CT of calcaneal fractures: 3-D-reformations with electronic disarticulation

Purpose: To evaluate the clinical value of 3-D-reformations with and without electronic disarticulation of cal caneal fractures compared to axial CT and sagittal reformations. Material and methods: 25 patients with intra-articular calcaneal fractures underwent diagnostic CT-examinations. Axial slices, sagittal and 3-D-reformations with and without electronic disarticulation were performed. The sagittal and both types of 3-D-reformations were compared to the axial slices with regard to the diagnostic criteria: involvement of articular facets, number of fragments, and traumatic changes of the hindfoot. Results: The best proof of involvement of articular facets is found in axial slices and 3-D-reconstructions after disarticulation followed by sagittal reconstructions. Usually on 3-D-reconstructions without disarticulation articular facets cannot be identified because of overlapping bones. The number of fragments is clearly demon strated by axial slices and sagittal reconstructions followed by S-D-reconstructions after disarticulation. Traumatic changes of the hindfoot can be diagnosed in all four forms of visualisation. Conclusion: The decisive diagnosis for treatment planning is made based on the axial slices supported by sagittal reformations. In unclarified cases 3-D-reformations after electronic disarticulation may provide further information. 3-D-reformations without disarticulation are useless.