Orthopaedics for the Pediatrician

Thomas E. Kuivila

Orthopaedic problems, conditions, and abnormalities are presenting complaints frequently encountered by pediatricians and other primary care physicians who treat children. The intent of this chapter is to familiarize the practitioner with the common and some of the less common orthopaedic conditions of the neonate, toddler, child, and adolescent.

Orthopaedic congenital abnormalities can be categorized as:

Structural
Developmental
Secondary to intrauterine molding
Traumatic

Structural problems that represent abnormal intrauterine development are typically caused by an event, teratogenic influence, or genetic abnormality and are manifested in the first trimester of pregnancy. Orthopaedic conditions that fall into this category are frequently associated with visceral abnormalities, most often of the heart and genitourinary tract, because of the temporal proximity of events in development. So-called developmental abnormalities (fetal arrest) typically appear later in pregnancy and may be thought of as development that has stopped before completion. These conditions may affect the axial or appendicular skeleton. When an abnormality is in a lateral location, it is not infrequent for it to be manifested bilaterally. Packaging or molding abnormalities are a result of intrauterine forces and are therefore most common in cases of significant “tight packaging.” Scenarios contributing to this phenomenon include the primigravida uterus, multiple fetuses, oligohydramnios, and other uterine abnormalities, such as significant fibrosis or a bicornuate uterus.

ABNORMALITIES OF THE NECK

The most common abnormality noted in children at birth is congenital muscular torticollis, which results from a sternocleidomastoid contracture. The sternocleidomastoid attaches to the mastoid process, and heads originate from both the sternum and the clavicle. When the muscle is tight or contracted, the head tilts toward and rotates away from the affected side. The condition is more common following prolonged labor and in first-born and high-birth-weight infants. It is associated with other packaging abnormalities, especially developmental dysplasia of the hip and metatarsus adductus.

Torticollis is thought to be caused either by prolonged intrauterine packaging in the noted position or possibly by an ischemic event within the substance of the sternocleidomastoid during a long labor process.

Treatment typically addresses the contracture. If the contracture has not resolved by the age of 12 months, surgical lengthening may be indicated. Persistent sternocleidomastoid contractures can result in long-term skull asymmetry and vision problems.

Klippel-Feil syndrome is a congenital synostosis of the cervical vertebrae. On radiography, the vertebral bodies appear to be fused. The condition results in diminished motion and increased stress across the vertebral segments that are not fused. Long-term instability of the neck and degenerative change can develop. Because this is a structural problem manifested in the first trimester, abnormalities of the genitourinary tract, cardiopulmonary system, and central nervous system are frequently associated with it. The congenital synostoses often cause the neck to appear short, and the hairline may appear low posteriorly.

Sprengel deformity is a failure of complete descent of a scapula. This is typically a unilateral condition. When it is severe, surgical intervention may be necessary to bring the scapula further caudal on the dorsal surface. Occasionally, an omovertebral bone may be present. This is a bony or cartilaginous band originating from the superomedial corner of the scapula that attaches to the spinous process.

Cleidocranial dysostosis is bilateral absence of the clavicles, which can result in problems of shoulder instability. However, the orthopaedic manifestations are typically not profound.

Congenital pseudoarthrosis of the clavicle is a condition in which an area of fibrous tissue is interposed in the right clavicle at the midshaft. A prominence in the midshaft of the clavicle is typically seen as early as 1 year. The etiology is unclear, but the condition is thought to be caused by underlying vascular structures on the right. The only reported case of congenital pseudoarthrosis of the left clavicle was associated with situs inversus.

The most common clavicular abnormality noted at birth or at any other time during childhood is a clavicle fracture. Birth fractures are typically caused by shoulder dystocia and paradoxically are good. In high-birth-weight infants, shoulder dystocia can stretch the brachial plexus and lead to lifelong debilitating problems. Fracture of the clavicle generally allows the shoulder to pass through the birth canal without nerve stretch. Clavicle fractures at birth and throughout childhood typically heal promptly without long-term sequelae.

DISORDERS OF THE UPPER EXTREMITY

Radial-ulnar synostosis is a congenital condition in which the radius and ulna are connected by a dense fibrous bridge or more commonly a bony bridge at the elbow. This prevents pronation and supination. When the condition is unilateral, typically no treatment is required because sufficient compensation develops. When it is bilateral and the hands are in an abnormal position, surgery is typically indicated to place the dominant hand in mild pronation and the nondominant hand in mild supination.

Another not uncommon finding in the forearm is a congenitally dislocated radial head. This condition, which limits pronation and supination in the upper extremity, although not to the same degree as radial-ulnar synostosis, is frequently noted incidentally on radiography performed to evaluate trauma to an upper extremity. It can be mistaken for an acute injury, but the radial head demonstrates classic signs of long-term dislocation, including a typical abnormal shape. Congenital dislocations of the radial head should be left alone because attempts to reduce the abnormality are fraught with complications.

Abnormalities of the hands include failure of formation of the digits with transverse or longitudinal deficiencies. Duplicated digits are not uncommon and frequently present as a “duplicate” thumb or sixth digit. These are typically excised early on for cosmesis and function. Syndactyly, a congenital connection between the digits, may be simple or complex, complete or incomplete. Complete or incomplete refers to the length of the digit that is attached to its neighbor. Simple or complex refers to radiographic appearance and whether or not the bones are similarly conjoined.

TORSIONAL AND ANGULAR ABNORMALITIES OF THE LOWER EXTREMITY

One of the most common reasons for referral to a pediatric surgeon is a malalignment syndrome of the lower extremity. To appreciate what is normal and abnormal, one must understand the etiology and natural history of lower extremity alignment.

Malalignment may be the result of a persistence of intrauterine positioning or part of the natural sequence of development. Children may exhibit deformities of the feet, tibiae, or femora. Although most of these are benign in nature and spontaneously resolve without treatment, some require manipulation, casting, or bracing, and some do eventually require surgery.

Important definitions are listed in Table 64.1.

Internal Tibial Torsion

Tibial torsion, or medial rotation of the tibiae relative to the knee axis, is commonly a result of intrauterine posturing and is frequently associated with metatarsus adductus. Within the uterus, the feet of the fetus are usually internally rotated; this position results in an internal or medial spin of the tibiae. The condition is most commonly noted at about the age a child begins to walk, and the parents bring the child for medical evaluation with concerns about in-toeing and frequent falling.

The natural history of this condition is spontaneous resolution in 95% of cases. Typically, 12 to 18 months after the child starts walking the tibiae are able to rotate to the normal final position of 10 to 15 degrees of external rotation relative to the axis of the knee.

Many braces and devices have been used in the past in an attempt to speed up this resolution. Excellent studies documenting their utility are entirely lacking, and most pediatric orthopaedists prescribe devices such as the Denis Browne bar, but usually only under significant parental pressure. Properly applied the Denis Browne bar does no harm, but it is uncertain whether it truly affects the natural history. Typically, the derotational process does not resolve spontaneously beyond the age of 4 years; therefore, if significant internal tibial torsion persists at this age, a surgical derotational osteotomy can be considered.

TABLE 64.1 IMPORTANT DEFINITIONS

Genu varum: commonly referred to as bowlegs.

Genu valgum: commonly known as knock-knees.

Genu recurvatum: commonly known as back kneeing or hyperextension of the knees.

Version: normal rotation present in many long bones with respect to plane of the joint motion axis.

Femoral version: angle between the transcondylar (knee) and transcervical (femoral neck) axes. Normal femoral version is 10 to 15 degrees—that is, a 10- to 15-degree angle is present between the two axes. If the transcondylar axis is aligned with the coronal plane, the transcervical axis is angled forward of the coronal plane.

Tibial version: angle between the axis of the knee and the transmalleolar axis. Normal tibial rotation is 5 to 10 degrees of lateral or external rotation.

Torsion: from the Latin torsio, “to twist.” Pathologic rotational values are those that are two standard deviations from the mean.

Simple rotational deformity: involves one level.

Complex rotational deformity: two levels of involvement. They may compensate or accentuate each other.

Foot progression angle: angle between the longitudinal axis of the foot and the line of travel in gait. By definition, the value is negative in-toeing and positive in out-toeing.

In-toeing: medial or “inward” pointing of toes relative to the line of travel in stance or gait.

Out-toeing: lateral or “outward” pointing of toes relative to the line of travel in stance or gait.

Thigh-foot angle: angle between the long axis of the foot and the femur with the knee flexed 90 degrees.

Tibial-femoral angle: angle on frontal view (with knees fully extended) between the long axis of the tibia and the femur.

Femoral Anteversion

Anteversion of the femur refers to the fact that the plane of the femoral neck is rotated anteriorly to the plane of the knee. The normal adult value of anteversion is 10 to 15 degrees. The average value of hip anteversion at birth is 30 to 45 degrees. One does not typically see medial femoral rotation from anteversion early in life (the first 2 years) because the short external rotators of the hip (piriformis, gemelli, and obturator) are somewhat short and take 1 to 2 years to lengthen slowly. Once these muscles have achieved a normal length, greater internal rotation of the lower extremity is possible, and the consequence of persistent femoral anteversion becomes apparent. The hip is typically held in a position roughly halfway between the two extremes of motion (internal and external rotation). In cases of significant femoral anteversion, the hip is typically held internally rotated halfway between the limits of internal and external rotation.

Genu Varum and Genu Valgum

Most cases of genu varum and genu valgum seen in children are physiologic, not pathologic, in nature. Most children at birth are in 15 degrees or so of varus (bowleggedness). The varus angulation typically improves, and by the age of 18 to 24months, the legs are straight on an average. The legs continue toward valgus alignment (knock-knees), reaching a nadir of 10 to 15 degrees of valgus at the age of 3 to 4 years. From this point, a gradual drift toward the average adult value occurs and is typically achieved by the age of 7 to 9 years—5 to 7 degrees of valgus in boys and 7 to 9 degrees of valgus in girls. Of course, values within a standard deviation constitute clinical normalcy. Individuals outside this range may have an underlying pathologic condition.

General management principles include the following:

Avoid predicting the outcome; 95% of cases improve, but it is often impossible to identify the 5% that will not.
Document the initial baseline values and those noted at subsequent examinations at 3- to 6-month intervals.
Avoid shoe wedges, certain night braces, and other expensive orthotic devices, which have no scientific documented value.
Reassure the family. This is important. Most cases improve. Surgery is rarely necessary, but it can correct deformities that do not improve. The features of specific entities causing genu varum and genu valgum are summarized in the following.

Physiologic Bowlegs

Lateral bowing: birth to 1 year of age, confined to tibia, no treatment required
Physiologic bowing: 1 to 2 years of age, tibia and femur, no treatment required
No bracing required

Physiologic Knock-Knees

Peak: 3 to 4 years of age
More pronounced in girls and obese children
Progression documented by intramalleolar distance (upper limit of 10 cm)
Resolution in most cases
Osteotomy/hemiepiphysiodesis if deformity persists

TABLE 64.2 TWO CLINICAL PATTERNS OF TIBIA VARA

Age	1-3 Years	6-18 Years
Bilateral	Yes	No
Symmetric	Yes	Variable
Physeal bridge	No	Sometimes
Anisomelia	Slight	Significant
Resolution	Sometimes	No
Treatment	Brace early; osteotomy if progressive	Physeal bridge resection plus osteotomy

Tibia Vara (Blount Disease)

Disordered growth of proximal medial physis and metaphysis
Secondary to osteochondrosis caused by mechanical stress
Frequently associated with medial tibial torsion
Increased incidence in African American and obese children
Two clinical patterns (Table 64.2)
Radiography
- Localized deformity at level of proximal tibia, medial metaphyseal lesion
- Lateral translation of tibia relative to femur
Treatment
- Long leg bracing (begin with night bracing)
- Osteotomy (before age of 4 years if possible)
- Osteotomy/resection of physeal bar