The Effect of Displaced Dorsal Rim Fragment in a Distal Radius Fracture

Background In intra-articular fracture of distal radius, the intra-articular fragments can be divided into some specific fragments. In particular, the poor outcomes have been well documented for reduction loss of the volar lunate facet, but the effect of a displaced dorsal rim fracture has rarely been addressed. Materials and Methods The records of 26 patients with dorsal rim fragment displaced by more than 2 mm after volar locking plate (VLP) fixation for a dorsally displaced distal radius fracture (DRF) treated from March 2006 to March 2009 were retrospectively reviewed. Clinical assessments including grip strengths, wrist range of motions, and Disabilities of Arm, Shoulder, and Hand (DASH) scores were performed at 12 months postoperatively. Widths of the distal ends of dorsal rims were determined by preoperative computed tomography (CT). Dorsal rim fragment displacements were measured in immediate postoperative plain lateral radiographs. Radial inclination, volar tilt, and ulnar variance were measured on immediate postoperative wrist radiographs. Arthritic changes of radiocarpal joints were graded using radiographs obtained at 12 months postoperatively. Description of Technique DRFs were fixed using a VLP in the usual manner. Although DRF displacement was noticed after plate fixation, no further procedure was performed. The sizes of articular portions of dorsal rim fragments were measured arthroscopically in 5 of the 26 patients at the time of plate fixation. Results At 12 months postoperatively, mean grip strength, wrist flexion arc, and mean wrist extension arc were 86 ± 13, 87 ± 11, and 91 ± 10%, respectively, of contralateral sides. Mean forearm supination and pronation were 96 ± 8 and 99 ± 5%, respectively, of contralateral sides. Mean DASH score was 11 ± 10 points. Preoperatively, mean width of the distal end of dorsal rim fragments and mean displacements of dorsal rim fragments were 2.0 ± 0.6 and 3.0 ± 0.9 mm, respectively. Mean width of the articular portions of dorsal rim fragment by arthroscopic examination was 1.0 ± 0.4 mm. Mean radial inclination was 21 ± 4.8 degrees, mean volar angulation was 4.8 ± 3.9 degrees, and mean ulnar variance was 0.6 ± 1.8 mm at immediate postoperatively. Two patients showed grade I arthritic changes at 12 months postoperatively. Conclusions The articular portions of dorsal rim fragments measured arthroscopically were smaller than determined by CT. Furthermore, the study shows that displaced dorsal rim fragments in dorsally displaced DRFs treated by VLP do not adversely affect wrist clinical outcomes.