Applicability of the Greulich and Pyle bone age standards to Taiwanese children: A Taipei experience

The Greulich and Pyle (GP) method is one of the most common radiographic techniques for bone age (BA) assessment. The applicability of this method to ethnic populations outside of the United States has been investigated in several recent studies worldwide. Currently, limited data are available on the accuracy of the GP method for the Taiwanese population. The purpose of this study was to determine whether the GP standards are applicable to contemporary Taipei children.

Clinical data from October 1, 2010, to March 31, 2020, were retrospectively collected from a general hospital in Taipei. BA was determined by a senior pediatrician and was reviewed by a senior pediatric radiologist according to the GP standards. Comparison of BA and chronological age (CA) was performed in children with body weight and height in the 15th to the 85th percentiles of normal children. Ethnic variations in the maturation process in the ulnar bone were investigated. All data were statistically analyzed.

In total, 2465 medical records were collected. After excluding those with diseases and unqualified data, 654 records of boys and 809 of girls were analyzed. In boys, the mean BA was significantly delayed between 6 and 9 years of age compared with the CA. In girls, the mean BA was generally advanced between 7 and 15 years of age. Ulnar bone maturation tended to be delayed in young boys.

A significant discrepancy between CA and BA was observed in our population. Delayed ulnar bone maturation in young boys was confirmed. Children in Taipei exhibit a different maturation pattern than children on whom the GP standards were based.