Popliteal angle in preterm infants with periventricular leukomalacia

The aim of this study is to clarify the usefulness of popliteal angle in infants with periventricular leukomalacia. The popliteal angle was measured at 1, 4, 8, and 12 months of corrected age in 47 infants with periventricular leukomalacia and in 103 control infants with normal development. The popliteal angle was categorized into two groups; tight, when it was < or =120 degrees , and wide, when it was >120 degrees . The severity of diplegia was defined at 2 years as follows: mild, when an infant could walk; moderate, when an infant could sit but could not walk; severe, when an infant could not sit. Tight popliteal angle was more often observed in infants with periventricular leukomalacia than in normal infants at any corrected age. The rate of tight popliteal angle was significantly lower in infants with mild diplegia than in those with moderate or severe diplegia at 8 and 12 months of corrected age. Specificity and positive predictive value were high at 8 and 12 months of corrected age, whereas sensitivity was relatively low. The results of this study suggest that evaluation of popliteal angle is useful for detection of infants with periventricular leukomalacia, although false-negative rate is high during late infancy.