The infant hip: real-time US assessment of acetabular development.

Abstract

Until recently, radiography was the only available means of assessing acetabular development in infants with congenital hip dysplasia. Now that real-time ultrasonography (US) is successfully employed to determine hip position in infancy, it also offers an alternative method for evaluating acetabular development. In a review of 377 US studies of infant hips, the coronal-flexion images, which show a coronal section of the acetabulum with the hip in flexion, were measured to determine the percentage of the femoral head that was covered. Radiographs were measured to determine the acetabular index (angle). Acetabuli with indices exceeding the normal range for the subject's age showed head coverage of less than 33%. The 51 sonograms in this category were all associated with clinical abnormalities, whereas the 107 with coverage greater than 58% were associated with no clinical abnormalities and with consistently normal acetabular indices. The use of US in assessing acetabular development warrants continued investigation.

Indicators of successful use of the Pavlik harness in infants with developmental dysplasia of the hip

“…Harding et al [3] concluded that measurement of the α angle defined by Graf [1] and percentage coverage of the femoral head as described by Morin et al [10] are not predictive of failure in Pavlik harness treatment. In contrast, Lerman et al concluded that an initially low α angle correlated with an increased likelihood of eventual failure of Pavlik harness treatment [9].…”

“…Ultrasonography is considered to be a safe method for detecting hip dysplasia within the first months or even days of life, and with Graf's classification, one can decide whether or not treatment is necessary. Most authors investigating hip ultrasonography have noted that it is a superior method for the early diagnosis of DDH [8,10,13,19,20].…”

Higher Pavlik Harness Treatment Failure Is Seen in Graf Type IV Ortolani-positive Hips in Males

“…During the initial clinic visit, static and dynamic ultrasound images [7,15] of the hip were obtained. A dislocated hip that was reducible on clinical examination by the Ortolani maneuver was defined as an Ortolani-positive hip.…”

“…Baseline ultrasound data collected at the time of diagnosis included the alpha angle [7] and the percentage of coverage of the femoral head [15]. A fellowship-trained pediatric radiologist (MM) who was blinded to clinical assessment, reviewed the baseline images and classified the hips based on the Graf classification system [7].…”

Diagnosis of congenital hip dysplasia in the newborn

“…The ultrasound method used in Norway at present is called Terjesen's method (Terjesen et al 1989). The method is a modified version of the methods of Graf (1983) and Morin (Morin et al 1985), in which the femoral head coverage is determined by measuring two distances: from the acetabular floor to the lateral bony acetabular rim (a) and from the acetabular floor to the lateral joint capsule (b). The femoral head coverage (FHC) is given as the ratio of distance a to distance b, expressed as a percentage (a/b × 100%).…”