Three-dimensional Mapping Analysis of Talus Fractures and Demonstration of Different Surgical Approaches for Talus Fractures

Abstract

Objective: The talus is an important component in the ankle, and its treatment after injury is crucial. However, complications and adverse events due to incomplete traditional classifications may still occur, and these classifications fail to analyze the patterns and distribution of fractures from a three-dimensional perspective. Therefore, in this study, we aimed to analyze the location and distribution of fracture lines in different types of talus fractures using three-dimensional (3D) and heat mapping techniques. Additionally, we aimed to determine the surface area of the talus that can be utilized for different approaches of internal fixation, aiding in the planning of surgical procedures.

Methods: We retrospectively analyzed data from CT scans from 126 patients diagnosed with talus fractures at our two hospitals. We extracted the CT data of a healthy adult and created a standard talus model. We performed 3D reconstruction using patients' CT images and superimposed the fracture model onto the standard model for drawing fracture lines. Subsequently, we converted the fracture lines into a heat map for visualization. Additionally, we measured 20 specimens to determine the boundary for various ligaments attached to the talus. We determined the surface area of the talus available for different surgical approaches by integrating the boundary data with previously reported data on area of exposure.

Results: Without considering the displacement distance of the fracture, fracture types were classified as follows, by combining Hawkins and Sneppen classifications: talar neck, 41.3%; posterior talar tubercle, 22.2%; body for the talus and comminuted, 17.5%; lateral talar tubercle, 11.9%; and talar head, 7.1%. We established fracture line and heat maps using this classification. Additionally, we demonstrated the available area for anteromedial, anterolateral, posteromedial, posterolateral, and medial malleolus osteotomy and Chaput osteotomy approaches.

Conclusion: Fracture line and heat map analyses can aid surgeons in planning a single or combined surgical approach for the reduction and internal fixation of talus fractures. Demonstrating the different surgical approaches can help surgeons choose the most effective technique for individual cases.

Keywords: 3D mapping; Heat map; Surface area of the talus; Surgical approach; Talus fracture.

FIGURE 1

Measurement of geometric morphometric of the talus. (A) medial view; (B) superior view; (C) inferior view; (D) anterior view.

FIGURE 2

All fracture lines and heat maps of talus fractures. The yellow area of the heat map shows the most concentrated position of the fracture line and, each red line represents the position of each fracture. The gradual change in color from yellow to gray indicates that the frequency of fracture lines changes from more to less.

FIGURE 3

Specimen anatomy and 3D scanning. (A) 3D scanning; (B) side view; (C) top view.

FIGURE 4

The distance between different ligaments and different planes of the talus was measured. The orange box indicates the ligament attachment area of the talus. (A) The upper plane of the talus fornix—the upper plane of the ATFL; (B) the upper plane of the anterior talus fornix—the upper plane of the ATFL; (C) the lower plane of the talus lateral tubercle—the upper plane of the ATFL; (D) the upper plane of the talus fornix—the upper plane of the PTFL; (E) the lower plane of the talus posterior tubercle—the upper plane of the PTFL; (F) the upper plane of the talus fornix—the upper plane of the DL; (G) medial lower plane of the talus—the upper plane of the DL. ATFL, anterior talofibular ligament; DL, deltoid ligament; PTFL, posterior talofibular ligament.

FIGURE 5

Fracture lines and heat map for each talus fracture type. Each red line represents the position of each fracture. The gradual change in color from yellow to gray indicates that the frequency of fracture lines changes from more to less. (A) talus neck fracture; (B) talus posterior tubercle fracture; (C) talus body and comminated fracture; (D) talus lateral tubercle fracture; (E) talus head fracture.

FIGURE 6

3D representations of virtual areas for the different surgical approaches base on boundary data and previously reported data. Anterolateral approach: 1.90–2.26 cm²;, anterolateral approach + distraction: 4.58 cm²; anteromedial approach: 2.27 cm²; Chaput osteotomy: 5.07 cm²; Chaput osteotomy + distraction: 6.39 cm²; posterolateral approach: 2.40 cm²; posteromedial approach: 6.7 cm²; posteromedial approach + distraction: 8.3 cm²; posteromedial approach + distraction + gastrocnemius recession: 9.9 cm²; medial malleolus osteotomy: 11.2 cm².