Background: There is no consensus that an arthroscopically guided operation can improve the anatomical and functional results of treatment of intra-articular fractures of the distal aspect of the radius. The purpose of the present prospective study was to determine the usefulness of arthroscopically assisted reduction of displaced intra-articular fractures of the distal aspect of the radius by comparing the results of that procedure with those of conventional open reduction and internal fixation.Methods: Thirty-four fractures were treated with arthroscopically guided reduction with use of one volar and two dorsal arthroscopic portals. The fractures were pinned, and external fixation was used with or without autogenous bone graft. Intraoperative fluoroscopy was not used. Forty-eight fractures were treated with conventional open reduction and internal fixation with a plate and screws or with pinning, with or without external fixation. The average duration of follow-up for all fractures was thirty-one months.Results: The scores for overall outcome, assessed with use of the system of Gartland and Werley and that of Green and O'Brien as modified by Cooney et al., demonstrated that the group that had had an arthroscopically assisted procedure had better outcomes than the group that had had conventional open reduction and internal fixation. The group that had had an arthroscopically assisted procedure also had significantly better ranges of flexion-extension and radial-ulnar deviation of the wrist and grip strength (p < 0.05).We detected an association between the maximum step and gap displacement and evidence of osteoarthritis of the radiocarpal joint (p < 0.001), but we did not find a significant association, with the numbers available, between the scores for osteoarthritis, graded according to the scale of Knirk and Jupiter, and the scores for overall outcome, assessed with the scale of Gartland and Werley and the modified system of Green and O'Brien, in either group (p = 0.376). The radiographic results showed that the patients who had had an arthroscopically assisted procedure had better reduction of volar tilt, ulnar variance, and articular (gap) displacement than did those who had been managed with conventional open reduction and internal fixation (p < 0.05 for each comparison).Conclusions: An arthroscopically guided operation achieved an accurate reduction of intra-articular fractures of the distal aspect of the radius. Minimum capsular and adjacent soft-tissue scarring reduced postoperative contracture, which improved the overall functional results. We recommend arthroscopically guided reduction and internal fixation not only for young adults but for all patients who are less than seventy years old and have an intra-articular fracture of the distal part of the radius with more than one millimeter of displacement on plain radiographs.