The distal radius palmar cortical angle in adolescent versus adult populations

Volar distal radius plates are pre-contoured to aid restoration of anatomy during open reduction internal fixation of distal radius fractures. Incorrectly contoured plates can result in malreduction, leading to malunion, pain, and loss of function. The purpose of this study was to investigate whether adolescent distal radius anatomy on the palmar cortical surface differs from that in adults, in order to determine whether adult plates are suitable for use in adolescents.

Lateral wrist radiographs were used to measure the distal radius palmar cortical angle (PCA) in adolescent age groups (12-13, 14-15, and 16-17 years old) and compared to a skeletally mature control group (30-50 years old). Two assessors measured 423 PCAs twice.

There was a statistically significant ( p = <0.05) difference in the PCA of the control group compared to each adolescent group. The mean PCA for both males and females decreased as age increased (increasing curvature of the volar distal radius with age). The mean PCA (male/female) was 164.38°/163.00° in ages 12-13, 162.14°/160.92° in ages 14-15, 157.52°/158.18° in ages 16-17, and 149.65°/154.03° in the control group aged 30-50 years. Agreement between assessors was high with an Interclass correlation coefficient (ICC) of 0.97.

There is a statistically significant and potentially clinically important difference in the curvature of the distal radius volar cortex between adolescents and adults. This difference persists even in the 16-17 age group. As the PCA curvature is significantly greater in adults compared to adolescents, plates pre-contoured for adults may lead to malreduction of distal radius fractures into flexion in adolescent patients.