Fracture edge features of diaphyseal clavicular fractures: a morphologic study.

BACKGROUND: Previous researchers used transverse fractures centered over the midpoint of the clavicle as the diaphyseal clavicular fracture models. However, as a result of shear stress concentration in sigmoid-shaped structures, most diaphyseal clavicular fractures have coronal fracture edges and are located distal to the midpoint. The purpose of this study was to quantify the morphology and utilize these parameters to establish clinically relevant fracture models. METHODS: The computed tomographic DICOM data of 100 consecutive patients were included. We investigated the morphologic characteristics of the fracture edges after virtual fracture reduction. The fracture orientation was determined based on the normal vectors of the best-fit plane of the fracture edges. The fracture location was measured by the extreme points of the edges. The fracture configuration was evaluated using fracture maps. RESULTS: There were 28 simple, 43 wedge, and 29 multifragmentary types. Coronal oriented fracture edges accounted for more than 70% of the simple, wedge, and multifragmentary types. The most proximal point of the proximal edge was located at 46.7% (42.0%-56.5%), 47.6% (42.5%-50.1%), and 46.3% (42.0%-49.3%) of the endpoint line in the simple, wedge, and multifragmentary types, respectively (P = .548). The most distal point of the distal edge was located at 72.2% (68.4%-75.0%), 73.2% (69.5%-76.9%), and 74.0% (69.6%-77.1%) of the endpoint line (P = .353). The longest proximal main fragments occurred in the simple types at 71.9% (66.3%-75.4%) of the endpoint line (P < .001), and the shortest distal main fragments occurred in the multifragmentary types at 55.8% (49.8%-59.3%) of the endpoint line (P = .001). The heatmaps showed a high concentration of anteriorly distributed wedge fragments (88%; n = 38/43) and coronally distributed multifragmentary fragments (62%; n = 18/29). CONCLUSIONS: We showed that typical diaphyseal clavicular fractures have coronal fracture edges and are located within the distal half of the diaphyseal segment. The fractured fragments were initiated anteriorly in the wedge types and then propagated coronally in the multifragmentary types. The features of these fracture edges could be useful in designing osteotomy models and provide different perspectives of anterior and superior plating techniques.