Assessing the Necessity for the "Joint Above and Below" Radiography Approach for Lower-extremity Long Bone Fractures in Children.

Abstract

A common strategy for evaluation of extremity fractures is the "joint above and below" (JAB) radiograph approach, which includes dedicated imaging of the joint proximal and distal to a fracture independent of clinical suspicion for an injury involving the joint. The incidence of concomitant ipsilateral lower-extremity fractures or dislocations associated with lower-extremity long bone fractures in children has not been commonly reported and represents an evidential gap for determining a radiograph approach. Our purpose was to determine the frequency of and risk factors for concomitant ipsilateral lower-extremity fractures or dislocations. A retrospective study of children aged 1 to 17 years treated at an academic medical center emergency department from 2015 to 2018 with any fracture involving the tibia, fibula, or femur. Children with pathologic fractures, transferred from another facility, and/or designated as a level I trauma were excluded. The primary outcome was the prevalence of a concomitant bony injury (fracture or dislocation) at a distinct site in the same extremity. Differences between the concomitant bony injury group and single injury group were characterized using Fisher exact tests. Regression analysis was used to determine predictors of concomitant bony injuries, including age, sex, and mechanism of injury (with injuries requiring level II or III trauma activation classified as high risk). During the study period, 241 patients with lower-extremity long bone fractures were included. Complete JAB radiographs, defined as dedicated orthogonal radiographs of the joint proximal to and distal to the fracture site, were taken in 85 (35.3%) of 241 patients. Concomitant bony injuries were found in 9 (3.73%) of 241 patients (95% confidence interval, 1.7-7.0%). No additional concomitant bony injuries were identified at follow-up. When comparing patients with and without concomitant bony injuries, there was no significant difference in age (P = 0.34) and sex (P = 0.73). However, patients with a high-risk injury were more likely to have a concomitant bony injury (P < 0.01; odds ratio, 21.9; 95% confidence interval, 3.6-131.5). Concomitant ipsilateral lower-extremity fractures or dislocations are uncommon in children sustaining tibia, fibula, and/or femur fractures. Although the JAB approach to radiographs may be useful in identifying additional injuries in children with lower-extremity injuries resulting from a "high-risk" mechanisms, its overall yield is low. To provide safe, cost-effective care, providers should continue to value clinical suspicion, history, and physical examination findings to guide selection of radiographs in those with lower-extremity long bone fractures as significant fractures can typically be identified with limited imaging in patients with low-risk injury mechanisms.