Classification system
Weber Classification
Danis-Weber Classification of Ankle Fractures
The Danis-Weber classification sorts ankle fractures into three types by the level of the fibular fracture relative to the tibiotalar joint line — type A below the syndesmosis, type B at it, and type C above it — because the height of the fibular fracture predicts how much of the syndesmosis is torn.
What the Weber category means
Weber scores run from 1 to 3, where a lower score is better. The bands below are conventional reporting categories, not diagnostic cut-offs.
- Weber A — infrasyndesmotic1–1
Syndesmosis intact. Usually stable and treated non-operatively unless there is a vertical medial malleolar fracture.
- Weber B — transsyndesmotic2–2
Variable syndesmotic injury. Stability depends on the medial structures; stress or weight-bearing views decide it.
- Weber C — suprasyndesmotic3–3
Syndesmosis disrupted up to the level of the fibular fracture. Usually unstable and usually requires syndesmotic stabilisation.
Published criteria and reliability
The published cut-offs that define this instrument, and the measured agreement between observers using it. Each is reported with the population it was derived in.
| Type | Value | Subscale | Population | Follow-up | Source |
|---|---|---|---|---|---|
| Criterion | Type C implies syndesmotic and interosseous disruption from the joint line up to the level of the fibular fracture | — | Rotational ankle fracture | — | Weber BG 1966 |
| Criterion | Agreement on the A/B/C level is substantially better than agreement on the AO/OTA subgroups | — | Orthopaedic surgeons reading plain radiographs | — | Malek IA 2006 |
Criterion is a published cut-off, definition or performance figure belonging to a classification or decision rule — it is not a change score and should not be read as one.
How the score is calculated
Stated in full so the calculation can be independently checked, and reproduced by hand if needed.
The level of the fibular fracture is read against the tibial plafond on an anteroposterior or mortise radiograph. Type A is a fracture entirely below the plafond, so the syndesmotic ligaments cannot have been torn; it is typically a transverse avulsion produced by supination and adduction. Type B is a fracture starting at the level of the plafond, typically spiral or oblique running from anteroinferior to posterosuperior and produced by external rotation of a supinated foot; the anterior syndesmosis may be injured, the interosseous membrane above the fracture is not. Type C is a fracture above the plafond, which can only occur once the syndesmosis and the interosseous membrane have torn from the joint line up to the fracture; the extreme form is the Maisonneuve fracture of the proximal fibula. The letter maps directly onto the AO/OTA codes 44A, 44B and 44C.
Missing data
Only the level of the fibular fracture is required to assign a Weber type. The medial-side and clear-space items are optional; when they are left blank the type is still reported, but the stability interpretation is withheld rather than assumed.
Instrument profile
- Developer
- Bernhard G. Weber, building on the work of Robert Danis
- Institution
- Kantonsspital St. Gallen, Switzerland
- First published
- 1966
- Custodian
- AO Foundation (as the basis of the AO/OTA 44 fracture codes)
- Items
- 3
- Response format
- Branching radiographic assessment
- Score range
- 1 to 3
- Direction
- Lower score = better
- Completion time
- About 1 minutes
- Age range
- Skeletally mature patients
- Regions
- Foot & Ankle
- Conditions
- Ankle fracture, Lateral malleolar fracture, Distal fibular fracture, Syndesmotic injury, Maisonneuve fracture
- Procedures
- Open reduction internal fixation of the fibula, Syndesmotic screw fixation, Suture-button syndesmotic fixation
- Validity
- The level of the fibular fracture is a reasonable proxy for the extent of syndesmotic injury, which is what makes the system useful operatively. It is not a measure of stability, and it says nothing about the medial side.
- Reliability
- Interobserver agreement on the three-letter level is good and better than for most ankle fracture systems; agreement falls once the AO/OTA subgroups (A1–A3, B1–B3, C1–C3) are added.
Normative values
Reference values from published cohorts, for comparison against the score you calculated.
| Population | Age | Mean | SD |
|---|---|---|---|
| Malleolar ankle fractures presenting to hospital | — | Type B is the most common pattern; types A and C are each considerably less frequent | — |
When to use the Weber
Well suited to
- Describing a malleolar ankle fracture concisely on a radiograph report or a referral.
- Anticipating whether syndesmotic fixation is likely to be needed — a type C fracture should prompt intra-operative syndesmotic assessment.
- As the entry point to the AO/OTA 44 coding used in trauma registries and trials.
Limitations and poor fits
- As a stability judgement on its own — a Weber B fracture may be stable or a bimalleolar-equivalent injury, and only the medial side and a stress or weight-bearing view distinguish them.
- For pilon fractures, which are axial-load injuries of the plafond rather than rotational malleolar fractures.
- In children, where the physis dictates the injury pattern and the Salter-Harris system applies.
- When the mechanism and the sequence of ligament failure matter — the Lauge-Hansen system describes those, Weber does not.
Weber compared with other instruments
Instruments measuring a related construct, with the practical difference between them.
| Instrument | Items | Range | What it adds |
|---|---|---|---|
| Lauge-Hansen | 2 | 1–4 | The Lauge-Hansen classification is a mechanistic system that sorts rotational ankle fractures into four patterns named for the position of the foot and the direction of the deforming force — supination–adduction, supination–external rotation, pronation–abduction and pronation–external rotation — each staged by how far the predictable sequence of bone and ligament failure has progressed. |
| AO/OTA | 3 | 1–3 | The AO/OTA classification gives every fracture an alphanumeric code in which the first digit is the bone, the second the segment and the letter the fracture type — extra-articular, partial articular or complete articular in an end segment, and simple, wedge or multifragmentary in a shaft — so that 32-A is a simple femoral shaft fracture and 43-C a complete articular pilon fracture. |
| Ottawa Ankle Rules | 7 | 0–1 | The Ottawa Ankle Rules determine whether an acute ankle or midfoot injury requires radiographs, based on bone tenderness at four specific sites and the ability to bear weight for four steps; they are approximately 98% sensitive for clinically significant fractures. |
Copyright and permitted use
Published openly because it is the question every clinician and researcher asks before using an instrument, and almost nobody answers it.
A published radiographic classification of fracture level. No licence is required to describe or apply it.
References
- Danis R. Théorie et pratique de l’ostéosynthèse. Masson, Paris (monograph). 1949.
- Weber BG. Die Verletzungen des oberen Sprunggelenkes. Aktuelle Probleme in der Chirurgie, Band 3 — Hans Huber, Bern (monograph). 1966.
- Malek IA, Machani B, Mevcha AM, Hyder NH. Inter-observer reliability and intra-observer reproducibility of the Weber classification of ankle fractures. Journal of Bone and Joint Surgery (British). 2006.
- Marsh JL, Slongo TF, Agel J, et al.. Fracture and dislocation classification compendium — 2007: Orthopaedic Trauma Association classification, database and outcomes committee. Journal of Orthopaedic Trauma. 2007.
Editorial status
This page has not yet been signed off by a named clinical reviewer. The scoring logic is stated in full above so it can be independently verified, and every threshold is traceable to its source. See our editorial methodology.