LisFranc Fracture/ Dislocations

Western Health Orthopaedic Registrar presentation – Lisfranc Injuries of the foot by Dr Peter Moore

Aims, Principles & Alternative

  • key is anatomical alignment of the involved joints
  • Diagnosis on Xray
    • weight bearing AP / obl / lateral
    • if NAD & patient can’t weight bear (and mechanism / swelling / bruising suspicious of Lisfranc) > BKPoP & repeat WB Xrays in 2 weeks
    • Look for loss of alignment
      • AP
        • 1st TMT joint or medial edges of 2nd MT & middle cuneiform (AP)
      • Oblique
        • medial edges of 4th MT & cuboid (obl)
        • Also check for a “fleck” sign in 2nd TMT space (avulsion of Lisfranc ligament), subluxated naviculo-cuneiform joint, or “nutcracker” fracture of cuboid
        • Alternative is an acute MRI of the ligament
  • Compartment Syndrome
    • Monitor all, but especially high energy injuries for compartment syndrome. If indicated, decompress foot with long medial incision (abduction. hall., calcaneal & deep compartments) & two dorsal incisions over 2nd & 4th MT’s for interosseous compartments
  • Closed, undisplaced injuries
    • 6 weeks NWB BKPoP, then 6 weeks WB BKPoP with frequent Xray monitoring for displacement
  • Alternative is treatment in PoP, or for severely contaminated or comminuted injuries, a spanning ex-fix temporarily or definitively.

Indications

  • Displaced or unstable (ie displaces on weight bearing stress views) Lisfranc injury

Contraindications

  • Swollen foot: can delay for around 2 weeks for wrinkle sign
  • PVD, Charcot foot, delayed diagnosis, undisplaced injury.

Preop Planning

  • Xray
    • AP, lateral & obl (weightbearing if able)
  • CT
    • avulsion fragment
    • subtle displacement (up to 2 mm may be missed on plain film)
    • other injuries
  • Consent
    • infection
    • loss of fixation if walk too early
    • removal of wires
    • midfoot post-traumatic arthritis

Technique

  • GA / regional, supine, IV anti’s, tourniquet, prep & drape
  • Dorsal incision lateral to EHL centred over interval between base of 1st & 2nd MTs. Preserve cutaneous nerve branches. Incise inferior extensor retinaculum. Retract dorsalis pedis & deep peroneal nerve with a vessel loop medially & laterally to allow inspection of Lisfranc joint. Remove any debris from this region to allow complete reduction
  • Expose medial aspect of 1st TMT joint,
    • reduce & fix with a countersunk 3.5 – 4.0 mm screw (cannulated) from base of 1st MT into medial cuneiform
    • Next, reduce 2nd TMT joint & insert a screw from base of 2nd MT into middle cuneiform
    • Then insert a screw from medial cuneiform into base of 2nd MT (or vice versa)
    • If 3rd TMT is still unstable after this, reduce & fix with screw from base of 3rd MT into lateral cuneiform
  • Usually 4th & 5th TMTs are reduced by now, so can fix with percutaneous oblique K wires into lateral cuneiform & cuboid, or reduce via dorsal incision over interval between the 4th & 5th MT bases
  • Associated cuboid fracture may need distraction with ex-fix then BG & plate
  • Close wounds with interrupted nylon.

Postop

Well padded back slab for 10 days, then BKPoP NWB for 6 – 8 weeks total. Remove wires at 6 – 8 weeks, then progressive WBAT in CAM walker over next 4 – 6 weeks ± medial arch support orthosis for 3 months. Remove screws if symptomatic after at least 4 months.

Results

Anatomic reduction reduces chance of post-traumatic arthritis from 60% to 16% (Kuo et al) (some will be asymptomatic).

Complications

  • General systemic – DVT
  • General local – infection, neurovascular injury (deep & superficial peroneal nerves)
  • Specific – posttraumatic arthritis (arthrodesis if non-op treatment fails), metalware failure