Two cohort populations consisting of 13 patients with an un-united fracture of the distal radius in whom the distal fragment had more than 5 mm of subchondral bone supporting the articular surface distal to the site of the nonunion and ten patients with an un-united fracture of the distal radius with a smaller distal fragment were compared. There were no preoperative differences with respect to age, gender, interval between injury and index procedure, preoperative amount of radius tilt, ulnar inclination and ulnar variance, or the preoperative function. Independent of the size of the distal fragment in all patients the distal radius was restored to gain bony union and realignment with preservation of some wrist motion. The length of the follow-up period averaged 30 months for the small fragment group compared with 22 months for the large fragment group. Bony union was achieved in 22 patients. One patient out of the large fragment group failed to heal the fracture and had wrist fusion. At the follow-up examination there were no significant differences in the radiological and clinical outcome between the two groups. No differences were seen on total range of motion of forearm supination and pronation with an average of 135 degrees in the large fragment group and 145 degrees in the small fragment group. Wrist motion revealed no significant differences in the flexion-extension arc, averaging 90 degrees in the large fragment group and 83 degrees in the small fragment group. Total range of motion of radial and ulnar deviation of the wrist was similar, averaging 39 degrees in the large fragment group and 43 degrees in the small fragment group. Grip strength averaged 59% compared with the opposite limb for the large fragment group and 67% for the small fragment group. We believe that the results of reconstruction of un-united fractures of the distal end of the radius for patients in whom the distal fragment had less than 5 mm of subchondral bone supporting the articular surface distal to the site of the nonunion are comparable to the results for patients with a larger distal fragment. Therefore, we believe that surgeons should try to preserve even a small amount of wrist motion and reserve wrist fusion as a final resort.