Quantifying the ossification of the carpus: radiographic standards for age estimation in a New South Wales paediatric population

Age estimation from radiographs is common when age is not documented, such as in forensic, refugee and asylum seeker cases. The methods currently used are outdated and not applicable to all human groups due to variations between populations and secular changes in growth. This study aims to use the ossification of the carpus in a modern sample of New South Wales children to produce an age estimation formula that can be applied to cases of undocumented age. Hand radiographs (n = 400; 194 left and 206 right) from the Sydney children’s hospital, aged from birth to 17 years (256 males and 144 females) were analysed. Bone area (BO) and carpal area (CA) were measured, and a carpus ossification ratio (BO/CA) was calculated for each individual. Linear regression analysis was used to produce a formula for age estimation. Analysis demonstrated no significant difference in the ossification ratio (95% CI) between wrists of left and right sides and a regression formula for age was determined to be [−0.972 + 1.403 g + 21.758 (BO/CA)] ± 1.40 (g is 1 for males and 0 for females). This regression formula accounted for 88% of total variance. The median of the absolute values of residual (MAR) and the standard error of estimate (SEE) were −0.03 years, 1.40 years respectively. Using the ossification ratio of the carpus, an age estimation formula with a relatively high degree of reliability and accuracy was generated for a modern sample of New South Wales Children.