Detecting Ankle Instability With an Instrumented Ankle Arthrometer: An Experimental Study.

Area of Science:

• Orthopaedic biomechanics
• Sports medicine
• Musculoskeletal research

Background:

• Ankle joint instability is a common clinical problem.
• Accurate quantification of ankle stability is crucial for diagnosis and treatment.
• Existing methods for assessing anterior talar drawer test outcomes have limitations.

Purpose of the Study:

• To validate a novel instrumented device for quantifying ankle joint stability during the anterior talar drawer test.
• To compare the device's bone kinematic measurements with arthrometer outcomes.
• To assess the device's sensitivity in detecting ligamentous injury.

Main Methods:

• Developed a custom instrumented ankle arthrometer.
• Utilized 14 cadaver legs for testing.
• Measured 3D bone kinematics using bone-pin markers (calcaneus, talus, fibula).
• Performed anterior talar drawer tests on intact and sequentially sectioned ligaments (ATFL, CFL, PTFL).

Main Results:

• Sectioning the anterior talofibular ligament (ATFL) significantly increased anterior translations measured by both bone-pin markers and the arthrometer.
• Receiver operating characteristic curve analysis showed fair to good discrimination between intact and ATFL-sectioned states.
• The arthrometer detected changes in bone movement after ATFL sectioning but struggled to differentiate between single and multiple ligament injuries.

Conclusions:

• The instrumented anterior talar drawer tester is sensitive to changes in bone kinematics following ATFL rupture.
• The device shows potential for augmenting current clinical assessments of ankle instability, particularly for ATFL injuries.
• Further investigation may be needed to improve differentiation between complex multi-ligament injuries.