family of a child with a spica cast, including cast care, travel difficulties, and loss of time at work.
We counsel the family, immediately after reduction in casting, that wedging of the cast may be necessary at about 10 to 14 days after injury.
We schedule the family to return 1 week and 2 weeks after injury; at that time true AP and lateral radiographs are obtained of the injured femur in the cast. If there is unsatisfactory alignment or either angulation or shortening, we will wedge the cast at the clinic and repeat radiographs. This frequently avoids unnecessary trips back to the operating room in the postoperative period for loss of reduction.
Prior to callus formation, if shortening of more than 2 cm occurs, one of three options may be required: cast change, traction, or external fixation.
Shortening of more than 2 cm once callus has formed may be treated with osteoclasis and lengthening techniques at a pace of 1 mm per day.
At union, acceptable angulation and shortening varies by age (Table 1).
OUTCOMES
Typically the spica cast is worn for 4 to 8 weeks, depending on the extent of the injury.
Infant fractures heal in 3 to 4 weeks.
Toddler fractures heal in 6 weeks.
On removal of the cast, children are encouraged to stand up and walk as soon as they are comfortable.
Illgen and colleagues6 found that standard spica casting was successful (without cast change or wedging) about 86% of the time.
Immediate spica casting in the emergency department under conscious sedation and discharge has been shown to have similar rates of complication and re-reduction as “early” spica casting.3
Single-leg “walking spica” casts have been shown to be a safe and effective way to manage low-energy isolated femoral shaft fractures.4
COMPLICATIONS
Nonunion
Delayed union
Malunion (angular and rotational deformity)
Leg-length discrepancy (shortening and overgrowth)
Compartment syndrome
Neurovascular injury
REFERENCES
1. Beaty JH. Femoral-shaft fractures in children and adolescents. J Am Acad Orthop Surg 1995;3:207–217.
2. Bridgman S, Wilson R. Epidemiology of femoral fractures in children in the West Midlands region of England 1991 to 2001. J Bone Joint Surg Br 2004;86B:1152–1157.
3. Cassinelli EH, Young B, Vogt M, et al. Spica cast application in the emergency room for select pediatric femur fractures. J Orthop Trauma 2005;19:709–716.
4. Epps HR, Molenaar E, O'Connor DP. Immediate single-leg spica cast for pediatric femoral diaphysis fractures. J Pediatr Orthop 2006;26: 491–496.
5. Hinton RY, Lincoln A, Crockett MM, et al. Fractures of the femoral shaft in children: incidence, mechanisms, and sociodemographic risk factors. J Bone Joint Surg Am 1999;81A:500–509.
6. Illgen R II, Rodgers WB, Hresko MT, et al. Femur fractures in children: treatment with early sitting spica casting. J Pediatr Orthop 1998;18: 481–487.
7. Landin LA. Epidemiology of children's fractures. J Pediatr Orthop 1997;6:79–83.
8. Large TM, Frick SL. Compartment syndrome of the leg after treatment of a femoral fracture with an early sitting spica cast: a report of two cases. J Bone Joint Surg Am 2003;85A:2207–2210.
9. Mubarak SJ, Frick S, Sink E, et al. Volkmann contracture and compartment syndromes after femur fractures in children treated with 90/90 spica casts. J Pediatr Orthop 2006;26:567–572.
10. Rewers A, Hedegaard H, Lezotte D, et al. Childhood femur fractures, associated injuries, and sociodemographic risk factors: a populationbased study. Pediatrics 2005;115:e543–552.