Saturday, January 16, 2010

Ankle Sprains and a "New" Lateral Ligament

Photo by sarowen

Ankle sprains are extremely common injuries, with virtually every active individual sustaining one sometime in their lives. The most frequent ankle sprain is an inversion injury, typically resulting in injuries of the lateral ligaments.

The commonly known lateral ligaments are the anterior talofibular, calcaneofibular, and posterior talofibular ligaments. A recent article by Pastore et al. (AJR 192:967-973, 2009) beautifully describes some lesser known ligaments of the ankle, including the lateral talocalcaneal ligament.

The lateral talocalcaneal ligament (LTCL) is located in close proximity to the calcaneofibular ligament, but is just anterior and medial to it. The LTCL can be difficult to separate from the calcaneofibular ligament on MRI due to their close relationship. With 3T MRI, one will typically see the LTCL as a distinct structure, and it should not be confused with the calcaneofibular ligament.

Coronal intermediate images, posterior to anterior, reveal the familiar calcaneofibular ligament (green arrows) coursing from the calcaneus, superiorly and anteriorly, to attach on to the fibula. The LTCL ligament (red arrows) is easily identified, clearly distinct from the calcaneofibular ligament.

Axial proton density images, superior to inferior, show the relationship of the calcaneofibular ligament (green arrow) and the LTCL (red arrow):

The clinical significance of injuries of LTCL injuries is still uncertain, but I have seen this ligament injured in many individuals, often in conjunction with ATFL injuries.

Vic David MD