Reliability of greulich and pyle method of age determination among children undergoing left wrist xrays at Moi Teaching and Referral Hospital

Abstract

Background: Age determination is crucial in people who want to be recognized as adults to access government services such as driving licenses, employment and to be issued with marriage certificates. In the judicial system, there is an established age of legal importance, below which a person cannot be handled as an adult if they have been accused of a criminal offence. There are many people worldwide who do not have official birth notification documents so their chronological age cannot be verified. Several methods can be used to do age determination. The most commonly used radiological method is the Greulich and Pyle (GP) method. This method has been shown to be unreliable when applied to certain populations. GP method is said to be reliable when the difference between the mean GP age and the chronological age is not statistically significant. The purpose of this study was to statistically compare the chronological age with the GP age in children undergoing left wrist and hand x-ray at MTRH, with an aim of determining the reliability of GP method of age determination when applied to the local population. Objective: To compare the chronological age with GP age in order to determine the reliability of Greulich and Pyle method of age determination. Methods: This was a cross-sectional study carried out at the Moi Teaching and Referral Hospital (MTRH) between April 2019 and March 2020. 139 patients aged below 18 years scheduled to undergo left wrist and hand x-rays were recruited. Imaging was done by the principal researcher and/or a trained radiographer and radiographs stored in the PACS system. Age determination by the GP method was done by the principal investigator and findings verified by two consultant radiologists. Chronological age was calculated from the date of birth as recorded in the birth certificate/notification by a trained research assistant. Data was analyzed using STATA version 23. Descriptive statistics were done and presented in tables and graphs. Comparison between the mean GP age and chronological age was done using paired T-test and Bland-Altman test done to test the agreement between GP age and CA. Mean difference between GP age and chronological age was compared among male and females grouped into one year cohorts. Results: The chronological age of the participants ranged from 1 month to 18 years. The mean age as determined by the GP method was 8.7 years, 10.5 years in males and 6.1 years in females. The mean difference between chronological age and GP age was 0.15 years (1.8 months) in males which was statistically significant with a p value of 0.015. The mean difference between chronological age and GP age was 0.08 years (1 month) in females with a p value of 0.159, which was not statistically significant. Conclusions: There is a statistically significant difference between chronological age and GP age in males. There is no statistically significant difference between the chronological age and GP age in females. Recommendations: Greulich and Pyle method of age determination should be used with caution in boys, where high accuracy is required. Further studies on bone development in children should be done and a customized bone age chart developed for the local population.