The applicability of Greulich and Pyle atlas to assess skeletal age for four ethnic groups.

BACKGROUND Recently, determination of skeletal age, defined as the assessment of bone age, has rapidly become an important task between forensic experts and radiologists. The Greulich-Pyle (GP) atlas is one of the most frequently used methods for the assessment of skeletal age around the world. After presentation of the GP approach for the estimation of the bone age, much research has been conducted to examine the usability of this method in various geographic or ethnic categories. This study investigates on a small-scale and compares the reliability of the GP atlas for assessment of the bone age for four ethnic groups - Asian, African/American, Caucasian and Hispanic - for a different range of ages. MATERIALS AND METHODS Plain radiographs of 184 left hands and wrists for males from the healthy sample between 1 to 18 years of age for four ethnic groups were taken. The skeletal age (SA) was estimated by a radiologist using the GP atlas. The blind method was utilized. The mean (SA) results were compared with mean chronological ages (CA) for the separate ethnic groups. SPSS was used to conduct the analysis and the paired t-test was applied to show the difference between the mean CA and mean SA achieved from the GP atlas. RESULTS The results from the GP atlas were compared to the CA of the samples. In Asian subjects the mean difference was 0.873 years. The GP atlas showed delayed bone age at 2-7 ages (from 0.2 to 2.3 year) and then advanced bone age for age 8. In the African/American subjects the difference between CA and SA was statistically significant (P-value = 0.048). The mean difference in the Caucasian and Hispanic subjects reflects no considerable distinction with a standard deviation (SD) of 0.3088 and 0.3766, respectively, (P-value >0.05 for both groups). CONCLUSION According to the present study, it is concluded that although the GP atlas is reliable for Caucasian and Hispanic ethnic groups it is not applicable for other ethnic groups for different ranges of age, especially in the sample of the male African/American group from 8 years to 15 years and Asian during childhood. Although it is not clear whether the other references are more useful than this standard, we believe that some enhancement is vital for the GP atlas to obtain more consistent results.