EMERGENCY DEPARTMENT EVALUATION AND TREATMENT OF PEDIATRIC ORTHOPEDIC INJURIES

ORTHOPEDIC EMERGENCIES, PART I

0733-8627/99 $8.00

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EMERGENCY DEPARTMENT EVALUATION AND TREATMENT OF PEDIATRIC ORTHOPEDIC INJURIES Karen Della-Giustina, MD, FAAP, and David A. Della-Giustina, MD, FACEP

Orthopedic injuries in children are unique because of the dynamic state of growth and development of children. The cliche that states ”children are just small adults” certainly does not apply. The biochemical and physiologic differences of the child’s skeleton from that of the adult lead to distinctly different mechanisms of injury, fracture patterns, healing, and treatment needs that are crucial for the emergency physician to understand. Moreover, every age group from infancy through adolescence has its own typical fracture patterns, which one should be able to anticipate. In this country, unintentional injuries are the leading cause of death and disability in children, and up to one half of all emergency department (ED)-related visits are orthopedic in nature.I5 The importance of knowing how to diagnose and treat children with orthopedic injuries lies in the desired outcome of minimal morbidity, especially normal growth and development of the child. PEDIATRIC ORTHOPEDIC BASICS

Children’s bones have certain structural properties that allow them to withstand greater force and to heal more quickly than do fractures in skeletally mature persons. The child’s remarkable remodeling potential From the Department of Pediatrics, Madigan Army Medical Center (KD-G); and from the Department of Emergency Medicine, Madigan-University of Washington Emergency Medicine Residency Program, Tacoma, Washington; and the Uniformed Services University of the Health Sciences, Bethesda, Maryland (DAD-G)

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allows for some longitudinal malalignment and greater degrees of angulation. Regarding pediatric fracture remodeling, new bone is laid down according to local forces, especially in the plane of motion in the joint. If a child has at least 2 years of growth remaining, a fracture adjacent to a hinged joint will remodel acceptably if the angulation is less than 30 degrees in the plane of motion.= Precise anatomic reduction is required for fractures with rotational deformities, excessive degrees of angulation, or those that are intra-articular and displaced, however. Interestingly, children rarely need physical therapy as part of their treatment plan for fractures because they tolerate even lengthy immobilization without resultant stiffness. The pediatric periosteum further contributes to the biomechanical and healing differences in young patients. Notably, nonunion is rare owing to the significant osteogenic potential of the immature periosteum. Furthermore, the pediatric periosteum is thicker and stronger than mature periosteum, which results in diminished fracture displacement, fewer open fractures, and more stability in contrast to adults. In addition to the expected fracture patterns seen in adults, the more porous and pliable pediatric bone allows for four unique types of fractures seen in children: (1) plastic deformity, (2) torus (buckle) fractures, (3) greenstick fractures, and (4)fractures involving the physis. In plastic deformity, the bone is deformed beyond its ability to recoil, but not to the point at which an actual fracture occurs. Plastic deformity does not occur in the more dense mature bone. Radiographically, a plastic deformity appears as an excessively bowed bone without actual cortical disruption. Torus fractures occur at the junction of the metaphysis and diaphysis and result from compressive forces. Because the bone is more porous, it "buckles" because of the compression rather than breaking. A greenstick fracture occurs when the bone is fractured on the side opposite of an impact force; however, this is an incomplete fracture with the compressed side's cortex and periosteum remaining intact, possibly with a plastic deformity (Figs. 1 and 2). PHYSEALFRACTURES

In terms of understanding and treating orthopedic injuries, the most significant difference of the child's skeleton from that of the adult's is the presence of the physis or growth plate. Composed of cartilage, the physis represents the "weak l i n k in pediatric bone. The physis will separate or fracture before disruption or "spraining" of an adjacent strong and flexible ligament. Injures that produce sprained ligaments or even joint dislocations in skeletally mature individuals usually result in physeal injuries in children. Physeal injures represent up to 18% of pediatric fractures.22These physeal injuries are commoner during times of rapid growth and generally occur through the hypertrophic zone of the physiS. Although physeal injuries generally heal in one half the time of

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Figure 1. Torus fractures of the distal radius (A), best seen on the lateral view (B). (From Raby N, Berman L, de Lacey G: Accident and Emergency Radiology: A Survival Guide. Philadelphia, WB Saunders, 1995, p 230; with permission.)

long-bone injuries, they are the fractures in which anatomic alignment is most critical for optimal growth and minimal deformity. If the injured child is tender at the physis, the treating physician should suspect a fracture and not a sprain, even in the presence of normal radiographs. In 1963, Robert Salter and Robert Harris discussed epiphyseal plate (physis) injuries and classified them in terms of clinical treatment and prognosis. The injuries are classified numerically I through V, with the higher numbers corresponding to an increased risk for growth disturbances." Ogden supplemented this classification system in the 1980s. The Ogden augmentation to the Salter-Harris Classification system is added to the Salter-Harris classification numerically, starting at the Salter-Harris (Ogden) VI (Fig. 3).39 SALTER-HARRIS CLASSIFICATION Type I

Type I is a fracture that involves epiphyseal separation because of a fracture through the physis only. Although the radiographs appear nor-

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Figure 2. Plastic deformity of the ulna with associated greenstick fracture of the radius. (from Raby N, Berman L, de Lacey G: Accident and Emergency Radiology: A Survival Guide. Philadelphia, WB Saunders, 1995, p 231; with permission.)

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Ogden

Salter-Horris

I

II

111

IV

B

A

C

V

VI

VII

c1

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Figure 3. Classification of physical injuries by Salter-Harris and Ogden. Note that the Ogden classification adds more subclasses to the Salter-Harris system. (From Canale ST [ed]: Campell's Operative Orthopaedics. St. Louis, Mosby, 1998, p. 2365; with permission.)

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mal, the injury actually can be nondisplaced. Evidence of a nondisplaced Salter-Harris I fracture is point physeal tenderness on physical examination. If the patient has any tenderness over the physis, even in the presence of an otherwise normal examination (including radiographs), one should treat this as a physeal fracture with appropriate cast or splint immobilization. The prognosis for this type of fracture is excellent.

Type II

Type I1 is a fracture through the physis and metaphysis, with a fragment of the metaphysis remaining attached to the epiphysis. This triangular metaphyseal fragment is commonly referred to as the Thurston-Holland sign. This is the commonest type of physeal fracture. This injury requires treatment with appropriate cast or splint immobilization. The prognosis for this type fracture is also excellent.

Type 111

The Salter-Harris type I11 fracture involves a fracture line that begins intra-articularly and travels through the epiphysis into the physis. Because this is an intra-articular fracture, precise anatomic reduction is imperative to minimize future joint and growth abnormalities as well as post-traumatic arthritis. With appropriate reduction, the prognosis for this injury is good.

Type IV

The Salter-Harris type IV fracture involves a fracture line that begins intra-articularly and travels through the epiphysis, physis and the metaphysis. As in the Salter-Harristype I11 fracture, precise anatomic reduction is imperative. This fracture commonly requires surgical fixation to maintain the reduction. This type of fracture has a significant incidence of growth disturban~e.~~

In a Salter-Harris type V fracture, the physis is crushed without any other injury. This injury is often difficult to diagnose except in retrospect, because displacement of the epiphysis is unusual and the initial radiographs are usually unremarkable. The prognosis for this injury is poor owing to the premature cessation of growth."

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Type VI (Ogden)

In a type VI fracture, the peripheral borders of the physis are sheared along with small portions of the adjacent metaphysis and epiphysis. This leads to a potential future angular deformity owing to the formation of an osseous bridge between the metaphysis and epiphysis in the healing process of such a fracture. This osseous bridge causes the deformity because it halts growth on its side of the physis, while the opposite side of the physis continues to grow.

Type VII (Ogden)

In this injury, a ligament avulses a distal portion of the epiphysis only, without any physeal involvement. This injury is significant in that it is an intra-articular fracture and thus requires precise reduction to prevent future joint problems.

Type Vlll (Ogden)

A Salter-Harris (Ogden) type VIII fracture is a fracture that passes through the metaphysis only, without any physeal involvement. This fracture is significant in that it causes a temporary disruption of the bony circulation distal to the injury.

Type IX (Ogden)

A Salter-Harris (Ogden) IX involves a significant loss or damage to the periosteum in association with a fracture in a skeletally immature patient. This injury is significant owing to the significant contribution of the periosteum to pediatric fracture healing. One must always counsel the patient and his or her parents about the potential for future growth abnormalities following physeal injuries. The potential problems include asymmetric healing and growth, premature closure of the physis, and post-traumatic arthritis if the joint is involved.

TREATING THE ORTHOPEDICALLY INJURED CHILD

Obviously, in the multiply injured child, resuscitation takes precedence over all else.

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HISTORY

Obtaining a history in an injured child is quite challenging. In most cases, the child and parents are frightened and thus perhaps unable to focus and give a clear history. Additionally, the child may be preverbal or unable to localize pain because of a very young age. The physician can often predict the type of injury through knowledge of the commonest types of injuries for the child’s developmental level. Finally, pain in a child often limits the completeness of a history of injury. A calm, gentle approach in addition to the proper use of analgesia can aid in obtaining the history. PHYSICAL AND DIAGNOSTIC EXAMINATION

Keeping in mind a child’s fear, pain, and developmental level, a gentle and systematic approach is best for evaluation and treatment. Administering appropriate analgesia will aid not only in reducing the child’s pain and anxiety but also in examining the injured part. Before palpating the injured area, one should examine the skin carefully for any breaks. Next, the physician should evaluate the neurovascular status of the limb carefully, especially before and after reduction and splinting. Finally, one should examine the injured area by palpating the areas away from the area of complaint rather than going directly to the area of injury. For additional comfort, the injured limb should be splinted before obtaining radiographs. The injured region should be radiographed using plain radiography in at least two different planes, usually anteroposterior (AP) and lateral views. There are some areas, such as the elbow or wrist, where oblique views are also obtained. The radiographs should include the joint above and below the injury. UPPER EXTREMITY INJURIES

Injuries to the upper extremity are extremely common. Noteworthy, a small number of injuries make up a significant portion of upper extremely injuries. Clavicle

The clavicle is the most frequently fractured bone in the pediatric 30 Incomplete fractures are more prevalent in the younger pop~lation.~~, child, whereas complete fractures are more predominant in older children. The commonest fracture site is between the middle and outer thirds. Because of its subcutaneous location, a fractured clavicle is often simple to detect. Although often fractured at birth, a clavicle fracture in a newborn actually can be diagnosed in the ED, after the baby’s dis-

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charge from the nursery, when the new parents detect the palpable callus of healing. Older children usually sustain clavicle fractures from short falls onto an extended arm. Direct trauma to the clavicle itself from high-energy forces should alert the physician to investigate the possibility of coexisting rib and thoracic trauma.

Diagnosis and Treatment The child with a clavicle fracture after the newborn period will have pain with arm and neck movement. Local swelling and crepitus will be present and perhaps even displacement of the affected shoulder downward and inward if the fracture is complete. The examining physician should perform a careful neurovascular examination to detect damage to the underlying vessels and structures. For diagnosing a clavicle fracture, an AP radiograph is usually sufficient. Ordinarily, newborns who have sustained a clavicle fracture require no further treatment. However, the parents should be educated about the fracture and the probability of a detectable callus developing over the next several weeks. Additionally, they should be instructed not to lay the infant on the injured side. In older children with a simple clavicle fracture, immobilization with a sling and swath for 4 to 6 weeks is generally sufficient. Shoulder Dislocations Dislocation of the humeral head is quite rare in the young pediatric patient. Newborns may have an injury that resembles a shoulder dislocation, particularly if there is a history of shoulder dystocia. These infants actually have a Salter-Harris type I fracture of the proximal humerus, with the epiphysis remaining in the g l e n ~ i dBecause .~~ the epiphysis is nonossified, it is not visible on plain radiography, thus giving the appearance of a shoulder dislocation. If diagnosed, these injuries require evaluation and reduction by an orthopedic surgeon. Adolescents sustain shoulder (glenohumeral) dislocations more commonly than do young children. In most of these cases, the dislocation is anterior. These dislocations are usually reducible by the emergency physician in the ED and require orthopedic evaluation within 1 week. The various techniques for reduction are discussed elsewhere in this issue (see "Emergency Department Evaluation and Treatment of the Shoulder and Humerus"). Humerus The proximal humeral epiphysis is responsible for 80% of the longitudinal growth of the humerus.30Thus, for proper growth, diagnosis and treatment of physeal fractures in this region are vital. Noteworthy,

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fractures to the proximal epiphysis are the major type of injury to the proximal humerus in children. In newborns and preschoolers, the typical injury is a Salter-Harris type I fracture, whereas children who are 11 to 15 years old typically sustain Salter-Harris I1 fractures. The usual history is that of a fall backward onto an extended arm. The humeral metaphysis is thus forced laterally and anteriorly. A severe fracture or one in which the history is inconsistent with the injury should raise suspicion of abuse, especially in very young children. The entire shoulder girdle should be radiographed after the neurovascular examination. The physician should pay particular attention to possible axillary nerve damage with resulting abnormal deltoid function and paresthesia or anesthesia over the lateral shoulder. Treatment

Most children can be treated with a sling and swath if the separation is less than 1 cm, the angulation is less than 40 degrees, and there is no 30 An orthopedic surgeon should reevaluate the child malr~tation.’~, within 24 to 48 hours. Supracondylar Fractures

Supracondylar fractures are the commonest elbow fracture in pediatric patients. They typically occur between the ages of 3 and 10 years and more frequently in boys than girls. These fractures require treatment as an acute emergency, especially as flow through the brachial artery can be affected at the site of injury. Accurate diagnosis and prompt treatment are vital with supracondylar fracture to minimize morbidity. The typical history for a supracondylar fracture is a fall onto an extended arm, such as a fall from ”monkey bars,” which forces the distal fragment upward and posteriorly after fracturing the supracondylar area. The injured child will hold the arm in pronation and resist elbow flexion because of pain. The physician who suspects a supracondylar fracture should do a careful neurovascular examination, checking for the five “Ps” of arterial injury or compromise: pain, pallor (poor perfusion), weak radial pulse (to pulselessness), paralysis, and paresthesias.3O Worsening pain or pain with passive extension of the fingers are also ”red flags” for ischemia. An orthopedic surgeon must immediately evaluate and treat (reduce) a supracondylar fracture with any sign of ischemia. Compartment syndrome of the volar forearm can develop in less than 12 to 24 hours, with subsequent necrosis and fibrosis of the involved musculature. This ischemia/ infarction can lead to Volkman’s ischemic contracture, which is characterized by fixed elbow flexion, forearm pronation, wrist flexion, metacarpal phalangeal (MCP) joint extension, and interphalangeal flexion. If no orthopedic surgeon is available and there is evidence of arterial injury or ischemia, then the emergency physician must reduce

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the fracture. The technique for fracture reduction is placement of the forearm in supination, then applying longitudinal traction, and direct pressure to the displaced fragment in a downward and anterior direction.3O Oblique fractures usually require open reduction. In a child without neurovascular compromise, an AP view in extension and a lateral view in 90 degrees of flexion should be performed. Because the fracture line is often difficult to visualize, one can use the anterior humeral line and pathologic ”fat pads” as indirect evidence of subtle fractures. The anterior humeral line is a line that is visualized on the lateral view, being drawn down the anterior margin of the humerus. This line should intersect the capitellum in its posterior two thirds. If this line intersects the anterior one third of the anterior capitellum or appears anterior to the capitellum, it is strongly suggestive of a supracondylar fracture with posterior displacement of the distal fragment (Figs. 4 and 5). Additionally, one can use the fat pads as nonspecific indicators of elbow joint effusion or hemorrhage that is seen with an occult elbow fracture. Both fat pads are visualized on the lateral elbow view. The posterior f a t pad is recognized as a radiolucency posterior to the distal humerus adjacent to the olecranon fossa; the presence of a posterior fat pad is always pathologic and indicative of elbow effusion. The anterior f a t pad, which can be seen in normal children, is an area of radiolucency located superior to the radial head and anterior to the distal humerus.

A

B

I

Figure 4. On a good lateral view, the anterior hurneral line should intersect that capitellum in its posterior two thirds (A). If the anterior hurneral line is anterior to the posterior two thirds, one should suspect a supracondular fracture with posterior displacement of the distal fragment (B).(From Raby N, Berrnan L, de Lacey G: Accident and Emergency Radiology: A Survival Guide. Philadelphia, WB Saunders, 1995, p 72; with permission.)

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Figure 5. This patient has an abnormal anterior humeral line that does not intersect the capitellum (A). Further inspection demonstrated the cortical break demonstrated by the arrows (B).(From Raby N, Berman L, de Lacey G: Accident and Emergency Radiology: A Survival Guide. Philadelphia, WB Saunders, 1995, p 73; with permission.)

The anterior fat pad is considered pathologic when it “sails” anteriorly from its normal position. A supracondylar fracture without neurovascular compromise that is not oblique does not require emergent orthopedic evaluation in the ED. Rather, it can be splinted with the elbow flexed at 90 degrees, with the forearm splinted in either pronation or a neutral position, posteriorly from the wrist to the axilla. One must always evaluate the neurovascular status of the forearm, wrist, and hand following splinting. These patients should be evaluated by an orthopedist within 24 hours. Radial Head Subluxation

Radial head subluxation, commonly known as nursemaid’s elbow, is seen frequently in the ED because of parental concern over a child’s not moving his or her arm. This injury occurs primarily in toddlers but can appear in the infant or preschooler. Often, the history is difficult to obtain because the caretaker may not realize the cause of the injury. The typical mechanism is abrupt longitudinal traction on the child’s pronated

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wrist or hand. This action forces the annular ligament over the radial head, lodging it between the radial head and the capitellum. Usually, the child refuses to move the affected arm, holding it close to his or her body. Treatment

After carefully examining the child’s arm and shoulder girdle, the physician who is confident of a radial head subluxation can attempt reduction without obtaining any radiographs. If there is focal bony tenderness on examination, then one should obtain plain radiographs to rule out a fracture. Although there are many reduction techniques, supination is the integral part of most of the reduction methods. A popular method is for the physician to place his thumb of one hand over patient’s radial head and with other hand holding the patient’s wrist to pull the elbow into extension gently. Next, the physician should quickly supinate and flex the elbow. In many cases, there is a palpable click over the child’s radial head when the annular ligament is reduced. In the absence of a click, the physician should fully pronate and extend the elbow, then repeat the supination and flexion maneuver. If no click is felt or heard at this time, the physician should allow the child to rest. A younger child should start to move his arm in less than 20 minutes. If the child fails to move his or her arm in that period, then another attempt at reduction can be repeated. If repeated attempts at reduction are unsuccessful, then one should obtain radiographs (if not already obtained) and place the child in a posterior elbow splint. These children should be followed up in 24 to 72 hours. Fortunately, most reduction attempts are successful, and the parents are usually impressed with their child’s rapid return to normal. Because many parents do not realize the harm in lifting a child’s entire body from the hand or wrist, the physician should explain the mechanism causing nursemaid’s elbow and caution against lifting the child in this manner. LOWER EXTREMITY Hip Pain Hip pain in children is disturbing for both parents and physicians. Because the causes of hip pain are numerous, it is prudent for the physician to become familiar with the significant features and epidemiology of the commoner and more serious causes of hip pain in children. Acute Transient Synovitis Acute transient synovitis (ATS), or ”toxic” synovitis, is a self-limiting inflammatory process that occurs in children between the ages of

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1.5 to 7 years, with a peak between the ages of 3 and 6 years.3l This entity, which occurs more commonly in boys than girls, is the commonest hip disorder that causes a limp in a child. The onset, which is generally acute in nature, often follows a viral upper respiratory illness or mild trauma. Interestingly, ATS has no known cause but has a good clinical outcome in most patients. One potentially confusing factor is that although the child limps, he or she actually may complain of thigh or knee pain rather than hip pain. On evaluation, the child usually does not appear ill but holds the 34 Additionally, affected hip in flexion, abduction, and external on examination, he or she may have tenderness with direct palpation of the hip as well as pain with passive range of movement of the hip. Many children will have a low-grade fever with otherwise normal vital signs. Laboratory studies that should be obtained include the complete blood count (CBC) and the erythrocyte sedimentation rate (ESR). The laboratory findings usually demonstrate a normal or only slightly elevated white blood count and ESR. Plain radiographs of the hip also can be normal or show hip joint widening medially. Ultrasonography that is extremely accurate reveals hip joint effusion in 95% of cases.31 ATS is a diagnosis of exclusion after one has considered the more serious causes of hip pain such as septic arthritis, osteomyelitis, fracture, Legg-CalvM'erthes disease (LCPD) monoarticular rheumatoid arthritis, sickle cell, and tumor. Children with leukemia and other neoplasms also can present initially with limb pain.5A history typical for ATS in association with normal laboratory and radiographic studies will rule out most of the other diagnoses in the differential; however, if the patient's temperature is greater than 37.5" C and the ESR is greater than 20 mm/ hr, septic arthritis should be excluded by arthrocentesis. Relying on the peripheral white blood cell (WBC) count alone to distinguish between septic arthritis and ATS has not been found helpful. Using an elevated ESR and an elevated temperature as criteria for joint aspiration, however, will detect 97% of septic arthritis, with the caveat that 50% of patients will have normal arthrocentesi~.'~ Treatment includes symptomatic relief with rest and nonsteroidal anti-inflammatory medications. The duration of symptoms is 1 week or less in 67% of patients, and less than 1 month in an additional 21% of patients.25The use of antibiotics or traction does not alter the clinical course. Follow-up visits are important for children with a diagnosis of ATS, because some patients actually suffer from early LCPD. ATS also can recur over the subsequent 6 months after diagnosis; this risk has been reported to be between 4% to 17%.31 Septic Arthritis

The major concern with the patient with ATS is that they do not have a septic hip. Usually, one is able to differentiate the child with the septic hip from the patient with ATS; nevertheless, this is not always

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possible, especially early in the course of the illness. Children suffering from septic arthritis usually appear ill, typically with fever and hip pain, tenderness, and warmth. Physical examination also shows the hip held in flexion, abduction, and external rotation, with limited internal rotation. The ESR is almost always elevated and the WBC count is typically but not always elevated. Plain radiography may reveal joint space widening and soft tissue swelling, with obliteration of fat shadows. Ultrasonography of the hip demonstrates an effusion. Children suspected of septic arthritis require diagnostic arthrocentesis of the affected hip. If child is found to have septic arthritis, treatment includes surgical drainage and intravenous antibiotics. Prompt treatment is vital because the most important factor for the best outcome of septic arthritis is early treatment. Empiric intravenous antibiotics should be given in the ED after successful arthrocentesis. The antibiotic choice should be made based on the most likely organisms, with antistaphlococcal coverage being a good first choice, with the addition of gramnegative coverage in neonates and adolescent^.^^ Legg-Calve-Perthes Disease

LCPD is an idiopathic avascular necrosis of the femoral head with subsequent repair. This disorder is commoner in boys than in girls, with a peak incidence between 4 and 9 years of age. Of note, children with LCPD often have delayed bone age and a history of low birthweight. The ratio of white to African American children is 10:1. The reported of the incidence of LCPD varies between 1 in 120031 to 1 in 20,000.10 Conversely, the incidence of LCPD in patients with siblings who have LCPD is 1 in 35.’O The incidence of bilateral involvement is reported at 10%to 12%.36 The etiology of LCPD is unknown. Recent studies suggest a genetic hyperfibrinolysis coagulation disorder as being linked to LCPD. The commonest thrombotic disorder described in children with LCPD has been factor V Leiden mutation. This is a genetic disorder commoner in whites, and it is associated with resistance to activated protein C. Gmppo et a1 recently described a family in which siblings had LCPD associated with factor V Leiden mutati0n.2~This proposes more compelling evidence for the role of familial thrombotic disorders in LCPD and the promise for limiting morbidity with anticoagulant medicine in the future. In fact, it is not a single episode of thrombosis that leads to the problem; rather, it is the recurrent episodes of thrombosis and infarction with subsequent resorption of the infarcted bone that lead to the symptoms and radiographic changes. Children with LCPD frequently present with limp and have limited hip internal rotation and abduction. Children often complain of either no pain or of pain that is referred to thigh or knee. Radiographs, which allow one to make the diagnosis, vary with the stage of disease at presentation. AP and frog-leg lateral views should be obtained. Early in

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the illness, the radiographs demonstrate a small femoral head, especially in comparison with the contralateral side, as well as a widened medial joint space. As the disease process progresses, a crescent-shaped radiolucent line (crescent sign) appears along the proximal femoral head. Next, the ossific nucleus of the femoral head becomes more radiopaque with subsequent fragmentation and collapse of the epiphysis as avascular bone is resorbed (Fig. 6). This point is usually where the symptoms are the most prominent. Reossification occurs last. Many times, there are residual deformities, such as an abnormal femoral head and acetabular configuration. If the child’s radiographs appear normal but LCPD is suspected, MRIzOor bone scanz6can be the next helpful step in diagnosis. Laboratory test values are generally normal. Treatment includes orthopedic referral, restriction of activity, and NSAIDs. Surgery or braces can be used in selected cases, with the goals of pain control and minimizing morbidity. A child with LCPD occasionally limps for 2 to 4 years or longer.3l Age at the onset of the symptoms is the best predictor of outcome. Those patients with the symptoms occurring before the age of 6 years have the best outcome, whereas those aged 8 years or older have the worst prognosis.1z Slipped Capital Femoral Epiphysis

x

SIipped capital emoral epiphysis (SCFE)is a disorder in which there is disruption throug the capital femoral physis (Fig. 7).The term SCFE is

Figure 6. This AP view of the pelvis demonstrates bilateral hip involvement with LeggCalve-Perthes disease. The right hip demonstrates early signs of the avascular stage with diminished femoral head size. The left hip demonstrates the fragmentation stage. (From Koop S, Quanbeck D: Three common causes of childhood hip pain. Pediatr Clin North Am 43:1059, 1996; with permission.)

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\ \

Figure 7. Line drawing of slipped capital femoral epiphysis. The line is drawn along the superior cortex of the femoral neck on the anteroposterior view. Normally, the line will intersect the femoral head (B, 0). If a slipped capital femoral epiphysis is present, the line will not intersect the head (A, C). In some cases, only a frog leg view (C and 0)will show a slip. (From Chung MK: Disease of the developing hip joint. Pediatr Clin North Am 33:1469, 1986; with permission.)

actually a misnomer, because the epiphysis remains in normal position in the acetabulum, whereas the femur distal to the physis displaces anterolaterally and superiorly. SCFE typically occurs during adolescence, being found twice as often in boys than in girls.31Additionally, obesity is also a factor in the disorder, with one half of the patients exceeding the 95th percentile of weight for their It also occurs in tall, thin, rapidly growing adolescents, however.", l2 SCFE can be classified either in terms of duration of symptoms or the severity of the displacement. If the symptoms have been present for less than 3 weeks, it is considered an acute slip, whereas when symptoms last longer than 3 weeks it is considered chronic. It is possible for a child with a chronic slip to experience an acute slippage, however, sometimes known as an "acute on chronic" slip.31 Mild slips can demonstrate displacement up to one third of the metaphyseal width. Moderate slips occupy from one third to one half the metaphyseal slips, whereas severe slips have a slippage of greater than one half of the metaphyseal width?' The determination of the amount of slippage is best evaluated on the lateral view. Children with SCFE usually have a limp and hip pain that is often referred to the thigh, knee, or deep in the groin. Physical examination,

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usually shows loss of internal rotation of the affected hip, decreased flexion, and perhaps shortening of the affected limb. Diagnostically, the CBC and ESR are normal. Radiographic studies of children suspected of having SCFE should include AP pelvis and lateral view of both hips. On the AP view, a line drawn along the superior margin of the femoral neck cortex is useful for demonstrating subtle slips. The line should intersect or fall within the epiphysis, usually by at least 20%?4 In patients with SCFE, the line passes along or outside the epiphysis. In subtle cases, the more remarkable finding will be an asymmetry from the normal hip. Because the slip in most cases of SCFE is usually posterior, the lateral view can actually reveal the slip better than AP view. The physician making the diagnosis of SCFE should prescribe no weight bearing for the child and promptly refer him or her to an orthopedic surgeon. Studies have shown that surgical pinning in situ (rather than complete reduction and then pinning) provides the best results in terms of function and m~rbidity.~ Another useful but most times impractical treatment includes continuous bedrest for 3 to 4

month^.^ Bilateral SCFE can occur in 5% to 37% of children.35Thus, one must examine the opposite hip closely and inform the patient and his or her parents of the potential for this problem. Interestingly, subsequent slips can occur within 18 months after the first slip is diagnosed.35Because of the possibility of sequential SCFE, patients should be followed closely for at least 1.5 years. The prognosis of SCFE is based on the chance of developing avascular necrosis or chondrolysis with the subsequent arthritis. These problems are less likely to occur when there has been a minimal amount of time of symptoms, when the slip is mild, and when the slip is surgically fixed in situ, rather than attempted reduction then fixation.", 31 CERVICAL SPINE INJURY

Traumatic spinal cord injuries in children are uncommon, representing only 1%to 10% of all reported spinal injuries;28however, cervical spine injuries in children have many unique characteristics that the physician must understand to limit morbidity and mortality in these patients. In fact, up to 5% to 10% of lesions occur after the initial injury and during the early course of emergency management? With appropriate management in the prehospital and ED, the outcome is optimistic for many children with spinal cord lesions. Annually, there are approximately 1100 newly spine-injured children.29The leading causes of spinal cord injury in children vary by age, but heading the list are motor vehicle-related injuries and falls. During the second decade of life, athletics, other recreational activities, and motor vehicle crashes cause most of the spinal cord injuries. Many children who sustain spinal cord injuries die from their injuries and the subsequent complications. In an epidemiologic study performed in

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California, the case fatality rate was reported as 59%. In fact, 75% of child pedestrians hit by automobiles who sustained spinal cord injury died.29Additionally, all children who sustained spinal cord injury from auto-bicycle or auto-motorcycle crashes died.29Moreover, 60% of pediatric spinal cord injury patients also have associated significant head injuries? Thus, in the presence of a head injury, the emergency physician should consider the possibility of a concomitant spinal injury. Anatomy The cervical spine is composed of the vertebrae, ligaments, intervertebral disks, muscles, neural structures, and vessels. The ligamentous and osseous structures of the cervical spine act to protect the neural components while providing functional motion. All of the components of the spine undergo significant maturation during childhood. Naturally, the most evident developmental changes are those of the osseous structures, which can be seen radiographically. Interestingly, although the spine appears fully mature on plain radiographs at 8 to 10 years of age, the adult patterns of injury are not manifest until the age of 15 years.29 The anatomic and biomechanical differences in the immature cervical spine account for the differing patterns of injury between the pediatric and adult age groups. These differences are most notable in children younger than 8 years of age. The most prominent differences are the predisposition for upper cervical spine injuries and a condition termed SCIWORA, an acronym for spinal cord injury without radiographic abnormality. Some of most notable characteristics are greater laxity of the intervertebral ligaments, disc annulus, and transverse ligament of the odontoid. Additionally, the articular surfaces of the vertebral bodies and facet joins are oriented horizontally, which allows for an increased susceptibility to subluxation. The immature cervical spine contains physes and incomplete ossification of the odontoid, making fracture through the cartilaginous structures more likely than ligamentous disruption. Moreover, children have underdeveloped neck musculature and relatively large heads, leading of the high fulcrum of the cervical spine at C2 and C3. Thus, children suffer higher cervical spine lesions than do adults. The vertebral arteries in the pediatric cervical spine are more vulnerable to ischemia, perhaps in part due to the relative instability of the atlanto-occipital joint. In one study, a subpopulation of children aged 3 years or younger emerged as a separate group when regarding cervical spine injuries. These children had a significantlyhigher requirement for surgical stabilization and a higher level of injury than did other age gr0ups.~1 Although younger children are more likely to have a high cervical spine injury, the commonest injury in all ages of children is a combined fracture and dislocation injury. In adolescents, the second commonest injury is fracture alone, whereas in young children, the second commonest spinal cord injury is either subluxation or dislocation alone.

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Evaluation and Treatment

Children with a history of significant trauma, including head, neck, or back injury, high-speed injury, or falls from heights, should be evaluated for possible spinal cord injury. Symptoms of SCI in young children are often difficult to obtain. Jaffe et a1 developed an algorithm with high sensitivity for early management of pediatric cervical spinal and injuryTS Basically, an injured child with one or more of the following findings should be immobilized and undergo cervical spine radiography: neck pain or tenderness, abnormal reflexes, diminished strength or sensation, history of neck trauma, limitation of neck mobility, and abnormal mental statusJS An additional tool for the evaluation of the potentially spinal cord injured patient is the mnemonic of the six Ps: pain, position sense, paralysis, paresthesias, ptosis, and priapism. Most of these Ps are selfexplanatory; however, ptosis is meant to be part of the miotic pupil, suggesting Horner’s syndrome and cervical cord injury. Physical Examination

Obviously, vital signs and more specifically airway management and oxygenation require initial management and emphasis. Spinal cord injury can produce apnea, loss of diaphragmatic breathing, or loss of abdominal or intercostal breathing. Additionally, the emergency physician should be aware of the finding that children placed in supine position in spinal immobilization have reduction to a mean of 80% of FVC.43 Other vital signs can also be affected by spinal cord injury: hypotension with a relative bradycardia and hypothermia. These require aggressive management to limit further spinal cord damage and to ensure the best possible outcome for the patient. The neurologic examination of the patient actually should begin with an assessment of the work of breathing by evaluating adequate chest wall excursion. Mental status should be quickly assessed. For a rapid gross motor examination, evaluation of dorsiflexion of the wrist and great toe, extension of the forearm and flexion of the lower leg at the knee are useful in all except in young infants. In children with suspected spinal cord injury, evaluation should include sensory examination, deep tendon reflexes, and superficial reflexes. A rectal examination should be performed to evaluate for rectal tone and the bulbocavernosus reflex. The absence of the bulbocavemosus reflex is indicative of spinal (neurologic)shock. Radiographic Studies

Injured children who have clinical signs or symptoms of possible spinal cord injury require accurate radiographic evaluation. The radiographic cervical spine series is the same as that for adults, consisting of

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the cross-table lateral view (CTLV),AP, and the open-mouth (OM) odontoid views. When younger children are uncooperative for obtaining the OM view, one can substitute the Water’s view, which allows one to visualize the odontoid through the foramen magnum. One should be able to clearly evaluate all seven cervical vertebral bodies, including the C7-T1 junction. The vertebral bodies should be inspected for fracture and uniform density. The predental space should be measured, with the upper limit of normal being 4 mm to 5 mm in children (rather than the 3 mm seen in adults)? The tips of the spinous processes should align uniformly; an analogy often used to describe this alignment is ”shingles on a r00f.”~Non-uniform alignment suggests a ligamentous disruption. The intervertebral and interspinous spaces also should be evaluated for uniformity, loss of height, and angulation. On CTLV the four lines of lordotic curvature should be assessed: the anterior vertebral body line, the posterior vertebral body line, the spinolaminar line, and the tips of the spinous processes. In children, another useful line on CTLV is the posterior cervical or Swischuk line, which helps to differentiate physiologic pseudosubluxation from a true fracture-dislocation of C2 on C3, as seen in the ”hangman’s fracture” of traumatic spondyl~lysis.~~ This line is drawn from the anterior cortex of the spinous process of C1 to the anterior cortex of the spinous process of C3. A normal finding that is consistent with pseudosubluxation is if this line intersects or passes within 1 mm anteriorly of the anterior cortex of the C2 spinous process (Fig. 8).46If the posterior cervical line passes anterior to the posterior arch of C2 by more than 2

Predental space

\

Figure 8. Normal posterior cervical line. (From Rosen P, Barkin R, Danzl DF, et al [eds]: Emergency Medicine: Concepts and Clinical Practice. St. Louis, Mosby, 1997, p 489; with permission.)

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mm, then true dislocation of C2 on C3 must be assumed, and the patient requires appropriate evaluation with CT scan or MRI (Fig. 9). One caveat to the utility of the posterior cervical line is that it will be normal in a purely ligamentous injury without fracture.46 In cases in which there is a neurologic deficit, a fracture, or the possibility of a fracture, further imaging of the spine using either CT scanning or MRI is warranted. CT of the cervical spine is useful in selected patients especially in those in whom there is a concern primarily of a bony injury. CT has been shown to be 97% to 100% sensitive in adults in identifying cervical spine lesions in trauma patients. MRI has an important role in diagnosing pediatric cervical spine injury; especially in those with neurologic deficit, obtunded patients with injuries, those with equivocal plain films, or those with history concerning for SCIWORA. MRI is the "gold standard test for evaluating spinal cord injuries because it allows better visualization of the spinal cord and spinal canal than does CT scanning. In one study evaluating children, it was demonstrated that in 19% of cases in which the practitioner had a suspicion for neck injury despite negative plain cervical spine radiographs, the spinal MRI was po~itive.'~ Thus, consider using spinal MRI in pediatric patients when there is a high suspicion of spinal injury, especially very young and preverbal patients, or those with altered mental status.

Posterior arch

Posterior cervical line

Figure 9. Abnormal posterior cervical line. (From Rosen P, Barkin R, Danzl DF, et al [eds]: Emergency Medicine: Concepts and Clinical Practice. St. Louis, Mosby, 1997, p 476; with permission.)

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Spinal Cord Injury Without Radiographic Abnormality

SCIWORA is phenomenon that is commonly seen in pediatric patients but much less commonly seen in adults. SCIWORA is defined as a spinal cord injury with significant neurologic involvement, but without radiographic evidence of injury on plain spinal radiography, including flexion-extension views and spinal CT. A good example of SCIWORA is the central cord syndrome that is commonly seen in elderly patients after a hyperextension injury. SCIWORA is commonly found in children because of their ”elastic” and developing spinal column, which makes them more likely to sustain ligamentous, physeal, cartilagenous, and vascular injuries without findings on plain radiography. The reported incidence of SCIWORA varies between 4% and 65%, with the true incidence probably being around 20% of all pediatric spinal injuries.37 SCIWORA can manifest itself initially after trauma as a profound or progressive paralysis, even up to 48 hours after the injury. Children who experience even mild transient SCIWORA with resolution before being seen in the ED are susceptible to ”recurrent” SCIWORA. One half of all children with SCIWORA had delayed neurologic deterioration, most likely due to repeated trauma in an unrecognized unstable spinal injury.32Even a history of a seemingly trivial transient neurologic symptoms, such as shock-like sensations after trauma, should concern the physician for the possibility of SCIWORA and the potential for “recurrent” SCIWORA. The patient and parents should be thoroughly questioned for such symptoms. Children younger than 8 years old are particularly susceptible to SCIWORA and are more likely to have a complete spinal cord injury. The child with a neurologic deficit or a history of significant neurologic symptoms (e.g., paralysis or anesthesia) with normal plain spinal radiography should be evaluated further using preferably spinal MRI or CT scan if one is unable to obtain a MRI.I9 Patients with persistent or transient significant neurologic deficits or documented ligamentous instability require hospital admission and appropriate spinal immobilization. Patients with minor transient symptoms (e.g., bilateral paresthesias) who are neurologically intact and have a negative cervical spine radiographic series to include flexion-extension views, can be discharged to home. It is questionable whether they should be discharged home in a cervical collar, although this has not been studied. They should be counseled to refrain from physical activity for several weeks and should be reevaluated within 48 to 72 hours to ensure that there are no new or progressive deficits. If there is a concern over the significance of the neurologic symptoms, then they should be imaged further, as discussed earlier. The degree of neurologic injury at presentation, with any MRI findings, can enable the physician to evaluate the patient’s prognosis. TreatmenVManagement

The goal in treating cervical spine injury is to limit neurologic injury by spinal immobilization and careful attention to cardiopulmonary func-

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tion. Additionally, limiting hypoxia and hypotension is essential to good outcome. Hypothermia also should be actively assessed and monitored. In 1990, investigators reported the results of the second National Acute Spinal Cord Injury Study concerning the role of glucocorticoids in spinal injury. They found that high-dose methylprednisolone, given within 8 hours of acute spinal cord injury as a 30 mg/kg bolus over 1 hour followed by 5.4 mg/kg/hr for the next 23 hours, was associated with improved neurologic recovery.6 Although children under 13 years of age were excluded from the study, the physician treating a child with cervical spine injury, including SCIWORA, should strongly consider using methylprednisolone because it can affect the child’s outcome positively. CHILD ABUSE

There are many forms of child abuse; orthopedic injuries are the form in which abuse is most readily apparent, however. Orthopedic injuries, including soft tissue trauma, are the commonest presentation of child abuse, otherwise known as nonaccidental trauma (NAT). Abused children who are returned to their homes without social intervention face a 50% chance of repeated abuse and 10% chance of death.13 Thus, making a prompt diagnosis of child abuse in the ED is vital. Unfortunately, no easy or comfortable manner for the physician to initiate a child abuse investigation exists. Faced with the staggering statistics of a 1 in 10 chance of death of a child, however, the physician must report potential cases of abuse for the protection of the child. Moreover, not only does the physician have a moral obligation to report potential cases of child abuse; he or she also has a legal obligation. Physicians are required by state law to report suspected child abuse and are afforded legal immunity for doing so. The exact requirements vary for each state. Additionally, most regions impose penalties on professionals for failing to report child abuse. Fractures from child abuse tend to occur in very young children. In fact, one half of such skeletal injuries occur in babies 12 months old or younger. Additionally, in children under the age of six years presenting to the ED with injuries, up to 30% of the head and limb injuries are inflicted as a result of child abuse.13 Diagnosis History

After necessary resuscitative efforts are completed, the physician should obtain a detailed history of the injury from the child’s caretaker. Suspicion should be raised if the mechanism of injury is inconsistent with the history or the child’s developmental stage. For example, a baby

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who is obviously not yet walking should not be able to fracture his femur accidentally by falling down. Furthermore, a history of the mechanism of injury that changes should raise the examining physician’s suspicion. Likewise, the historian can also be evasive, inappropriately angry with the child or medical professionals, or obviously lying by being contradictory. If the child is verbal, the experienced physician can ask him or her about the injury in a nonthreatening manner, without the presence of the caregiver. Physical Examination

A thorough and gentle approach is best. The child should be examined head to toe, including the genitalia. Any scaring, ecchymosis, lacerations, burns, or other lesions should be documented carefully. The skeletal examination should be complete, considering that multiple fractures may be present. Radiography

A complete skeletal survey is required for all physically abused children less than 2 years old and for infants suffering from neglect. Highly detailed radiographs are essential. A ”babygram,” or an anteroposterior (AP) view of the entire child on one film, is an unacceptable alternative, because it usually misses more subtle evidence of child abuse. A skeletal survey consists of the following: AP and lateral views of the extremities in total, AP and lateral views of thoracolumbar spine, and AP and lateral views of the skull.3sAll positive findings should be evaluated in at least two planes. Additionally, oblique views may be necessary to reveal a suspected fracture not apparent on the biplane views. Radionuclide skeletal scintigraphy (bone scan) is often used as a screening tool for child abuse. Bone scanning is useful owing to its sensitivity for rib, spine, and subtle diaphyseal trauma, which may not be evident on plain films; however, bone scanning has limitations in that symmetric fractures and epiphyseal-metaphyseal fractures can be missed.38 If bone scans are used, a physician knowledgeable in the interpretation of pediatric bone scans should evaluate the study. In the ED, a bone scan is not generally necessary except as an adjunct to the skeletal survey. Another useful tool to evaluate the injuries of abuse is ultrasonography. In areas of incomplete ossification, such as the capital femoral epiphysis, ultrasound examination can help the physician define an injuryDistinctive Radiographic Features of Child Abuse Because the history of definite NAT is usually not present, the physician must understand the various fracture patterns that suggest NAT, otherwise he or she could overlook seemingly innocuous fractures

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that portend future injury. The finding of healing fractures of different ages found in a child is highly suspicious for NAT. Another finding highly specific for NAT is the classic metaphysical lesion (CML), often termed a corner or bucket-hundle~ucture.The CML is a disklike fragment of bone and calcified cartilage that is wider on the outer edges than it is centrally. This fracture is transmetaphyseal through the primary spongi38 osa and leaves the disklike fragment attached to the epiphy~is.'~, Corner and bucket-handle fractures are probably the same entity, just viewed in different planes. Although these fractures appear relatively benign in terms of healing, it is the clear association with NAT that one needs to understand. These classic metaphysical lesions are specific for abuse because of the mechanism that causes them: traction and torsional forces, rather than falling. Rib fractures in a young child without a history of significant trauma are telling of child abuse. Chest compressions from CPR have not been shown to cause rib fractures in children. Posterior rib fractures are highly specific for NAT. Complex skull fractures, again without history of significant trauma, are also highly specific for NAT. Although linear skull fractures are commonly seen in accidental trauma, they are also seen in child abuse.13,38 History and clinical judgment are essential components to make a determination of child abuse as the cause of a linear skull fracture. Other orthopedic injuries that are insensitive yet highly specific for NAT include scapular fractures, sternal fractures, spinous process, and vertebral body fractures, especially in the setting of an inconsistent history. Long-bone and clavicular fractures often occur in abuse, as well as unintentional injuries. If the history is inconsistent with the fracture pattern, NAT should be considered. CONCLUSION

The emergency physician will inevitably encounter child abuse if his or her practice includes the care of children. One must be cognizant of this possibility when evaluating every skeletally injured child, especially when the child is young. One must also understand that it is not the injury itself that is the problem, rather it is the potential for further injury or death if the child is placed in the same setting without any intervention. The emergency physician is potentially the child's only advocate and as such can have an impressive impact on the child's future. References 1. Bimey TJ,Hanley EN: Traumatic cervical spine injuries in childhood and adolescence. Spine 141277-1282, 1989 2. Bohn D, Armstrong D, Becker L, et al: Cervical spine injuries in children. J Trauma 30:463-469, 1990

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3. Bonadio WA: Cervical spine trauma in children: I. General concepts, normal anatomy, radiographic evaluation. Am J Emerg Med 11:158-165, 1993 4. Bonadio WA: Cervical Spine Trauma in Children: 11. Mechanisms and manifestations of injury, therapeutic considerations. Am J Emerg Med 11:256-278, 1993 5. Bowyer S, Hollister, J R Limb pain in childhood. Pediatr Clin North Am 31:10531079, 1984 6. Bracken MB, Shepard MJ: A randomized, controlled trial of methylprednisolone or naloxone in the treatment of acute spinal cord injury. N Engl J Med 3221405-1411,1990 7. Burke TF, Rusnak RA, Hurley WT, et al: Refusal to walk in a 12-month-old child: A clinical-pathological case conference. Am J Emerg Med 12472476, 1994 8. Cabral DA, Tucker L: Malignancies in children who initially present with rheumatic complaints. Pediatr 13453-57, 1999 9. Carney B, Weinstein S: Long-term follow-up of slipped capital Femoral Epiphysis. Bone Joint Surg 73A667-674, 1991 10. Chung SM Diseases of the developing hip joint. Pediatr Clin North Am 33:14571473, 1986 11. Chung SM Identifying the cause of acute limp in childhood. Clin Pediatr 13:769-772, 1974 12. Clark M The limping child: Meeting the challenges of an accurate assessment and diagnosis. Emergency medicine reports 2:123-133, 1999 13. Cramer KE: Orthopedic aspects of child abuse. Pediatr Clin North Am 43:1035-1051, 1996 14. Del Beccaro MA: Septic arthritis vs. transient synovitis of the hip. Ann Emerg Med 21~1418-1422,1992 15. England SP, Sundberg S Management of common orthopedic fractures. Pediatr Clin North Am 43:991-1012, 1996 16. Egund N, Wingstrand H, et al: Computed tomography and ultrasonography for diagnosis of hip joint effusion in children. Acta Orthop Scand 57211-215, 1988 17. Evans D, Bethen D: Cervical spine injuries in children. J Pediatr Orthop 956>568,1989 18. Finch G, Barnes MJ: Major cervical spine injuries in children and adolescents. J Pediatr Orthop 18:811-814, 1998 19. Flynn JM, Closkey RF: A prospective evaluation of the role of MRI in the assessment of pediatric cervical spine injuries. Pediatrics 102742,1998 20. Fordham L, Auringer S Pediatric imaging perspective: Acute limp. J Pediatr 132:906908, 1998 21. Givens TG, Polley KA: Pediatric cervical spine injury: A three-year experience. J Trauma 41:310-314, 1996 22. Greenfield R Orthopedic Injuries. In Strange G, h e n s W, et a1 (eds): Pediatric Emergency Medicine. New York, McGraw-Hill, 1996, pp 113-118 23. Greenfield R Fractures of the pelvis and femur. In Strange G, Ahrens et a1 (eds): Pediatric Emergency Medicine. New York, McGraw-Hill, 1996, pp 130-133 24. Gruppo R, Glueck C, Wall E, et al: Legg-Perthes disease in three siblings, two heterozygous and one homozygous for the factor V Leiden mutation. J Pediatr 132:885887,1998 25. Haueisen D, Weiner D S The characterization of transient synovitis of the hip in children. J Pediatr Orthop 6:ll-17, 1986 26. Hensinger RN: Limp. Pediatr Clin North Am 33:1355-1364, 1986 27. Hill SA, Miller CA, Kosnik EJ, et al: Pediatric neck injuries. J Neurosurg 60:700-706, 1984 28. Jaffe DM, Binns H, Radkowski MA, et al: Developing a clinical algorithm for early management of cervical spine injury in child trauma victims. Ann Emerg Med 16:270276, 1987 29. Jaffe D: Evaluation for cervical spine injuries. In Strange G, Ahrens W, et a1 (eds): Pediatric Emergency Medicine. New York, McGraw-Hill, 1996, pp 66-75 30. Joffe M Upper Extremity. In Strange G, Ahrens, et a1 (eds): Pediatric Emergency Medicine. New York, McGraw-Hill, 1996, pp 340-354 31. Koop S, Quanbeck D: Three common causes of childhood hip pain. Pediatr Clin North Am 43:1053-1066, 1996

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32. Kriss VM, Kriss T SCIWORA (spinal cord injury without radiographic abnormality) in infants and children. Clin Pediatr 35:119-123, 1996 33. Lynch JM, Meza MP: Direct injury to the cervical spine of a child by a lap-shoulder belt resulting in quadriplegia: Case report. J Trauma 41:747-749, 1996 34. Lawrence L: The limping child. Emerg Med Clin North Am 16:911-129, 1998 35. Loder RT, Aronson D: The epidemiology of bilateral slipped capital femoral epiphysis. J Bone Joint Surg 75A:1141-1147, 1993 36. McGory BJ, Klassen RA: Acute fractures and dislocations of the cervical spine in children and adolescents. J Bone Joint Surg 75A98S995, 1993 37. Medina, Francisco A Neck and spinal cord trauma. In Strange G, Ahrens W, et a1 (eds): Pediatric Emergency Medicine. New York, McGraw-Hill, 1996, pp 230-256 38. Nimkin K, Kleinman P: Imaging of child abuse. Pediatr Clin North Am 44:615-635, 1997 39. Ogden J A Skeletal growth mechanism injury patterns. J Pediatr Orthop 2371-377,1982 40. Orenstein JB, Klein BL: Age and outcome in pediatric cervical spine injury: 11-year experience. Pediatr Emerg Care 10:132-137, 1994 41. Ruge JR, Sinson G: Pediatric spine injury: The very young. J Neurosurg 68:25-30, 1988 42. Salter RB, Harris W R Injuries involving the epiphyseal plate. J Bone Joint Surg 45A:587-621, 1963 43. Schafermeyer RW, Ribbeck BM, Gaskins J, et al: Respiratory effects of spinal immobilization in children. Ann Emerg Med 201017-1019, 1991 44. Schwartz GR, Wright SW Pediatric cervical spine injury sustained in falls from low heights. AM Emerg Med 30949-252, 1998 45. Schwend RM, Geiger J: Outpatient pediatric orthopedics. Pediatr Clin North Am 45:943-971, 1998 46. Swischuk LE: Anterior displacement of C2 in children: Physiologic or pathologic. Radiology 122:759-763, 1977 47. Torrey, SB: Lower extremity and pelvis. In Strange G, Ahrens W, et a1 (eds): Pediatric Emergency Medicine. New York, McGraw-Hill, 1996, pp 357-365

Address reprint requests to David A. Della-Giustina, MD, FACEP Department of Emergency Medicine Madigan Army Medical Center Tacoma, WA 98431