Purpose: The immature skeleton demonstrates a remarkable capacity for correcting residual deformations after fracture. Classically, a residual angle of less than 25° can be tolerated for distal fractures of the forearm in children. The degree of remodelling depends on the distance between the fracture line and the epiphyseal line, the time remaining before closure of the growth cartilage, the residual angle after reduction, and is orientation in relation to the motion of the adjacent joint. The purpose of the present study was to better define the upper limit for acceptable deformation by age in order to determine when surgical correction is indicated.

Material and methods: We reviewed the radiography files of 106 children with one or two fractures of the distal third of the forearm who had required closed reduction and brachio-antebrachial cast immobilisation. We measured the angle of deformity on the AP and lateral views after reduction, at six weeks and at three, six, and twelve months after trauma. The series included 79 boys and 27 girls, mean age 8.5 years (range 2.5 – 15). Twenty-five fractures were epiphyseal fractures and 81 were metaphyseal fractures.

Results: Remodelling was nearly complete one year after fracture in most cases, especially in younger children and more distal fractures. Salter I or II fractures remodelled very rapidly, within four to five months of trauma. This remodelling was mainly achieved by apposition-resorption in the metaphyseal area by reorientation of the epiphyseal line. For the metaphyseal fractures, rate of remodelling was inversely proportional to the distance between the fracture line and the growth cartilage. Remodelling was greatly perturbed in case of open fracture requiring surgical reduction and in case of secondary infection.

Discussion and conclusion: These data show that posterior inclination can be tolerated up to 30° for children under eight years of age and up to 25° between eight and ten years and up to 20° at prepuberty. Knowledge of these limits for distal fractures of the forearm is important for proper management and can be helpful in reducing the number of primary or secondary reductions under general or locoregional anaesthesia.