Aim We asked the following questions:

Are there reliable clinical signs that herald an impending disorganisation of the Lisfranc’s joint in a diabetic foot?

Does the Charcot changes begin at the Lisfranc’s joint?

Is conventional radiography reliable in making the diagnosis?

Method Forty-five consecutive patients (63% male, 37% female) with a mean age of 59.9 years (range 38–80) were prospectively studied. All had either Type I/II diabetes (75% had Type II diabetes). Diagnosis of Char-cot foot was made using a standardised clinical protocol. Patients with a definite history of trauma/open injuries were excluded. All had a standard follow up programme. The mean follow up was 20 months (range 7–46).

Results In 75% of cases radiographs showed malalignment of the Lisfranc joint, 25% had navicular and 6% had fracture of the medial cuneiform. Thirteen per cent had fractures of the metatarsal and another 13% had fracture of the calcaneum. In all patients, Charcot changes were heralded buy a silent, red swollen foot and in few patients these features did exist in spite of no clear-cut radiological findings. As the Charcot changes progressed, more fractures were seen and in 80% of the patients we saw rapid disorganisation of the intertarsal joints of the midfoot. In 80% the earliest radiological change was seen at the Lisfranc’s region.

Conclusion and significance of this study The pattern of changes in the Charcot foot varies with the type of diabetes. Conventional radiography is reliable if there is a high degree of suspicion. Charcot changes often appear first at Lisfranc’s joint and usually there are no clear-cut signs in order to make a clinical diagnosis.