Complications of Diabetes Mellitus: Lisfranc Fracture and Dislocation

A 53-year-old man with a 20-year history of type 2 diabetes mellitus (for which he required insulin) sought evaluation of a hot, swollen right foot that seemed to have become "flat." He had no pain, fever, or chills. The patient's metatarsal bones were readily movable, consistent with Charcot joint. Further workup ruled out osteomyelitis. Plain films demonstrated extensive deformity of the tarsal and metatarsal bones with Lisfranc fracture/dislocation through the base aspects of all 5 metatarsals.Although the pathophysiologic source remains controversial, there is some evidence of a neuropathic component in Charcot foot, in which involvement of the autonomic nervous system results in an arterial "autosympathectomy." This leads to arterial dilation, increased vascularity of the involved bone and, eventually, bone reabsorption, dissolution, and fragmentation. The continued trauma of weight bearing results in stress fractures and then dislocation (the so-called Lisfranc dislocation between the tarsal and metatarsal bones). The rocker-bottom foot seen here is the typical deformity.Treatment consists of non-weight bearing and immobiliza-tion until the acute process abates. Once the bones become stabilized, treatment may consist of surgical fusion and/or use of customized orthotics. (Case and photographs courtesy of Bernardo B. Fernandez, MD.)