Acutrak versus Herbert screw fixation for scaphoid non-union and delayed union.

Purpose: To compare the treatment outcome of Acutrak versus Herbert screw fixation for scaphoid non-union and delayed union.

Methods: Records of 132 patients who underwent Herbert screw fixation (n=61) or Acutrak screw fixation (n=71) with or without bone grafting for scaphoid non-union and delayed union by a single surgeon were reviewed. The most common fracture site was the waist of the scaphoid (n=95), followed by the proximal pole (n=31) and the distal pole (n=6). Screw placement was considered accurate (n=120) when the screw was placed in the central one-third (axially) of the scaphoid; otherwise it was eccentric (n=12). Bone union was assessed radiographically and clinically. Functional outcome was assessed using the modified Mayo wrist score.

Results: Respectively in the Herbert and Acutrak screw groups, the mean patient ages were 25.3 and 27.3 years (p=0.28), the mean intervals between injury and screw fixation were 12.2 and 17 months (p=0.38), the mean durations to bone union were 2.1 and 1.8 months (p=0.63), and the union rates were 77% and 93% (p=0.01). The union rate was significantly higher in fractures of the waist of the scaphoid than in the proximal and distal poles (94% vs. 71% vs. 33%, p=0.001). The union rate was significantly higher when the screw was placed accurately (axially) than eccentrically (Herbert screw: 84% vs. 40%, p=0.006; Acutrak screw: 96% vs. 0%, p=0.004). 84% of the Herbert screws were placed axially, compared to 97% for the Acutrak screws. Respectively, 67% and 85% of patients had satisfactory functional outcomes (p=0.03), whereas 23% and 7% of the patients had persistent non-union (p=0.05).

Conclusion: The Acutrak screw enabled more accurate screw placement and achieved higher union rates and modified Mayo wrist scores than the Herbert screw did.