Common Neonatal Orthopedic Conditions

Developmental Dysplasia of the Hip

The term developmental dysplasia of the hip (DDH) encompasses a spectrum of diseases from acetabular dysplasia to hips that are located but unstable (femoral head can be moved in and out of the confines of the acetabulum), to frankly dislocated hips in which there is a complete loss of contact between the femoral head and acetabulum. Although geographic and racial variations have been reported, DDH occurs in 11.5 of 1000 infants, with frank dislocations occurring in 1 to 2 per 1000. Studies have suggested that breech positioning, family history of DDH, limited hip abduction, talipes, female sex, swaddling, large birth size, and first-born infants have all been associated with a higher probability of finding DDH. The left hip alone is affected in 60% of infants, the right hip alone is affected in 20% of infants, and both hips are affected in 20% of infants.

With regards to dislocated hips, they can be divided into two groups: syndromic and typical. Syndromic dislocations are most frequently associated with neuromuscular conditions such as myelodysplasia and arthrogryposis or with syndromes such as Larsen syndrome. Syndromic dislocations probably occur between week 12 and week 18 of gestation. Typical dislocations occur in otherwise healthy infants in the third-trimester prenatal period or postnatally.

Congruent reduction and stability of the femoral head are necessary for normal growth and development of the hip joint. The natural history of untreated DDH is controversial as newborn hip instability may resolve or progress to painless dislocation. In cases that progress to subluxation, individuals have significantly increased risk of developing precocious arthritis with moderate to severe hip pain as young adults. This pain can be debilitating and the reconstruction difficult. Early detection and treatment of DDH are thus important in avoiding the devastating sequelae of a late diagnosis.

While the physical exam of an infant hip is paramount to the diagnosis of DDH, there are no pathognomonic signs of a dislocated hip. The physical examination requires patience on the part of the examiner and may be facilitated by having the baby feed from a bottle or swaddling the arms. Communication between providers is encouraged if the practitioner examining the newborn in the hospital is different from the 2-week follow-up examiner. The presence of asymmetric hip abduction is suggestive of a unilateral dislocation. Limitation of hip abduction in babies older than 12 weeks is the most reliable examination finding suggestive of DDH. Hip abduction of 75 degrees should be possible in most newborns. The Galeazzi sign is elicited with the baby placed supine on an examining table so that the pelvis is level, with the hips and knees flexed to 90 degrees. With the baby’s hips in neutral abduction, the examiner determines if the knees are at the same height. If one femur appears shorter than the other, the hip may be dislocated posteriorly ( Fig. 89.1 ). Each of these signs, individually or in combination, may serve to increase the index of suspicion of the examiner and lower the threshold for further diagnostic studies or referral to a pediatric orthopedist. A unilateral dislocated hip may result in asymmetric thigh folds; however, extra thigh folds are a normal variant and do not necessarily indicate hip dislocation. It is important to note that in an infant with bilateral hip dislocations, the Galeazzi sign will be negative and the hip abduction symmetric .

There are two common methods of assessing hip stability in the newborn ( Fig. 89.2 ). The Ortolani test aims to reduce a dislocated hip. This is performed on one leg at a time, with the infant supine on the examining table. The index and middle fingers of the examiner are placed along the greater trochanter, while the thumb is placed on the medial aspect of the thigh. The pelvis is stabilized by the placing of the thumb and ring or long finger of the opposite hand on top of both anterior iliac crests simultaneously. The hip is flexed to 90 degrees and gently abducted while the leg is lifted with the hip in neutral external/internal rotation. A palpable clunk is felt as the dislocated femoral head reduces into the acetabulum. This finding is reported as the Ortolani sign (positive result on the Ortolani test). The Barlow test is an attempt to dislocate or subluxate a located but unstable hip. The thigh is held, and the pelvis stabilized in the same manner as for the Ortolani test. With the hip in neutral external/internal rotation and at 90 degrees of flexion, the leg is then gently adducted with a mild posteriorly directed pressure applied to the knee. A palpable clunk or sensation of posterior movement constitutes a positive result (i.e., the Barlow sign). High-pitched clicks are frequently elicited with hip range of motion. These sounds are most frequently attributed to snapping of the iliotibial band over the greater trochanter and are not associated with dysplasia. With progressive soft tissue contractures and loss of ligamentous laxity, both the Ortolani test and the Barlow test become unreliable after approximately 3 months of age.

Imaging of the immature hip can be a valuable adjunct to the physical examination. An anteroposterior (AP) radiograph of the pelvis can be difficult to interpret before the age of 4 to 5 months as the femoral head is composed entirely of cartilage until the secondary center of ossification appears. Before the appearance of the secondary center, ultrasound examination is the method of choice for visualizing the cartilaginous femoral head and acetabulum. Static ultrasound images allow visualization of acetabular and femoral head anatomy, while the complementary dynamic images give information on the stability of the hip joint. The primary limitation of hip ultrasonography is that the results are dependent on the experience and skill of the operator, especially when performed within the first 3 weeks after birth. For these reasons, ultrasonography is recommended as an adjunct to clinical evaluation rather than as an independent screening tool. Studies conducted before 6 weeks after birth may be useful for confirming equivocal physical examination findings and for monitoring treatment of hips with known dislocations. Clinicians must be aware, however, that ultrasound images in this age group often reveal minor degrees of dysplasia (physiologic immaturity) that usually resolve spontaneously and may lead to overtreatment of physiologic hip variations. Ultrasonography is the technique of choice for assessment of infants at high risk of DDH after 4 to 6 weeks of age and again is useful in following up the results of intervention. After 6 months of age, the gold standard remains the AP radiograph of the pelvis.

All newborns should be screened for DDH by a properly trained healthcare provider by physical examination. Risk factors for DDH should be determined by the treating physician. A Cochrane review found that neither universal nor targeted ultrasound screening strategies have been demonstrated to improve clinical outcomes, including the incidence of late-diagnosed DDH and need for surgery. Adding further confusion to the debate over the approaches to optimal DDH screening procedure is a report by the US Preventive Services Task Force, which found “insufficient evidence” to recommend any routine DDH screening, including physical examination. This recommendation was based on the lack of clear evidence for the efficacy of infant screening to reduce the incidence of late-presenting DDH. In response to these findings, the American Academy of Orthopedic Surgeons (endorsed by the American Academy of Pediatrics, the Pediatric Society of North America, and the Society for Pediatric Radiology) has published a revised clinical practice guideline to aid in the early diagnosis of and initiation of appropriate intervention for DDH. These recommendations are summarized as follows:

• 1.

  Universal ultrasound screening. Moderate evidence supports not performing universal ultrasound screening of newborn infants.

• 2.

  Evaluation of infants with risk factors for DDH. Moderate evidence supports performing an imaging study before 6 months of age in infants with one or more of the following risk factors: breech presentation, family history, or history of clinical instability.

• 3.

  Imaging of the unstable hip. Limited evidence supports that the practitioner might obtain an ultrasound image in infants younger than 6 weeks of age with positive instability examination findings to guide the decision to initiate brace treatment.

• 4.

  Imaging of the infant hip. Limited evidence supports the use of an AP radiograph of the pelvis instead of an ultrasound image to assess DDH in infants beginning at 4 months of age.

• 5.

  Surveillance after normal findings from an infant hip examination. Limited evidence supports that a practitioner reexamine infants previously screened as having normal hip examination findings on subsequent visits before 6 months of age.

• 6.

  Stable hip with ultrasound imaging abnormalities. Limited evidence supports observation without a brace for infants with a clinically stable hip with morphologic ultrasound imaging abnormalities.

• 7.

  Treatment of clinical instability. Limited evidence supports either immediate or delayed (2 to 9 weeks) brace treatment for hips with positive instability examination findings.

• 8.

  Type of brace for the unstable hip. Limited evidence supports use of the von Rosen splint over Pavlik, Craig, or Frejka splints for initial treatment of an unstable hip.

• 9.

  Monitoring of patients during brace treatment. Limited evidence supports that the practitioner perform serial physical examinations and periodic imaging assessments (ultrasound or radiograph depending on age) during management for unstable infant hips.

If there are no risk factors, then serial examinations are recommended according to a standard periodicity schedule until the child is 6 months old. If during these periodic visits physical findings raise suspicion of DDH, or if a parental concern suggests hip disease, confirmation is recommended by an expert physical examination, by referral to a pediatric orthopedist (or other practitioner with expertise in medical and surgical management of newborn hip disease), or by age-appropriate imaging. When a positive Ortolani or Barlow test is present at birth and persists beyond the usual age of spontaneous resolution (2 to 9 weeks), the infant should be referred to an orthopedist for management. However, if the positive Ortolani or Barlow test disappears, then age-appropriate imaging (ultrasonography at 6 weeks or radiograph by 6 months) is warranted. If the infant has positive risk factors, such as breech positioning at birth or a family history but stable hip examination findings, then age-appropriate imaging is recommended (ultrasonography at 6 weeks or radiograph at 6 months).

Treatment of DDH is dependent on the age at presentation. Although previously recommended, double diapering is not an accepted form of treatment in DDH. For children aged 0 to 6 months, a reducible hip is treated in a Pavlik harness or another appropriate orthosis. The Pavlik harness is a dynamic orthosis that allows the infant to actively move the hips through a sphere of motion that encourages deepening and stabilization of the acetabulum ( Fig. 89.3 ). The harness is applied as soon as possible after the diagnosis of DDH is made. The length of treatment is dependent on the age at presentation and severity of dysplasia. Progress is judged by serial physical examinations and ultrasonography. In the case of a frankly dislocated hip, treatment is abandoned if the hip is not reduced within 4 weeks of harness application. The success of Pavlik harness treatment is variable and correlates with the severity of the hip dysplasia. Treatment is successful in nearly 100% of stable hips, greater than 90% of dislocatable (Barlow-positive) hips, 61% to 93% of dislocated but reducible (Ortolani-positive) hips, and only 40% of irreducible dislocations.

For a persistently irreducible dislocation, or a child that presents late with a dislocated hip (after 6 months of age), either closed or open reduction of the hip under general anesthesia, with subsequent spica casting, is often required.

Foot Deformities

Congenital deformities of the foot are relatively common but often overlooked in newborns. Consequently, the true incidence of the milder, self-limited deformities is unknown. For identification purposes, congenital foot abnormalities can be divided into those that result in the toes pointing upward (calcaneovalgus, congenital vertical talus), those that result in the toes pointing inward (metatarsus adductus, clubfoot), and those with too many toes or toes stuck together (polydactyly, syndactyly).

Calcaneovalgus is thought to be a postural deformity secondary to intrauterine positioning in which the dorsum of the foot is, or can be, directly opposed to the anterior aspect of the leg ( Fig. 89.4 ). Plantar flexion of the foot is often limited from contracture of the anterior ankle and lateral soft tissues. The estimated incidence of calcaneovalgus is 0.4 to 1 per 1000 live births. It appears to be more common in girls and after breech deliveries. There may be an increased association with hip dysplasia, so a thorough hip examination is warranted, as outlined in Developmental Dysplasia of the Hip. Complete resolution with gentle stretching exercises conducted by the parents can be achieved, although generally occurs spontaneously by 3 to 6 months of age. In the more severe calcaneovalgus feet where the ankle cannot be plantar flexed past the neutral position, serial casting to facilitate correction is often required. Calcaneovalgus may be seen in conjunction with external rotation of the tibia and posteromedial bowing of the tibia. A deformity that fails to resolve mandates referral to a pediatric orthopedist.

Calcaneovalgus should be differentiated from congenital vertical talus (CVT), a rarer condition that is frequently associated with neuromuscular conditions and syndromes such as arthrogryposis and spina bifida. In CVT the hindfoot is fixed in equinus (plantar flexion), giving the sole of the foot a characteristic “rocker bottom” appearance because of dorsal dislocation of the midfoot though the talonavicular joint ( Fig. 89.5 ). Treatment during infancy consists of serial casting to stretch dorsal soft tissues and reduce the midfoot, followed by limited surgical release if needed, pinning of the talonavicular joint, and Achilles tenotomy. Most children require surgery between 6 and 12 months of age, and best outcomes are achieved when surgery is performed before age 2 years. When casting fails to reduce the midfoot, more extensive surgical releases are required.

The two common neonatal foot deformities resulting in medial deviation of the toes are metatarsus adductus and talipes equinovarus (clubfoot). Metatarsus adductus is present at birth but frequently diagnosed later during the first year of life. It has been estimated to occur in 1 in 100 births and is thought to result from intrauterine crowding.

Characteristic features include a concave medial border of the foot with a curved lateral border, a “bean-shaped” sole of the foot, a higher-than-normal-appearing arch, and a neutral heel ( Fig. 89.6 ). Metatarsus adductus can be classified into cases that undergo passive correction and those that do not. Feet which passively correct are best left alone and will improve spontaneously. Feet in which passive correction is not possible (the curved lateral border cannot be straightened) should be treated with manipulation and serial casting by age 6 to 9 months. The corrections can then be maintained with reverse or straight last shoes if necessary. Operative treatment should be considered only in children older than 3 years who have a rigid deformity and have failed to respond to a casting program.

The term clubfoot describes a foot with hindfoot equinus, heel varus, and adduction and supination of the forefoot ( Fig. 89.7 ). Clubfoot deformities range from mild to severe and occur in 1 in 1000 to 2 in 1000 live births. A risk factor for clubfoot is early amniocentesis (11 to 13 weeks’ gestation), which is hypothesized to cause decreased fetal movement during a critical phase of foot development. Although the cause of clubfoot remains unproven, there appears to be dysplasia of all osseous, muscular, tendinous, cartilaginous, skin, and neurovascular tissues distal to the knee in the affected limb.

The mild, “postural” clubfoot appears to represent a packaging problem due to intrauterine positioning. This deformity is passively correctible, demonstrates minimal or no calf atrophy, and resolves spontaneously or responds quickly to a stretching and casting regimen. At the opposite end of the spectrum is the arthrogrypotic or neuromuscular clubfoot that demonstrates severe rigidity. Between these two extremes lies the classic, idiopathic clubfoot deformity. Idiopathic clubfeet demonstrate a deep, single medial skin crease, curved lateral border with a high arch, and rigid varus and equinus of the heel with a deep, single, posterior skin crease. This gives the foot its “down and in” position and toes pointing to the midline. In unilateral cases the affected limb has a smaller foot and calf circumference (see Fig. 89.7 ).

All clubfoot deformities should be referred to a pediatric orthopedist for treatment. Initial treatment for all cases of congenital clubfoot is nonoperative. Untreated clubfoot has a poor natural history, with development of early degenerative changes in the foot joints. Historically, clubfeet were treated with early and extensive surgical correction. The long-term results, however, are poor, with high recurrence rates. Consequently, this approach was abandoned, and surgeons began advocating nonoperative methods of clubfoot correction. Although many forms of nonoperative clubfoot treatment exist, the Ponseti method of cast correction has achieved preeminence in this regard. Studies show excellent mid-term to long-term results with decreased stiffness.

The Ponseti method uses a specific set of manipulations and serial corrective long-leg casts, followed by a prolonged period of bracing. Treatment is ideally commenced within the first few weeks after birth, but successful treatment is commonly achieved when treatment is initiated up to 1 year of age. We prefer to initiate treatment 1 to 2 weeks after discharge from the hospital to allow parental adjustment for the new infant at home. Every 5 to 7 days, manipulation of the foot is performed with passive stretching, and the correction is maintained with a new long-leg cast, with an average of four to five casts in the idiopathic clubfoot. This is followed by percutaneous Achilles tenotomy in most patients and a further 3 weeks of casting. Children are then placed into a foot abduction orthosis full-time for a period of 3 months and then part-time, while sleeping, until approximately age 4 years.

The “French functional method” has also been successfully duplicated in at least one US hospital with good results. This method necessitates daily manipulations by a trained physical therapist for 8 weeks, with the addition of continuous passive motion during the first 4 weeks. This is followed by strapping and continued bracing.

The Ponseti and the French “nonoperative” methods both frequently use Achilles tenotomy and, at times, tendon transfers to attain the ultimate desired result. Recurrences of deformity are common (16% to 37%), requiring further casting. A smaller percentage of patients (8% to 16%) require surgical release of the hindfoot to various degrees.