Ossification variation of the medial clavicular epiphysis in children, adolescents and young adults

Introduction

Ossification of the medial clavicular epiphysis correlates with the chronological age and is used for forensic age estimation. This retrospective study aimed to refine these age intervals by using a more balanced dataset with regards to age and gender distribution, achieved by conducting a power analysis beforehand to ensure sufficient representation across all ossification stages.

Methods

Computed tomography scans from individuals aged 10–25 were conducted using our hospital's imaging archive. The retrospective data collection continued until the required number of cases per ossification stage was achieved. Two blinded readers—a radiology senior physician and a medical student—assessed ossification stages according to established classification systems (stages 1–5 with substages 2a–c and 3a–c). In case of disagreement, a third senior radiologist and head of forensic imaging, resolved discrepancies. Gender differences and diagnostic accuracy between 0.75 mm and 1.5 mm CT slice thickness were assessed.

Results

A total of 408 individuals were included, of which 314 could be assessed for clavicular ossification stage. The analysis revealed no statistically significant differences in ossification stages between male and female individuals. Stage 3c was frequently observed only in individuals aged 18 years and older. Inter-reader agreement was substantial (Cohen's κ = 0.72). Diagnostic accuracy was comparable between 0.75 mm and 1.5 mm slice thickness.

Conclusion

This study provides refined age estimates for clavicular ossification stages based on a European population and suggests that both 0.75 mm and 1.5 mm CT slice thicknesses may be suitable for forensic age estimation.

Implication for practice

Data obtained from this study may contribute to a better understanding of the progression of ossification of the medial clavicular epiphysis and distribution of different ossification stages and the correlation with age.