Osteochondral Lesions of the Talus Wheeless

Description: Although a traumatic etiology is believed to play a major role in production of these lesions, idiopathic osteonecrosis may be another factor;
Anterolateral lesions:
- may result from impaction of talus on fibula as the dorsiflexed ankle is forced into inversion (see ankle sprain);
- the vast majority are caused by trauma;
- these lesions tend to be shallow;
Posteromedial lesions:
- most of these lesions probably arised from trauma (but many will have an atraumatic etiology);
- may result from impaction of posteromedial talus on tibia, as plantar flexion ankle is forced into inversion and exteranal rotation;
- these lesions are deeper and cup shaped;
- exam: palpate just posterior to the medial malleolus with the ankle dorsiflexed (may resemble pending rupture of posterior tib)