The added value of cross-sectional imaging in the detection of additional radiographically occult fractures in the setting of a Chopart fracture

Purpose: Radiography has a low sensitivity for the detection of fractures related to the talonavicular and calcaneocuboid articulations, also known as Chopart fractures. The purpose of this study is to determine the sensitivity of radiographs for detecting additional foot and ankle fractures related to Chopart fracture using CT or MRI as the reference standard. Method: We performed an IRB-approved, retrospective review of radiology reports between 2010 and 2014. Inclusion criteria were (1) diagnosis of a Chopart fracture and (2) at least one radiograph and subsequent cross-sectional imaging (CT or MR). CT or MRI was considered the diagnostic reference standard. Results were stratified by the energy of trauma and by type of radiograph performed (weight-bearing (WB) versus non-WB). Results: One hundred eight patients met the inclusion criteria. The calcaneocuboid articulation was the most commonly involved type of Chopart fracture, seen in 75% of cases (81/108). Chopart fractures were detected on the initial radiographs in 67.6% of cases (73/108). Additional fractures of the ankle and midfoot were diagnosed in 34.2% of cases (37/108), with 56.7% (21/37) of these cases having at least one additional fracture seen on CT or MRI that was not seen on the initial radiographs, with fractures of the midfoot most often missed. In 56.7% (17/30) patients whose radiographs detected Chopart fractures, at least one additional fracture was missed; 30% of them demonstrated intra-articular extension and 56.7% were considered displaced. High-energy trauma was related to higher incidence of additional fractures. There was no significant difference in the sensitivity of radiographs to detect additional fractures between high versus low-energy trauma (p = 0.3) and WB versus non-WB radiographs (p = 0.5). Most patients were treated nonoperatively (56.5%, 61/108), with surgical intervention more frequent in patients with a high energy of trauma (51.7% versus 33.3%, p = 0.05). Conclusion: In the setting of a Chopart fracture, CT or MRI can add significant value in the detection of additional ankle or midfoot fractures, irrespective of the energy of trauma. Since additional fractures can have important management implications, CT or MRI should be considered as part of the standard workup for all midfoot fractures. © 2018, American Society of Emergency Radiology.