Influence of Fractures and Dislocations in Severity of Rocker-Bottom Deformity in Patients with Charcot Foot.

The objective of this study was to identify bone fractures and joint dislocations that have greater association with the severity of arch collapse in patients with Charcot foot involving the midfoot.A retrospective study in 28 (N = 29 feet) patients who had Charcot foot deformity of the midfoot. The study included stage III of Eichenholtz classification, and Schon classification types I to III. Talar-first metatarsal and calcaneal pitch angles and cuboid height were used to evaluate the severity of the midfoot deformity in a weightbearing lateral radiograph. Two investigators evaluated the bone fracture and joint dislocation involved in weightbearing antero-posterior and lateral radiographs.There were 13 (46%) feet that showed pattern 1, 9 (31%) feet with pattern 2, and 7 (25%) feet with pattern 3 according to the Schon classification. One foot had a combination of patterns 1 and 2. Midfoot ulceration occurred in 64% (n = 19) of feet. In the multivariate analysis, plantarflexion of talar-first metatarsal angle was predicted by navicular-medial cuneiform dislocation (p = .007 [-20.620-3.683]), an increase of the negative calcaneal pitch angle by fragmentation of the cuboid (p = .003 [-15.568-3.626]), and increment of the negative cuboid height by navicular-medial cuneiform and medial cuneiform-first metatarsal dislocations (p = .040 [-12.779-0.317], p = .002 [-13.437-3.267], respectively).Bone fractures and dislocations in the sagittal plane seem to contribute to midfoot collapse, but navicular-medial cuneiform dislocation/non-union and cuboid fragmentation predict severe rocker-bottom deformity in cases of Charcot foot.