Distal metaphyseal radius fractures in children following closed reduction and casting: can loss of reduction be predicted?

The aim of this study was to identify factors which contribute to loss of reduction (LOR). Outpatient records and initial, post-reduction (PR) and follow-up radiographs of patients with a distal radial metaphyseal fracture were reviewed to determine demographic factors; fracture characteristics (obliquity, comminution, intact ulna); three-point cast index (3PI); and initial, PR, and follow-up displacement (angulation and translation in the sagittal and coronal planes). Univariate and multivariate regression were used to identify significant risk factors for LOR. A total of 161 patients were included in our series (119 boys and 42 girls). Fifty-seven (35%) patients met the criteria for LOR. Multivariate logistic regression revealed that patients over 14 years old were 4.8 times more likely (p = 0.01) to lose reduction, and those with more than 10% PR translation in the sagittal plane were four times more likely (p = 0.03) to lose reduction. In younger patients, initial coronal translation and PR sagittal translation were independent risk factors. Patients with over 10% initial translation in the coronal plane were 2.4 times more likely (p = 0.01) to lose reduction, and those with over 10% PR translation in the sagittal plane were 2.7 times more likely (p = 0.03) to lose reduction. Three point cast index was not found to be a significant risk factor (1.64 vs. 1.57, p = 0.43). Our study, the largest dedicated series of distal radial metaphyseal fractures, indicates that loss of reduction is common. Our analysis suggests that an anatomical reduction, which minimises residual translation, is the most important variable in preventing a loss of reduction.