The anterior inferior tibiofibular ligament (AITFL) is the primary syndesmotic ligament, running obliquely from the anterior tubercle of the distal tibia (Chaput's tubercle) to the anterior fibula (Wagstaffe's tubercle). It is the first syndesmotic ligament to fail in external rotation ankle injuries and is the most commonly torn component in high ankle sprains.
Primary restraint to external rotation of the fibula; maintains the tibiofibular mortise width; the first syndesmotic stabiliser to fail in high ankle sprain.
AITFL tears produce the classic high ankle sprain with tenderness above the ankle joint and a positive squeeze test. MRI demonstrates AITFL disruption as increased signal and waviness at the anterior ankle. The Chaput fragment (Tibia) and Wagstaffe fragment (Fibula) are avulsion fractures at the ligament attachments. In ankle fractures with syndesmotic disruption, AITFL repair alone is insufficient — syndesmotic fixation (screw or tightrope) is required to maintain mortise reduction.
AITFL rupture from external rotation injury producing tenderness above the ankle joint line, a positive squeeze test, and prolonged return to sport compared with lateral ankle sprains, managed by syndesmotic taping, bracing, or surgical fixation in unstable cases.
Avulsion of the anterior tibial AITFL attachment producing an anterior ankle bony fragment (Chaput fragment) in high-energy ankle fractures, requiring fixation as part of ankle fracture management.
