Functional and radiographic results of patients with syndesmotic screw fixation: implications for screw removal

Abstract

Objective: Screw fixation of the injured syndesmosis restores stability but may reduce motion. The purpose of this study is to determine whether functional outcomes and radiographic results after ankle fracture are affected by the status of the syndesmosis screw.

Design: Retrospective review of a consecutive clinical series.

Setting: Level 1 academic trauma center.

Patients: One hundred six adults were reviewed radiographically; mean follow up was 15 months (range, 4-30 months). Seventy-six of the 106 patients completed formal functional testing; mean follow up was 23 +/- 13 months (range, 12-32 months).

Intervention: Open reduction and internal fixation, including fixation of the tibiofibular syndesmosis.

Main outcome measurements: Patients with intact, broken or loose, or removed syndesmosis screws were compared. Functional outcomes were measured using the Lower Extremity Measure and the Olerud Molander ankle score. Radiologic review included tibiofibular clear space, tibiofibular overlap, and medial clear space.

Results: Functional outcomes were improved in patients with fractured, loosened, or removed screws compared with those with intact screws. The Lower Extremity Measure score for patients with intact screws was 70 +/- 6 compared with 85 +/- 3 for fractured, loosened, or removed screws (P = 0.01). The Olerud Molander ankle score for patients with intact screws was 47 +/- 8.0 compared with 64 +/- 4 for fractured, loosened, or removed screws (P = 0.04). There was no difference in outcome comparing fractured, loosened, and removed screws. The tibiofibular clear space was narrowed in patients with intact screws compared with removed, fractured, or loose screws. The tibiofibular clear space for intact screws was 3.1 +/- 0.2 compared with 4.1 +/- 0.2 for removed, fractured, or loosened screws (P = 0.005). There was no difference in outcome comparing large and small fragment screws.

Conclusions: An intact syndesmosis screw was associated with a worse functional outcome compared with loose, fractured, or removed screws. However, there were no differences in functional outcomes comparing loose or fractured screws with removed screws. Screw removal is unlikely to benefit patients with loose or fractured screws but may be indicated in patients with intact syndesmosis screws.