Danis–Weber Classification

Danis R. Les fractures malleolaires. In: Théorie et pratique de l’ostéosynthèse. First described grouping malleolar fractures by the level of the fibular fracture relative to the syndesmosis.

Weber BG. Die Verletzungen des oberen Sprunggelenkes. Popularised and refined the Danis grouping into the A/B/C system used here, adopted into the AO/OTA classification as infrasyndesmotic (A), transsyndesmotic (B), and suprasyndesmotic (C).

The fibular fracture level is only a guide to syndesmosis stability, not a direct measurement of it — the syndesmosis is torn in a minority of Weber A injuries, in up to about 40% of Weber B injuries (mechanism-dependent), and in up to about 80% of Weber C injuries. Stability is confirmed by the full picture: the medial side (deltoid ligament integrity or a medial malleolar fracture), any posterior malleolar fracture, and stress or intraoperative testing where the diagnosis is unclear — not the Weber type alone.