Etiologies, Pathophysiology, and Clinical Presentation: Erb palsy is caused by birth trauma to the C5 and C6 nerve roots. It is associated with prolonged, difficult delivery (dystocia) and with larger infants. Infants present soon after birth with decreased motion of the involved extremity. Children with a persistent defect will hold their arms in internal rotation with pronation of the forearm and flexion of the wrist. The brachial plexus injury is the primary insult leading to secondary glenohumeral dysplasia.

Imaging: At birth, radiographs serve to exclude fractures of the clavicle and humerus. Ultrasonography and magnetic resonance imaging (MRI) have been used to directly evaluate the brachial plexus;1,2 however, the primary goal of advanced imaging is to evaluate orthopedic anatomy to determine function and orthopedic treatment since primary repair of the brachial plexus injury is difficult.

Progressive deformity with secondary glenohumeral dysplasia manifests as a small, flattened humeral head, which may sublux, usually in the posterior direction relative to a small, shallow, abnormally retroverted glenoid (Fig. 134-1).³ In normal shoulders, the glenoid is mildly retroverted by approximately 5 degrees posteriorly relative to a line perpendicular to the axis of the scapular body.⁴ With Erb palsy, glenoid retroversion averages 25 degrees. The scapula is hypoplastic and elevated; the acromion is tapered and inferiorly directed, as is the coracoid; the clavicle is shortened.

Many of these findings are seen on radiography; however, computed tomography (CT) or MRI can be used to quantify the degree of glenoid retroversion, deformity of the glenoid and humeral head, glenoid–humeral head congruence, and relative muscle volume and quality of the affected shoulder.5–9 The glenoid normally has a concave shape. With glenohumeral dysplasia, the glenoid becomes progressively flat, convex, or biconvex with a pseudoarticulation with the humeral head. MRI is preferred in young children (<5 years old) (e-Fig. 134-2) and CT in older children. To determine glenoid version, the articular cartilage should be used when MRI is performed; the glenoid cortical bone should be used when CT is performed. In infants, ultrasonography may be used to assess instability of the glenohumeral joint.^10–12

Treatment: Microsurgery techniques may be attempted to address the underlying traumatic neural injury.¹³ Controversy exists as to their role and proper timing. The main focus of treatment is on the reconstructive surgical techniques of the shoulder, elbow and forearm, and hand and wrist, aimed at preserving joint integrity and maximizing function.^13,14 Therefore, imaging optimization should be tailored for orthopedic anatomy rather than the brachial plexus.

Etiologies, Pathophysiology, and Clinical Presentation: In Madelung deformity, the radius is short and its distal articular surface tilted toward to ulna.¹⁵ In most cases, the cause of Madelung deformity is unknown. Madelung deformity occurs more often in girls.¹⁶ Patients may have pain; however, treatment is more often sought because of deformity or limited range of motion. With an underlying syndrome, the deformity is more likely to be bilateral. Madelung deformity is occasionally seen with Turner syndrome and is a characteristic in dyschondrosteosis (Léri-Weill syndrome) (Fig. 134-3).¹⁵ Among these cases, 10% to 15% are familial. A Madelung-like deformity may also be seen in patients with hereditary osteochondromatosis or enchondromatosis, also suggesting a defect in normal distal radial maturation. Madelung deformity may occur as a complication of infection or trauma that results in medial and volar radial physeal growth disturbance.¹⁷

Imaging: The distal articular surface of the radius is tilted in an ulnar and volar direction.18,19 The radius is short and bowed dorsally and laterally (“bayonet deformity”). Secondary distortion of the carpus is observed with an abnormally narrow carpal angle and proximal lunate migration.^18,19 The distal ulna is subluxed. The distal radial growth plate may prematurely fuse along its ulnar aspect. CT or MRI may be used to assess the extent of distal radial physeal fusion.²⁰

Treatment: Treatment is aimed at relieving pain caused by ulnocarpal impingement and improving wrist mobility.¹⁷ Ulnar shortening and radial wedge osteotomies are common techniques.¹⁷

Etiologies, Pathophysiology, and Clinical Presentation: Trauma, infection, inflammatory disease (juvenile idiopathic arthritis) or other causes of premature fusion may lead to shortening of the ulna relative to the radius (negative ulnar variance) or shortening of the radius relative to the ulna (positive ulnar variance) (Fig. 134-4).²¹ Most cases are idiopathic. Processes associated with hyperemia, for example, fracture healing, infection and vascular lesions, may lead to over growth of one of the bones.

Imaging: At skeletal maturity, the distal radial and ulnar articular surfaces are nearly at the same level, and the radial styloid projects 9 to 12 mm distal to the ulnar articular surface.21,22 With negative ulnar variance, the ulna ends more proximally, and with positive ulnar variance, the ulna ends more distally (e-Fig. 134-5).^21,23 Ulnar variance may be exaggerated with forearm pronation and decreased with forearm supination.

Treatment: Osteotomy with ulnar or radial shortening may be indicated to reduce symptoms and avoid sequelae. Negative ulnar variance is associated with the development of avascular necrosis of the lunate (Kienböck disease).²⁴ Positive ulnar variance is associated with ulnolunate impaction syndrome (Fig. 134-6) and triangular fibrocartilage complex degeneration.

Etiologies, Pathophysiology, and Clinical Presentation: The normal neck-shaft angle of the proximal femur is approximately 150 degrees at birth and decreases to 120 to 130 degrees in adulthood.²⁵ External or internal rotation of the hip or femoral anteversion may affect measurement.²⁶

Functional coxa vara occurs with disorders that result in femoral neck shortening, as in trauma, infection, or epiphyseal osteonecrosis.²⁷ True coxa vara occurs as a congenital anomaly that is caused by bone softening (e.g., rickets, osteogenesis imperfecta, fibrous dysplasia) or to abnormal growth (e.g., spondyloepiphyseal dysplasia congenita, spondyloepimetaphyseal dysplasia, cleidocranial dysplasia).^28,29 Children with developmental coxa vara present with a limp (unilateral deformity) or a waddling gate (bilateral deformities). Coxa vara may occur as the result of abnormal growth at the proximal femoral physis that results in abnormal angulation of the physis. Congenital coxa vara occurs with a congenital short femur (i.e., proximal focal femoral deficiency) and does not spontaneously resolve.²⁸ With infantile or developmental coxa vara, the hip is normal at birth, and deformity is noted when the child begins to walk.^28,30 Infantile coxa vara may be self-limited. Acquired coxa vara is caused by another process such as trauma.²⁸

Imaging: In coxa vara, the femoral neck-shaft angle is decreased from normal. A measurement below 110 degrees is considered coxa vara.³¹ Fragmentation and sclerosis may be seen at the medial margin of the proximal femoral metaphysis (Fig. 134-7).³⁰ The Hilgenreiner epiphyseal angle is the angle between the Hilgenreiner line and a line drawn through the physis (e-Fig. 134-8).^28,31 If it is less than 45 degrees, progression is unlikely. If over 60 degrees, progression is likely. If 45 to 60 degrees, prognosis is less predictable.

Treatment: Surgical management may be warranted for progressive disease, especially if asymmetric or associated with pain, leg length discrepancy, or both.²⁸ Valgus osteotomy is performed, and physeal fixation or tendon transfers may also be performed to deter progression and improve mechanical function.

Etiologies, Pathophysiology, and Clinical Presentation: With coxa valga, the neck-shaft angle of the proximal femur is increased.³² Coxa valga is most often seen in patients who are nonambulatory and nonerect, such as those with cerebral palsy and other neuromuscular disorders (Fig. 134-9).^26,33

Imaging: The femoral neck-shaft angle is measured on radiographs. External rotation may mimic coxa valga and can be differentiated through the positioning of the greater trochanter.²⁶ With external rotation, the greater trochanter projects through the femur, whereas with true coxa valga, it is located laterally. Increased femoral anteversion may cause the femoral neck-shaft angle to be overestimated.³² Acetabular dysplasia and femoral subluxation are frequently concomitant findings.³²

Treatment: Varus osteotomy and iliac osteotomy are often performed together in patients with cerebral palsy to better direct the femoral head into the acetabulum.

Etiologies, Pathophysiology, and Clinical Presentation: Increased femoral anteversion may hinder proper localization of the femoral head relative to the acetabulum. Increased femoral anteversion is seen in hip deformity caused by developmental dysplasia of the hip, Legg-Calvé-Perthes disease, and cerebral palsy.³² With increased anteversion, in-toeing of feet is noted.

Femoral version is the angulation of the femoral neck in the transverse plane measured relative to the femoral condyles distally (Fig. 134-10). If the femoral neck is anteriorly angulated with respect to the femoral condyles, the femur is anteverted. If the femoral neck is posterior with respect to the femoral condyles, the femur is retroverted. Normal femoral anteversion is 35 to 50 degrees at birth, decreasing steadily to 10 to 15 degrees in adulthood (Fig. 134-11).²⁷

Imaging: On CT, femoral anteversion is the angle between the axis of the femoral neck and the transcondylar axis at the distal femur (Fig. 134-12).^34–36 Limited low-dose axial images are usually performed; however, axial oblique or three-dimensional images may improve measurement.^37,38

Treatment: Most children with increased femoral anteversion are managed conservatively. Surgical indications for treatment include symptomatic in-toeing secondary to excessive femoral anteversion. Femoral rotational osteotomy may be performed to optimize femoral version.

Etiologies, Pathophysiology, and Clinical Presentation: Tibial torsion is the degree of rotation of the distal end of the tibia relative to the upper end of the tibia. Newborns have internal tibial torsion relative to older children and adults. Lack of normal progression results in in-toeing. Internal tibial torsion is the most common cause of in-toeing in the preschool age group.

Imaging: Assessment of tibial torsion is often performed with assessment of femoral version. Limited axial low-dose CT images are obtained through the proximal and distal tibias.⁴¹ Tibial torsion is best measured as the angle between the posterior epiphyseal cortical margin of the tibia proximally and a bimalleolar line distally. Normal values are 5 degrees of external rotation in a newborn, which progresses to 15 to 20 degrees of external rotation in an adult.^40,42

Treatment: Surgery is rarely needed as more than 95% of cases resolve spontaneously, usually by 8 years of age. Tibial rotational osteomy may be performed to optimize tibial alignment.

Etiologies, Pathophysiology, and Clinical Presentation: Bowleg deformity manifests as separation of the knees, with the legs in anatomic position. Pathologic causes include rickets, osteogenesis imperfecta, neurofibromatosis, skeletal dysplasias (i.e., campomelic dysplasia, achondroplasia), focal fibrocartilaginous dysplasia, congenital bowing, Blount disease, and, occasionally, growth plate trauma.43–46 Recently, greater prevalence of bowleg and tibia vara has been noted in some adolescent athletes, most notably soccer players.^47–49 Repetitive stress on the proximal tibial physis may play a role in this.⁴⁸ Most lateral bowing in otherwise normal infants and children younger than 2 years of age is normal and developmental (“physiologic”) and resolves without treatment.^44,50–52 Similar to Blount disease, exaggerated physiologic bowing is seen in early walkers, African Americans, and heavier children.⁴⁴

Imaging: Ozonoff described the following findings as characteristic of physiologic lower extremity bowing: (1) The tibia is abducted relative to the femur, and both bones are intrinsically bowed laterally; relative tibial torsion produces external rotation of the upper tibia relative to the distal tibia; (2) margins of the distal femoral and proximal tibial metaphyses are mildly accentuated with small beaks; (3) medial cortices of the tibia and femur are thickened; (4) distal femoral and proximal tibial epiphyses are not well ossified medially and are wedge shaped; (5) the distal tibial growth plate may be tilted lateral.⁵³

Radiographically, the femur and the tibia are also mildly bowed anteriorly, with beaking occurring posteriorly (Fig. 134-13). Physiologic bowing is usually more marked in the tibias. Occasionally, lateral bowing may almost exclusively be seen in the distal femur (e-Fig. 134-14). The varus deformity is common in normal infants and converts to valgus between 18 and 36 months of age. Degree of valgus reduces spontaneously by 6 to 7 years of age to a mild degree that remains throughout life. Approximate normal angles are 17 degrees varus in a newborn, 9 degrees varus at 1 year, 2 degrees valgus at 2 years, 11 degrees valgus at 3 years, and 5 to 6 degrees valgus at 13 years (e-Fig. 134-15).^52,54,55

Radiographs should be taken with the patient bearing weight as soon as he or she is able to stand (Fig. 134-16). The radiographs may suggest an underlying disorder such as rickets or a dysplasia.

Treatment: Persistent varus with delayed conversion to valgus may indicate a higher likelihood of Blount disease (tibia vara). In the second year, it may be difficult to distinguish normal physiologic bowing from Blount disease.⁵⁶ Exaggerated varus during the second year is likely developmental or physiologic and does not require treatment.^50,51,54 Any varus at the knee after 2 years of age should raise concern. Such patients must be monitored to exclude progression to Blount disease.^55,57 Realignment surgery is rarely needed in isolated bowleg without underlying dysplasia, metabolic bone disease, or Blount disease.

Etiologies, Pathophysiology, and Clinical Presentation: Blount disease (tibia vara; osteochondrosis deformans tibiae) is a progressive deformity affecting the proximal tibia (Fig. 134-17).^58–60 It is theorized that stress on the posteromedial proximal tibial physis causes growth suppression.

The infantile form of Blount disease, which develops in children between 1 and 3 years of age, must be differentiated from developmental bowing.⁶¹ Infantile Blount disease may represent normal developmental bowing that fails to correct and progresses. The diagnosis is made when progressive clinical bowing is seen in the presence of characteristic radiographic changes in the proximal tibia.⁶¹ The disease is typically bilateral (60% to 80%) but often asymmetric and occasionally unilateral (Fig. 134-18). A family history is often reported. The disorder is more common in early walkers, African Americans, and obese children.^44,60,62

Adolescent or late-onset tibia vara is a separate entity from the infantile form. It occurs in children 8 to 14 years of age; obese African American males of normal height are at particular risk (Fig. 134-19).⁴³ Adolescent tibia vara is commonly unilateral but may be bilateral. Adolescent Blount disease is slowly progressive and probably results from the repetitive trauma of weight bearing on the medial physis of the proximal tibia.⁴³ Patients often present with knee pain.

Imaging: The characteristic radiographic feature of infantile Blount disease is deformity of the medial metaphysis of the proximal tibia (Fig. 134-20).⁴⁴ Irregularity with a more vertically oriented growth plate creates a beaked appearance. The severity of radiographic changes has been described by the six-stage Langenskiöld classification (e-Fig. 134-21).⁶³ Higher stage denotes greater abnormality; bone bridging between the diaphysis and the metaphysis is seen with stage IV and higher. The medial portion of the epiphyseal ossification center is often smaller than the lateral portion. The tibia may subluxate laterally.

The metaphyseal–diaphyseal angle is measured by drawing a single line through the widest portion of the proximal tibial metaphysis (between the medial and lateral beaks) and another line perpendicular to the long axis of the tibia.⁵¹ With physiologic bowing, this angle measures approximately 5 degrees, whereas with Blount disease, average angle measurement is 16 degrees (e-Fig. 134-22). A metaphyseal–diaphyseal angle greater than 11 degrees suggests Blount disease.^44–51 However, several studies have questioned the validity of the metaphyseal–diaphyseal angle, and measurement may be affected by tibial rotation.

Changes related to infantile Blount disease should be distinguished from those of adolescent Blount disease (see Figure 134-19). The metaphyseal angular deformities, diminished medial epiphyseal height, and degree of tibia vara are less severe with adolescent Blount disease.

CT or MRI can assess the degree of proximal tibial growth plate fusion and epiphyseal cartilage abnormalities (e-Fig. 134-23).^64,65 Cartilage-sensitive MRI sequences display the cartilage model of the proximal tibial epiphysis.⁶⁵

Treatment: Although spontaneous resolution of infantile Blount disease is reported in some instances, treatment with bracing is begun usually between ages 18 and 24 months and is continued during waking hours for an average of 2 years. If conservative management fails, the patient may undergo a realignment osteotomy, which is most effective when performed before 5 years of age. For adolescent Blount disease, a lateral tibial epiphyseodesis may be performed if sufficient growth still remains. If the proximal tibla physis are near fused, a proximal tibial valgus osteotomy to produce normal alignment may be performed.⁶⁰

Etiologies, Pathophysiology, and Clinical Presentation: Genu valgum is a normal developmental phase that lasts from 2 to 12 years of age and is most apparent at 3 to 4 years of age in normal children.52,54,55,66 Persistent knock-knee can be related to pathologic causes such as trauma, skeletal dysplasia, obesity, metabolic disease, or laxity of muscles and ligaments.

Imaging: In knock-knee, the legs deviate laterally when in anatomic position. Wide separation is noted at the ankles (Fig. 134-24). Radiographs may show evidence of an underlying disorder or complicating process.

Treatment: Treatment is conservative, particularly for children with physiologic knock-knee. Bracing is occasionally employed. Rarely, surgical osteotomies are performed for realignment.

Overview: A leg length discrepancy of less than 1 cm is considered within normal limits; however, in most normal individuals, the legs are within 1 mm of each other in length. The presence of a leg length discrepancy may reflect overgrowth of the long limb or decreased size or growth of the short limb. Leg length discrepancy is often of clinical significance because of associated alteration of gait and resultant pelvic tilt. With significant pelvic tilt, secondary compensatory scoliosis may develop.

Etiologies, Pathophysiology, and Clinical Presentation: The differential diagnoses for overgrowth and undergrowth is lengthy. Overgrowth is associated with a number of syndromes and vascular abnormalities. Mild overgrowth may occur as the result of fracture healing. In many cases, the cause is unknown. Undergrowth may be caused by hypoplasia or aplasia of a segment of the limb. Acquired shortening most often occurs as a consequence of premature growth plate fusion due to trauma, infection, or vascular insufficiency.

Imaging: Radiographic techniques seek to determine bone lengths in a manner that minimizes magnification and other technical factors. Orthoroentgenography (“scanogram”) uses three separate exposures collimated to the hip, knee, and ankle with a radiopaque ruler.⁶⁷ CT digital scout images may be used to measure bone length.^68,69 It is preferable to quantify length and alignment abnormalities with standing radiographs.

In addition to determining quantitative length and discrepancies in length of the lower extremities, leg-length studies should also be evaluated and comments should be made with regard to the alignment of the hips, knees, and ankles. Any underlying cause of the leg length discrepancy such as physeal growth disturbance or abnormal nonosteoarticular bowing deformities should also be discussed.

Treatment: Mild leg length discrepancy does not warrant treatment. The type of treatment varies with age, amount of projected growth remaining, site of abnormality, and degree of leg length discrepancy. Treatment may be aimed at halting growth on the longer side (i.e., epiphyseodesis) or lengthening the shorter side (i.e., lengthening osteotomy procedure).⁷⁰ With a lengthening osteotomy procedure, bone on either side of a diaphyseal corticotomy is distracted slowly utilizing an external frame. New bone forms within the gap to add length.

Overview: Alignment disorders of the feet may be idiopathic or caused by an underlying disorder. The standard method of radiologic evaluation of the foot involves weight bearing or simulated weight bearing anteroposterior (dorsoventral) and lateral views. Diagnosing alignment abnormalities of the feet should be approached with caution when non-weightbearing radiographs are obtained.

The talus is more proximal and is considered fixed at the ankle because it has no musculotendinous attachments of its own. The calcaneus is linked to the midfoot and forefoot and moves as a unit with these structures relative to the talus. In a normal foot, on the anteroposterior view, the axis of the talus extends through the base of the first metatarsal (Fig. 134-25). With hindfoot varus, the more distal calcaneus is angulated inward, and the axis of the talus passes lateral to the base of the first metatarsal. With hindfoot valgus, the more distal calcaneus is angulated outward, and the axis of the talus passes medial to the base of the first metatarsal.⁸¹ The normal lateral talocalcaneal angle is approximately 45 degrees, decreasing to 30 degrees in older children and adults.^71–73 With hindfoot varus, the lateral talocalcaneal angle is decreased, whereas with hindfoot valgus, the angle is increased.

Normal elevation of the middle metatarsals relative to the fifth metatarsal reflects the transverse arch of the foot. The anterior calcaneus is slightly inclined upward. Accentuation of this upward inclination is called “calcaneus” position of the hindfoot. Equinus is downward inclination of the distal calcaneus. Normal calcaneal tilt and normal slight downward tilt of the distal metatarsals create slight longitudinal concavity in the osseous contour of the bottom of the foot.

Etiologies, Pathophysiology, and Clinical Presentation: Talipes (“talus” = ankle; “pes” = foot) equinovarus, or clubfoot, is a common congenital anomaly that is clinically obvious at birth. The principal components of clubfoot deformity include plantar flexion of the ankle (equinus), inversion of the heel (varus), and adduction of the forefoot (varus) (Fig. 134-26). Abnormal intrauterine pressures contribute to the development of clubfoot.⁷⁴ Genetics also appear to play a role.⁷⁴

Imaging: Radiographs are obtained with true or simulated weight bearing, as this is the position of best correction.⁷⁴ An anteroposterior radiograph shows superimposition and parallelism of the talus on the calcaneus with the talar axis directed lateral to the first metatarsal (hindfoot varus). Parallelism of the talus and calcaneus is also seen on a lateral view. The lateral view shows plantar flexion of the calcaneus (equinus) and a step-ladder arrangement of the metatarsals, with the first metatarsal highest and the fifth metatarsal at the weight-bearing surface of the foot. Ultrasonography has been used in select centers to assess the flexibility of clubfoot and to guide therapeutic decision making (e-Fig. 134-27).^75–78

Treatment: Approaches to treatment include serial casting for supple clubfoot deformity, and casting followed by surgical correction for rigid clubfoot deformity.74,79,80 Anatomic deformities persist after treatment of clubfoot and should be recognized as children grow. Many treated clubfeet have small, squared tali with flattened heads, decreased talocalcaneal angles, subtalar joint changes, and medial displacement of the navicular. Valgus deformity may result from overcorrection.

Etiologies, Pathophysiology, and Clinical Presentation: Congenital vertical talus (congenital rigid flatfoot) may be an isolated condition or may be seen in association with various syndromes (e.g., trisomies) or other systemic abnormalities (i.e., central nervous system defects, arthrogryposis, and neurofibromatosis).81,82

Imaging: The talus is almost completely vertical in this condition (parallel with the longitudinal axis of the tibia), and the calcaneus is fixed in plantar flexion (equinus) (Fig. 134-28). In the anteroposterior projection, the talar axis is medial to the base of the first metatarsal (valgus). The navicular dislocates dorsally, and clinically, a pronated rocker-bottom foot is present. After the navicular ossifies, its abnormal position helps to distinguish congenital vertical talus from severe planovalgus or flatfoot deformity. Prior to ossification, the position of the navicular can be determined by ultrasonography.⁸³

Treatment: Congenital vertical talus is initially managed with conservative measures, followed by surgical correction for recalcitrant cases.⁸²

Etiologies, Pathophysiology, and Clinical Presentation: Rocker-bottom foot is seen with congenital vertical talus and severe cerebral palsy with hindfoot valgus, and it occurs as a complication of incorrectly treated clubfoot with persistent equinus.

Imaging: In rocker-bottom foot, the calcaneus is in equinus position and the metatarsals are dorsiflexed, producing a convex surface on the bottom of the foot.

Etiologies, Pathophysiology, and Clinical Presentation: Metatarsus adductus is a cause of in-toeing that is usually seen in children younger than 5 years of age. Forefoot adduction differs from clubfoot in that midfoot and hindfoot relationships are normally maintained. The affected foot has a C-shaped contour on examination. Forefoot adduction simulating metatarsus adductus may occur as a result of excessive internal tibial torsion or increased femoral neck anteversion.

Imaging: The metatarsals are adducted and hindfoot alignment is normal.

Treatment: Metatarsus adductus commonly resolves with normal maturation and no treatment.⁸⁴

Etiologies, Pathophysiology, and Clinical Presentation: Skewfoot (Z-foot; serpentine metatarsus adductus) is considered a severe form of metatarsus adductus. It is not a congenital deformity but develops in the young child idiopathically or may result from the treatment of other congenital foot deformities such as treated clubfoot or vertical talus. Skewfoot occurs in children with cerebral palsy and with some dysplasias and in otherwise normal children as well.⁸⁵

Imaging: In skewfoot, the forefoot is adducted, the midfoot is abducted, and the hindfoot is in valgus, resulting in a “Z”-like distortion of the bones of the foot (Fig. 134-29).⁸⁵

Treatment: Conservative management suffices in most idiopathic cases, with resolution of the abnormality. A variety of surgical techniques have been applied to reduce deformity in children with fixed or progressive deformity.84,85

Etiologies, Pathophysiology, and Clinical Presentation: Flatfoot (pes planus) is a descriptive term. The differential diagnosis of pes planus includes flexible planovalgus foot, peroneal spastic (rigid) flatfoot related to tarsal coalition, congenital vertical talus (congenital rigid flatfoot), and congenital calcaneovalgus (congenital flexible flatfoot).81,86–88 Tarsal coalition is discussed in Chapter 128.

The common flatfoot is a painless, flexible planovalgus foot.⁹¹ Variable degrees of hindfoot valgus, plantar arch flattening, and forefoot pronation occur. Pathology is thought to involve excess ligamentous laxity, which allows the calcaneus to shift into a valgus position under the talus. Abduction and eversion result from loss of calcaneal support. Patients may develop peroneal muscle spasm and pain caused by irritation.

Imaging: With flexible planovalgus foot, the anteroposterior projection shows hindfoot valgus with an increased talocalcaneal angle and the midtalar line passing medial to the first metatarsal. On the lateral projection, hindfoot valgus causes the talus to be more vertical than normal. The navicular subluxes dorsally and laterally with respect to the talar head. The calcaneus and metatarsals are horizontal longitudinally, and loss of the plantar arch is noted.⁸¹ Similar deformity may occur in some children with cerebral palsy (e-Fig. 134-30). With a rigid or painful flatfoot (peroneal spastic flatfoot), CT may be performed to detect an underlying subtalar coalition.

Treatment: Therapy for pes planus depends on the etiology and type of deformity.⁸⁶ Flexible planovalgus deformity is managed conservatively.⁸⁸ Rigid (spastic) flat foot with tarsal coalition requires surgery.⁸⁷

Etiologies, Pathophysiology, and Clinical Presentation: Calcaneovalgus feet are reflective of intrauterine positioning. A total of 30% to 50% of newborns have mild calcaneovalgus deformity.⁹¹ In severe congenital calcaneovalgus, the foot is dorsiflexed with respect to the talus. The defect is flexible and correctable.

Imaging: Radiographs show the hindfoot in severe valgus position with a plantar flexed talus. The navicular is not dislocated. The defect is flexible and correctable.

Treatment: Calcanovalgus foot is treated conservatively with physical therapy.

Etiologies, Pathophysiology, and Clinical Presentation: An idiopathic congenital form of cavus foot exists, but more commonly, the finding is related to neuromuscular abnormalities, including peroneal muscular atrophy (Charcot-Marie-Tooth disease), Friedreich ataxia, myelomeningocele, poliomyelitis, and other paralytic conditions.89,90 A cavus foot may also result from treated clubfoot deformity.

Imaging: In pes cavus, the longitudinal plantar arch is increased. The anterior calcaneus is abnormally dorsiflexed and the metatarsals are plantarflexed (Fig. 134-31).

Treatment: Treatment may involve conservative measures and surgery (soft tissue and plantar fascia release, osteotomy, tendon transfers).⁸⁹

Etiologies, Pathophysiology, and Clinical Presentation: Hallux valgus deformity begins to develop and may occasionally present in childhood.⁹¹ Hallux valgus affects females ten times as frequently as males. Patients present with pain and deformity which may interfere with proper shoe fitting.

Imaging: The upper normal limit of medial angulation of the proximal phalanx of the great toe to the first metatarsal is 14 to 16 degrees. Higher angles are considered hallux valgus (e-Fig. 134-32). With increasing angulation, the medial margin of the first metatarsal head may become more uncovered and protuberant.

Treatment: First metatarsal osteotomy may be performed to correct alignment.⁹¹

Overview: Children with cerebral palsy are afflicted with multiple orthopedic disorders requiring radiographic investigation and surveillance.102,103 Variable manifestations of cerebral palsy are caused by variation in severity and location of the original insult.¹⁰² In most cases, cerebral palsy is the consequence of fetal or perinatal insult to the brain, usually hypoxic–ischemic or hemorrhagic in nature. Cerebral palsy also occurs as the result of injury to the brain matter that occurs during early childhood.

Etiologies, Pathophysiology, and Clinical Presentation: The orthopedic disorders of cerebral palsy are caused by imbalanced muscular forces. Although cerebral palsy is a static encephalopathy, the resultant musculoskeletal disease may be progressive, even after skeletal maturity.

Imaging: About 25% of cerebral palsy patients have scoliosis.32,104 Scoliosis is more prevalent and severe with greater neurologic deficit. Scoliosis occurs as the result of imbalanced forces on the two sides of the spinal column. As opposed to the S-shaped curves of idiopathic scoliosis, curves in cerebral palsy often have a long C-shaped contour, and the curves may progress after skeletal maturation.^32,94 Associated findings may include accentuated thoracic kyphosis or lumbar lordosis, spondylolysis or spondylolisthesis, and pelvic obliquity. Nonambulatory patients also show caninization of the vertebral bodies (narrow anteroposterior diameter) caused by lack of weightbearing forces during development.

Upper extremity defects include radial head dislocation (Fig. 134-33) and contractures at the elbow, wrist, and fingers.^95,96 Kienböck disease and negative ulnar variance are of increased incidence in cerebral palsy, but a link between the two findings has not been shown in these patients.⁹⁷ Accelerated degenerative changes in the elbow and wrist are common in older patients with cerebral palsy.⁹⁵

Abnormalities at the hip include coxa valga caused by lack of weightbearing, increased femoral anteversion, prominence of the lesser trochanter caused by external rotation forces by the iliopsoas tendon, femoral head subluxation or dislocation, acetabular hypoplasia and dysplasia, and flattening of the femoral head (see Fig. 134-9).^32,98 Posterior and superior acetabular deficiency is seen. Patients may experience pain with progressive hip subluxation, which progresses to dislocation. The “windswept” pelvis is seen when one hip has an adductor contracture and the other hip has an abductor contracture, reflecting the asymmetric neuromuscular defects often seen in nonambulatory patients with severe spasticity. Older patients with cerebral palsy show evidence of superimposed degenerative disease at the hips.

At the knee, flexion contractures may be present. The patella is often high (patella alta) and elongated.32,99 Tug lesions are common at the lower pole of the patella, producing a fragmented appearance.^32,100 The tibial tuberosity may appear elevated and irregular. Genu recurvatum may be seen with rectus femoris contracture. Valgus is seen at the ankle, and equinus and hindfoot valgus are common in the foot (see e-Fig. 134-30).^32,101 Osteopenia predisposes patients with cerebral palsy to fracture.¹⁰²

Treatment: Treatment of orthopedic conditions in cerebral palsy is aimed at maximizing function and limiting the progression of deformity.

Overview: Children with myelomeningocele and related spinal disorders may be afflicted with multiple orthopedic disorders of the spine and lower extremity requiring radiographic investigation and surveillance.103,104 Variable manifestations of myelomeningocele relate to the level of the defect. Children with other spinal pathologies, including those suffering injury to the spinal cord at a young age, may develop orthopedic disorders similar to those with myelomeningocele.

Etiologies, Pathophysiology, and Clinical Presentation: Orthopedic disorders in myelomeningocele patients are caused by lack of normal muscle development and function. This leads to scoliosis and joint malalignments.

Imaging: Scoliosis in patients with myelomeningocele may be congenital or developmental and progressive.¹⁰⁴ In 20% of patients with myelomeningocele, congenital scoliosis is often caused by vertebral segmentation errors. Congenital kyphosis is most common at L1-L2. Kyphosis may also be acquired.¹⁰⁴ Lumbar lordosis is commonly accentuated.

One third to one half of patients with myelomeningocele have hip dysplasia. The hips are occasionally dislocated at birth; however, more often, dysplasia develops over time as the result of paralysis of the hip extensors and abductors with unopposed hip flexors and adductors (e-Fig. 134-34).¹⁰⁴ Coxa valga and increased femoral anteversion are common.¹⁰⁴ Excessive external tibial torsion with out-toeing or internal tibial torsion with in-toeing may be seen. In all, 80% to 95% of patients have foot deformities. Equinovarus (clubfoot), congenital vertical talus, and other foot deformities may also be seen in these patients.¹⁰⁴

Infants with myelomeningocele have an increased incidence of fracture of a lower extremity during birth.¹⁰⁵ A higher incidence of fracture is seen with contractures and higher levels of spinal defect. Patients with myelomeningocele may develop neuropathic injuries as the result of osteoporosis and lack of sensation.^104,106,107 Fractures are most commonly metaphyseal or diaphyseal, but they may occur through a physis. Periosteal new bone and callous may be exuberant because of delayed diagnosis without immobilization and abundant subperiosteal hemorrhage.^104,106 Such injuries may be mistaken for tumor or infection.

Treatment: Treatment of orthopedic conditions in patients with myelomeningocele is aimed at maximizing function and limiting the progression of deformity.