Weber A, B, C in Thirty Seconds: The Ankle Fracture Call-Room Reference

When the ED calls about an ankle, the conversation runs on Weber letters. Lauge-Hansen describes mechanism more completely, but at 2 a.m. the orthopedist wants to know one thing, and Weber answers it: where is the fibular fracture relative to the syndesmosis? That relationship is a proxy for whether the syndesmosis — and therefore the mortise — can still be trusted.

The classification itself

• Weber A — below the syndesmosis. Transverse avulsion at or distal to the tibial plafond level, usually a supination injury. The syndesmosis is intact; these are typically stable and often managed non-operatively.
• Weber B — at the level of the syndesmosis. An oblique or spiral fracture starting at the plafond and extending proximally. This is the common one, and the honest answer about stability is "it depends" — specifically on the medial side (see below). Roughly half the operative decisions in ankle trauma live in this letter.
• Weber C — above the syndesmosis. The syndesmotic ligaments are torn by definition of the level, and these are treated as unstable until an orthopedist says otherwise.

State the letter only when there is a fracture to classify. A report that says "no fracture; therefore no Weber classification applies" is noise — if nothing is broken, say the ankle is intact and stop.

The mortise is the actual question

The letter is shorthand; the mortise is the point. On the mortise view check:

• Medial clear space — the gap between the medial malleolus and the talus. More than 4 mm (or asymmetric to the superior clear space) implies deltoid ligament injury, which converts a "simple" lateral malleolar fracture into an unstable bimalleolar-equivalent injury.
• Tibiofibular overlap and clear space — diminished overlap suggests syndesmotic widening.
• Talar shift or tilt — any lateral talar displacement is an operative conversation.

A Weber B with a normal medial side is a different injury from a Weber B with a widened medial clear space, and your report should make that distinction explicitly.

The Maisonneuve trap

If the medial side is injured — medial malleolar fracture or a wide medial clear space — and the fibula looks intact on the ankle series, the fracture may simply be above your images: a proximal fibular (Maisonneuve) fracture with the entire interosseous membrane torn along the way. The ankle series cannot exclude it. Recommend dedicated tibia–fibula radiographs, and say why. This is the single most cited miss in this injury pattern, and it is a miss of field-of-view, not of perception.

Don't stop at the fibula

The rest of the thirty seconds:

• Posterior malleolus — best seen on the lateral; a large fragment changes management.
• Base of the fifth metatarsal — the other avulsion that presents as "ankle pain," and it is on your film.
• Talar dome — osteochondral fragments hide at the corners of the dome, especially after the mortise reduces.
• Soft tissues — an ankle effusion or lateral swelling on a technically negative study still earns a sentence.
• In children, the same mechanism produces physeal injuries; a Salter-Harris fracture of the distal fibula is the age-appropriate reading of "normal-looking" bones with focal swelling.

Writing it so the orthopedist can act

A useful call-room line has four parts: the fracture and its Weber level, the medial side, the syndesmosis, and displacement — "Oblique distal fibular fracture at the level of the syndesmosis (Weber B), medial clear space normal, tibiofibular relationship preserved, no talar shift." That sentence answers the operative question in one breath.

Classification systems only help when they are applied consistently — the same discipline that drives the guideline calculators we publish for the follow-up systems. And if you want to watch a structured MSK report assemble itself from a scratch dictation, there's a live ankle case in the demo — no signup, thirty seconds, and it applies the Weber call exactly as above.