Bony Anatomy
- The talus has complex anatomy; over 60% of the bone is covered with articular cartilage.
- The talus articulates superiorly with the tibia and fibula at the ankle joint, inferiorly with the calcaneus at the subtalar joint and anteriorly with the navicular at the talonavicular joint.
- The inferior portion of the talus has anterior, middle, and posterior facets, which articulate with their respective calcaneal facets.
- Between the posterior and middle facets is a groove, which exits laterally to form the sinus tarsi.
- Fractures of the talus are often classified into the body, neck, head, and processes.
- The talar neck, in relation to the talar body, is oriented 10 to 44 degrees medial and 5 to 50 degrees plantar.
- Different radiographic views are required to accurately assess each of the anatomic segments and their articulations.
Radiographic Anatomy
AP/Mortise View Ankle
- Assess involvement and fracture displacement of the talar body.
- Assess congruence of the tibiotalar articulation.
- Visualize the lateral process (Figs. 27-1–27-3).
Figure 27-1 AP view of the ankle: tibiotalar dislocation with evidence of talar neck fracture. Note the talonavicular articulation appears to be intact on this view.
Figure 27-2 Mortise view of the ankle: there is a talar body fracture with an associated vertical medial malleolus fracture.
Figure 27-3 Intraoperative mortise view with definitive fixation of the medial malleolus, talar body, and talar neck.
Lateral View Ankle/Foot
- Assess congruence of the subtalar articulation.
- Assess sagittal plane alignment of the tibiotalar, talonavicular, and midfoot articulations (Figs. 27-4–27-6).
Figure 27-4 Lateral view of the ankle: there is loss of normal contour of the tibiotalar joint with evidence of a talar neck fracture. The talonavicular joint appears congruent on this view.
Figure 27-5 Postreduction lateral view of the ankle: there is a minimally displaced talar neck fracture with intact articulations at the tibiotalar and talonavicular joints. A CT would help assess the subtalar articular congruency and fracture morphology in more detail.
Figure 27-6 Intraoperative lateral view after definitive fixation of a talar neck fracture.
Canale View
- Oblique imaging of the talar neck that removes the overlap of the calcaneus to more accurately assess the talar neck.
- Taken with 75 degrees cephalad tilt with foot in 15 degrees eversion and plantar flexion.
- Allows visualization of the lateral shoulder and medial cortex.
- This is not a standard injury film; it is more widely used intraoperatively to assess the reduction of the talar neck.
- AP view of the foot can also assist in evaluating the reduction of the talar neck; however, the Canale view provides more valuable information by assessing the neck in profile while removing the overlap of the talus and calcaneus (Fig. 27-7).
Figure 27-7 Intraoperative Canale view demonstrating reduction and fixation of a comminuted talar neck fracture with dual plating and screw fixation of an associated medial malleolus fracture.
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