To guarantee equal chances for different age groups, age-related tournaments for male and female players have been established in soccer. However, as registration at birth is not compulsory in some countries, other methods of age determination are needed to prevent participation in the incorrect age group. To evaluate the age of soccer players of international U-17 competitions from the degree of fusion of the distal radius and to compare the findings with an age-related normative population. MRI scans of the wrist of a representative sample of 189 players from four U-17 competitions (FIFA U-17 World Cups 2003 and 2005, and Asian (AFC) U-17 championships 2004 and 2006) were analysed using a previously published grading system. Because of different regulations, all players in the AFC U-17 championships were younger than 17 years, whereas 71% of the players in the FIFA U-17 World Cup competitions were 17 years old. The distal radius of 15% of players from the AFC U-17 tournaments and 27% of the players from the FIFA U-17 tournaments were graded as completely fused on the MRI scans, which is a substantially higher percentage than in the respective age groups of a previously published normative population of soccer players. Furthermore, in contrast with the normative population, no significant correlation between the age category and the fusion grading (r = 0.13) was observed in U-17 players. From the MRI results, U-17 soccer players seem to be more mature than a normative population of the same age category. However, the lack of correlation between age category and degree of fusion in U-17 players supports the suspicion that the age stated in the official documents of the U-17 players examined might not be correct in all cases.
