Occult syndesmotic malreduction detected by postoperative CT despite acceptable radiographs: Association with 24-month functional outcomes.

BACKGROUND: Plain radiographs are routinely used to assess syndesmotic reduction after ankle fracture fixation; however, their ability to detect subtle malreduction remains uncertain. This study evaluated the prevalence and clinical relevance of CT-detected syndesmotic malreduction in patients with radiographically acceptable postoperative reduction.

MATERIALS AND METHODS: Adult patients undergoing ankle fracture fixation with syndesmotic stabilization and acceptable postoperative radiographs were prospectively enrolled. All patients underwent early postoperative bilateral CT assessment with side-to-side comparison of translational and rotational parameters. Patients were stratified into anatomical reduction, minor malreduction, and major malreduction groups. Functional outcomes were assessed at 24 months using the AOFAS ankle-hindfoot score.

RESULTS: Eighty-six patients were included. CT detected syndesmotic malreduction in 52.3% of patients despite acceptable radiographs. Mean AOFAS scores progressively decreased from the anatomical reduction to the major malreduction group (91.3 ± 5.9 vs 83.5 ± 3.5 vs 74.4 ± 3.2; p < 0.001). Both minor and major malreduction were independently associated with worse functional outcomes.

CONCLUSION: Postoperative radiographs may underestimate syndesmotic malreduction. CT identified occult malreduction in a substantial proportion of cases and demonstrated a significant association between malreduction severity and inferior functional outcomes.

LEVEL OF EVIDENCE: Level II, prospective cohort study.