Role of metaphyseal cancellous bone defect size in secondary displacement in Colles' fracture.

The purpose of this study was to evaluate the role of the metaphyseal cancellous bone defect size in secondary dislocation of Colles' fracture. Thirty-five patients with a dislocated Colles' fracture were examined by computed tomography (CT) for metaphyseal bone defects. The size of the defect was assessed and related to the surface area of the cross-section of the distal radius at the site of the defect. The relative size of the defect correlated with the severity of dorsal angulation of the fracture but not with the shortening of the radius seen after cast immobilization. We concluded that secondary displacement of the distal radius is partly mediated through the metaphyseal cancellous bone defect, and to prevent malunion in dorsal angulation, operative treatment or possibly filling of the defect should be considered even as early as during primary reduction if a large defect is suspected.