Original Research

Using 3-Dimensional Fluoroscopy to Assess Acute Clavicle Fracture Displacement: A Radiographic Study

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Midshaft clavicle fractures are often treated successfully by nonoperative means. However, recent clinical studies have found benefit from surgical fixation in cases with particular fracture characteristics, such as complete fracture fragment displacement with no cortical contact, and fractures with axial shortening of more than 20 mm. Accurately determining the extent of displacement and shortening can therefore be important in guiding treatment recommendations.

To our knowledge, the literature includes only 2 reports of studies that have compared different radiographic views and their accuracy in measuring fracture shortening, and no study has determined the best radiographic view for evaluating fracture displacement.

We retrospectively studied the cases of 10 patients to determine which radiographic view best captured the most fracture fragment displacement. Acute midshaft clavicle fractures were assessed with simulated angled radiographs created from preoperative upright 3-dimensional fluoroscopy scans.

Results showed that 15° angulated radiographs captured the most fracture fragment displacement. Given this finding, we recommend upright posteroanterior 15° caudal radiographs for midshaft clavicle fractures to best assess the extent of fracture displacement.


 

References

Clavicle fractures are common injuries, accounting for 2.6% to 5% of all adult fractures.1,2 Most clavicle fractures (69%-82%) occur in the middle third or midshaft.3,4 Midshaft clavicle fractures are often treated successfully with nonoperative means consisting of shoulder immobilization with either a sling or a figure-of-8 brace. Operative indications historically have been limited to open or impending open injuries and to patients with underlying neurovascular compromise. However, recent clinical studies have found that fractures with particular characteristics may benefit from surgical fixation. Important relative indications for open reduction and internal fixation of midshaft clavicle fractures are complete fracture fragment displacement with no cortical contact, and fractures with axial shortening of more than 20 mm.5,6

Accurately determining the extent of displacement and shortening can therefore be important in guiding treatment recommendations. The standard radiographic view for a clavicle fracture is upright or supine anteroposterior (AP). Typically, an AP radiograph with cephalic tilt of about 20° is obtained as well. On occasion, other supplemental radiographs, such as a 45° angulated view, as originally described by Quesada,7 are obtained. To our knowledge, the literature includes only 2 reports of studies that have compared different radiographic views and their accuracy in measuring fracture shortening8,9; no study has determined the best radiographic view for evaluating fracture displacement.

We conducted a study to determine which radiographic view best captures the most fracture fragment displacement. Acute midshaft clavicle fractures were assessed with simulated angled radiographs created from preoperative upright 3-dimensional (3-D) fluoroscopy scans. Our hypothesis was that a radiographic view with 20° of cephalic tilt would most often detect the most fracture displacement. In addition, we retrospectively reviewed our study patients’ initial AP injury radiographs to determine if obtaining a different view at maximum displacement would have helped identify a larger number of completely displaced midshaft clavicle fractures.

Patients and Methods

Institutional review board approval was obtained. Using our institution’s trauma registry database, we retrospectively identified 10 cases of patients who had undergone preoperative 3-D fluoroscopy for midshaft clavicle fractures. Study inclusion criteria were age 18 years or older, acute midshaft clavicle fracture, and preoperative 3-D fluoroscopy scan of clavicle available. Pediatric patients, nonacute injuries, and clavicle fractures of the lateral or medial third were excluded.

Three-dimensional fluoroscopy was used when the treating surgeon deemed it necessary for preoperative planning. All imaging was performed with a Philips MultiDiagnost Eleva 3-D fluoroscopy imager with patients in the upright standing position. (Informed patient consent was obtained.) Software bundled with the imager was used to create representative radiographs of differing angulation.

The common practice at most institutions is to obtain 2 radiographic views as part of a standard clavicle series. The additional AP angulated radiograph typically is obtained with 20° to 45° cephalic tilt from the horizontal axis. Therefore, simulated radiographs ranging from 15° to 50° of angulation in 5° increments were created, and the amount of superior displacement of the medial fragment was measured. As the simulated views were constructed from a 3-D composite image, there was none of the magnification error that occurs with AP or posteroanterior (PA) views. The stated degree of angulation mimics a radiograph’s AP cephalic tilt or PA caudal tilt (Figures 1A, 1B). For all radiographic images, displacement between fracture fragments was determined by measuring the distance between the superior cortices at the fracture site of the medial and lateral fragments. Each simulated radiograph was measured by 2 readers using standard computerized radiographic measurement tools. Final displacement was taken as the mean of the 2 measurements.

After determining which radiographic angulation demonstrated the largest number of maximally displaced fractures, we compared the simulated radiographs at that angulation with the injury AP images for all patients. Total number of patients with a completely displaced midshaft clavicle fracture and no cortical contact was recorded for the 2 radiographic views.

The Orthopaedic Trauma Association classification system8 was used to classify the clavicle fractures. Statistical analysis was performed with the Fisher exact test and a regression model, using SPSS Version 19.0 (IBM SPSS Statistics).

Results

Ten patients met the study inclusion criteria. Mean age was 32.9 years (range, 18-65 years). Seven of the 10 patients were male. Six patients had right-side clavicle fractures. Of the 10 patients, 5 had the comminuted wedge fracture pattern (15-B2.3), 2 had the simple spiral pattern (15-B1.1), 2 had the spiral wedge pattern (15-B2.1), and 1 had the oblique pattern (15-B1.2).

Table 1 summarizes the fracture displacement measurements obtained with the different radiographic views. Of the 10 cases, 5 showed the most displacement with the 15° tilted view (P = .004), and the other 5 showed maximum displacement with different radiographic angulations. In addition, 6 patients showed the least displacement with the 50° angulated view (P < .001). Results of the regression analysis are summarized in Tables 2 and 3.

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