Isolated dorsal fracture-dislocation of the tarsal navicular.

Two cases of isolated fracture and dorsal dislocation of the tarsal navicular are reported. Analysis of the mechanism of injury is made, and it is suggested that the dislocation of the tarsal navicular does not occur without a fracture because of anatomical considerations. The necessity for accurate reduction and internal fixation to hold the fracture is emphasized which, when healed, maintains the reduction. The possibility of orthotic treatment for postfracture morbidity is mentioned. Late pain may occur due to degenerative disease affecting the navicular articulations.