Anterolateral Drawer Versus Anterior Drawer Test for Ankle Instability: A Biomechanical Model

Area of Science:

• Orthopedic biomechanics
• Sports medicine
• Anatomy

Background:

• Subtle ankle instability can be challenging to diagnose with standard physical examination techniques.
• The addition of unconstrained internal rotation may enhance the detection of ankle ligamentous injuries.

Purpose of the Study:

• To compare the diagnostic efficacy of a novel anterolateral drawer test against the traditional anterior drawer test in a cadaveric ankle model.
• To quantify lateral talar displacement and ankle rotation under simulated instability conditions.

Main Methods:

• Ten cadaveric lower extremities were subjected to anterior drawer and anterolateral drawer tests in a custom apparatus.
• Tests were performed on intact and anterior tibiofibular ligament-sectioned specimens under 25 N and 50 N anterior forces.
• Lateral talar displacement was measured using a differential variable reluctance transducer.

Main Results:

• No significant differences were observed in intact specimens.
• In sectioned specimens, the anterolateral drawer test demonstrated significantly greater lateral talar displacement (P < .001) and ankle rotation (P < .001) compared to the anterior drawer test.
• Specifically, displacement was nearly doubled with the anterolateral drawer test at both force levels.

Conclusions:

• The anterolateral drawer test is more sensitive in provoking lateral talus displacement, suggesting improved detection of ankle instability.
• Incorporating unconstrained ankle rotation into physical examination can identify more subtle degrees of ankle instability.