Which test is used to diagnose a syndesmosis sprain by applying a compression across the tibia and fibula above the ankle?

• A. Navicular Drop Test
• B. Anterior Drawer
• C. DF Compression Test
• D. Thompson Test

Answer: (C)

The key idea is measuring the distal tibiofibular (syndesmotic) joint under stress to detect a high ankle sprain. The test does this by compressing the tibia and fibula where they meet above the ankle while the foot is held in dorsiflexion. This position widens the syndesmosis and places tension on the interosseous ligaments and the anterior/posterior inferior tibiofibular ligaments. If there’s a syndesmotic injury, this loading reproduces pain and can reveal instability, making the test positive.

This is the best choice because it targets the specific structures involved in a syndesmosis sprain. The navicular drop test assesses arch height and is unrelated to the syndesmosis. The anterior drawer test checks stability of the anterior talofibular ligament, which is more relevant to lateral ankle Sprains. The Thompson test checks the integrity of the Achilles tendon. So, the dorsiflexion compression (DF compression) test directly stresses the syndesmotic complex, aligning with the diagnosis.