Direct coronal computed tomography arthrography of osteochondritis dissecans of the talus

Although radiographs, arthrography, tomography, and computed tomography can all be used to diagnose osteochondritis dissecans of the talus, these imaging methods may not demonstrate whether an undisplaced osteochondral fragment has any attachment to the articular cartilage or bony bed of the talus. As lack of such attachment is a relative indication for surgery, we studied the feasibility of using coronal computed tomography (CT) after double contrast arthrography to demonstrate attachment in four patients with osteochondritis dissecans seen on radiographs. Direct coronal CT arthrographic images showed intact articular cartilage in three patients. In the fourth patient, overlying cartilage was virtually absent and contrast tracked beneath the fragment, an appearance that correlated with arthroscopic findings of partial articular cartilage attachment and no union at the osteochondral fracture line. Our initial experience suggests that direct coronal CT arthrography clearly shows the state of attachment of the osteochondritic fragment to the talus.