High-yield overview
4 patternssupination-adduction, supination-external-rotation, pronation-abduction, pronation-external-rotation
SER most commonsupination-external-rotation accounts for majority of ankle fractures
Stage sequencepredicts exact order of ligament then bone failure
Guides fixationidentifies syndesmosis injury and medial structures at risk
Critical Must-Knows
- Lauge-Hansen classifies ankle fractures by the position of the foot at injury and the direction of the deforming force and predicts the precise sequence in which ligaments and bones fail.
- Supination-external-rotation (SER) is the commonest pattern — stage I anterior tibiofibular ligament, stage II spiral fibula fracture, stage III posterior tibiofibular ligament or posterior malleolus, stage IV deltoid or medial malleolus.
- The pattern dictates reduction manoeuvres and what must be fixed — SER and PER injuries often require syndesmotic stabilisation while supination-adduction vertical medial malleolus fractures need buttress plating.
- Always obtain a true lateral radiograph before classifying — the fibular fracture level and orientation plus medial clear space widening tell you the stage and the mechanism.
The examiner trap
Never classify from the anteroposterior radiograph alone. The fibular fracture in SER stage II looks transverse on AP but is oblique on the lateral; missing the posterior malleolus or failing to recognise a high fibula (Maisonneuve) in pronation-external-rotation stage III changes both classification and fixation. Always restore the medial clear space and talar shift before deciding syndesmotic screws are unnecessary.
The Four Injury Patterns and Their Stages
Lauge-Hansen describes four foot-position and force-direction combinations. Each pattern produces a predictable, staged sequence of soft-tissue then bony failure.
| Pattern | Stage I | Stage II | Stage III | Stage IV |
|---|---|---|---|---|
| Supination-Adduction (SA) | Transverse lateral malleolus or ATFL tear | Vertical medial malleolus fracture | — | — |
| Supination-External Rotation (SER) | AITFL tear or avulsion | Oblique fibula fracture at syndesmosis level | PITFL tear or posterior malleolus | Deltoid tear or medial malleolus fracture |
| Pronation-Abduction (PA) | Transverse medial malleolus or deltoid tear | AITFL and syndesmosis disruption | Short oblique fibula fracture above syndesmosis with lateral comminution | — |
| Pronation-External Rotation (PER) | Transverse medial malleolus or deltoid tear | AITFL and syndesmosis disruption | High oblique fibula fracture (Maisonneuve possible) | PITFL or posterior malleolus fracture |
Mnemonic
SA • SER • PA • PERThe four patterns
Mnemonic
Anterior • Oblique • Posterior • MedialSER stages — the commonest
Clinical Pearl
The fibular fracture level on the lateral radiograph is the key to staging. In SER the fracture begins at the syndesmosis and spirals proximally; in PER the fracture is higher and the medial injury precedes the fibular fracture. A high fibular fracture with medial tenderness always prompts a full-length tibia radiograph to exclude a Maisonneuve injury.
Clinical Application and Reduction Principles
The classification directly informs closed reduction technique and the structures that must be restored at surgery.
| Pattern | Key Reduction Move | Structures Requiring Fixation | Syndesmosis Likely? |
|---|---|---|---|
| SA stage II | Direct medial buttress plating of vertical malleolus | Medial malleolus (buttress plate) | Rare |
| SER stage II–IV | Internal rotation of foot after fibular reduction | Fibula (plate), posterior malleolus if large, medial if unstable | Yes if stage III or IV |
| PA stage III | Abduction stress then fibular plating with possible syndesmotic screw | Medial malleolus, fibula (often with intercalary fragment) | Yes |
| PER stage III–IV | External rotation correction then syndesmotic reduction | Medial, high fibula (often intramedullary or plate), posterior if unstable | Yes — almost always |
Mnemonic
SER III–IV • PA III • PER III–IVWhen to stabilise the syndesmosis
Caution
After anatomic fibular reduction and medial repair, test syndesmotic stability with the hook test or external rotation stress under fluoroscopy. Persistent widening greater than 2 millimetres on the mortise view after fixation indicates the need for a syndesmotic screw or suture-button construct.
Limitations and Modern Context
- The original description was based on cadaveric sectioning and does not account for combined or atypical mechanisms seen in high-energy trauma.
- Inter-observer reliability is only moderate for exact stage assignment once the medial injury is reached; the fibular fracture pattern on the lateral view is the most reproducible element.
- CT is now routine for posterior malleolus assessment and changes management in up to 30 percent of cases initially classified as stage II or III.
- Modern locking plates and minimally invasive techniques have reduced the need for perfect anatomic reduction of every fragment, yet the ligament sequence still dictates which structures must be addressed.
- The classification remains valuable for teaching reduction logic even though fixation decisions increasingly incorporate CT and intra-operative stress examination.
Evidence Base
Evidence
Fractures of the ankle: analytic and experimental roentgen studies
Lauge-Hansen N • Arch Surg (1950)
Key Findings:
- Original cadaveric study defining the four foot-position and force combinations
- Demonstrated the staged, sequential failure of specific ligaments before bone
- Established that the fibular fracture pattern reflects the mechanism and stage
Clinical implication: Provided the mechanistic framework still used to understand and reduce ankle fractures today.
Limitation: Cadaver model without muscle tone or modern imaging; single-author series.
Source: Arch Surg 1950 May;60(5):957-85
Evidence
The Lauge-Hansen classification of ankle fractures
Yde J • Acta Orthop Scand (1980)
Key Findings:
- Prospective clinical validation of the Lauge-Hansen system in 300 patients
- Confirmed that SER was the commonest pattern and that stage correlated with need for syndesmotic fixation
- Showed good correlation between radiographic stage and operative findings
Clinical implication: Demonstrated that the classification predicts both ligament injury and the structures requiring stabilisation.
Limitation: Pre-CT era; relied on plain films and intra-operative observation only.
Source: Acta Orthop Scand 1980 Feb;51(1):181-92
Evidence
Reliability of the Lauge-Hansen classification
Nielsen JO, Dons-Jensen H, Sorensen HT • Acta Orthop Scand (1990)
Key Findings:
- Inter-observer study showing only moderate agreement on exact stage
- The fibular fracture level and orientation on the lateral radiograph were the most reproducible features
- Disagreement increased once medial injury was present
Clinical implication: Use the lateral radiograph and stress views rather than attempting precise staging from the AP film alone.
Limitation: Small observer panel; no correlation with functional outcome.
Source: Acta Orthop Scand 1990 Oct;61(5):385-7
Evidence
CT evaluation of the posterior malleolus in ankle fractures
Haraguchi N, Haraguchi T, Toga H, et al. • J Bone Joint Surg Am (2006)
Key Findings:
- CT changed classification or fixation plan in 28 percent of cases thought to be Lauge-Hansen stage II or III
- Posterior malleolus involvement was under-estimated on plain films
- Size and displacement of the posterior fragment altered the decision for direct fixation
Clinical implication: Obtain CT whenever a posterior malleolus fragment or syndesmotic injury is suspected on plain radiographs.
Limitation: Single-centre; focused on posterior malleolus rather than full classification validation.
Source: J Bone Joint Surg Am 2006 May;88(5):1085-92
Exam Viva
Practise clinical reasoning and management decisions out loud
Viva scenarioStandard
Clinical prompt
“A 35-year-old footballer presents after an inversion injury. The mortise radiograph shows an oblique fibular fracture at the level of the syndesmosis with 3 millimetres of medial clear-space widening. What is the Lauge-Hansen stage and what fixation is required?”
Practical approach
This is a supination-external-rotation stage IV injury. The oblique fibular fracture at the syndesmosis indicates stage II, the medial clear-space widening indicates deltoid ligament disruption (stage IV), and the posterior tibiofibular ligament is presumed torn. I would perform open reduction internal fixation of the fibula with a lateral plate, assess the syndesmosis with a hook or external-rotation stress test under fluoroscopy, and stabilise the syndesmosis with a tricortical syndesmotic screw or suture-button if widening persists after fibular reduction. The medial side is managed non-operatively once the lateral and syndesmotic structures are restored.
Key clinical points
Oblique fibula at syndesmosis plus medial widening equals SER stage IV
Stage IV implies syndesmotic and deltoid injury
Fix fibula first, then test and stabilise syndesmosis
Medial clear space normalises once lateral column is stable
Common pitfalls
Calling it stage II because only the fibula is fractured on the film
Fixing the fibula and omitting the syndesmotic test
Operating on the medial malleolus when the deltoid is intact
Further questions
“How would the management change if the fibular fracture were 8 centimetres above the joint?”
“What is the role of CT in this pattern?”
“When would you remove the syndesmotic screw?”
Viva scenarioAdvanced
Clinical prompt
“A 42-year-old pedestrian is struck by a car. The AP radiograph shows a transverse medial malleolus fracture and a high fibular fracture 12 centimetres above the joint. What is the Lauge-Hansen classification, and what additional imaging and fixation decisions follow?”
Practical approach
This is a pronation-external-rotation stage III injury. The transverse medial malleolus is stage I, the high fibular fracture indicates stage III after syndesmotic disruption (stage II). I would obtain full-length tibia and fibula radiographs to assess for a Maisonneuve extension and a CT scan to evaluate the syndesmosis and any posterior malleolus involvement. Fixation would include anatomic reduction of the medial malleolus with screws or a buttress plate, reduction and fixation of the fibula (often with an intramedullary device or long plate), and syndesmotic stabilisation with two tricortical screws or a suture-button construct because the syndesmosis is completely disrupted in this pattern.
Key clinical points
Medial malleolus plus high fibula equals PER stage III
Always image the entire fibula to exclude Maisonneuve extension
CT clarifies posterior malleolus and syndesmotic reduction
Syndesmosis almost always requires fixation in PER stage III
Common pitfalls
Missing the high fibular fracture and classifying it as a simple medial malleolus injury
Failing to obtain full-length films
Attempting closed reduction without recognising the syndesmotic and high fibular components
Further questions
“How does the reduction manoeuvre differ from an SER injury?”
“What are the consequences of missing a Maisonneuve component?”
“When is direct posterior malleolus fixation indicated in this pattern?”
Exam day cheat sheet
Lauge-Hansen — Exam Cheat Sheet
The four patterns and hallmark features
- SA: vertical medial malleolus after transverse lateral ligament or bone injury
- SER (commonest): anterior ligament, spiral fibula, posterior ligament, medial injury
- PA: medial transverse first, then syndesmosis, then high fibula with lateral comminution
- PER: medial first, syndesmosis, very high fibula (Maisonneuve), posterior injury
Key radiographic signs
- Oblique fibula at syndesmosis level on lateral view equals SER stage II or higher
- Medial clear-space widening greater than 4 millimetres indicates deltoid or medial malleolus failure
- High fibular fracture demands full-length tibia radiograph
- Posterior malleolus fragment on lateral view indicates stage III or IV
Fixation implications
- SER and PER stage III–IV almost always need syndesmotic stabilisation after fibular plating
- SA stage II vertical medial malleolus requires buttress plate, not simple screws
- PA stage III often needs syndesmotic screw plus attention to intercalary fibular fragment
- Test syndesmosis after every fibular reduction — do not rely on classification alone