Standard perioperative imaging modalities are unreliable in assessing articular congruity of ankle fractures

Objectives: To determine the sensitivity, specificity, and interobserver and intraobserver reliabilities of intraoperative fluoroscopy and postoperative plain radiographs (XR) in the assessment of articular congruency after open reduction and internal fixation (ORIF) of ankle fractures involving the tibial plafond. Design: Retrospective cohort. Setting: Academic level 1 trauma center. Patients/Participants: One hundred five patients treated surgically for rotational ankle fractures. Intervention: ORIF. Main Outcome Measurements: Sensitivity, specificity, and interobserver and intraobserver reliabilities of fluoroscopy and plain radiographs when compared with computed tomography imaging. Results: The sensitivities of fluoroscopy and XR were 21% and 36%, respectively. Specificities were 95% (fluoroscopy) and 89% (XR). Fluoroscopy interobserver reliability was κ = 0.15, and mean intraobserver reliability was κ = 0.32. XR interobserver and mean intraobserver reliabilities were κ = 0.30 and κ = 0.59. Conclusions: Although results show acceptable specificity, the reliability and sensitivity of both intraoperative fluoroscopy and postoperative XR in the assessment of ankle articular congruency are low. This calls into question available literature correlating clinical results with articular reduction. During ORIF of an intra-articular ankle fracture, surgeons should be highly critical of fluoroscopic imaging that seems adequately reduced and direct visualization of the articular surface should be used as a reduction aid if possible. Furthermore, in the postoperative period, axial imaging may be warranted in patients who have poor clinical outcomes despite apparent anatomic articular reduction to evaluate for occult joint incongruence.