Tear of the lateral (calcaneofibular) ligament of the ankle

Definition:

A partial or complete discontinuity in the connective tissue fibre matrix comprising the calcaneofibular ligament of the ankle.

Causes:

Causes of calcaneofibular ligament tears are very similar to those of anterior tibiofibular ligament, and injuries of the lateral ligaments of the ankle tend to involve both the aforementioned ligaments. Please refer to ‘Tear of the lateral (talofibular) ligaments of the ankle’ for mechanisms of injury and causes.

Examination:

The patient will usually present with pain over the lateral aspect of the ankle. Lateral ankle ligamentous sprains are sub-divided into three grades.

Grade I: mild tear of the involved ligament(s), associated with slight pain, and oedema. The stability of the ankle is not compromised and the patient is usually able to weight-bare.

Grade II the tear is more extensive, and associated with more severe ecchymoses, and oedema. Weight-baring is usually painful, but can be achieved.

Grade III is a complete tear of the affected ligament(s), with severe oedema and ecchymoses. Ankle stability is severely compromised, and weight-baring is not usually achievable.

Orthopaedic tests for lateral talofibular ligament sprain.

Drawer’s foot sign: with the patient supine, grasp the patient’s foot and invert it. Excessive motion with pain can be interpreted as a positive.