Lisfranc Injury Flashcards
What is Lisfranc Injury?
Severe injuries to the tarsometatarsal (Lisfranc) joint between the medial cuneiform and the base of the 2nd metatarsal.
Can be either solely ligamentous injuries or involving the bony structures of the midfoot.
Provision of stability of Lisfranc joint
By the keystone configuration of the base of the second metatarsal fitting into a mortise created by the medial and middle cuneiforms.
Multiple interosseous ligaments support the area of which the Lisfranc ligament is the largest and strongest.
Mechanism of injury
Severe torsional or translational forces applied through a plantar flexed foot.
Can occur during RTCs or athletic injuries
Clinical features
Severe pain in the midfoot and difficulty in weight-bearing
Examination findings
Swelling and tenderness over midfoot
Plantar bruising is highly suggestive of Lisfranc injury
Pain may be provoked by stressing the mid foot.
Any tarsometatarsal injury from high-energy trauma and swelling should be monitored for compartment syndrome.
What is piano key test?
The metatarsals are grasped
Passive dorsiflexion and plantarflexion are carried out at the tarsometatarsal joint.
Subluxation or pain suggest injury.
Dx
Ankle fracture
Other tarsal fractures
Proximal metatarsal fracture
Ix
Managed and investigated as per ATLS guidelines.
1st line -> X-ray in AP, oblique and lateral foot views whilst weight bearing.
CT scanning is useful in pre-operative planning of more comminuted fractures.
MRI can also assess the presence of purely ligamentous injury.
X-ray features of Lisfranc injury
They are usually very subtle and often missed
- Widening of the interval between the base of 1st and 2nd metatarsal
- Bony fragment visible (Fleck Sign) in the space between the 1st and 2nd metatarsal. This indicates avulsion of the Lisfranc ligament from the base of second metatarsal
- Disruption of a line drawn from the medial base of the 2nd metatarsal to the medial side of the middle cuneiform on AP view
- Malalignment of the medial border of the lateral cuneiform and the medial edge of the 3rd metatarsal.
- Dorsal displacement of the proximal bases of the 1st or 2nd metatarsals.
Classification system for Lisfranc injury
Hardcastle and Myerson
Explain Hardcastle and Myerson classification
Type A - Complete homlateral dislocation
Type B1 - Partial injury, medial column dislocation
Type B2 - Partial injury, lateral column dislocation
Type C1 - Partial divergent dislocation
Type C2 - Complete divergent dislocation
Initial management
Per ATLS guidelines with ensuring haemodynamic stability.
Bloods with coag and G&S might be done as well.
Initial management of significantly displaced injuries.
Closed reduction in A&E to correct any gross deformity and help protect the soft-tissue envelope.
This involves gentle traction to the midfoot and then a corrective pressure to the metatarsal base.
It is then placed in a backslab.
Management of Lisfranc injuries without significant displacement.
Conservative management with cast immobilisation / air-cast boot and non-weight bearing mobilisation for 6-12 weeks with regular orthopaedic follow-up and review.
Indications of surgical management.
Clear displacement
Explain surgical management
Temporary external fixation if there is significant soft tissue swelling.
Screw fixation between medial cuneiform and 1st metatarsal and between middle cuneiform and second metatarsal.
Primary arhtrodesis can be used for severely comminuted or displaced fracture-dislocations.
