There are two provocative tests that can assess ankle
instability—the anterior drawer test and the talar tilt test.
The anterior drawer test assesses the integrity of the ATFL
as the ATFL prevents anterior translation of the talus with
respect to the tibia. The test is performed after positioning
the ankle in neutral to 10° of plantar flexion with the patient
seated and the knee flexed (Fig. 2). The examiner holds the
calcaneus in one hand while stabilizing the distal tibia in
the other, and the calcaneus is translated forward. Increased
translation of 3 mm compared to the uninjured side or an
absolute value of 10 mm of displacement correlates to ATFL
incompetence.
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The talar tilt test is described as the angle formed by the
talar dome and the tibial plafond during forced hindfoot
inversion with the tibiotalar joint held in neutral (Fig. 3).
The test is not a useful physical examination tool as it is
hard to distinguish ankle motion from subtalar motion, but it
can be as useful as a stress radiograph. The normal range of talar tilt is variable and can range from five to 23°. However,
10° of absolute talar tilt or 5° difference compared to the
contralateral side is generally considered a positive talar tilt
test.
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The Telos Stress Device (Telos, Marburg, Germany)
can be utilized to perform more consistent stress measure
-
ments for talar tilt and anterior talar translation by placing
the lower extremity in the apparatus.