THE FELS METHOD FOR SKELETAL AGE ASSESSMENT OF HANDWRIST - 1ST RESULTS OF A COMPARISON WITH MODIFIED GREULICH-PYLE AND TANNER-WHITEHOUSE METHODS IN A SAMPLE OF ITALIAN CHILDREN AND ADOLESCENTS

Skeletal age is a reliable index of physiologic maturational processes and the most commonly used measure of individual biological age. Assessments of skeletal maturity are currently made in clinical practice from the hand-wrist radiographs, using either the atlas method of Greulich-Pyle and/or the Tanner-Whitehouse scoring method. Recently a new technique has become available, named "Fels method" published in 1988 by Roche et al. The system represents a potential valuable approach to skeletal maturity assessment, since it should provide very close estimates, relevant when accuracy and precision of skeletal age assessment may be crucial, as in predicting adult height and/or in monitoring treatment or the course of a disease. The aim of the present study is to evaluate Fels skeletal age assessment in comparison with ratings by modified Greulich-Pyle and Tanner-Whitehouse (TW2-RUS) methods in a group of italian children and adolescents. The hand-wrist radiographs of subjects referred to the "Istituto di Puericultura e Medicina Neonatale" of the University of Genoa between 1985-1990 have been assessed according to modified Greulich-Pyle, TW2-RUS and Fels methods in 421 males and 360 females with age ranging between 1.0 and 15.9 years. The following three subset of subjects were considered separately: normal healthy subjects (group A), subjects with growth disorders associated with delayed or anticipated skeletal maturation (group B and C respectively). The difference between Fels and Greulich-Pyle skeletal ages are generally positive in both sexes with slight great values at older ages in all the groups considered. On the contrary, Fels skeletal ages do no reveal any great deviation from the TW2-RUS estimates. Scatterplots and linear regression of Greulich-Pyle and respectively TW2-RUS minus chronological age vs Fels skeletal ages minus chronological age are reported in figure 2-5 in the A, B and C group, for both sexes separately. To determine the sensitivity of the methods defined as the percentage of subjects who are over a threshold determined on the control population and establishing a one tail specificity of 95%, the reference point corrisponding to the 5th (threshold for delayed subjects) and 95th (threshold for anticipated subjects) centile of the differences in control subjects was chosen. Sensitivity of the methods, calculated as the percentage of delayed or anticipated subjects with Fels, Greulich-Pyle or TW2 values below the 5th or over the 95th centile, is resulted about 79% for delayed and 58% for anticipated subjects; for Greulich-Pyle values are respectively 98% and 71% while for TW2-RUS 78% and 65%. It is important however to take into account the differences observed, when very accurate assessments are required for clinical or research purposes.