Calcaneofibular Ligament

- Discussion:
    - calcaneofibular ligament is a extra-articular round and cordlike ligament which connnects tip of distal fibula to small tubercle on posterior & lateral aspect of calcaneus;
    - crosses two joints, talocrural and the talocalcaneal;
    - 2 cm long, 5 mm wide, and 3 mm thick;
    - calcaneal attachment of calcaneofibular lig is 13 mm from subtalar joint, & that insertion of anterior talofibular ligament onto talus is 18 mm posterior to subtalar joint;
    - calcaneofibular lig attaches posteriorly on calcaneus to form 133-deg angle w/ fibula when ankle is in neutral dorsiflexion-plantar flexion
    - it is in close contact with medial peroneal sheath, but is not associatted with either the ankle capsule or peroneal tendon sheath;

- Function:
    - it is lax in normal, standing position due to relative valgus orientation of calcaneus;
    - it acts primarily to stabilize sub-talar joint & limit inversion;
    - this ligament is extra-articular but it has an intimate connection to overlying peroneal-tendon sheath;
    - calcaneofiblar ligament may be lax until supination force is applied;
    - greatest strain occurrs when inversion moment is applied w/ ankle in dorsiflexion;
    - because of its unique anatomical orientation, calcaneofibular ligament also has major role in stabilization of subtalar joint;
    - isolated rupture of the calcaneofibular ligament probably does not cause demonstrable ankle laxity;

- Exam:
    - inversion (supination) test;
    - w/ ankle in plantarflexion: evaluates anterior talofibular ligament;
    - in neutral / slight dorisflexion: evaluates calcaneofibular ligament;
    - talar tilt:
            - talar instability is assessed w/ talar tilt test, in which angle formed by tibial plafond & talar dome is measured as inversion force is applied to  hindfoot;
            - talar tilt test is useful for evaluation of combined injury of both anterior talofibular & calcaneofibular ligament;
    - talar tilt to ranges from 0 to 23 degrees in normal ankles, while but normal ankles tend to have < 5 degrees of talar tilt;

- Arthrography:
    - w/ ankle arthrography, contrast medium often fails to enter peroneal sheath, despite operatively proved tears of calcaneofibular ligament;
    - technique of peroneal tenography was developed has proved to be more accurate in the diagnosis of disruption of calcaneofibular ligament;
    - leakage of the dye through a particular ligament or thru the distal tibiofibular syndesmosis will pin point structure torn;
    - performed by inserting 22 gauge needle into the medial side of joint;
    - extra articular dye anterior to the laterala malleolus is always associatted with a rupture of ATFL;
    - dye seen in peroneal sheath usually is caused by rupture of CFL;
    - extension of contrast > 3.5 cm above joint is c/w ligamentous injury;
    - arthrography needs to be performed within 1 week of injury or fibrin clots may seal any capsular tear

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Monday, October 29, 2012 11:55 am