Age estimation methods using hand and wrist radiographs in a group of contemporary Thais

The aim of this study was to evaluate the accuracy and reliability of three commonly used age estimation methods in Thailand: Greulich-Pyle, Tanner-Whitehouse and Fishman.

Three hundred and sixty-five hand and wrist radiographs of 8-20 years old Thai patients were retrospectively collected. The radiographs were taken between 2011-2016. Greulich-Pyle, Tanner-Whitehouse 3 radius, ulna and selected short bones (RUS), and Fishman method were applied for each radiograph. Comparisons between the estimated age from each method and the chronological age were done using Wilcoxon signed ranks test with Bonferroni correction. Sensitivity, specificity and accuracy tests were performed on the important legal age thresholds in Thailand (10, 13, 15 and 18years old). Intra- and inter-observer reliability were evaluated by weighted kappa analysis.

The estimated ages from the three methods were significantly different from the chronological age, except for Tanner-Whitehouse 3 RUS in males. Regarding the legal age thresholds, Greulich-Pyle showed the best accuracy (83.2% for females and 79.63% for males) for legal age threshold of 10years old. Fishman method showed the best accuracy for legal age threshold of 13 (77.5% for females and 74.31% for males) and 15years old (83.08% for females and 73.77% for males). For age threshold of 18years old, Greulich-Pyle showed an accuracy of 53.85% for females and 54.44% for males. The reliability tests showed substantial to almost perfect agreement.

This study showed no significant difference between Tanner-Whitehouse 3 RUS age and chronological age for male subjects of contemporary Thai children and adolescents. However, Greulich-Pyle and Fishman method were superior regarding the accuracy of prediction based on Thai legal age thresholds. Due to the possible effects from ethnical difference and secular changes, adaptation of age estimation methods specifically for contemporary Thai population should be further studied.