Ossification of the Triradiate Cartilage and Posterior Acetabulum

Purpose This study attempts to evaluate the skeletal maturation patterns of the triradiate cartilage (TRC) and the posterior acetabular wall (PA), which can be easily assessed on body computerized tomography (CT). It also examines the effect of gender and age on ossification of both TRC and PA. Materials and Methods This retrospective study included a total of 1324 CT scans for children between the ages of 6 and 16 years. Depending on the extent of ossification in each right or left aspect, determined by the consensus of two observers, the TRC and PA scans were categorized into Grades 4 and 3, respectively. Results The TRC for boys began to ossify at age 10 and closed completely at 14, while the PA for boys started ossification at age 11 and entirely fused at 13. The ages of ossification center appearance and complete fusion in both TRC and PA for girls were exactly two years earlier than boys. The TRC fused within one year after the closure of the PA. Conclusion The appearance and closure of the TRC and PA ossification centers show predictable patterns of development, appearance and merger earlier in females than in males. The suggestion is that development and morphogenesis of both TRC and PA ossification centers can be adequately assessed by using 3-dimensional body CT.