Maisonneuve Fracture

The Maisonneuve fracture is an uncommon but clinically important ankle injury pattern first described by the French surgeon Jules Germain François Maisonneuve in 1840. It represents approximately 1 to 5 percent of all ankle fractures, though its true incidence may be higher due to missed diagnoses.

Key epidemiological points:

• Most commonly occurs in young to middle-aged adults (20 to 50 years) following a twisting or external rotation injury
• Males predominate in younger age groups (sporting injuries); females are more commonly affected in older age groups (low-energy falls)
• The injury is biomechanically equivalent to a Weber C (suprasyndesmotic) ankle fracture but the fibula fracture is located proximally — at or near the fibular neck — rather than at the lateral malleolus
• The Maisonneuve fracture is one of the most commonly missed unstable ankle injuries because standard ankle radiographs do not demonstrate the proximal fibula fracture
• Associated posterior malleolus fractures are present in a significant proportion of cases and affect both surgical planning and prognosis

A Maisonneuve fracture consists of three essential elements:

1. A proximal fibula fracture — typically in the proximal third or at the fibular neck, resulting from an external rotation force transmitted through the interosseous membrane
2. Syndesmotic disruption — the anterior inferior tibiofibular ligament (AITFL), posterior inferior tibiofibular ligament (PITFL), and interosseous membrane are torn from distal to proximal up to the level of the fibula fracture
3. Medial-sided injury — either a deltoid ligament rupture or a medial malleolus fracture

The key pathoanatomical principle is that the ankle mortise is rendered unstable because all three stabilising columns are disrupted: the medial deltoid complex, the syndesmotic ligaments and interosseous membrane, and the lateral fibula (fractured proximally). The interosseous membrane tears from the level of the syndesmosis proximally to the fibula fracture, creating a long zone of instability.

The Maisonneuve fracture results from an external rotation force applied to the ankle. The sequence of tissue failure follows the Lauge-Hansen classification:

Pronation-External Rotation (PER) pattern:

• Stage I: Medial injury — deltoid ligament rupture or medial malleolus avulsion
• Stage II: Anterior syndesmotic disruption — AITFL tear
• Stage III: Proximal fibula fracture — the external rotation force spirals up the interosseous membrane and fractures the proximal fibula (typically a spiral or oblique pattern)
• Stage IV: Posterior syndesmotic disruption — PITFL tear or posterior malleolus avulsion

Supination-External Rotation (SER) variant can also produce a Maisonneuve pattern, though the pronation-external rotation mechanism is more classic.

The force propagates from the ankle mortise through the interosseous membrane to the proximal fibula. The more proximal the fibula fracture, the greater the extent of interosseous membrane disruption and the more unstable the syndesmosis.

History:

• External rotation or twisting mechanism to the ankle (sport, fall, pedestrian struck)
• Inability to weight-bear
• Pain at the ankle medially AND laterally — the patient may localise pain to the medial ankle only
• Subjective sense of instability or giving way

Examination — CRITICAL points:

• Palpate the entire length of the fibula from the lateral malleolus to the fibular head and neck. Proximal fibula tenderness in the context of an ankle injury is the hallmark clinical finding of a Maisonneuve fracture
• Assess medial-sided tenderness (deltoid ligament region or medial malleolus)
• Assess for syndesmotic tenderness: squeeze test, external rotation stress test, Cotton test
• Assess neurovascular status — the common peroneal nerve runs near the fibular neck; a very proximal fracture may cause a peroneal nerve palsy
• Evaluate for compartment syndrome (rare but possible with high-energy patterns)
• Look for swelling and ecchymosis along the course of the interosseous membrane (may be delayed)

Mandatory: Full-length tibia-fibula AP and lateral radiographs (ankle to knee on a single film). Ankle-only films are insufficient and represent the single most common reason this injury is missed.

Key radiographic findings:

• Proximal fibula fracture (spiral or oblique, often at the fibular neck)
• Widening of the medial clear space on the ankle mortise view (greater than 4 mm is abnormal)
• Increased tibiofibular clear space (greater than 6 mm on the AP view at 1 cm proximal to the plafond)
• Loss of tibiofibular overlap (less than 1 mm on the mortise view is abnormal)
• Possible posterior malleolus fragment
• The proximal fibula fracture may be very subtle — look carefully at the fibular neck region

CT scan is useful for pre-operative planning and to assess syndesmotic reduction, particularly the size of any posterior malleolus fragment. Post-operative CT is increasingly recommended to confirm anatomic syndesmotic reduction.

MRI is the most sensitive imaging modality for syndesmotic injury and can confirm AITFL, PITFL, and interosseous membrane disruption when the diagnosis is uncertain. It is particularly useful in subtle cases where plain films and CT are equivocal.

External rotation stress radiograph (under fluoroscopy) assesses syndesmotic instability when the diagnosis is equivocal. Medial clear space greater than 5 mm under stress confirms instability.

All Maisonneuve fractures are inherently unstable and require operative management. Non-operative treatment is not appropriate because the syndesmosis is disrupted and the ankle mortise is unstable.

• Syndesmotic malreduction — the most significant complication; occurs in up to one-third of cases with fluoroscopic guidance alone; leads to altered ankle biomechanics, post-traumatic arthritis, and poor functional outcomes
• Post-traumatic ankle arthritis — secondary to persistent syndesmotic instability or malreduction, or chondral damage at the time of injury
• Peroneal nerve palsy — the common peroneal nerve courses around the fibular neck; a proximal fracture or intra-operative retraction may cause a neuropraxia
• Hardware irritation — syndesmotic screws or suture-button devices may cause local symptoms, particularly if placed superficially; screw removal is common
• Loss of syndesmotic reduction — may occur if fixation fails before ligamentous healing (typically 6 to 12 weeks)
• Compartment syndrome — rare but reported with high-energy patterns
• Non-union of the proximal fibula — uncommon but possible; usually asymptomatic if the syndesmosis is stable

• Syndesmotic fixation technique varies globally. North American practice has traditionally favoured syndesmotic screws (one or two 3.5 mm cortical screws, three or four cortices), while European centres increasingly use suture-button devices as first-line fixation.
• AO Foundation guidelines recommend anatomic syndesmotic reduction confirmed intra-operatively; the choice of fixation device (screw vs suture-button) is surgeon-dependent, though evidence supports suture-button devices for improved functional outcomes.
• BOAST guidelines (UK) emphasise that all unstable ankle fractures with syndesmotic disruption require fixation, and recommend CT confirmation of syndesmotic reduction post-operatively when there is doubt.
• Post-operative weight-bearing protocols differ: some centres allow early weight-bearing in a boot with suture-button fixation, while others maintain 6 weeks of non-weight-bearing with screw fixation. Current evidence supports earlier weight-bearing with suture-button devices without increased risk of loss of reduction.
• Screw removal practices vary — some surgeons routinely remove syndesmotic screws at 3 to 6 months, while others leave them in situ unless symptomatic. Suture-button devices are typically left permanently.
• Registry data from national databases show that syndesmotic injuries complicate a significant proportion of operatively treated ankle fractures, with malreduction rates remaining a concern across all fixation methods.