Pediatric Orthopedic Trauma

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Pediatric Orthopedic Trauma

Musculoskeletal trauma is the most common medical emergency in children.1 In children ages 1 to 14 years, accidents are the leading cause of death.2 However, not all orthopedic injuries sustained by children are life threatening. The chance of a child sustaining a fracture before age 16 is 42% for boys and 27% for girls.3 It has been estimated that between 1–2% of children present with a fracture each year.4 As participation in sports and other recreational activities increases, the number of fractures is likely to increase. A study in 2006 looking at the impact of trauma on an urban pediatric orthopedic practice demonstrated that fracture management (both operative and nonoperative) accounted for approximately one-third of the total work-related relative value units. The most common fracture-related operations were performed on the elbow (23%), tibia (12%), femur (9.8%), forearm (5.5%), and the distal aspect of the radius (5%).5 The same practice reported that trauma care comprised 44% of their operative volume in 2006 and 2007.6

Patient gender, age, climate, time of day, and social situation in the home have been shown to impact the frequency of orthopedic injuries. In children, boys sustain fractures at 2.7 times the rate of girls.7 However, as girls become involved in more athletic events, this margin may narrow. It has been shown that fracture location varies with chronologic age, a finding that is probably due to a combination of the anatomic maturation of the child and the age-specific activities of childhood.3 Several authors have shown that fractures are more common during the summer months when children are out of school.4,7,8 It has also been shown that there is also a strong association between sunshine and fractures, and a negative association between rain and fractures.9 Likewise, two studies have proven that the afternoon is the most frequent time for fractures to occur.10,11 This correlates with the time of peak activity for children. Injuries in the home during the late afternoon and evening account for more than 83% of all injuries to children.12 Moreover, the overall incidence of fractures occurring at home increases with the age of the child.4,13 In a Swedish study, fracture incidence was correlated with the degree of social handicaps such as welfare or alcoholism in the family.14 Similarly, a study from Manitoba elicited the social situation at home as a major influence of children’s injuries.15

No discussion of pediatric orthopedic trauma is complete that does not include a discussion of nonaccidental trauma. The incidence of physical abuse to children is estimated to be 4.9 per 1,000. Of those abused, 1 of every 1,000 will ultimately die as a result.16 Early recognition and reporting is essential because children who return home after hospitalization with unrecognized abuse have a 25% risk of serious injury and a 5% risk of death.17 Children at highest risk for abuse are first-born children, premature infants, stepchildren, and handicapped children.18 Most cases of child abuse involve children younger than 3 years of age. Any child presenting with fractures, particularly if they involve the long bones, should be viewed with circumspection as to cause (Table 18-1).19,20

TABLE 18-1

Specificity of Musculoskeletal Radiologic Findings in Nonaccidental Trauma

image

aLow specificity, but these findings are commonly seen in nonaccidental trauma.

Adapted from O’Connor JF, Cohen J. Dating fractures. In: Kleinman PK, editor. Diagnostic Imaging of Child Abuse. Baltimore: Williams & Wilkins, 1987. p. 6.

Pathophysiology

In the immature skeleton, longitudinal and appositional growth takes place through the physes (growth plates) that are located at the ends of the long bones, in the endplates of the vertebral bodies, or at the periphery of the round bones in the feet and hands. Thus, the physis is essential for normal skeletal growth, but is also the weakest portion of the bone in children. It is estimated that approximately 30% of fractures of the long bones include an injury to the physis.21–23 Most fractures that involve the growth plates heal without consequence. However, some injuries can result in permanent damage with significant sequelae such as angular deformity or complete cessation of growth.

The ends of every long bone consist of an epiphysis (near the joint), physis, and metaphysis (area of newly formed bone). At the time of skeletal maturity, the physis closes, which means there is no more longitudinal growth. Fracture healing in children is rapid and the potential for remodeling is great due to the growth potential and dynamism of the immature skeleton. These characteristics allow for nonoperative treatment of some fractures in children that demand operative treatment in skeletally mature patients. Remodeling of fractures predictably occurs in the plane of primary motion of the adjacent joint (usually flexion/extension) and, to a lesser degree, in the coronal plane (varus and valgus deformities). Remodeling is virtually nonexistent in the transverse plane with rotational malalignment.24

Physeal fractures are classified to predict outcome and guide treatment. Currently, most orthopedic surgeons use the Salter Harris classification (Fig. 18-1).25 Classic teaching states that type I and II injuries heal without growth abnormalities if reduced appropriately. However, some reports dispute some of this dogma.2628 Types III and IV injuries usually occur in older children and require anatomic realignment via open reduction to restore congruity of the joint to minimize the risk of arthritis. Reduction also restores continuity of the physis to decrease the risk of growth disturbance. Type V are crush injuries that are not usually recognized at presentation, but have a high risk of growth arrest.29

Complex Injuries

Children sustain injuries that are different from adults due to their size and activities. A common example is a pedestrian struck by a car. An adult will frequently sustain an injury to the tibia or knee from the car’s bumper. However, the same mechanism will result in a fracture of the femur or pelvis in conjunction with a chest or head injury in a small child.30 Motor vehicle accidents (MVAs) are the most common cause of multiple injuries to children, both as occupants and pedestrians.30,31

Open fractures are considered one of the true orthopedic emergencies in children.32 These injuries usually result from high-energy mechanisms and are often seen in the setting of multiple trauma. Open fractures in children and adults are classified according to the system of Gustilo–Anderson (Table 18-2).3335 The four goals of treatment of open fractures are: prevention of infection, bony union, prevention of malunion, and return to function of limb and patient.32,36 To attain these goals, open fractures must be treated by early irrigation and debridement along with broad-spectrum antibiotics. 3335 Kindsfater and colleagues found that early treatment of tibial shaft fractures in children resulted in fewer cases of osteomyelitis when compared to those treated later.37 As a counterpoint, data from our institution demonstrated no difference in infection or nonunion rates with delayed debridement in 390 open fractures of the lower extremities in adults.38 Additionally, in a study of 554 pediatric open fractures, there was no difference in infection rates when debridement was within 6 hours of injury as compared to seven to 24 hours.39 There is no consensus on the effect of delayed operative treatment of open fractures in regards to rates of infection and need for secondary surgical procedures to promote bone healing.32,3945 Our practice is to debride open fractures within 24 hours of presentation and more urgently if there is severe contamination.

TABLE 18-2

Severity Classification for Open Fractures

Grade Description
I Wound <1 cm
II Transitional wound (1–10 cm)
III Wound >10 cm
IIIA Extensive soft tissue injury
IIIB Reconstructive soft tissue injury
IIIC Vascular injury

From Gustilo RB, Mendoza RM, Williams DN. Problems in the management of type III (severe) open fractures: A new classification of type III open fractures. J Trauma 1984;24:747–96; Gustilo RB, Anderson T. Prevention of infection in the treatment of 1025 open fractures of long bones: Retrospective and prospective analyses. J Bone Joint Surg Am 1976;50:453–58.

Push and riding lawn mowers produce complex wounds and open fractures in children with an annual incidence of approximately 11 per 100,000.46 These injuries frequently require serial debridement, internal or external fixation, and reconstruction of soft tissue defects. Unfortunately, amputation is often needed.

Fractures of the Lower Extremity

Due to the high energy required, fractures of the pelvis and proximal femur are rare but serious injuries in children. Approximately two-thirds of patients with pelvic fractures have associated injuries, and approximately one-third have residual, long-term morbidity.47,48 Pelvic fractures rank second to head injuries in terms of complications, including life-threatening visceral injuries. The mortality rate of pelvic fractures is between 9–18%.47 Children with multiple injuries should be checked carefully to exclude fractures of the pelvis. Some common findings of fractures of the pelvis are the presence of a hematoma beneath the inguinal ligament (Desot sign); decreased distance between the greater trochanter and anterior superior iliac spine on the affected side in lateral compression injuries (Roux sign); the presence of a bony prominence or hematoma on rectal exam (Earl sign). An anteroposterior pelvis radiograph is usually sufficient as the initial screening study, although increasingly these injuries are diagnosed by computed tomography (CT) as part of the initial trauma evaluation.49 Most pediatric pelvic fractures, even those in which the pelvic ring is disrupted, can be treated nonoperatively with good outcomes.48

Fractures of the femoral neck are serious injuries that typically require operative treatment.50–59 Osteonecrosis caused by disruption of the blood supply to the femoral epiphysis is a dreaded complication of this fracture that occurs in up to 75% of children after this injury.50–55,5962 The risk of developing osteonecrosis correlates with a higher anatomic location of the fracture in the femoral neck, extent of displacement, and delay in reducing the fracture. Accordingly, fractures and dislocations of the proximal femur are orthopedic emergencies. They require immediate anatomic reduction, which may be achieved by closed or open techniques, and internal fixation (Fig. 18-2).52,56,59,6366

Femoral shaft fractures are common injuries in children. The incidence and mechanism of these fractures varies with patient age and gender. Child abuse accounts for up to 67% of femur fractures in children younger than age 1, but only 11% of fractures in children between ages 1 and 2 years old.67–69 Classic teaching states that spiral fractures in preambulatory children are pathognomonic for abuse. However, studies have demonstrated that any fracture pattern can occur as the result of abuse.68 Falls are the leading cause of femur fractures in children age 2 to 3 years, and MVAs are the most common cause in older children.67 Although bleeding following a femur fracture can be fairly extensive, transfusion in isolated, closed injuries is rarely needed. Therefore, other causes of blood loss must be considered if there is hemodynamic instability or a falling hematocrit at 24 hours after injury in a patient with a femur fracture, especially in the setting of multiple trauma.70

Treatment of femur fractures also varies with age.69 Younger children (<4 to 5 years) are usually treated nonoperatively by closed reduction and immediate spica cast immobilization.7174 Older children (4 to 10 years) are managed with flexible nails7582 or plates.8385 Adolescents (>10 years or >100 pounds) may be treated as adults with solid, reamed, femoral nails, which should be introduced through the tip of the greater trochanter rather than through the piriformis fossa to avoid injury to the vascular supply to the femoral head (Fig. 18-3). A recent review of rigid nails for older children and adolescents noted no cases of osteonecrosis with nail entry via the lateral aspect of the greater trochanter.86 In contrast to adults, the timing of femur fracture stabilization in children, even in the setting of multiple trauma, does not appear to have an effect on the development of pulmonary complications.87 The implications are that operation can be deferred until the general medical condition of the child permits, with the caveat that expeditious stabilization of femur (as well as other long bone) fracture(s) will facilitate mobilization and nursing care in the overall management of the child.

Knee injuries in children differ from those in adults. In children, the cartilage of the physes, apophyses, menisci, and articular surface are weaker than the knee ligaments and are thus more prone to injury.88 Therefore, fractures about the knee occur more commonly than ligamentous injuries in skeletally immature individuals.89 The distal femoral physis is the largest and fastest growing physis. It is often injured as a result of a direct blow and is a common injury in American football players. Most fractures are Salter Harris type I or II injuries. These fractures can usually be treated by closed reduction and percutaneous, cross-pin stabilization. Fractures extending into the articular surface (type III and IV injuries) require open reduction and internal fixation if displacement of the articular surface is greater than 2 mm. Because of the size of this growth plate, its complex, undulating anatomy, and the forces required for displacement, fractures of the distal femoral physis, even type I and II injuries, may result in permanent growth disturbance in up to 50% of cases.90 All of these fractures should be followed for a minimum of 1 year to evaluate for sequelae of growth arrest.

Proximal tibial physeal injuries are uncommon due to the reinforcement provided by the knee joint capsular attachments and collateral ligaments. Vascular compromise of the lower leg due to popliteal artery injury is possible, particularly with extension-type injuries in which the proximal portion of the tibial metaphysis is displaced posteriorly. Such injuries tent the popliteal artery at the level of the physis and proximal to the trifurcation, where it is relatively tethered by the peroneal branch as it courses thru the fascia entering the anterior compartment of the leg (Fig. 18-4). Close attention to the vascular examination of the lower extremity is critical following injuries to the proximal tibia. Intra-articular knee injuries typically present with a hemarthrosis and include patellar fractures or dislocations, tibial spine/plateau fractures, osteochondral fractures, and ligamentous/meniscal injuries. These injuries are typically not emergencies and can be splinted with delayed definitive treatment.

Nonphyseal fractures of the tibia and fibula are among the most common injuries involving the lower extremity in children.91,92 Fortunately, most of these injuries are low energy and can be treated nonoperatively. However, one must always be cognizant of the possibility of compartment syndrome following closed or open fractures of the tibial shaft.93 Indications for operative treatment of tibial shaft fractures include: open fractures, neurovascular injury, impending compartment syndrome, unacceptable alignment following closed reduction, and fractures occurring in the setting of multiple trauma.

Ankle fractures are typically caused by indirect, torsional forces. Injuries to the distal tibial and fibular physes account for 25% to 38% of all children’s physeal injuries.94,95 Sports injuries account for up to 60% of physeal fractures about the ankle.96 Nonoperative management has historically been the preferred approach, except for intra-articular fractures and those unable to be adequately reduced by closed techniques. Newer data suggests improved results with open reduction of distal tibial physeal injuries.26 CT is very useful in defining the pathoanatomy of fractures with intra-articular involvement or unusual patterns, and is useful in making management decisions and in preoperative planning.97 Foot fractures are uncommon and most can be treated nonoperatively with immobilization and restricted weight bearing. More complex problems that require operative intervention include fractures of the talar neck and calcaneus, fractures or dislocations of the tarsometarsal (Lisfranc) joint, open fractures, and lawn mower injuries.97

Spine Injuries

Cervical Spine Injuries

Cervical spine injuries in children are relatively uncommon but potentially catastrophic. Accurate diagnosis requires an awareness of the injury patterns, anatomic characteristics, and radiographic variants of the immature cervical spine.98 These injuries account for approximately 1% of all pediatric fractures and only 2% of all spine fractures.99101 Pediatric cervical spine injuries are fundamentally different from their adult counterparts due to the anatomic characteristics of the immature spine and, and to a lesser extent, the differences in the mechanisms of injury.102 The cervical spine in children is inherently mobile because of the presence of generalized laxity of the interspinous ligaments and joint capsules, underdeveloped neck musculature, thick cartilaginous end plates, incomplete vertebral ossification (wedge-shaped vertebral bodies), and shallow-angled facet joints, particularly between the occiput and C4.102

In infants and young children, injuries to the upper cervical spine (above C3) predominate because the head is disproportionately large and creates a large bending moment in the upper cervical spine. In an 11-year experience with 122 pediatric neck injuries, none of the 21 patients age 8 years or less had evidence of injury below C3.103 Also, multiple level spinal injuries are common, occurring in approximately 25% of children with cervical spine fractures.103106 Spinal cord injury without radiographic abnormality (SCIWORA) occurs more frequently in children than in adults.100,102 After age 8 to 10 years, the anatomical and biomechanical characteristics of the cervical spine are more like an adult, and injuries to the cervical spine are much more likely to occur in the subaxial region (below C3). Evaluation and treatment of these injuries is essentially the same as in an adult.98,100,102,107

Mechanisms of injury vary somewhat with age. In neonates, birth trauma is the most common cause of cervical spine injury and occult spinal cord injury has been demonstrated at necropsy in 30% to 50% of stillborns. Excessive distraction and/or hyperextension of the cervical spine are thought to be the most common mechanisms of injury, and may be associated with abnormal intrauterine position (transverse lie) or a difficult cephalic or breech delivery.108,109 In infants and young children, nonaccidental trauma is a significant cause of injury to the cervical spine. Avulsion fractures of the spinous processes, fractures of the pars or pedicles (most commonly C2), or compression fractures of multiple vertebral bodies are the most common patterns of injury and are thought to result from severe shaking or battering.110,111 These injuries may be associated with other signs of nonaccidental trauma including fractures of the skull, rib, or long bones, and superficial ecchymoses. In older children (up to about age 10), the most common causes are pedestrian-MVAs and falls. In children over 10 years of age, the most common etiologies are passenger-related MVAs, sports-related injuries, and diving accidents.

Appropriate methods of immobilizing children for transport and proper clinical and radiographic evaluation are crucial to avoid detrimental outcomes. The goal of immobilization during transport of the injured child with potential spine trauma is to avoid excessive angulation of the spinal column so as to avoid causing or exacerbating spinal cord injury. Immobilization of children less than 8 years of age on a standard spine board during emergency transportation will cause excessive flexion of the cervical spine due to the disproportionately large diameter of the head relative to the torso. It has been recommended that the child’s spine board be modified by building up the area under the torso with padding to allow the head to fall back slightly or cutting out the area under the occiput to recess the skull (Fig. 18-5).112 In addition to proper spine-board immobilization, an appropriately fitting cervical collar is necessary to achieve neutral alignment of the cervical spine after injury.113

Clinical evaluation of a child suspected of having an injury to the cervical spine is often hampered by an inability to obtain an accurate history and the unreliability of the physical examination.98,100,107,114–116 Historically, overt or occult injury to the cervical spine is more likely to occur as a result of falls from a height of more than four feet, pedestrian or cyclist MVAs, and unrestrained occupant MVAs. Head or facial trauma, altered mental status and/or loss of consciousness are also risk factors. Neck pain, guarding, and torticollis are the most reliable signs of an injury to the cervical spine in children. Extremity weakness, sensory changes, bowel and bladder dysfunction, and, less frequently, headaches, seizures, syncope, and respiratory distress are signs of injury to the spinal cord.98,99,104,117–126 When these conditions present, the cervical spine should be immobilized until imaging studies can be completed and the spine cleared.98

Radiographic evaluation of the cervical spine in children is hampered by the presence of normal anatomic variants that can be mistaken for trauma. Synchondroses and incompletely ossified, wedged-shaped vertebral bodies can simulate fractures.127–130 Anterior angulation of the odontoid is a normal variant in approximately 5% of children and may be mistaken for a Salter Harris type I fracture of the dens. Physiologic subluxation of C2 on C3 or C3 on C4 of up to 3 mm is a normal variant (pseudosubluxation) in about 40% of children younger than age 8 years and is often misinterpreted as pathologic instability.129,131 Focal kyphosis of the mid-cervical spine is a normal variant in about 15% of children under age 16 years that can also be misinterpreted as pathologic.

Initial radiographic evaluation should include cross-table lateral and anteroposterior radiographs. On the lateral view, it is essential to see the C7–T1 disc space. Oblique radiographs provide detail of the pedicles and facet joints.127 Open mouth odontoid radiographs are technically difficult to perform and rarely helpful.132 CT is a much better way to image the upper cervical spine and also provides excellent definition of known fractures, confirmation of suspicious areas, and excellent visualization of the cervicothoracic level, which can be difficult to adequately image on plain radiography. CT has been shown to be more efficacious than conventional images in evaluating the cervical spine in adult and pediatric trauma and to lower institutional costs and complications in urban trauma centers.124,133,134 Magnetic resonance imaging (MRI) is the preferred study to evaluate the spinal cord and soft tissue structures including ligaments, cartilage, and intervertebral discs.

Once a cervical collar has been placed on a child or the neck immobilized, either at the scene of an accident or in the emergency department, formal clearance of the cervical spine is necessary before immobilization is discontinued.115 In general, the cervical spine may be cleared based on clinical examination alone if the child is awake, alert, and cooperative; if there are no signs of cervical injury; and if the mechanism of injury is not consistent with cervical trauma.98,115 For children under age 8 to 10 years who are obtunded or otherwise unable to be examined, and all those with a profile suggestive of injury to the cervical spine, clearance may be based on a five-view cervical spine radiographic series, consisting of anteroposterior, lateral, open mouth odontoid, and two oblique views, and a CT of the axial region of the spine, from occiput to C2. In a study at our institution in which this protocol was followed, eight of 112 children were diagnosed with cervical spine injuries. Two of six children with bony injuries (33%) were diagnosed only by CT scan. No injuries were missed and cervical immobilization was discontinued in a timely fashion.135 The rationale for CT include the predisposition for injuries to occur in the upper cervical region in children younger than 8 years old and the technical difficulty imaging this area with plain radiographs.98 In a subsequent study from our institution, helical CT was shown to be have higher specificity, sensitivity and negative predictive value than conventional radiographs in evaluating the cervical spine in children with blunt trauma.134

Others have advocated for the definitive role of MRI, particularly in identifying soft tissue injury.136–138 In a study of 79 children, MRI revealed injuries in 15 patients with normal radiographs and excluded injuries suspected on plain radiographs and CT scans in 7 and 2 patients, respectively. In 25 obtunded or uncooperative children, MRI demonstrated three with significant injuries.136

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