Lisfranc Injury Diagnosis: What Is the Diagnostic Reliability of New Radiographic Signs Using Three-dimensional CT?

Area of Science:

• Orthopedic Surgery
• Radiology
• Medical Imaging

Background:

• Lisfranc injuries are frequently misdiagnosed, leading to poor outcomes.
• Delayed diagnosis of Lisfranc injuries can result in irreversible functional disability.
• Three-dimensional CT (3D CT) shows promise for diagnosing Lisfranc injuries, but its specific signs are not well-documented.

Purpose of the Study:

• To evaluate the diagnostic performance of novel radiographic signs on 3D CT for Lisfranc injuries.
• To assess the interobserver and intraobserver reliability of the Mercedes sign, peeking metatarsal sign, and peeking cuneiform sign.
• To compare the diagnostic accuracy of these 3D CT signs against intraoperative findings.

Main Methods:

• Retrospective analysis of 3D CT reconstructions from 52 confirmed Lisfranc injuries and 50 asymptomatic feet.
• Two foot and ankle specialists and three orthopaedic residents evaluated the 3D CT scans twice.
• Diagnostic performance was assessed using sensitivity, specificity, and area under the ROC curve, with intraoperative stability testing as the gold standard.

Main Results:

• All examined 3D CT signs exhibited excellent sensitivity (92-97%) and specificity (92-93%).
• The Mercedes sign showed a higher area under the curve (0.91) compared to other signs (0.87, 0.8).
• Excellent mean intraobserver and interobserver reliability (kappa values) were recorded for all evaluated signs.

Conclusions:

• Novel 3D CT radiographic signs demonstrate excellent diagnostic performance and reliability for Lisfranc injuries.
• These 3D CT signs can serve as a valuable tool for initial screening in the acute injury setting.
• Further research comparing 3D CT with weight-bearing radiographs is warranted.