The DF Compression Test is most indicative of which injury?

• A. ATFL sprain
• B. Syndesmosis sprain
• C. Deltoid ligament sprain
• D. Calcaneal fracture

Answer: (B)

The dorsiflexion compression test stresses the distal tibiofibular syndesmosis—the joint where the tibia and fibula meet just above the ankle. By dorsiflexing the ankle, the tibiofibular interval tightens and the syndesmotic ligaments are put on stretch. Applying compression between the tibia and fibula further loads that area, so if there is injury to the syndesmosis, pain or reproduction of symptoms occurs. This makes the test particularly specific for a syndesmotic (high ankle) sprain.

In contrast, injuries to the lateral ligaments (like ATFL) or the deltoid ligament typically show different patterns—lateral ligament injuries respond to anterior drawer or talar tilt tests, and deltoid injuries produce medial pain with eversion. A calcaneal fracture would present with focal calcaneal tenderness and inability to bear weight, not a selective syndesmotic pain pattern.