Six cadaver feet were used for radiological and computed tomographic (CT) evaluation. The tarsometatarsal joints of each specimen were displaced dorsolaterally in successive 1-mm increments. None of the 1-mm and two thirds of the 2-mm dorsolateral Lisfranc dislocations could be visualized on routine radiographs; they could all be noted on CT scans. There was good assessment on CT scan for the extent of the minor lesions that are normally obscured by overlapping projection in routine radiographs. A Lisfranc injury that appears undisplaced on radiographs or acceptable after closed reduction may still have an unpredictable outcome because of the presence of an occult joint subluxation. CT scanning is more sensitive than radiography for detecting the minor amounts of Lisfranc displacement. If there is any doubt on the radiographs, a CT scan should be performed. The early diagnosis and treatment of Lisfranc injuries may minimize development of post-traumatic degenerative arthritis.
