RADIOGRAPHIC AND COMPUTED TOMOGRAPHIC EVALUATION OF LISFRANC DISLOCATION - A CADAVER STUDY

Six cadaver feet were used for radiological and computed tomographic ( CT) evaluation. The tarsometatarsal joints of each specimen were displ aced dorsolaterally in successive 1-mm increments. None of the 1-mm an d two thirds of the 2-mm dorsolateral Lisfranc dislocations could be v isualized on routine radiographs; they could all be noted on CT scans. There was good assessment on CT scan for the extent of the minor lesi ons that are normally obscured by overlapping projection in routine ra diographs. A Lisfranc injury that appears undisplaced on radiographs o r acceptable after closed reduction may still have an unpredictable ou tcome because of the presence of an occult joint subluxation. CT scann ing 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 Lis franc injuries may minimize development of post-traumatic degenerative arthritis.