Osteochondritis dissecans (OCD) of the ankle is the end result of the aseptic separation of an osteochondral fragment of the talar dome with the gradual fragmentation of the articular surface. See the main osteochondritis dissecans article for a general discussion on this condition, which mostly affects the knees.
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Epidemiology
The definition of osteochondritis dissecans says that these lesions occur in an immature growing skeleton, however, the symptoms usually have their onset in the adulthood.
Clinical presentation
May be asymptomatic for a long period. A common complaint is an intermittent weight-bearing pain. When there is a loose body within the joint, symptoms may be more severe and include intense pain, swelling, instability during walking, and locking.
Pathology
See the main osteochondritis dissecans article for a general discussion on the pathology of this condition.
Radiographic features
Plain radiograph
Radiographs are more sensitive if dedicated projections are obtained, such as dorsiflexion and plantarflexion AP of the ankle or with 15° of internal rotation. Osteochondritis dissecans is predominantly located in the superomedial corner of the talus:
- subchondral halo outlining the osteochondral fragment
- a focal concavity of the articular surface
- an intra-articular bone fragment may be seen
History and etymology
It was first described in the ankle by M Kappis in 1922 1,4.