Clubfoot

Clubfoot, or talipes equinovarus, affects one in 1000 live births and is often diagnosed in utero. The condition is characterized by a smaller foot on the affected side, rigidity to plantar flexion, adductus of the forefoot, and inward angulation of the hindfoot (Figure 23-1). Half of cases are bilateral. Although many cases are idiopathic, maternal smoking, certain ethnic backgrounds, and genes affecting both the musculoskeletal and nervous systems have been identified as risk factors. Some believe that disordered development of the talus in utero causes the disorder.

Figure 23-1 Congenital clubfoot.

Management of clubfoot has trended away from immediate surgical reconstruction because of the need for multiple corrective procedures, which can result in muscle weakness or stiffening. Currently, patients with the disorder are treated by progressive treatments that include more specific surgical repair if indicated to prepare for normal ambulation. The Ponseti method is typically used, which begins with tenotomy in most cases and is followed by serial casting and manipulation procedures. The less common French method involves daily physical therapy and binding over the first 2 months of life. Both methods are started early in the neonatal period, so early referral to a pediatric orthopedist is necessary. This visit may be arranged prenatally if the diagnosis is known. Clubfeet that do not respond to these conservative measures necessitate operative management.

In-toeing

In-toeing is expected in children until the lower limbs laterally rotate with time; adult walking patterns are not observed until about 7 or 8 years of age. The cause of in-toeing varies by age, often caused by metatarsus adductus in infants, internal tibial torsion in toddlers, and excessive femoral anteversion in preschool-aged children.

Internal Tibial Torsion

Internal tibial torsion is the most common cause of in-toeing and can be associated with metatarsus adductus. It is usually noted in toddlerhood when children begin to walk. It affects boys and girls equally and is bilateral in about two-thirds of cases. On examination, the knee remains in neutral position while the foot is medially rotated (Figure 23-2). Most cases self-resolve as children begin to walk independently, with normal alignment noted as early as 4 years or as late as 10 years of age.

Figure 23-2 Internal tibial torsion.

Bowlegs

Bowlegs, or genu varum, are noted when children begin walking and can be considered normal until about 3 years of age. Past this age group, however, bowing of the legs is pathologic, and other causes must be considered to establish proper treatment plans.

Developmental Dysplasia of the Hip

Developmental dysplasia of the hip (DDH) bears special mention because it must be diagnosed promptly and does not resolve without intervention. DDH is a rare disorder with high morbidity when the diagnosis is made after 6 months of age. It is characterized by an abnormal relationship between the hip socket, or acetabulum, and the femoral head. DDH represents a spectrum of disorders ranging from mild ligamentous laxity of the hip joint to a fully displaced femoral head. Diagnosis is made by physical examination of the neonate; finding a hip clunk on the Barlow or Ortolani maneuvers warrants immediate orthopedics referral. Whereas the Barlow test can identify a dislocatable hip, the Ortolani test attempts to reduce a dislocation (Figure 23-3). After the first few months of life, limitation or asymmetry of hip abduction is a more reliable examination finding.

Figure 23-3 Developmental dysplasia of the hip.

Babies who are born in the breech presentation have additional stress placed on the developing hip joint and are therefore at higher risk for the disorder. Further risk factors include female gender, positive family history, and high birth weight. The AAP recommends consideration of this constellation of risk factors for ultrasound screening of infants with no clear dislocation on examination. For instance, breech girls have two risk factors and are at relatively high risk for DDH, so screening is warranted. Plain radiographs are more accurate as ossification centers form and are the imaging modality of choice when the infant is older than 6 months of age.

Very mild abnormalities of the hip joint often resolve spontaneously in the first few months of life. When a true dislocation is diagnosed before 6 months of age, the Pavlik harness is the treatment of choice. It is a splint that prevents hip extension and adduction, which can be adjusted as the child grows (see Figure 23-3). Triple diapering or other measures to force the hip into place are no longer seen as effective treatment measures. Diagnosis after age 6 months usually requires surgical repair. When not diagnosed in infancy, parents or pediatricians may notice that the affected child has a waddling or Trendelenburg gait when beginning to walk (see Figure 23-3). DDH may be more difficult to detect in older children because they often have bilateral involvement and therefore may not have a markedly asymmetric gait. These children require an urgent orthopedic referral because they are at high risk for long-term morbidity.

Slipped Capital Femoral Epiphysis

Slipped capital femoral epiphysis (SCFE) refers to an instability of the proximal femoral growth plate in which the femoral head slips posteriorly and inferiorly relative to the femoral neck (Figure 23-4). Although rare, SCFE is an extremely important diagnosis to make because prompt surgical repair is required, and a delay in diagnosis can lead to avascular necrosis. Patients with SCFE are typically obese children in their preadolescent and early adolescent years. A recent study found an incidence of 10.8 SCFE cases per 100,000 children. This incidence is higher in boys than girls and African Americans than whites. Obesity places increased force on the proximal femoral growth plate, putting children at risk for slippage.

Figure 23-4 Slipped capital femoral epiphysis.

Children with SCFE may complain of hip, knee, thigh, or groin pain. Hip pain can refer to the knee via the obturator nerve, so it is imperative to examine the hip in children complaining of isolated knee pain. The most common presentation is that of insidious pain over weeks or months that has gradually worsened and may cause an intermittent limp. SCFE can, however, present acutely as well, often in the setting of minor trauma.

On physical examination, patients with SCFE often hold the affected limb in passive external rotation and have pain with internal rotation. When asked to walk, they may have an antalgic gait. Both hips should be examined to allow for a comparison of range of motion of the two sides. Furthermore, about 20% of SCFEs are bilateral at the time of presentation, and another 20% will progress to bilateral slips if not prevented. Patients diagnosed with SCFE at younger ages are more likely to develop a contralateral slip over time.

Diagnosis is made on anteroposterior (AP) and frog-leg radiographs of the pelvis. The AP view can show widening of the physis and misalignment of the femoral capital epiphysis. On the AP view, the lack of intersection of a line drawn along the femoral neck (Klein’s line) and the femoral epiphysis can confirm the diagnosis. On the frog-leg view, the posterior portion of the femoral head becomes medial, making the slippage more apparent and giving a slipped “ice cream cone” appearance (see Figure 23-4). Patients found to have SCFE should be made non–weight bearing and need to see an orthopedist emergently. Treatment consists of internal fixation using a single cannulated screw, which prevents further slippage and provides symptom relief. There is a great deal of controversy surrounding the role of prophylactic fixation of the unaffected hip in unilateral SCFE.

Legg-Calvé-Perthes Disease

Legg-Calvé-Perthes (LCP) is the eponym given to a disease of idiopathic osteonecrosis of the femoral head. LCP affects children age 3 to 12 years and peaks in the early school years. As with SCFE, there is a male predominance, with males afflicted four times as often as females. Unlike SCFE, however, whites are far more likely to have LCP.

These patients usually have an insidious onset of mild pain worsened by activity that may refer to the thigh or knee. On examination, patients may have a Trendelenburg gait, pain, or decreased range of motion with internal rotation and abduction and even atrophy of the muscle groups in the thighs and buttocks. In advanced disease, radiographs can be helpful and may show fragmentation of the femoral head (Figure 23-5). In early cases, however, radiographic changes can be subtle or nonexistent. A significant concern for LCP may mandate further imaging such as a bone scan or MRI.

Figure 23-5 Legg-Calvé-Perthes disease: ancillary prognostic indicators.

As in SCFE, patients with LCP should be made non–weight bearing and referred to an orthopedic surgeon. Treatment consists of conservative management, including administration of nonsteroidal antiinflammatory drugs (NSAIDs), crutches, and immobilization with the goal of containing the femoral head within the acetabulum. Older children with LCP have a worse prognosis because of the decreased potential for bone remodeling and may experience disabling osteoarthritis in the adult years.

Transient Synovitis

Transient synovitis (TS) is characterized by inflammation of the hip synovium and is the most common cause of acute hip pain in young children. Children with TS are generally well appearing but have hip pain, a limp, or both. They often have low-grade fevers as well. TS typically presents at 3 to 8 years of age, and boys are affected twice as often as girls. It is often attributed to an infectious cause because many children have a history of a preceding upper respiratory infection. The principal concern with TS is distinguishing it from septic arthritis, which can result in significant morbidity if not promptly diagnosed and treated. To this end, inflammatory markers can be helpful. Children with high fevers or elevated inflammatory markers often require hip ultrasonography and aspiration of hip fluid if effusion is identified. The difference between TS and septic arthritis is discussed in greater detail in Chapter 88. TS is self-limited, but NSAIDs have been shown to shorten the duration of symptoms.

Osteoid Osteoma

Osteoid osteoma is a relatively common benign skeletal neoplasm that typically occurs in the femur, although it can occur anywhere. Most cases of osteoid osteoma occur in children and young adults, and males are affected twice as often as females. They typically present with localized pain at the site of the lesion, which is worse at night and responds well to NSAIDs. A limp may be observed as well. Osteoid osteomas usually appear as a dense central nidus smaller than 2 cm surrounded by a well-circumscribed lucency on plain radiographs or CT. Osteoid osteomas have no malignant potential and usually regress or become dormant spontaneously. If pain persists, the lesion can be surgically excised or ablated.