Maisonneuve Fractures

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):

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 indications:

• Assess posterior malleolus involvement (size, fragment pattern)
• Complex fracture patterns
• Subtle syndesmotic widening on plain films
• Post-reduction assessment of mortise congruity

CT findings:

• Can measure tibiofibular distance precisely
• Shows fibular rotation (malreduction)
• Identifies osteochondral lesions of talus (associated injury)

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:

Cotton test (external rotation stress):

• Apply lateral translation to talus under fluoro
• Positive: greater than 3-4mm lateral shift compared to contralateral side
• Repeat after syndesmotic fixation to confirm stability

Gravity stress test:

• Lateral view with stress applied by gravity
• Assess talar tilt and anterior drawer

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.

Surgical goals:

1. Restore anatomic ankle mortise
2. Stabilize distal tibiofibular syndesmosis
3. Fix medial malleolus if fractured and displaced
4. Allow healing of interosseous membrane

Surgical timing:

• Ideally within 1-2 weeks of injury
• May need to stage if severe swelling (wrinkle test)
• Delay increases difficulty due to early callus/scarring

Fixation options for syndesmosis:

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

Patient positioning:

• Supine on radiolucent table
• Bump under ipsilateral hip (10-15 degree internal rotation of leg)
• Tourniquet on thigh (optional)
• Fluoroscopy accessible for AP, lateral, and mortise views

Equipment:

• Standard fracture set
• Reduction clamps
• 3.5mm or 4.5mm cortical screws for syndesmosis
• OR suture button device (TightRope, etc.)
• Small fragment set if medial malleolus ORIF needed

Incisions: Lateral approach over distal fibula for syndesmotic fixation. Medial approach if medial malleolus ORIF required. The proximal fibula is NOT approached surgically.

Reduction technique:

Screw fixation technique:

1. Position

   • Insert 2cm proximal to ankle joint
   • Aim 25-30 degrees anterior to coronal plane (parallels syndesmosis)
   • Perpendicular to long axis of tibia

2. Drill and insert

   • 3.5mm or 4.5mm cortical screw
   • Tricortical (lateral fibular cortex, medial fibular cortex, lateral tibial cortex) OR
   • Quadricortical (through medial tibial cortex as well)
   • Tricortical generally sufficient, quadricortical may be stronger

3. Number of screws

   • Single screw usually adequate
   • Consider 2 screws if very unstable or large patient
   • Second screw placed 1-2cm proximal to first

4. Confirm fixation

   • Repeat Cotton test under fluoro - should be stable
   • Check all views for maintained reduction

Suture button technique:

• Similar positioning as screws
• Drill hole through 4 cortices
• Pass suture device and tension appropriately
• Advantage: no removal surgery needed

If medial malleolus fractured and displaced:

Approach:

• Medial longitudinal incision over medial malleolus
• Protect saphenous nerve and vein
• Expose fracture and joint

Fixation options:

• Two partially threaded cancellous screws (4.0mm)
• Lag technique with washer
• Antiglide plate if large fragment
• Tension band wire if small fragment

Key points:

• Anatomic reduction of articular surface
• Must not leave medial joint incongruity
• Check mortise view for symmetric medial clear space

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.