Purpose or Case Report: Treatment pathways for isolated distal radius fractures in children are evolving and becoming more tailored to specific fracture types, including different management plans for stable buckle fractures (BFs) versus unstable distal radius fractures (DRFs). We propose a measurement rule to aid differentiation of stable BFs from unstable DRFs in children.

Methods & Materials: IRB approval was waived for this retrospective QI project. Medical record search identified children with closed radius fractures during a 14month period. Demographic and other study data were collected and recorded using REDCap. Original radiology reports were compared to consensus diagnosis of two senior readers, which was used as the reference standard. Agreement was calculated using Cohen’s Kappa statistic. Fracture to distal radial physis distance was measured in mm on PA and Lateral (LAT) views. Diagnostic accuracy using fracture distance as a predictor for buckle fractures was analyzed on both views. An ROC curve was used to determine the cutoff values tested.

Results: There were 148 BFs (73%), 55 isolated DRFs (27%). Agreement between the original report and final diagnosis was ‘slight’ (κ=0.120, SE=0.058, n=203). The BF to physis distance was < 1cm in only 1 of 106 (0.9%) children 7-16y on PA view. No older children had a BF to physis distance <1 cm on LAT view and the sensitivity, specificity and accuracy for BF diagnosis were all above 82% using a cut off of 14mm (PA) and 13 mm (LAT). The BF to physis distance was < 1cm in 1 (2.4%) of 42 children 3-6y on PA view and another 1(2.4%) on LAT view. Diagnostic accuracy was low for children <7 years old for all tested distances. The areas under the ROC curve increased after excluding patients <7y: 0.822 to 0.867 (PA) and 0.819 to 0.874 (LAT). Diagnostic odds ratios also increased when excluding patients < 7y: from 11.375 to 24.612 (>14mm PA) and from 10.095 to 22.815 (>13mm LAT).
Conclusions: An isolated distal radius fracture in a child is not likely to be a BF if the fracture to physis distance is < 1 cm. We propose measurement cut offs to increase diagnostic accuracy in children ≥ 7y. Using measurements to differentiate stable BFs and unstable DRFs is less reliable in younger children.