Maisonneuve Fractures

The syndesmosis is a complex of ligaments that stabilize the distal tibiofibular joint:

1. Anterior inferior tibiofibular ligament (AITFL)

   • Runs obliquely from anterolateral tibia to anterior fibula
   • First structure injured in external rotation
   • Prevents anterior fibular translation

2. Posterior inferior tibiofibular ligament (PITFL)

   • Strongest syndesmotic ligament
   • Runs from posterolateral tibia to posterior fibula
   • Includes the posterior malleolus component

3. Interosseous ligament

   • Thickened distal portion of interosseous membrane
   • Primary restraint to syndesmotic widening
   • Disrupted along entire length in Maisonneuve

4. Transverse tibiofibular ligament

   • Deep component of PITFL
   • Inferior continuation of posterior ligament

Interosseous membrane:

• Connects tibia and fibula along their entire length
• Transfers load from tibia to fibula (10-15% of axial load)
• In Maisonneuve, membrane torn from ankle to level of fibula fracture
• Allows proximal migration of injury energy

Medial structures:

For ankle instability, medial injury is required:

Weber Classification Context

Maisonneuve fractures are classified as Weber C equivalent:

The key point is that Maisonneuve fractures have the same syndesmotic implications as Weber C - complete disruption requiring fixation.

Lauge-Hansen Classification

Maisonneuve represents the Pronation-External Rotation (PER) mechanism:

The Maisonneuve pattern represents PER Stage 4 with propagation through the entire interosseous membrane.

The pronation component (foot everted) combined with external rotation creates maximum stress on the medial structures first, then the injury spirals around to the lateral side.

Classification by Medial Injury:

The medial injury pattern affects surgical planning. Medial malleolus fracture usually requires ORIF through separate incision. Deltoid rupture may not need repair if syndesmosis stabilized. Some surgeons explore deltoid through medial approach if clinically indicated.

Ankle series (AP, lateral, mortise):

Read all of these as conventional thresholds, and know their two weaknesses. They are measured 1 cm above the tibial plafond, published cut-offs vary between sources (tibiofibular clear space appears as under 5mm and under 6mm), and none has an established sensitivity or specificity - so a normal measurement does not exclude the injury. Do not confuse the two clear spaces: tibiofibular clear space under 5mm, medial clear space under 4mm. Most importantly, this page's own evidence shows how insensitive plain films are: in Kasper's series of 70 Maisonneuve fractures, tibiofibular clear space widening was demonstrated radiographically in only 40 of 70 cases. If the mechanism and examination suggest a Maisonneuve injury, normal measurements are a reason for CT rather than reassurance.

Full-length tibia/fibula films:

Essential for diagnosis! Shows:

• Proximal fibula fracture (usually spiral pattern)
• Location of fracture (typically junction of proximal and middle thirds)
• Extent of interosseous membrane disruption inferred

Radiographic parameters for syndesmotic injury: Tibiofibular clear space greater than 5mm (AP view), tibiofibular overlap less than 1mm (mortise view), and medial clear space greater than 4mm (mortise view).

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CT is often obtained but may not change management if plain films clearly show Maisonneuve pattern with widened syndesmosis.

MRI indications:

• Confirm deltoid ligament rupture (if equivocal clinically)
• Assess syndesmotic ligaments in detail
• Rule out occult injury patterns
• Research purposes (mapping injury extent)

MRI not routinely needed - clinical and plain film diagnosis usually sufficient. MRI may be useful if:

• Medial malleolus intact but questioning deltoid injury
• Planning deltoid ligament repair
• Medicolegal documentation

MRI adds cost and rarely changes surgical plan if syndesmotic instability is confirmed clinically/radiographically.

Intraoperative stress testing:

Before and after fixation to confirm stability:

Stress testing under anesthesia is more reliable than awake examination due to patient guarding.

Key principles:

1. The fibula fracture does NOT need fixation

   • Proximal fibula heals well without surgery
   • No mechanical advantage to fixing it
   • Would require additional proximal incision with peroneal nerve risk

2. Syndesmotic fixation is mandatory

   • Complete disruption = unstable ankle mortise
   • Without fixation, chronic instability and arthritis develop
   • Syndesmotic screws or suture button

3. Medial malleolus fixation if displaced

   • Standard ORIF with screws/plate
   • Separate medial incision

4. Deltoid ligament may not need repair

   • If syndesmosis stabilized and mortise congruent
   • Some surgeons explore and repair
   • Evidence unclear on benefit of routine repair

Nonoperative management is NOT appropriate for Maisonneuve fractures.

The complete syndesmotic disruption creates an unstable ankle mortise. Without fixation:

• Chronic lateral talar shift
• Post-traumatic arthritis
• Chronic instability
• Poor functional outcomes

The only exception would be a non-ambulatory patient or severe medical comorbidities precluding surgery - this is rare.

All patients with Maisonneuve fracture should be counseled for surgical stabilization of the syndesmosis.

Most surgeons use syndesmotic screws (1-2 screws) or suture button devices. Both produce good outcomes when properly positioned.

Reduction technique:

If medial malleolus intact (deltoid rupture), some surgeons explore and repair deltoid. Evidence for deltoid repair is limited - most important is syndesmotic stability.

Intraoperative checklist:

All parameters must be within acceptable limits before leaving the OR. Any residual widening or talar shift will result in poor outcomes.

Final films: Obtain AP, mortise, and lateral views. Compare to preoperative films and document anatomic mortise restoration.

Syndesmotic malreduction:

The most important complication to avoid. Malreduction occurs when:

• Fibula is externally rotated in the incisura
• Fibula is posteriorly translated
• Fibula is overcompressed or undercompressed

Even 1-2mm of malreduction increases contact pressures and leads to arthritis. Intraoperative CT may detect subtle malreduction not seen on fluoroscopy.

Screw management:

• Many surgeons remove syndesmotic screws at 3-4 months
• Allows return to full activity without screw breakage
• If screw breaks after union, fragments can be left
• Suture button devices avoid this issue (no removal needed)

Proximal fibula concerns:

The proximal fibula fracture typically heals without intervention. Rarely:

• Delayed union (very rare)
• Painful hardware if inadvertently fixed
• Peroneal nerve injury if surgical approach attempted

Leave the proximal fibula alone - it will heal.

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