Sagittal mobility of the normal ankle

Area of Science:

• Orthopedics
• Biomechanics
• Sports Medicine

Background:

• The talus exhibits physiological anterior sagittal displacement during ankle examinations.
• This displacement is influenced by examination conditions, including manual stress and weight application.

Purpose of the Study:

• To investigate the effect of ankle positioning on talar sagittal displacement.
• To elucidate the role of the anterior talofibular ligament in limiting talar mobility.

Main Methods:

• Ankle examinations were performed on children and adults.
• Talus displacement was assessed with the ankle in neutral and equinus positions.
• Stress tests were conducted with and without apparatus, manual stress, and weights.

Main Results:

• Physiological anterior sagittal talar displacement decreased when the ankle was examined in equinus.
• This reduction is attributed to the taut anterior talofibular ligament in the equinus position.
• An isolated tear of the anterior talofibular ligament resulted in a pathological drawer sign and increased sagittal instability, unaffected by equinus positioning.

Conclusions:

• The anterior talofibular ligament plays a crucial role in limiting sagittal talar mobility, particularly in the equinus position.
• Assessment in equinus can mask subtle talar instability caused by isolated anterior talofibular ligament tears.