Quantifying the ossification of the carpus in skeletal age estimation: Radiographic standards for Australian subadults

•This study describes a reliable quantitative method to estimate age from the carpus.•Results demonstrate that the formula is most accurate in younger individuals.•Acceleration of ossification observed, likely at the time of onset of puberty.•The model determines whether a child is under 12 years (female) or 13 years (male). An evaluation of the development of a child’s skeleton and estimation of bone age provides an insight into a child’s overall maturation. This study aimed to introduce a contemporary method for assessing bone age of Australian children using formulae incorporating carpal areal measurements. The standards introduced in this study can be used to assess the developmental status of Australian children who may be affected by growth-related illnesses. Additionally, in situations where the living age of a subadult is unknown, methodologies to accurately estimate age are required, particularly in the Western world where knowledge of the age of an individual is necessary for legal reasons. The sample consisted of retrospective hand and wrist radiographs acquired from 541 children (females: 246, males: 295) aged from birth to 20 years. Using the DICOM viewer Weasis, the carpal area ratio (B.Ar/T.Ar) was calculated for each individual radiograph by measuring the carpal bone area (B.Ar) and total tissue area of the carpus (T.Ar). A changepoint regression model demonstrated that the model constructed in this study was the most accurate in the younger age groups and was able to accurately determine whether a child was under 12 years if female and 13 years if male. A rapid acceleration of growth was observed at approximately 12–13 years in our sample, which may represent the onset of the pubertal growth spurt; this resulted in a high data variance and low model prediction accuracy in female and male children older than 12 and 13 years, respectively.