Analysis of scaphoid fracture displacement by three-dimensional computed tomography.

Scaphoid fracture displacement was studied in twenty-five patients using three-dimensional computed tomography. Fracture displacement was more readily detected and distinct in three-dimensional computed tomography images than in plain radiography. Two different types of offset of the distal fragment with respect to the proximal fragment are described on three dimensional computed tomography; volar type and dorsal type. In the volar type, the distal fragment overhung in the volar direction relative to the proximal fragment and was frequently accompanied by humpback deformity and axial rotation. In the dorsal type, the distal fragment slipped dorsal on the proximal fragment and was commonly accompanied by humpback deformity. The volar type had a transverse or vertical fracture line on both the volar and dorsal surfaces of the scaphoid, while the dorsal type had a horizontal fracture line. The volar type was frequently found when the fracture was distal, whereas the dorsal type was noted more frequently for proximally located fracture.