Background: The management of intra-articular calcaneal fractures (ICFs) still faces a challenge. Available research about the anatomic patterns of ICFs is lacking. We aimed to define the pattern of ICFs by a three-dimensional (3D) mapping and determine whether there are consistent fracture patterns and comminution zones.
Methods: 67 patients of ICFs with available computed tomographic (CT) scans were identified. The calcaneal fractures fragments on CT were multiplanar reconstructed and virtually reduced. 3D heat mapping was subsequently created by graphically superimposing all fracture lines onto a standard calcaneal template. Mapping of fracture lines and comminution zones in both the axial and sagittal planes were performed.
Results: The cohort included 26 (38.8%) left calcaneal fractures, 27 (40.30%) right calcaneal fractures, and 14 (20.9%) cases with bilateral fractures. Comminuted fractures accounted for 92.5% of all fractures. Sagittal 3D mapping demonstrated that fracture lines were concentrated in the critical angle of Gissane and extended posteriorly to the rear of the tuberosity of the lateral wall and the anterior of the medial process of the calcaneus tuberosity but with more significant variation in the medial wall. The mean angle of fracture lines concerning the long axis of the calcaneal (LAC) was 29.1°and 19.2° in the lateral wall and medial wall, respectively. Axial 3D mapping demonstrated that fracture lines were primarily concentrated in the area anterior to the posterior joint facet and extended along the posterior joint facet and calcaneus sulcus to the posteriorly of the tuberosity. The mean angle of fracture lines concerning the LAC was 11° in the axial wall. 3D mapping demonstrated that the comminution zones are closely related to the internal structure and fracture mechanism.
Conclusion: The data presented have elucidated there are consistent characteristic fracture patterns and comminution zones for ICFs. This study provides visual guidelines to understand fracture morphology, which may assist with fracture classification, preoperative planning, fixation concepts development, and internal structure analysis.