Displaced spiral and oblique fractures of the proximal phalanx are unstable and non-operative treatment frequently results in malunion. Such fractures are therefore treated operatively. No previous study has compared the two common techniques used. Patients with an isolated spiral or oblique fracture of the proximal phalanx were prospectively randomised into two groups. One was treated by closed reduction and Kirschner wire fixation and the second treated by open reduction and lag screw fixation. An independent observer assessed function, pain, movement, grip strength and intrinsic muscle function. X-rays were assessed for malunion. 32 patients entered the study. At follow-up (mean 40 months) there were 15 in the Kirschner wire and 13 in the lag screw group. All returned to their normal employment and 18 described a full functional recovery. There was no significant difference in the functional recovery rates (Fischer exact test p=0. 3) or in pain scores for the two groups (median 0 for both). Radiographs showed similar rates of malunion and there was no statistically significant difference in range of movement or grip strengths. This prospective randomised study has shown no significant difference in outcome for the two techniques. We would recommend that surgeons should choose the method with which they are most familiar and competent, or the technique that utilises the least health care resources.