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18.4 Tarsal oint Luxations 291

(A) (D) (E) (G)

(B) (C) (F) (H) TARSAL REGION

Figure 18.6 Examples of traumatic tarsal joint injuries: Patient I (A–C) was diagnosed with a medial
collateral and talar ridge fracture; (A) lateral radiographs were nondiagnostic, (B) dorsoplantar radiographs
show (white arrow) soft tissue swelling on the medial side, (C) stress radiographs confirm disruption of the
medial collateral ligament as indicated by the (white arrow) opening of the joint and also illustrate the
talar ridge fracture. Stress views were performed by applying (blue arrows) medial pressure proximal to the
tarsus and lateral pressure distal to the tarsus (valgus stress view). Patient II (D–F) was diagnosed with a
central tarsal bone fracture that could be missed on the (D) standard lateral view since it only shows (white
arrow) mild displacement of the fracture; however, (E) with gentle flexion, the (white arrow) displacement
becomes more evident and (F) dorsoplantar views also clearly show the (white arrow) displaced fragment.
Radiographs of Patient III (G, H) show severely displaced (white arrows) fracture luxation of the proximal
intertarsal joint.

but oblique views can be useful. Images taken with the tarsus in flexion, extension, and mediolateral
stress (with a fulcrum placed on the tarsus to lever the metatarsus against; Figure 18.6) can help
define the level and direction of instability. CT is the most sensitive modality, but it is seldom needed
for detecting the presence of tarsal fractures; it can, however, help to define the nature of the frac-
ture and guide its repair (Butler et al. 2018).

18.4 Tarsal Joint Luxations

Tarsal joint luxations can occur at any level and may be due to ligament disruption or fractures of
the associated bones. Injuries to the collateral ligaments cause instability at the level of the tar-
socrural joint. The two other reasons for tarsocrural joint luxations are shearing injuries or frac-
tures of the medial and or lateral malleoli, which are the origins of the collateral ligaments. These