Assessment of Ankle-Subtalar-Joint-Complex Laxity Using an Instrumented Ankle Arthrometer: An Experimental Cadaveric...

Area of Science:

• Biomechanics
• Orthopedics
• Sports Medicine

Background:

• Ankle injuries, particularly lateral ligamentous injuries, are common.
• Accurate assessment of ankle joint laxity is crucial for diagnosis and rehabilitation.
• Existing methods for measuring laxity may have limitations in reliability and portability.

Purpose of the Study:

• To establish the relationship between direct tibial-calcaneal bone motion and instrumented ankle-subtalar-joint-complex laxity measurements.
• To evaluate the reliability of measurements obtained using a portable ankle arthrometer.
• To determine the arthrometer's ability to detect increased laxity after simulated lateral ankle ligament injury.

Main Methods:

• Six human cadaver ankle specimens were used.
• Direct tibial-calcaneal bone motion and instrumented laxity were measured concurrently under load.
• Linear regression and intraclass correlation coefficients (ICC) were employed for analysis.
• Simulated lateral ankle ligament injuries (anterior talofibular and calcaneofibular ligaments) were created.

Main Results:

• Strong correlations were found between bone motion and instrumented measurements for anterior-posterior displacement (r=0.878) and inversion-eversion rotation (r=0.858).
• The arthrometer demonstrated high intratester and intertester reliability (ICC=0.80-0.97).
• Ligamentous sectioning significantly increased ankle-subtalar-joint-complex laxity, which was detected by the arthrometer.

Conclusions:

• A significant relationship exists between direct bone motion and arthrometric measurements of ankle-subtalar-joint-complex laxity.
• The portable ankle arthrometer is a reliable tool for assessing ankle laxity.
• This instrument shows potential as a diagnostic aid for evaluating lateral ankle ligament injuries.