Dorsoradial avulsion of the triangular fibrocartilage complex with an avulsion fracture of the sigmoid notch of the radius

We report two extremely rare cases of dorsal radial avulsion injury of the triangular fibrocartilage complex accompanied by an avulsion fracture of the sigmoid notch of the radius. Anatomical reduction of the bone fragment in conjunction with reattachment of the dorsal portion of the radioulnar ligament to the radial sigmoid notch were necessary to restore stability of the distal radioulnar joint and tension of the triangular fibrocartilage proper.