Evaluation of Rotational Displacement of the Posterior Facet on the Sagittal Plane in Computed Tomographic Images of Calcaneal Fractures

PURPOSE: To find out whether or not the computed tomographic (CT) classification systems of the calcaneal fracture are efficient in illuminating displaced posterior facet fragment and the degree of displacement can be evaluated by analyzing serial CT images. MATERIALS AND METHODS: Seventy-seven hundred calcaneal fractures were classified by CT classification systems including Sanders classification, and the sagittal rotation angle of the posteior facet fragment was measured on the plain lateral radiograph. Among the serial axial CT images, a number of images with the cortical bone embedded in the cancellous portion were recorded and any significant relationship between each data were evaluated. RESULTS: The conventional CT classification systems are rather insufficient in illuminating the extent of sagittal rotatory displacement. However, the number of CT images in which the cortical radiodensity was observed showed a significantly related with the degree of displacement. CONCLUSION: The conventional CT classification of the calcaneal fractures is unsatisfactory in expressing the degree of sagittal rotatory displacement of the posterior facet fragment; this problem may be alleviated by observing the number of axial CT images in which cortical radiodensity was revealed within the calcaneal body.