In recent years, operative management of intra-articular calcaneus fractures has gained increasing momentum. Precise anatomical reduction with reconstruction of tuber angle, tuber length and, especially, subtalar joint are required. The mobile Siremobil Iso-C3D is an important aid to the accurate reconstruction of the anatomical structures; dislocation persisting after reposition can be detected and corrected at a very early stage. From October 2002 to May 2004, 49 patients with fractures of the calcaneus underwent internal fixation of intra-articular fractures of the calcaneus with a fixed-angle titanium plate system with intraoperative 3D imaging. On average, the tuber angle was improved by 16°. In 18 cases, the intraoperative 3D imaging disclosed dislocations, which it was possible to correct. Secondary dislocation of the central fragment did not occur in any of these cases.