Three-dimensional analysis of displacement characteristics of dorsally angulated intra-articular distal radial fractures.

Understanding the complex fragmentation of intra-articular distal radial fractures contributes to achieving anatomical reduction during surgery. This study aimed to clarify three-dimensional displacement patterns of intra-articular fragmentation in dorsally angulated, intra-articular distal radial fractures. We identified five characteristic intra-articular fragments: a key fragment, dorsal ulnar corner, dorsal wall, radial column and anterior radial column. The key fragment was displaced with radial deviation, pronation and extension and with dorsal, proximal and radial translations. The dorsal ulnar corner displacement resulted in a gap, a step-off and a deepened concavity for the lunate facet and sigmoid notch. The dorsal wall displacement resulted in a deepened concavity, a gap and a step-off of the dorsal scaphoid facet. The displacements of the radial column and anterior radial column caused a step-off between the scaphoid and lunate facets. The five characteristic intra-articular fragments each created a characteristic gap and step-off in the articular surface. Level of evidence: IV.