Normal instability of the hip in the neonate: US standards

Musculoskeletal sonography in the neonate and infant

Babies are ideal subjects for investigation by sonography. They are small and easily examined with the use of high-frequency transducers. Their unique status in US imaging tends to get lost amid the array of other available modalities, such as MRI and CT imaging. Some of the questions posed in pediatric musculoskeletal imaging that are routinely directed to other imaging modalities can be solved quickly at a lower cost by sonography in neonates and infants without sedation or any known clinical risk. These small children not only have thinner soft tissues but they have long bones and midline spine structures whose ends are largely composed of cartilage, which provides an early opportunity to examine these regions by US. And we cannot overestimate the value of new parents being able to stay next to their baby during imaging in a warm, friendly and non-threatening environment.

Sonography of hip dysplasia

Early diagnosis of developmental dysplasia of the hip (DDH) is important to institute appropriate treatment and reduce the incidence of long-term complications. Risk factors for DDH include genetic, developmental, mechanical, and physiologic factors. Physical examination using Ortolani and Barlow maneuvers is standard for early detection. Plain film radiography is limited for the diagnosis of DDH even when applying several classic landmarks, lines, and measurements, due to the lack of visualization of the cartilaginous components of the infant's hip. Ultrasound arose as a tool for evaluation of the cartilaginous structures of the hip in the early 1980s. Graf's method of examination by ultrasound stresses morphology, whereas dynamic examination uses physical maneuvers to elicit laxity of the hip. The Pavlik harness is the mainstay of treatment of DDH in the young infant, and ultrasound examination in the harness is useful to monitor progress. Closed or open surgical reduction is reserved for unresponsive or advanced cases. Universal ultrasound screening of newborns is not deemed cost effective by most North American authors, although in Europe non-selective screening has been more widely used.

Ultrasound in pediatric musculoskeletal disease: techniques and applications

The increased ratio of nonossified cartilage to bone in children makes ultrasound (US) a particularly suitable technique for evaluating pediatric musculoskeletal disorders. US allows the examiner to compare quickly and meticulously an affected to unaffected area of interest in different orthogonal planes without a need for sedation. Developmental dysplasia of the hip is the most common indication for pediatric musculoskeletal US. Sonography is also a cost-effective, useful, and complementary imaging tool for evaluating pediatric musculoskeletal trauma, inflammation-infection, and masses.

Imaging of pediatric hip disorders

Developmental and acquired abnormalities of the hips are common in childhood. Radiographs, MR imaging, CT, and nuclear medicine play an important role in the diagnosis and management of these disorders. Knowledge of the surgical and clinical treatments of these disorders is important to interpret accurately the radiology studies and impact treatment of the children.

Ultrasonography of clinically unstable hips. A prospective study of 143 neonates at birth and early follow-up

We evaluated the ability of ultrasonography to reduce the treatment rate of hips with clinical instability or uncertain findings at birth. Among 9,514 live births during the period 1988-1990, unstable hips were detected in 143 neonates by the Ortolani and Barlow tests, whereas the physical examination was inconclusive in 59 cases. These 202 neonates were also examined by ultrasound and instability was confirmed in 108 neonates who were treated with the Frejka pillow. The mean femoral head coverage (FHC) was 37%, indicating slight subluxation in the majority of unstable hips. The remaining 94 infants had normal ultrasonographic findings and were not treated. Their mean FHC was 53% and all these hips developed normally, except in 2 girls, who were treated with an abduction splint from age 4-5 months because subluxation developed. We conclude that ultrasound improved the reliability of the neonatal hip evaluation, thus markedly reducing the number of treated infants. Sonography also reduced the use of radiography during followup.

Prospective evaluation of newborn soft-tissue hip "clicks" with ultrasound

Fifty infants with soft-tissue hip "clicks" persisting after age 3 months were prospectively studied by using ultrasound. All children demonstrated a stable hip examination by Barlow and Ortolani maneuvers; however, a click was palpated with abduction and adduction of the hip. Static ultrasonography demonstrated an average alpha angle of 63 degrees in uninvolved hips and 62 degrees in the clicking hips. All hips had > 50% femoral-head coverage by the acetabulum. Dynamic ultrasound examination was normal in all cases. The soft-tissue clicks were not related to instability in this series of 50 infants.

Prospective evaluation of newborn soft-tissue hip "clicks" with ultrasound

Fifty infants with soft-tissue hip "clicks" persisting after age 3 months were prospectively studied by using ultrasound. All children demonstrated a stable hip examination by Barlow and Ortolani maneuvers; however, a click was palpated with abduction and adduction of the hip. Static ultrasonography demonstrated an average alpha angle of 63 degrees in uninvolved hips and 62 degrees in the clicking hips. All hips had > 50% femoral-head coverage by the acetabulum. Dynamic ultrasound examination was normal in all cases. The soft-tissue clicks were not related to instability in this series of 50 infants.

Development of late congenital hip dysplasia: significance of ultrasound screening

Ultrasound for detecting congenital hip dysplasia was performed in 5970 infants, 2121 of whom were reinvestigated. Of those reinvestigated 726 belonged to the screened group not at risk examined as newborns, 70 were infants at risk first investigated as newborns and 363 were infants at risk first examined after the newborn period; the remainder were infants not at risk first investigated after the newborn period. Pathological findings were obtained in 7.7% of the entire group, in 3.9% of children at no risk, and in 5% of patients at risk. Deterioration of Graf's classification of types was seen in 3.2%. 13 children, 3 of the screened group and 10 of the nonscreened group developed hip dysplasia. None of them would have been missed since they were borderline type IIA on at least one side, which warranted mandatory follow-up.

Assessment of congenital hip dislocation with real-time ultrasound: a pictorial essay

Real-time ultrasound (US) is the imaging method of choice for diagnosis and follow-up of congenital dislocation of the infant hip (CDH). Clinical aspects and the role of imaging are reviewed. Technique and anatomy, both normal and abnormal, are illustrated, as well as, the use of sonography during treatment with Pavlik harness and spica cast. Correlation of ultrasound findings with clinical examination, other available imaging studies and long-term patient follow-up shows 100% sensitivity and 100% specificity for real-time US diagnosis of CDH.

Neonatal screening and staggered early treatment for congenital dislocation or dysplasia of the hip

In 14 264 consecutive newborn babies the results of screening and early treatment for congenital dislocation and/or dysplasia of the hip (CDH) were evaluated in a prospective follow-up study. Barlow's test was done and the family history was recorded. Babies who were positive (n = 140) were immediately given abduction treatment. If the screening result was doubtful (133) or if the test was negative but the family history positive (685) the child was radiographed at 5 months and abduction treatment was started if any form of CDH was seen. Among Barlow-negative children with no family history (13,306), two reference groups were selected--at age 5 months (596) and at age 2 years (4365). Dislocation was missed at screening in 0.02%. Dysplasia was seen at 5 months in 15% of Barlow-negative children with a positive family history and in 2-3% of the reference group children. Crude estimates of the lower limits of validity indices for the screening test showed that the test is efficient in the identification of dislocation but probably has no value for dysplasia. Of the babies in whom treatment was started immediately 17% had relapse dysplasia after withdrawal of therapy, 3% had avascular necrosis, and 78% were normal at 2 years. When treatment was started at 5 months we found no relapse dysplasia, only 1% avascular necrosis, and 53-63% success at 2 years. In children with dislocatable hips we propose a wait-and-see treatment strategy, with early ultrasonography or radiography at 5 months.