Knee-heel length measurement in healthy preterm infants

Arch Dis Child Fetal Neonatal Ed. 1999 Jul;81(1):F50-5. doi: 10.1136/fn.81.1.f50.

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.

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.

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.

Conclusions: KHL was less reproducible than CHL, especially in larger infants, and a poor predictor of CHL.

MeSH terms

  • Humans
  • Infant, Low Birth Weight / growth & development*
  • Infant, Newborn
  • Infant, Premature
  • Knee / growth & development*
  • Leg / growth & development*
  • Reference Values
  • Reproducibility of Results
  • Research Design*