Abnormal Development of the Femoral Head Epiphysis in an Infant with no Developmental Dysplasia of the Hip Apparent on Ultrasonography

INTRODUCTION In the investigation of hip development in newborns and infants, ultrasonography and radiography are widely used, but their optimal roles in this setting remain controversial. CASE REPORT Here we describe an 8.5-month-old infant who had undergone hip radiography at a primary care facility and was referred to our hospital to be evaluated for developmental dysplasia of the hip. Ultrasonography showed no developmental dysplasia of the hip according to standard criteria, but developmental retardation of the femoral head was apparent on the radiograph. CONCLUSION This patient's findings demonstrate that abnormalities in femoral head epiphysis development can go undetected during routine ultrasonographic evaluations for developmental dysplasia of the hip.