title: Knee-heel length measurement in healthy preterm infants.
abstract: OBJECTIVE
  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.
authors.affiliation: Neonatal Nutrition Research Group Royal Victoria Infirmary University of Newcastle Newcastle-upon-Tyne, UK.
authors.forename: I J
authors.initials: IJ
authors.lastname: Griffin
authors.forename: N M
authors.initials: NM
authors.lastname: Pang
authors.forename: J
authors.initials: J
authors.lastname: Perring
authors.forename: R J
authors.initials: RJ
authors.lastname: Cooke
mesh_terms: D006801:Humans; D007230:Infant, Low Birth Weight / Q000254:growth & development*; D007231:Infant, Newborn; D007234:Infant, Premature; D007717:Knee / Q000254:growth & development*; D007866:Leg / Q000254:growth & development*; D012016:Reference Values; D015203:Reproducibility of Results; D012107:Research Design