The Lauge Hansen Series: Ankle Fracture Mechanisms Including Danis Weber
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This is the combined page for the Lauge Hansen and Danis Weber Classifications. The scripts for these videos are also included for educational purposes.
Introduction to Lauge Hansen & Danis Weber Classifications:
Lauge-Hansen is perhaps one of the most commonly utilized classifications for ankle fractures. Dr. Lauge-Hansen in 1948, broke down the mechanism of injury into two simplistic terms for a complicated three-dimensional fracture. The first term describes the position of the foot at the time of injury. The second term was originally described as the direction and/or force in which the talus moves relative to the tibia and the fibula. Since, the original classification was based off of a cadaver study the second term has been modified to describe the way the tibia moves relative to the talus, which is what occurs in a weight-bearing individual.
Lauge-Hansen's classification is a numerical system which describes a step-wise approach through the injuries progression. One must look at rotational injuries in a clockwise fashion while direct blow injuries must be looked at in a transverse abductory /adductory fashion. Generally pronation injuries will start at the medial aspect of the ankle joint while supination injuries will start at the lateral aspect of the ankle joint. This classification not only allows you to visualize the osseous injury to the tibia & fibula but also incorporates the ligamentous structures that may become damaged within the ankle joint. The Lauge-Hansen system can provide insight into the proper maneuvers required for closed reduction.
Another classification that is commonly correlated with the Lauge-Hansen classification system is the Danis Weber classification. Danis Weber is based on the fibular fracture line's relationship to the ankle joint. Danis Weber type A injury starts below the level of the ankle joint and corresponds with a Lauge-Hansen Supination Adduction injury. Danis Weber type B starts at the level of the ankle joint and correspond with Lauge-Hansen Supination External rotation and Pronation Abduction injuries. Last but not least, Danis Weber type C injuries start above the level of the ankle joint and correspond with a Lauge-Hansen Pronation External Rotation injury. The Danis Weber classification although more simplistic in nature than the Lauge Hansen classification, is limited by its anatomical focus on the fibula. Danis Weber also fails to take into consideration the soft tissue structures that are often associated with these injuries. The AO group has expanded this classification to include some of the shortfalls of this system.
It is important remember that these classification systems are guidelines and atypical fracture patterns do occur.
SA - Supination AD-duction:
With the foot in a fixed supinated position a lateral Adductory force is exerted along the lateral malleolus as the talus inverts with-in the ankle mortise. In Stage 1, one of three injuries may occur, a rupture of the lateral collateral ligaments, an avulsion fracture the lateral malleolus, or a transverse fracture of the distal fibula below or at the level of the ankle joint. (Note: The syndesmotic ligaments are not involved with Supination ADduction injuries). If the ADductory force continues medially the talus will abut against the tibia and progress to a Stage 2 injury resulting in an oblique to near vertical fracture of the medial malleolus.
One must note that this is a multi-factorial injury; the relative position of the foot, the amount of force involved, and the inherent strength of both the ligamentous and osseous structures all play an intricate role in the development of this type of injury.
(Take home points)
Rupture of the lateral collateral ligaments or a fracture of the fibula below the level of the ankle joint in stage 1. Oblique to near vertical fracture of the medial malleolus seen in stage 2.
PA - Pronation AB-duction:
With the foot in a fixed pronated position, an abductory force is placed along the medial aspect of the medial malleolus; creating either a TRANSVERSE medial malleolar fracture and/or deltoid ligament failure, this is described as a STAGE 1 injury. As the abductory force continues to push the talus laterally the talus is driven into the tibio-fibular syndesmotic joint creating injury to BOTH the ANTERIOR & POSTERIOR-inferior TIBIO-FIBULAR ligaments creating a stage 2 injury. (Note: With the interosseus ligament still intact one cannot call this a true diastasis).
In STAGE 3: The ABductory force has continued into the fibula creating a fracture at or above the ankle joint that is short and OBLIQUE on the AP view but appears transverse on a lateral x-ray. Since the talus is driven in an inferomedial to superiorlateral direction a LATERAL SPIKE of cortex from the fibula may be visualized on an AP x-ray. Lateral comminution is quite common. One must remember to take a Lateral x-ray of the ankle joint to adequately differentiate this fracture from the posterior spike of the fibula seen with supination external rotation injuries. This is important for fixation purposes.
(Take home points)
The SHORT OBLIQUE fracture of the lateral malleolus seen in stage 3 will appear oblique on an AP x-ray, but transverse on a Lateral x-ray. This is unique to pronation- Abduction injuries.
SER - Supination Eversion (External Rotation):
With the foot in a fixed supinated position the forces start along the lateral axis of the fibula. The leg undergoes an internal rotation creating tension on the anterior inferior tibio-fibular ligament. In a Stage 1 injury, one of two pathologies may occur; rupture of the anterior inferior tibio-fibular ligament or a fracture of the distal lateral tibia (aka Tillaux-chaput fracture).
As the leg continues to internally rotate the talus collides with the distal fibula, creating a spiral fracture of the fibula beginning at the level of the syndesmosis. This describes a Stage 2 injury, which is the most commonly encountered ankle fracture. A Wagstaffe fracture can also occur during this stage.
As the force progresses a Stage 3 injury will either involve a rupture of the posterior tibio-fibular ligament or fracture of the posterior malleolus of the tibia (aka Volkman's fracture).
Supination external rotation injuries that reach stage 3 rarely stop at this point and usually progresses to the final stage. Continued unrestrained lateral rotation of the talus will result in a Stage 4 injury involving either a rupture of the deltoid ligament complex or a transverse fracture of the medial malleolus.
(Take home points)
-The injury begins along the lateral axis of the fibula.
-The spiral fracture seen in stage 2 is unique to supination-external rotation injuries.
PER - Pronation Eversion (External Rotation):
With the foot in a fixed pronated position the forces start along the medial axis of the tibia. The leg undergoes an internal rotation creating tension on the deltoid ligament complex.
In a Stage 1 injury, one of two pathologies may occur; rupture of the deltoid ligament complex or a transverse fracture of the medial malleolus.
As the injury progresses forward into Stage 2 the talus rotates further laterally putting tension on the anterior inferior tibiofibular ligament resulting in either a rupture of this ligament or an avulsion fracture off the anterior portion of the fibula or tibia.
As the forces continue past stage 2 rupture of the interosseus membrane begins to occur distally at the level of the anke joint. The exit point of this rupture creates a Stage 3 injury, described as a high short oblique fracture of the fibula beginning above the level of syndesmois. This fracture can be at various levels on the fibula. The most proximal fracture pattern occurs at the head and neck of the fibula which is described as a Maisonneuve fracture.
If the force progress into Stage 4 either a rupture of the posterior tibio-fibular ligament or a fracture of the posterior malleolus (Volkman’s fracture) will occur.
Note: The combined rupture of the anterior inferior tibiofibular ligament, the posterior inferior tibiofibular ligament, and the interosseus membrane results in a true ankle diastasis.
(Take home points)
-The injury begins along the medial axis of the tibia.
-Rupture of the interosseus membrane in conjunction with the rupture of the anterior inferior tibiofibular ligament, and the posterior inferior tibiofibular ligament creates a true ankle diastasis.
-The high fibular spiral fracture (Maisonneuve fracture) seen in stage 3 is unique to pronation external rotational injuires. It is important to always take proximal tibio-fibular x-rays when pronation external rotation injuries are suspected especially in the presence of posterior malleolar fracture with diastasis, because the high fibular fracture can be easily missed on a standard ankle x-ray series.