Knee-heel length measurement in healthy preterm infants.

Authors :: Griffin IJ
Pang NM
Perring J
Cooke RJ
Source :: Archives of disease in childhood. Fetal and neonatal edition [Arch Dis Child Fetal Neonatal Ed] 1999 Jul; Vol. 81 (1), pp. F50-5.
Publication Year :: 1999
Abstract: Aim: To examine the reproducibility of crown-heel length measurement; the precision and reproducibility of knee-heel length measurement; and the association between the two in healthy preterm infants.<br />Methods: Paired crown-heel and knee-heel lengths were measured on 172 occasions by three observers in 43 preterm infants between 205 and 458 days of postconceptional age.<br />Results: Crown-heel length (CHL) measurement was highly reproducible, with a coefficient of variation (CV) of 0.41%. Knee-heel length (KHL) measurement was relatively precise (CV 0.78%), but less reproducible (intra-observer CV 1.77%, intra-observer CV 2.11%), especially in larger infants. The association between KHL and CHL was not consistent and varied with age. KHL was a poor predictor of CHL, with a 95% predictive interval of +/- 27.5 mm.<br />Conclusions: KHL was less reproducible than CHL, especially in larger infants, and a poor predictor of CHL.