The Radiology Assistant: Ankle Fracture - Weber and Lauge-Hansen Classification
The Radiology Assistant: Ankle Fracture - Weber and Lauge-Hansen Classification
The Radiology Assistant: Ankle Fracture - Weber and Lauge-Hansen Classification
Classification
Robin Smithuis
Short overview
These fractures are identical to the fractures described by Lauge-Hansen as supination-adduction, supination-exorotation and pronation-exorotation.
We will first give a short overview of these fractures and then discuss them in more detail.
Weber A
Occurs below the syndesmosis, which is intact.
According to Lauge-Hansen, it is the result of an
adduction force on the supinated foot.
Stage 1 - Tension on the lateral collateral
ligaments results in rupture of the
ligaments
or avulsion of the lateral malleolus below
the syndesmosis.
Stage 2 - Oblique fracture of the medial
malleolus.
Weber B
Weber C
This is a fracture above the level of the syndesmosis. Usually there is a total rupture of the
syndesmosis with instability of the ankle.
According to Lauge-Hansen, it is the result of an
exorotation force on the pronated foot.
Stage 1 - Avulsion of the medial
malleolus
or - ligamentous rupture
Stage 2 - Rupture of the anterior
syndesmosis
Stage 3 - Fibula fracture above the level
of the syndesmosis (this is the true Weber
C fracture)
Stage 4 - Avulsion of the malleolus
tertius
or - rupture of the posterior syndesmosis
Exorotation injury
Anterior syndesmosis
Fibula
Posterior syndesmosis
Medial malleolus
Medial malleolus
Anterior syndesmosis
Fibula
Posterior syndesmosis
First impression
The radiographs show a fracture of the
malleolus tertius.
If you would just report this as - a
fracture of the malleolus tertius - you
would miss the point.
This is probably an unstable ankle
fracture.
A malleolus tertius fracture as an isolated
finding is very uncommon.
Re-examination
On the ankle films there was no sign of an
oblique fracture of the lateral malleolus,
so we can exclude a Weber B fracture.
There is still the possibility of a Weber C
fracture stage 4, i.e. medial rupture or
avulsion, high fibular fracture and finally a
malleolus tertius fracture.
At reexamination you notice the subtle
avulsion of the medial malleolus (red
arrow), which is stage 1.
Notice also the soft tissue swelling on the
medial side (blue arrow)
PE stage 1
Weber A in detail
Stage 1
The images show the usual Weber type A fractures.
These are all stage-1 fractures.
Stage-2 is extremely uncommon.
Weber A - stage 2
Stage 2
Weber B in detail
Stage 1-2
Weber B is the most common type of ankle fracture and occurs in about 60 %.
According to Lauge-Hansen the fracture results
from an exorotation force on the supinated foot.
Weber B fracture
Stage 3-4
Stage 3 More posterior displacement of the lateral malleolus fragment by the talus results in
tension on the posterior syndesmosis with rupture or avulsion of the malleolus tertius.
The sequences in a Weber B fracture or LaugeHansen supination exorotation injury take place
in a clockwise manner:
1. Rupture of the anterior tibiofibular
ligament
2. Oblique fracture of the distal fibula
3. Avulsion of the posterior malleolus or
rupture of the posterior tibiofibular
ligament
4. Avulsion of the medial malleolus or
rupture of the medial collateral ligament
Weber C in detail
Stage 1
Stage 2-3
Continuous force will twist the fibula and displace it distally, while proximally it is fixed to
the tibia.
Finally the interosseus membrane will rupture
up to the point where the fibular shaft fractures.
This is stage 3.
This is always above the level of the syndesmosis.
In many cases it is visible on the radiographs of
the ankle, but in some cases the fracture is lo-
cated high and will only be visible on a radiograph of the lower leg.
This last type of fracture is also called Maisonneuve fracture.
Here we see the different stages in the axial
plane.
1. Medial avulsion fracture or rupture of the
collateral band
2. Rupture of the anterior syndesmosis
3. Suprasyndesmotic rupture of the fibula
due to rotation
4. Malleolus tertius fracture or rupture of the
posterior syndesmosis
Scroll through the images.
Stage 4
Finally the posterior syndesmotic ligament ruptures, or there is an avulsion of the posterior
malleolus, also known as malleolus tertius fracture (red arrow).
Start with a first impression and look for fractures and signs of ligamentous rupture.
This impression will direct you to both a Weber
as well as a Lauge-Hansen classification.
The Lauge-Hansen classification will give you
the fracture mechanism and the preliminary
stage of the ankle injury.
In the final report the fracture is described according to Weber and/or Lauge-Hansen.
Describe the number of malleoli involved and
whether there are signs of instability or dislocation.
Example 1
Basic interpretation
There is a medial malleolar fracture.
You interprete this as an avulsion fracture.
Classification
Not possible to classify according to
Weber, but according to Lauge Hansen a
medial avulsion fracture indicates that the
foot probably was in pronation at the
moment of injury.
So this injury is probably a pronation
exorotation injury (PER) stage 1 or higher.
Click to enlarge
Re-examination
You re-examine the x-rays to look for
stage 2 (rupture or avulsion of the
anterior syndesmosis), stage 3 (high
fibular fracture = Weber C) or even stage
4 (rupture or avulsion of posterior
syndesmosis).
So at second look you notice a subtle
widening of the lateral clear space on the
original films, which could indicate but is
definitely no proof of a syndesmotic
rupture.
Although the patient is already in a cast
you order additional films to look for a
possible stage 3.
These films show a high fibular fracture
and a subtle malleolus tertius avulsion.
Final report
Weber C fracture or a PER stage 4
according to Lauge-Hansen. This is an
unstable fracture that needs surgical
repair.
The ankle circle is interrupted at two
places i.e. the medial malleolus and the
syndesmosis.
A syndesmotic screw was inserted.
Example 2
Basic interpretation
Transverse lateral malleolar fracture.
Classification
Weber A and Supination Adduction stage
1.
Re-examination
No sign of SA stage 2 (medial malleolar
fracture)
Final report
Stable Weber A or SA stage 1 fracture.
Patient will be treated conservatively.
Example 3
Basic interpretation
Dislocated bimalleolar fracture. Avulsion
fracture of the medial malleolar.
The lateral malleolus is 'pushed off' from
anterior to posterior.
Classification
The fracture starts at the level of the
ankle joint and extends proximally, i.e. a
Weber B fracture.
According to Lauge Hansen the oblique
fibular fracture indicates Supination
Exorotation injury stage 2 or higher.
Re-examination
Look for stage 3 (posterior syndesmotic
rupture or avulsion of the posterior
malleolus) and stage 4 (rupture of the
deltoid ligament or medial malleolar
avulsion).
Only now you notice the posterior
malleolar fracture on the lateral view.
Final report
Trimalleolar fracture. Weber B. SER stage
4 (Lauge-Hansen).
This is an unstable fracture with
dislocation that needs surgical repair.
The size of the posterior malleolar
fragment is probably less than 25% of the
articular AP-diameter and will need no
separate repair.
Sometimes CT is needed to get a better
impression of the size of the fracture
fragment of the posterior malleolus.
Example 4
Basic interpretation
Fracture of the lateral malleolus starting
anteriorly at the level of the joint
extending proximally posteriorly.
Classification
The fracture is classified according to
Weber as a type B fracture.
Click to enlarge
1. Anatomy of the distal tibiofibular syndesmosis
in adults: a pictorial essay with a multimodality
approach
by John J. Hermans, Annechien Beumer, Ton A.
W. de Jong and Gert-Jan Kleinrensink.
J. Anat. (2010) 217, pp633-645
2. AO-foundation ankle fractures
3. Introduction to Lauge Hansen & Danis Weber
Classifications Ankle Fracture
Animation on YouTube by Dr Glass.