Visualization of complicated fractures by 3D-printed models for teaching and surgery: hands-on transitional fractures of the ankle

Abstract

Aims: Understanding the orientation of fracture lines and mechanisms is the essential key to sufficient surgical therapy, but there is still a lack of visualization and teaching methods in traumatology and fracture theory. 3D-printed models offer easy approach to those fractures. This paper explains the use of the teaching possibility with 3-dimensional models of transitional fractures of the ankle.

Methods and results: For generating 3D printable models, already obtained CT data were used and segmented into its different tissues, especially parts concerning the fracture. After the segmentation process, the models were produced with FFF (fused filament fabrication) printing technology. The fracture models then were used for hands-on teaching courses in AO course (Arbeitsgemeinschaft für Osteosynthesefragen) of pediatric traumatology in 2020 in Frankfurt. In the course fracture anatomy with typical fracture lines, approaches, and screw placement could be shown, discussed and practiced.

Conclusion: The study shows the use of 3D-printed teaching models and helps to understand complicated fractures, in this case, transitional fractures of the ankle. The teaching method can be adapted to numerous other use cases.

Keywords: Fracture models; Teaching; Training; Transitional fractures 3D printing; Traumatology.

Fig. 1

Example of a threshold-based segmentation. The voxels are assigned to one group (green) using different HU-borders

Fig. 2

Left: A schematic overview of region growing: Seed points are placed within the desired regions. The voxels surrounded by the seed point are compared and are included or excluded to the different groups. Right: The placed dark red seed points are assigned to the red group of interest, while the chosen voxels in green are the basis for the light green group

Fig. 3

Preoperative X-Ray of Twoplane (1) and Triplane II (2). Due to medical referral, there exists no preoperative x-ray of Triplane I shown in this study

Fig. 4

Preoperative CT images. The fracture line can be distinguished exactly by CT or MRI. Here are shown CT images of Twoplane (1), Triplane I (2) and Triplane II (3) fractures

Fig. 5

The resulting three different models in an animated figure and below with its printed life-sized model. Left: Twoplane, Middle: Triplane I, Right: Triplane II Fracture

Fig. 6

During the AO course of pediatric traumatology, correct placement of the screws was practiced. On the left is shown Twoplane, on the middle Triplane I and on the right Triplane II fracture

Fig. 7

The postoperative control of screw placement of the Twoplane (1), Triplane I (2) and Triplane II (3) fracture