The Tibiofibular Line: A Reliable Method of Syndesmosis Assessment in Certain Fibula Morphologies.

Background The tibiofibular line (TFL) technique was initially proposed to assess syndesmosis reduction. Clinical utility was limited by low observer reliability when applied to all fibulas. This study aimed to refine this technique by describing TFL's applicability to various fibula morphologies. Methods Three observers reviewed 52 ankle CT scans. Observer consistencies for TFL measurement, anterolateral fibula contact length, and fibula morphology were assessed using intraclass correlation (ICC) and Fleiss' Kappa. Results TFL measurement and fibula contact length intra-observer and inter-observer consistencies were excellent (minimum ICC, 0.87). Fibula shape categorization intra-observer consistency was substantial to almost perfect (Fleiss' Kappa, 0.73 to 0.97). Six to 10 mm of fibula contact length corresponded to excellent TFL distance consistency (ICC, 0.80 to 0.98). Conclusion The TFL technique appears best for patients with 6 mm to 10 mm of straight anterolateral fibula. Sixty-one percent (61%) of fibulas featured this morphology, indicating most patients may be amenable to this technique.

Reliability of the "Clinical Tibiofibular Line" Technique for Open Syndesmosis Reduction Assessment.

BACKGROUND: When intraoperative computed tomography (CT) is unavailable, open syndesmosis assessment is a universally available, safe alternative that is more accurate than radiographic assessment. However, it has a documented malreduction rate of up to 16%. This may be improved upon with a validated technique for assessing the accuracy of open syndesmosis reductions. The "tibiofibular line" (TFL) is a CT-based technique found to be sensitive for malreduction. The purpose of this study was to assess the feasibility of adapting the CT-TFL method into a reliable intraoperative open technique by refining the methodology of previous work exploring the clinical TFL technique. METHODS: Three observers were instructed to clinically simulate the TFL on cadaveric lower limbs. For each specimen, observers repeated and recorded 3 clinical TFL measurements for each of 4 measurement series representing different degrees of fibula reduction. Intraclass correlation was used to assess intra- and interobserver reliabilities. RESULTS: Mean intraobserver reliability was .88. Mean interobserver reliability was .75. Both intra- and interobserver reliabilities were highest for anatomic syndesmosis reduction. CONCLUSION: The findings of excellent to near perfect intraobserver and good to excellent interobserver reliability indicate the feasibility of translating the CT-TFL into a reliable open technique. LEVELS OF EVIDENCE: Level III: Diagnostic study.