Reliability of the Greulich & Pyle Method for Bone Age Estimation in a Spanish Sample

Abstract

As an indicator of growth rate, bone age is used to determine the level of development and to predict chronological age when this is not known. The repeatability of the measurement (intra-and inter-observer) and the systematic error inherent to Bone Age (BA) estimation using the Greulich & Pyle (GPA) method has been estimated using a sample from the Spanish population. The inter-observer Lin’s concordance correlation coefficient was ρc=0.98, with a value of 0.05±0.52 for girls and 0.06±0.44 for boys (difference between observations in years), whereas the intra-observer Lin’s concordance correlation coefficient was ρc=0.99 (0.05±0.27 for girls and 0.10±0.36 for boys). The mean difference between the bone and chronological ages was 0.51±1.13 years in girls and 0.32±1.11 years in boys. Given the systematic errors with regard to the reference population, we propose the adjustment required to apply the ages calculated according to the atlas and indicate the limitations inherent to predicting chronological age when only information from the bones in the hand and wrist is used.