Internal fixation of scaphoid non-union: a comparative study of three methods

In this study we compared the results of three methods of fixation for scaphoid non-union. The implants used were the AO 2 mm mini-fragment screw, the Herbert screw and the Kirschner (K) wires. Between 1990 and 1999, 132 patients underwent surgery for scaphoid fractures. We used the modified Filan and Herbert classification. Patients with acute fractures and patients requiring vascularised bone grafts were excluded. Twenty-six non-unions were fixed with an AO mini-fragment screw, 58 with a Herbert screw, and nine with K-wires. Radiological union was achieved in 85% of cases using the AO screw, 77% using the Herbert screw and 55% using the K-wire fixation. Statistically there was no significant difference between the AO and Herbert screw groups in terms of rate and speed of radiological union. The mechanical strength of the implant and the compression achieved did not seem to influence the union rate and speed. The type of bone graft (iliac crest or distal radius) did not significantly affect the union rates. Finally, K-wire fixation, either as a primary method or as a salvage procedure, produced inferior results and required prolonged immobilisation in plaster.