The effects of maximal radial bowing on forearm rotation in pediatric diaphyseal forearm fractures

Purpose: To evaluate the effects of radial bowing on forearm rotation in forearm fractures compared with healthy children.

Methods: A retrospective study was conducted on children aged 1-16 years old. Group 1 was children with history of diaphyseal forearm fractures, and group 2 was healthy children. Children in group 1 with ≤ 70° forearm pronation and/or ≤ 80° supination on affected side are defined as "case." In group 2, children with forearm pronation > 70° and/or supination > 80° are defined as "control." Radial bowing was measured on AP radiograph of the forearm; maximal radial bowing (MRB) and location of the maximal radial bowing (LMRB) were recorded.

Results: Total of 112 children were included (group 1 = 70, group 2 = 42). In group 1, there were 28 children with ≤ 70° forearm pronation and/or ≤ 80° forearm supination (case group). In group 2, there were 33 children with > 70° forearm pronation and > 80° forearm supination (control group). Mean age of case and control group was 11.08 ± 3.02 and 7.85 ± 3.93 years, respectively. Average MRB was 6.15 ± 1.93% and LMRB was 61.94 ± 9.41% in case group. In control group, average MRB was 7.23 ± 1.03% and LMRB was 62.08 ± 4.24%. There was statistically significant correlation between children with ≤ 70° forearm pronation and MRB (P = 0.034) compared with control group. Also, there was statistically significant correlation between children with ≤ 80° forearm supination and MRB (P = 0.023) compared with control group. For ROC curve analysis, MRB ≤ 6.84% showed the association with ≤ 70° forearm pronation (72.2% sensitivity and 73.8% specificity) and MRB ≤ 5.75% associated with ≤ 80° forearm supination (54.6% sensitivity and 84.9% specificity).

Conclusions: Children with MRB ≤ 6.84% can result in ≤ 70° forearm pronation, and MRB ≤ 5.75% can be presented with ≤ 80° forearm supination.