FIGURE 27-1 The shaded area represents cortical thickness by age-group. This rapid increase in cortical thickness may contribute to the diminishing incidence of femoral fractures during late childhood. (Redrawn from Netter FH. The Ciba collection of medical illustrations. Musculoskeletal System. I. Anatomy, Physiology, and Metabolic Disorders. Vol 8. Summit, NJ: Ciba-Geigy; 1987, with permission.)

MECHANISM OF INJURY OF FEMORAL SHAFT FRACTURES

The etiology of femoral fractures in children varies with the age of the child. Before walking age, up to 80% of femoral fractures may be caused by abuse.^11,18,69,184 In a study of over 5,000 children at a trauma center, Coffey et al.³⁷ found that abuse was the cause of only 1% of lower extremity fractures in children older than 18 months, but 67% of lower extremity fractures in children younger than 18 months.

Baldwin et al.⁸ found three primary risk factors for abuse in young children presenting with a femur fracture: A history suspicious for abuse, physical or radiographic evidence of prior injury, and age under 18 months. Children with no risk factors had only a 4% chance of being a victim of abuse, whereas children with all three risk factors had a 92% chance that their femur fractures with result of abuse.

Older children are unlikely to have a femoral shaft fracture caused by abuse, because their bone is sufficiently strong to tolerate forceful blows, or is able to resist torque without fracture. In older children, femoral fractures are most likely to be caused by high-energy injuries; motor vehicle accidents account for over 90% of femur fractures in this age group.^42,77,121 Pathologic femur fractures are relatively rare in children, but may occur because of generalized osteopenia in infants or young children with osteogenesis imperfecta. Osteogenesis imperfecta should be considered when a young child, with no history suggestive of abuse or significant trauma, presents with a femoral shaft fracture.¹¹¹ Radiologic evaluation is often insufficient to diagnose osteogenesis imperfecta; skin biopsy, collagen analysis, and bone biopsy may be required to make a definitive diagnosis. Generalized osteopenia also may accompany neurologic diseases, such as cerebral palsy or myelomeningocele, leading to fracture with minor trauma in osteopenic bone.^62,105,111 Pathologic fractures may occur in patients with neoplasms, most often benign lesions such as nonossifying fibroma, aneurysmal bone cyst, unicameral cyst, or eosinophilic granuloma. Although pathologic femur fractures are rare in children, it is essential that the orthopedist and radiologists study the initial injury films closely for the subtle signs of primary lesions predisposing to fracture, particularly in cases of low-energy injury from running or tripping. Radiographic signs of a pathologic fracture may include mixed lytic–blastic areas disrupting trabecular architecture, break in the cortex and periosteal reaction in malignant lesions such as osteosarcoma, or better-defined sclerotic borders with an intact cortex seen in benign lesions such as nonossifying fibroma (Fig. 27-2).

Stress fractures may occur in any location in the femoral shaft.^28,101,137 In this era of high-intensity, year-round youth sports, orthopedists are more commonly encountering adolescents with femoral stress fractures from running, soccer, and basketball.²³ Although uncommon (4% of all stress fractures in children), femoral shaft or femoral neck stress fractures should be considered in a child with thigh pain because an unrecognized stress fracture may progress to a displaced femoral fracture. A high index of suspicion is important, because even nontraditional sports can lead to stress fractures with extreme overuse; a recent report of bilateral femoral stress fractures were reported in a Rollerblade enthusiast.²⁰¹

DIAGNOSIS OF FEMORAL SHAFT FRACTURES

The diagnosis of pediatric femoral shaft fractures is usually not subtle: There is a clear mechanism of injury, a deformity and swelling of the thigh, and obvious localized pain. The diagnosis is more difficult in patients with multiple trauma or head injury and in nonambulatory, severely disabled children. A physical examination usually is sufficient to document the presence of a femur fracture. In patients lacking sensation (myelomeningocele), the swelling and redness caused by a fracture may mimic infection.

In the setting of a femur fracture, a comprehensive physical examination should be performed looking for other sites of injury. Hypotension rarely results from an isolated femoral fracture. Waddell’s triad of femoral fracture, intra-abdominal or intrathoracic injury, and head injury are associated with high-velocity automobile injuries. Multiple trauma may necessitate rapid stabilization of femoral shaft fractures^121,164 to facilitate overall care. This is particularly true with head injury and vascular disruption.

The hemodynamic significance of femoral fracture has been studied by two groups.^35,124 Hematocrit levels below 30% rarely occur without multisystem injury. A declining hematocrit should not be attributed to closed femoral fracture until other sources of blood loss have been eliminated.^35,124

X-RAY FINDINGS OF FEMORAL SHAFT FRACTURES

Radiographic evaluation should include the entire femur, including the hip and knee, because injury of the adjacent joints is common. An anteroposterior (AP) pelvis x-ray is a valuable supplement to standard femoral shaft views, because there may be associated intertrochanteric fractures of the hip, fractures of the femoral neck, or physeal injuries of the proximal femur.^14,30 Distal femoral fractures may be associated with physeal injury about the knee, knee ligament injury, meniscal tears,²⁰⁴ and tibial fractures.¹¹⁶

Plain x-rays generally are sufficient for making the diagnosis. In rare circumstances, bone scanning and magnetic resonance imaging (MRI) may be helpful in the diagnosis of small buckle fractures in limping children or stress fractures in athletes. The orthopedist should carefully evaluate radiographs for comminution or nondisplaced “butterfly” fragments, second fractures, joint dislocations, and pathologic, as these findings can substantially alter the treatment plan.

CLASSIFICATION OF FEMORAL SHAFT FRACTURES

Femoral fractures are classified as (a) transverse, spiral, or short oblique; (b) comminuted or noncomminuted; and (c) open or closed. Open fractures are classified according to Gustilo’s system.⁸¹ The presence or absence of vascular and neurologic injury is documented and is part of the description of the fracture. The most common femoral fracture in children (over 50%) is a simple transverse, closed, noncomminuted injury.

The level of the fracture (Fig. 27-3) leads to characteristic displacement of the fragments based on the attached muscles. With subtrochanteric fractures, the proximal fragment lies in abduction, flexion, and external rotation. The pull of the gastrocnemius on the distal fragment in a supracondylar fracture produces an extension deformity (posterior angulation of the femoral shaft), which may make the femur difficult to align.

TREATMENT OF FEMORAL SHAFT FRACTURES

Treatment of femoral shaft fractures in children depends on two primary considerations: Age (Table 27-1) and fracture pattern. Secondary considerations, especially in operative cases, include the child’s weight, associated injuries, and mechanism of injury. Economic concerns,^{40,59,153,156,195} the family’s ability to care for a child in a spica cast or external fixator, and the advantages and disadvantages of any operative procedure also are important factors. Kocher et al.¹¹⁰ summarized the current evidence for pediatric femur fracture treatment in a clinical practice guideline summary.

Treatment Variation with Age for Femoral Shaft Fractures

Infants

Femoral shaft fractures in infants are usually stable because their periosteum is thick. In fractures occurring in infancy, management should include evaluation for underlying metabolic bone abnormality or abuse. Once these have been ruled out, most infants with a proximal or midshaft femoral fracture are comfortably and successfully treated with simple splinting to provide some stability and comfort, with a Pavlik harness to improve the resting position of the fracture. For the rare unstable fracture, the Pavlik harness may not offer sufficient stabilization. Morris et al.¹⁴⁹ reported a group of eight birth-related femoral fractures in 55,296 live births. Twin pregnancies, breech presentation, and prematurity were associated with birth-related femur fractures. The typical fracture is a spiral fracture of the proximal femur with flexion of the proximal fragment. With thick periosteum, and remarkable remodeling potential, newborns rarely need a manipulative reduction of their fracture, nor rigid external immobilization. For femoral fractures with excessive shortening (>1 to 2 cm) or angulation (>30 degrees), spica casting may be used. Traction rarely is necessary in this age group.

Preschool Children

In children 6 months to 5 years of age, early spica casting (Fig. 27-4) is the treatment of choice for isolated femur fractures with less than 2 cm of initial shortening (Fig. 27-5). In low-energy fractures, the “walking spica” is ideal (Fig. 27-6). Femur fractures with more than 2 cm of initial shortening or marked instability and fractures that cannot be reduced with early spica casting require 3 to 10 days of skin or skeletal traction. Internal or external fixation is rarely needed in children less than 5 years of age. In rare circumstances, external fixation can be used for children with open fractures or multiple trauma. Intramedullary fixation is used in children with metabolic bone disease that predisposes to fracture or after multiple fractures, such as in osteogenesis imperfecta, or following multitrauma. Flexible nailing can be used in the normal-sized preschool child²⁰ but is rarely necessary. Larger children (in whom reduction cannot be maintained with a spica cast) occasionally may benefit from flexible intramedullary nailing, traction, or in rare cases, submuscular plating.

Children 5 to 11 Years of Age

In children 5 to 11 years of age, many different methods can be used successfully, depending on the fracture type, patient characteristics, and surgeon skill and experience.⁶⁰ For the rare, minimally displaced fracture, early spica casting usually produces satisfactory results, although cast wedging or a cast change may be necessary to avoid excessive shortening and angulation. In children with unstable, comminuted fractures, traction may be necessary prior to cast application. Although traction and casting is still a very acceptable and successful method of managing femur fractures in young school-age children, the cost and the social problems related to school-age children in casts have resulted in a strong trend toward fracture fixation. Spica cast management is generally not used for children with multiple trauma, head injury, vascular compromise, floating knee injuries, significant skin problems, or multiple fractures. Flexible intramedullary nails are the predominant treatment for femur fractures in 5- to11-year olds, although submuscular plating and external fixation have their place, especially in length-unstable fractures, or in those difficult to manage fractures in the proximal and distal third of the femoral shaft.

Age 11 to Skeletal Maturity

Trochanteric entry, locked intramedullary nailing is now the primary mode of treatment for femur fractures in the preadolescent and adolescent age groups. Several studies designed to refine the indications for flexible intramedullary nailing have concluded that although most results are excellent or satisfactory in children older than 11, complications rise significantly when this popular technique is used for bigger and older children. In an international multicenter, retrospective study, Moroz et al.¹⁴⁸ found a statistically significant relationship between age and outcome, with children older than 11 years or heavier than 49 kg faring worse. Sink et al.¹⁸⁷ found a much higher rate of complications in length-unstable fractures. Fortunately, surgeons can now select from several different trochanteric entry nails that allow a relatively safe, lateral entry point, with the stability of proximal and distal locking. With this new information and technology, locked intramedullary nailing is used commonly for obese children of ages 10 to 12, and most femoral shaft fractures in children of ages 13 to skeletal maturity.

Treatment Variation with Fracture Pattern for Femoral Shaft Fractures

In addition to age, the treating surgeon should consider fracture pattern, especially when choosing implant. Elastic nailing is ideal for the vast majority of length-stable midshaft femur fractures in children between the ages of 5 and 11 years old. For length-unstable fractures, the risk of shortening and malunion increases substantially when elastic nailing is used.¹⁸⁶ Length-unstable fractures are best treated with locked trochanteric entry nailing in older children, external fixation in younger children, or submuscular plating in either of these age cohorts.

TREATMENT OPTIONS FOR FEMORAL SHAFT FRACTURES

Pavlik Harness for Femoral Shaft Fractures

Stannard et al.¹⁹⁴ popularized the use of the Pavlik harness for femur fractures in infants. This treatment is ideal for a proximal or midshaft femoral fracture that occurs as a birth-related injury. Reduction can be aided by a loosely wrapping cotton cast padding around the thigh if greater stability is needed. In a newborn infant in whom a femur fracture is noted in the intensive care unit or nursery, the femur is immobilized with simple padding or a soft splint. For a stable fracture, this approach may be sufficient and will allow intravenous access to the feet if needed. The Pavlik harness can be applied with the hip in moderate flexion and abduction. This often helps align the distal fragment with the proximal fragment (Fig. 27-7). Evaluation of angulation in the coronal plane (varus–valgus) is difficult because of hyperflexion. Stannard et al.¹⁹⁴ reported acceptable alignment in all patients with less than 1 cm of shortening. Morris et al.¹⁴⁹ showed that all treatments, including traction, spica cast, and Pavlik harness, are effective and resulted in satisfactory outcome in all patients regardless of treatment.

Podeszwa et al.¹⁶² reported infants treated with a Pavlik had higher pain scores when compared to a immediate spica cast; however, none of the Pavlik patients had skin problems but one-third of the spica patients did.

Spica Cast Treatment for Femoral Shaft Fractures

Spica casting^97,192 is usually the best treatment option for isolated femoral shaft fractures in children under 6 years of age, unless there is (a) shortening of more than 2 cm, (b) massive swelling of the thigh, or (c) an associated injury that precludes cast treatment. Several centers have adopted spica application in the emergency department as their standard treatment for infants and toddlers. Mansour et al.¹²⁸ compared spica cast placement in the emergency department versus the operating room, and concluded that the outcome and complications were similar, but the children treated in the operating room had longer hospital stays and significantly higher hospital charges. Cassinelli et al.³³ treated 145 femur fractures, all in children younger than age 7, with immediate spica cast application in the emergency department. All children younger than 2 years of age, and 86.5% of children of ages 2 to 5 years old, met acceptable alignment parameters on final radiographs. Rereduction in the operating room was needed in 11 patients. The investigators concluded that initial shortening was the only independent risk factor associated with lost reduction.

The advantages of a spica cast include low cost, excellent safety profile, and a very high rate of good results, with acceptable leg length equality, healing time, and motion.^54,96 Hughes et al.⁹⁰ evaluated 23 children ranging in age from 2 to 10 years who had femur fractures treated with early spica casting to determine the impact of treatment on the patients and their families. The greatest problems encountered by the family in caring for a child in a spica cast were transportation, cast intolerance by the child, and hygiene. In a similar study, Kocher¹⁰⁹ used a validated questionnaire for assessing the impact of medical conditions on families demonstrated that for family, having a child in a spica cast is similar to having a child on renal dialysis. They found that the impact was greatest for children older than 5 years, and when both parents are working. Such data should inform the decisions of orthopedic surgeons and families who are trying to choose among the many options for young school-age children.

Illgen et al.,⁹⁵ in a series of 114 isolated femoral fractures in children under 6 years of age, found that 90-degree/90-degree spica casting was successful in 86% without cast change or wedging, based on tolerance of shortening less than 1.5 cm and angulation less than 10 degrees. Similar excellent results have been reported by Czertak and Hennrikus⁴¹ using the 90/90 spica cast.

Thompson et al.¹⁹⁷ described the telescope test in which patients were examined with fluoroscopy at the time of reduction and casting. If more than 3 cm of shortening could be demonstrated with gentle axial compression, traction was used rather than immediate spica casting. By using the telescope test, these researchers decreased unacceptable results (>2.5 cm of shortening) from 18% to 5%. Shortening is acceptable, but should not exceed 2 cm. This is best measured on a lateral x-ray taken through the cast. If follow-up x-rays reveal significant varus (>10 degrees) or anterior angulation (>30 degrees), the cast may be wedged. However, Weiss et al.²¹¹ noted that wedging of 90/90 spica casts can cause peroneal nerve palsy, especially during correction of valgus angulation (a problem that rarely occurs). For unacceptable position, the fracture can be manipulated and a new cast applied, or the cast can be removed and the patient placed in traction to regain or maintain length. Angular deformity of up to 15 degrees in the coronal plane and up to 30 degrees in the sagittal plane may be acceptable, depending on the patient’s age (Table 27-2). Finally, if shortening exceeds 2 cm, traction or an external fixator can be used (Fig. 27-8).

The position of the hips and knees in the spica cast is controversial. Some centers prefer a spica cast with the hip and knee flexed 90 degrees each. Studies have shown that the results from the sitting spica cast are good.^133,143 The child is placed in a sitting position with the legs abducted about 30 degrees on either side. The synthetic material used for the cast gives it sufficient strength so that no bar is required between the legs. This not only allows the child to be carried on the parent’s hip but also aids in toiletry needs, making bedpans unnecessary. Also, a child who can sit upright during the day can attend school in a wheelchair. More recently, with reports about compartment syndrome of the leg after using the 90/90 spica cast, several centers have moved to a cast in which the hip and knee are more extended (about 45 degrees each) and the bottom of the foot cut out to prevent excessive shortening.¹³⁴ Varying the amounts of hip and knee flexion in the spica cast based on the position of the fracture also has been recommended: The more proximal the fracture, the more the hip should be flexed.¹⁹²

Recently, there has been a resurgence of interest in the “walking spica cast” (Fig. 27-6). Epps et al.⁵¹ reported on immediate single leg spica cast for pediatric femoral diaphyseal fracture. In a series of 45 children, 90% of the children pulled to stand and 62% of the children walked independently by the end of treatment. Fifty percent of patients were able to return to school or day care while in the cast. Only two children had unacceptable shortening, and two required repeat reduction. Flynn et al.⁵⁷ performed a prospective study of low-energy femoral shaft fractures in young children, comparing a walking spica cast to a traditional spica cast. Although the outcome with the two treatment method was similar, the walking spica cast resulted in substantially lower burden of care for the family. Children with a walking spica are more likely to have their cast wedged in clinic to correct early loss of reduction. Practitioners of the single leg, or walking spica, have learned to use the technique only on toddlers with very stable, low-energy fractures. The cast must be extensively reinforced at the hip. With the hip and knee much more extended, the single leg spica not only improves function and ease of care, but also avoids a technique that has been associated with compartment syndrome in several children (see below).^113,151 Increasingly, the walking spica is considered the best treatment for low-energy femur fractures in toddlers.^57,117

Spica Cast Application: Technique

The cast is applied in the operating room or, in some centers, the sedation unit or Emergency Department.¹²⁸ For the sitting spica cast technique, a long leg cast is placed with the knee and ankle flexed at 90 degrees (Fig. 27-9B). Knee flexion greater than 60 degrees improved maintenance of length and reduction.⁹⁵ However, if one applies excessive traction to maintain length (Fig. 27-10), the risk of compartment syndrome is unacceptably high. Less traction, less knee flexion, and accepting slightly more shortening is a reasonable compromise. Extra padding, or a felt pad, is placed in the area of the popliteal fossa. The knee should not be flexed after the padding is placed because the lump of material in the popliteal fossa may create vascular obstruction (Fig. 27-9A). Because most diaphyseal fractures lose reduction into varus angulation while in a spica cast, a valgus mold at the fracture site is recommended (Fig. 27-9C). The patient is then placed on a spica table, supporting the weight of the legs with manual traction, and the remainder of the cast is applied with the hips in 90 degrees of flexion and 30 degrees of abduction, holding the fracture out to length (Fig. 27-9D). It is mandatory to avoid excessive traction because compartment syndromes and skin sloughs have been reported. The leg should be placed in 15 degrees of external rotation to align the distal fragment with the external rotation of the proximal fragment. After the spica cast is in place, AP and lateral x-rays are obtained to ensure that length and angular and rotational alignment are maintained. We observe all patients for 24 hours after spica application to be sure that the child is not at risk for neurovascular compromise or compartment syndrome. Gore-Tex liners can be used to decrease the skin problems of diaper rash and superficial infection. Several centers have found that this has been beneficial, justifying the cost of a Gore-Tex liner.

For the single leg spica or “walking spica” technique, the long leg cast is applied with approximately 45 degrees of knee flexion, and when the remaining cast is placed, the hip is flexed 45 degrees and externally rotated 15 degrees. The hip should be reinforced anteriorly with multiple layers of extra fiberglass. The pelvic band should be fairly wide so that the hip is controlled as well as possible. A substantial valgus mold is important to prevent varus malangulation. We leave the foot out, stopping the distal end of the cast in the supramalleolar area, which is protected with plenty of extra padding. Seven to 10 days after injury, the child returns to clinic anticipating the need for cast wedging, if radiographs show the very common mild increase in shortening and varus angulation. Most toddlers pull to a stand and begin walking in their walking cast about 2 to 3 weeks after injury.

If excessive angulation occurs, the cast should be changed, with manipulation in the operating room. Casts can be wedged for less than 15 degrees of angulation. If shortening of more than 2 cm is documented, the child should be treated with cast change, traction, or conversion to external fixation, using lengthening techniques if the shortening is not detected until the fracture callus has developed. When conversion to external fixation is required, we recommend osteoclasis (either closed or open if needed) at the time of the application of the external fixator, with slow lengthening over a period of several weeks (1 mm per day) to reestablish acceptable length (Fig. 27-8).

Generally, the spica cast is worn for 4 to 8 weeks, depending on the age of the child and the severity of the soft tissue damage accompanying the fracture. Typically, an infant’s femoral shaft fracture will heal in 3 to 4 weeks; and a toddler’s fracture will heal in 6 weeks. After the cast is been removed, parents are encouraged to allow their children to stand and walk whenever the child is comfortable; most children will need to be carried or pushed in a stroller for a few days until hip and knee stiffness gradually results. Most joint stiffness resolves spontaneously in children after a few weeks. It is unusual to need formal physical therapy. In fact, aggressive joint range-of-motion exercises with the therapist immediately after cast removal make children anxious, and may prolong rather than hasten recovery. A few follow-up visits are recommended in the first year after femur fracture, analyzing gait, joint range of motion, and leg lengths.

Traction and Casting

Since as early as the 18th century, traction has been used for management of femur fractures. Vertical overhead traction with the hip flexed 90 degrees and the knee straight was introduced by Bryant in 1873,^25,38 but this often resulted in vascular insufficiency,¹⁵⁴ and it is now rarely used for treatment of femoral fractures. Modified Bryant traction, in which the knee is flexed 45 degrees, increases the safety of overhead skin traction.⁵⁵

Traction prior to spica casting is indicated when the fracture is length unstable and the family and surgeon agree that nonoperative measures are preferred. In general, skeletal traction then Spica casting is not currently used for children who are older than 12 years of age, because of the significant risk of shortening and angular malunion; in children older than 12 years of age, internal fixation is recommended. Children who rapidly shortened in an early spica cast can be salvaged with cast removal and subsequent traction. The limit of skin traction is the interface between skin and tape or skin and foam traction boot. Skin complications, such as slough and blistering, usually occur when more than 5 lb of traction is applied. When more than 5 lb of traction is required, or simply for ease in patient management, skeletal traction can be used to maintain alignment.⁵

The distal femur is the location of choice for a traction pin.^5,48,177 Although proximal tibial traction pins have been recommended by some clinicians,⁹² growth arrest in the proximal tibial physis and subsequent recurvatum deformity have been associated with their use (Fig. 27-11). Also, knee ligament and meniscal injuries that sometimes accompany femoral fractures may be aggravated by the chronic pull of traction across the knee.

Traction Pin Insertion: Technique

After preparation of the thigh circumferentially from the knee to the midthigh, the limb is draped in a sterile manner. The knee is held in the position in which it will remain during traction; that is, if 90/90 traction is being used, the traction pin should be inserted with the knee bent 90 degrees. Because this technique is typically used in very young children, traction pin is placed in the operating room under general anesthesia. The technique is safest and most efficient if it is done with fluoroscopic x-ray control for optimal pin location. The location of pin insertion is 1 fingerbreadth above the patella with the knee extended or just above the flare of the distal femur. A small puncture wound is made over the medial side of the femur. A medial-to-lateral approach is used so that the traction pin does not migrate into the area of the femoral artery that runs through Hunter canal on the medial side of the femur. The best traction pin is the largest available threaded Steinmann pin. The pin is placed parallel to the joint surface⁵ to help maintain alignment while in traction. After the pin protrudes through the lateral cortex of the femur, a small incision is made over the tip of the pin. The pin is then driven far enough through the skin to allow fixation with a traction bow. If 90/90 traction is used, a short leg cast can be placed with a ring through its midportion to support the leg. Alternatively, a sling to support the calf may be used. If a sling is used, heel cord stretching should be performed while the patient is in traction.

After the skeletal traction pin has been placed in the distal femur, traction is applied in a 90/90 position (the hip and knee flexed 90 degrees) (Fig. 27-12) or in an oblique position (the hip flexed 20 to 60 degrees). If the oblique position is chosen, a Thomas splint or sling is necessary to support the leg. The fracture may be allowed to begin healing in traction, and x-rays should be obtained once or twice a week to monitor alignment and length. In preschool age children, traction will be necessary for 2 to 3 weeks; in school-age children, a full 3 weeks of traction is usually necessary before the fracture is stable enough to permit casting. In a child under 10 years of age, the ideal fracture position in traction should be less than 1 cm of shortening and slight valgus alignment to counteract the tendency to angulate into varus in the cast and the eventual overgrowth that may occur (average 0.9 cm). If this method is used for adolescents (11 years or older), normal length should be maintained.

Spica Casting, with Traction Pin Incorporated

In rare circumstances, a child’s femur fractures best treated by spica casting, incorporating a traction pin in the cast to maintain fracture length. This technique may be particularly useful in an environment where there are limited resources. In a study by Gross et al.,⁶⁸ 72 children with femoral fractures were treated with early cast brace/traction management. In this technique, a traction pin is placed in the distal femur and then incorporated in a cast brace. The traction pin is left long enough to be used for maintaining traction while the patient is in the cast brace or traction is applied directly to the cast. The patient is allowed to ambulate in the cast brace starting 3 days after application. Radiographs are taken of the fracture in the cast brace to document that excessive shortening is not occurring. The patient then is returned to traction in the cast brace until satisfactory callus is present to prevent shortening or angular deformity with weight bearing. The technique was not effective in older adolescents with midshaft fractures but achieved excellent results in children 5 to 12 years of age. The average hospital stay was 17 days.

Complications of Spica Casting

Comparative studies and retrospective reviews have demonstrated unsatisfactory results in a small, yet significant, percentage of patients treated with skeletal traction.^{84,92,108,169} Recently, increased attention has been focused on the risk of compartment syndrome in children treated in 90/90 spica cast.¹⁵¹ Mubarak et al.¹⁵¹ presented a multicenter series of nine children with an average age of 3.5 years who developed compartment syndrome of the leg after treatment of a low-energy femur fracture in a 90/90 spica cast. These children had extensive muscle damage and the skin loss around the ankle (Fig. 27-13). The authors emphasize the risk in placing an initial below knee cast, then using that cast to apply traction while immobilizing the child in the 90/90 position. The authors recommend avoiding traction on a short leg cast, leaving the foot out, and using less hip and knee flexion (Fig. 27-14).

Flexible Intramedullary Nail Fixation for Femoral Shaft Fractures

In most centers, flexible intramedullary nailing is the standard treatment for midshaft femur fractures in children between the ages of 5 and 11 years old. The flexible intramedullary nailing technique can be performed with either stainless steel nails^168,209 or titanium elastic nails.

The popularity of flexible intramedullary nailing results from its safety, efficacy, and ease of implant removal. The flexible nailing technique offers satisfactory fixation, enough stress at the fracture site to allow abundant callous formation, and relatively easy insertion and removal. The implants are inexpensive and the technique has a short learning curve. The primary limitation of flexible nailing is the lack of rigid fixation. Length-unstable fractures can shorten and angulate, especially in older and heavier children. Compared to children with rigid fixation, children who have their femur fracture treated with flexible nailing clearly have more pain and muscle spasm in the early postoperative period. The surgeon should take this into consideration in planning the early rehabilitation.

As the flexible nailing technique has become more popular, there have been many studies to refine the technique and indications, and to elucidate the inherent limitations of fixation with flexible implants. Mechanical testing of femoral fracture fixation systems showed that the greatest rigidity is provided by an external fixation device and the least by flexible intramedullary rodding.¹¹⁵ Stainless steel rods are stiffer than titanium in bending tests. A study comparing steel to titanium flexible nails found a higher complication rate in the titanium group.²⁰⁹ They reported that a typical 3.5-mm stainless steel nail has the same strength as a 4 mm diameter titanium nail. Lee et al.¹¹⁵ analyzed a group of synthetic fractured femurs instrumented with Enders rods and determined that there was sufficient axial and torsional stiffness to allow “touch-down weight bearing” despite fracture type. Gwyn et al.⁷¹ similarly showed that 4-mm titanium rods impart satisfactory torsional stability regardless of fracture pattern. Recognizing this flexibility, the French pioneers^114,120 of elastic nailing stressed the critical importance of proper implant technique, including prebending the nails so that the apex of the bend was at the fracture site, and so that the two implants balance one another to prevent bending and control rotation. Frick et al.⁶¹ found there to be greater stiffness and resistance to torsional deformation when retrograde nails are contoured into a double C pattern than with the antegrade C and S configuration. Sagan et al.¹⁷⁸ noted that apex anterior malunion is less likely if at least one nail has its shoe tip point anteriorly, such that the nail is in procurvatum.

The prevailing technique for flexible nail insertion at most centers throughout the world has been retrograde, with small medial and lateral incisions just above the distal femoral physis. However, some prefer an antegrade technique, with entry in the subtrochanteric area. The primary advantages of a proximal insertion site are a fewer knee symptoms postoperatively. Bourdelat²¹ compared retrograde and antegrade (ascending and descending) flexible intramedullary rodding in a group of 73 femoral fractures. An antegrade transtrochanteric approach was recommended by Carey and Galpin,³¹ who reported excellent results in 25 patients without growth arrest of the upper femur and no osteonecrosis. Satisfactory alignment and fracture healing were obtained in all patients.

Retrograde intramedullary nailing with Ender nails or titanium nails has been reported by Ligier et al.,¹²⁰ Mann et al.,¹²⁷ Heinrich et al.,⁷⁹ Herscovici et al.,⁸⁵ and others.^31,104,135 Heinrich et al.⁷⁹ recommended a 3.5-mm Ender nail in children 6 to 10 years of age and a 4-mm nail in children over 10 years of age. Ligier et al.¹²⁰ used titanium nails ranging from 3 to 4 mm inserted primarily in a retrograde fashion. Heinrich et al.⁸⁰ recommended flexible intramedullary nails for fixation of diaphyseal femoral fractures in children with multiple system injury, head injury, spasticity, or multiple long bone fractures. Flynn et al.⁵⁸ published the first North American experience with titanium elastic nails. In this multicenter study, 57/58 patients had an excellent or satisfactory result, there was no loss of rotational alignment, but four patients healed with an angular malunion of more than 10 degrees. Narayanan et al.¹⁵² looked at one center’s learning curve with titanium elastic nails, studying the complications of 79 patients over a 5-year period. Nails that were bent excessively away from the bone led to irritation at the insertion site in 41. The center also had eight malunions and two refractures. They noted that complications could be diminished by using rods with similar diameter and contour, and by avoiding bending the distal end of the nail way from the bone and out into the soft tissues. Luhmann et al.¹²³ reported 21 complications in 43 patients with titanium elastic nails. Most of the problems were minor, but a hypertrophic nonunion and a septic joint occurred in their cohort. They suggested that problems could be minimized by using the largest nail possible and leaving only 2.5 cm out of the femoral cortex.

Flexible nails are removed after fracture union at most centers. However, some surgeons choose to leave the implants permanently. There is a theoretical concern that if flexible nails are left in young children, they will come to lie in the distal diaphysis as the child grows older. This may create a stress riser in the distal diaphysis, leading to a theoretical risk of fracture (Fig. 27-15). Morshed et al.¹⁵⁰ performed a retrospective analysis of 24 children treated with titanium elastic nails and followed for an average of 3.6 years. The original plan with these children was to retain their implants. However, about 25% of the children had their nails removed for persistent discomfort.

Fixation with Flexible Intramedullary Nails: Technique

Preoperative Planning. The ideal patient for flexible intramedullary nailing is the child between the ages of 5 and 11 years old with a length-stable femur fracture, in the mid-80% of the diaphysis (Fig. 27-16), who has a body weight less than 50 kg.¹⁴⁸ Unstable fracture patterns can also be treated with flexible nailing, but the risk of shortening and angular malunion is greater,¹⁸⁷ and supplemental immobilization during early healing phase may be valuable.

Initial radiographs should be studied carefully for fracture lines that propagate proximally and distally, and might be otherwise unnoticed (Fig. 27-17). Although it is technically difficult to obtain satisfactory fixation with a retrograde technique when the fracture is near the distal metaphysis, a recent biomechanical study¹³⁸ demonstrated that retrograde insertion provides better stability than antegrade insertion for distal femoral shaft fractures. Nail size is determined by measuring the minimum diameter of the diaphysis, then multiplying by 0.4 to get nail diameter. For instance, if the minimum diameter of the diaphyseal canal is 1 cm, the 4-mm nails are used. Always choose the largest possible nail size that permits two nails to fit medullary canal.

Flexible nailing is most effectively performed on a fracture table, with a fracture reduced to near-anatomic position before incisions are made. Alternatively, a fluoroscopic table can be used, but the surgeon should assure that a reduction can be obtained prior to the start of the procedure, and extra assistance may be necessary.

The procedure described is with titanium elastic rods, but other devices are available and can be used with slight variations in procedure.

Rod Bending. The distance from the top of the inserted rod to the level of the fracture site is measured, and a gentle 30-degree bend is placed in the nail. The technique of elastic fixation of femoral fractures as described by Ligier et al.¹²⁰ requires that a bend be placed in the midportion of the rod at the level of the fracture site. This produces a spring effect (Fig. 27-18) that adds to the rigidity of the fracture fixation. The spread of the rods in opposite directions provides a “prestressed” fixation, which increases resistance to bending. The opposite bends of the two rods at the level of the fracture significantly increase resistance to varus and valgus stress, as well as torsion. A second bend is sometimes helpful near the entering tip of the nail to facilitate clearance of the opposite cortex during initial insertion. Based on the report by Sagan et al.,¹⁷⁸ sagittal plane configuration should be considered as well. An apex-posterior bend in one of the nails, with the nail shoe pointing anteriorly in the proximal femur, resists apex-anterior malunion.

Most pediatric femur fractures are fixed with 4-mm diameter nails; in smaller children, 3.5-mm nails may be necessary. Two nails of similar size should be used, and they should be as large as possible. Using nails that are too small, or mismatched in size, increases the rate of complications.¹⁵² It is very unusual to use nails smaller than 3.5 mm, except in the very youngest, smallest children.

Retrograde Insertion. After the child is placed on the fracture table and the fracture reduced as much as possible, the leg is prepared and draped with the thigh (hip to knee) exposed. The image intensifier is used to localize the placement of skin incisions by viewing the distal femur in the AP and lateral planes. Incisions are made on the medial and lateral side distal to the insertion site in the bone. The proximal end of the 2- to 3-cm incision should be at or just distal to the level of the insertion site, which is about 2.5 to 3 cm proximal to the distal femoral physis (Fig. 27-19). A 4.5-mm drill bit or awl is used to make a hole in the cortex of the bone. The distal femoral metaphysis is opened 2.5 cm proximal to the distal femoral physis using a drill or awl. The drill is then steeply angled in the frontal plane to facilitate passage of the nail through the dense pediatric metaphyseal bone.

Upon insertion the rod glances off the cortex as it advances toward the fracture site. Both medial and lateral rods are inserted to the level of the fracture. At this point, the fracture reduction is optimized if necessary with a radiolucent fracture reduction tool which holds the unstable femoral fracture in the appropriate position to allow fixation. The surgeon judge which nail will be most difficult to get across the fracture site, and pass it first. If the easier nail is passed first, it may stabilize the two fragments such that the second, more difficult nail, cannot be passed easily. The two nails then are driven into the proximal end of the femur, with one driven toward the femoral neck and the other toward the greater trochanter. On the lateral, one nail should have its tip pointing anteriorly. When passing the second nail across the fracture site and rotating it, care must be taken not to wind one rod around the other. After the nails are driven across the fracture and before they are seated, fluoroscopy is used to confirm satisfactory reduction of the fracture and to ensure that the nails did not comminute the fracture as they were driven into the proximal fragment.

The nails are pulled back approximately 2 cm, the end of each nail is cut, then driven back securely into the femur. The end of the nail should lie adjacent to the bone of the distal femoral metaphysis, exposed just enough to allow easy removal once the fracture is healed. Do not bend the exposed to distal tip of the nail away from femoral metaphysis as this will irritate surrounding tissues.

A proximal insertion site can also be used. An insertion site through the lateral border of the trochanter avoids creating the stress riser that results from subtrochanteric entry.

Technique Tip. Mazda et al.¹³² emphasized that for insertion of titanium elastic nails, the nails have to be bent into an even curve over the entire length, and the summit of the curve must be at the level of the fracture or very close to it in comminuted fractures. The depth of curvature should be about three times the diameter of the femoral canal. Flynn et al.⁵⁸ also stressed the importance of contouring both nails with similar gentle curvatures, choosing nails that are 40% of the narrowest diaphyseal diameter and using medial and lateral starting points that are at the same level in the metaphysis.

In length-unstable fractures, an endcap has been shown to confer increased stability that might lessen the risk of shortening²⁰⁸ and nail backout.

Postoperative Management. A knee immobilizer is beneficial in the early postoperative course to decrease knee pain and quadriceps spasm. When the flexible nailing technique is used for length-unstable fracture, walking (or one leg) spica is recommended, generally for about 4 to 6 weeks until callus is visible on radiographs. For length-stable fractures, touch-down weight bearing could begin as soon as the patient is comfortable. Gentle knee exercises and quadriceps strengthening can be begun, but there should be no aggressive passive motion of the knee, which increases the motion at the fracture site and increases quadriceps spasm. Postoperative knee motion does return to normal over time. Full weight bearing generally is tolerated by 6 weeks. Ozdemir et al.¹⁶⁰ recommended the use of postoperative functional bracing, demonstrating effectiveness in a group of patients treated with elastic rodding. Such postoperative support may occasionally be required, but in most cases it appears not to be needed.

The nails can be removed 6 to 12 months after injury when the fracture is fully healed, usually as an outpatient procedure.

Complications of Flexible Intramedullary Nailing

Complications are relatively infrequent after flexible intramedullary nailing. In 351 fractures reported in seven studies^{10,31,53,80,120,123,132} one nonunion, one infection, and no occurrence of osteonecrosis were reported. Approximately 12% of patients had malunions, most often mild varus deformities, and approximately 3% had clinically significant leg length discrepancies from either overgrowth or shortening. A recent study noted overgrowth of more than 1 cm in 8.2% of preschool children treated with titanium elastic nailing.¹⁴⁹ This is a much higher rate of overgrowth than seen in older children, suggesting the technique should be used infrequently in preschool children. Mazda et al.¹³² pointed out a technique-related complication that occurred in 10 of their 34 patients: Rods were left too long and caused painful bursae and limited knee flexion. All 10 patients had the nails removed 2 to 5 months after surgery. Flexible nails inserted in a retrograde fashion may also penetrate into the knee joint, causing an acute synovitis¹⁷⁴ In a multicenter study⁵⁸ that included 58 femoral fractures stabilized with titanium elastic nails, irritation of the soft tissue near the knee by the nail tip occurred in four patients (7%), leading to a deeper infection in two patients. This study also reported one refracture after premature nail removal, leading to a recommendation that nail removal be delayed until callus is solid around all cortices and the fracture line is no longer visible. Ozdemir et al.¹⁶⁰ measured overgrowth with a scanogram and found that the average increase in length was 1.8 mm, suggesting that significant femoral overgrowth is not seen with this method of treatment.

Flynn et al.⁵⁹ compared traction and spica cast with titanium elastic nails for treatment of femoral fractures in 83 consecutive school-aged children. The three unsatisfactory results were treated with traction followed by casting. The overall complication rate was 34% in the traction group and 21% in the elastic nail group.

An international multicenter study focused on factors that predict a higher rate of complications after flexible nailing of pediatric femoral shaft fractures.²⁰ Analyzing 234 fractures in 229 patients from six different Level 1 trauma centers, the authors found significantly more problems in older, heavier children. A poor outcome was five times more likely in patients who weigh more than 108.5 lb. A poor outcome was also almost four times more likely in patients older than 11 years old. The authors concluded that results were generally excellent for titanium elastic nailing, but poor results were more likely in children older than 11 years and heavier than 50 kg. Ho et al.⁸⁷ reported a 34% complication rate in patients 10 years and older, but only a 9% complication rate in patients younger than 10 years, emphasizing the concept that complications of flexible nailing are higher in older, heavier children.

Salem and Keppler¹⁷⁹ noted a 47% incidence of torsional malunion ≥15 degrees in the patients they treated at one center in Germany. These authors could not determine if the torsional malunion was due to instability after fixation, or faulty surgical technique. In either case, the findings call attention to the need for rotational assessment after fixation.

External Fixation for Femoral Shaft Fractures

External fixation of femoral shaft fractures offers an efficient, convenient method to align and stabilize the fractured pediatric femur. It is the method of choice when severe soft tissue injury precludes nailing or submuscular plating, when a fracture shortens excessively in a spica cast, or as part of a “damage-control” strategy.¹⁴⁷ In head-injured or multiply injured patients and those with open fractures, external fixation offers an excellent method of rapid fracture stabilization. It is also valuable for very proximal or distal fractures, where options for flexible nailing, plating, or casting are limited. External fixation is particularly valuable for the benign pathologic fracture (e.g., through a nonossifying fibroma) at the distal metaphyseal–diaphyseal junction (Fig. 27-20), where the fracture will heal rapidly, but angular malunion must be avoided.