A grade II sprain of the anterior talofibular ligament occurs most often with which combination of foot and ankle motions at the time of injury?

• A. Dorsiflexion and inversion
• B. Plantar flexion and eversion
• C. Dorsiflexion and eversion
• D. Plantar flexion and inversion

Answer: (D)

The ATFL is the ligament most stressed during an inversion injury of the ankle, especially when the foot is in plantarflexion. In this position the talus sits more forward and the fibula allows greater anterior translation, so an inward roll (inversion) places a high tensile load on the anterior talofibular ligament. This combination commonly produces a partial tear with pain and some laxity, which is characteristic of a Grade II sprain. Inversions with dorsiflexion or eversion load other structures more than the ATFL, making them less likely mechanisms for this specific ligament injury. Therefore, plantar flexion with inversion best explains why the ATFL is injured in many ankle sprains.