Three-Dimensional Heat Map: The OTA/AO Type 43C Pilon Fracture Lines Distribution

This study aimed to create three-dimensional heat map and study the characteristic of fracture lines and represented fragments of OTA/AO type 43C pilon fractures.

CT scan was performed in105 fractures diagnosed with OTA/AO type 43C pilon fractures between January 2017 and December 2022. Three-dimensional pilon fracture maps were created and converted into fracture heat maps. CT scan graphic parameters including the fracture line height, α angle, β angle, the ratio of the area and size of bone fragment represented by the fracture line to the total articular surface were measured.

The study included 105 patients with 91 males and 14 females. The fractures included C1 (n=16), C2 (n=23), and C3 (n=66). There was no statistically different among the most parameters except in the fracture-line height of the anterior fracture line (p=0.03) and the sagittal fracture line (p=0.02) between C2 and C3 pilon fractures. The average size of the anterolateral fragment, occupied approximately 13.5% of the articular surface area, was (11.5±2.8) mm × (20.5±6.3) mm with the average height of 29.8 mm. The average size of the posterolateral fragment, occupied approximately 13.0% of the articular surface area, was (15.7±4.6) mm × (19.3±4.0) mm with the average height of 19.1 mm.

This study demonstrates that the articular surface fracture lines in the C type pilon fracture are formed by fixed main fracture lines. The understand of morphological and distribution characteristics of the fracture lines and size of fragments in OTA/AO type 43C pilon fractures would help the surgeons take suitable approach and fixation.