Chronic subtalar instability due to insufficiency of the calcaneofibular ligament: a case report.

Calcaneofibular ligament insufficiency in isolation is an uncommon cause of chronic instability of the subtalar joint. We report one case of chronic subtalar instability due to calcaneofibular ligament insufficiency after an ankle sprain. It was diagnosed with clinical findings and stress radiograph, and successfully treated with proximal advancement of the elongated calcaneofibular ligament.