Lisfranc Injury Flashcards

Questions and Answers

What is the mechanism of injury (MOI) for lisfranc injuries?

Excessive plantar flexion and abduction forces.

Which metatarsal dislocates or fractures and moves laterally?

2nd

What force is responsible for a substantially unstable lisfranc ligamentous injury?

External rotation on a pronated forefoot.

What is the consequence of axially loading the foot from the back of the heel while the ankle is plantar flexed and the forefoot is on the ground?

Buckle dorsally. Signup and view all the answers

Which type of injury is more common, HE or LE?

HE Signup and view all the answers

What percentage of lisfranc injuries presented to the ER are either unrecognized or misdiagnosed?

20% Signup and view all the answers

What is the key sign for a lisfranc injury?

Ecchymosis on the plantar surface of the midfoot. Signup and view all the answers

What test elicits pain when toes are grasped and moved in a plantar and dorsal direction?

Piano Key Test. Signup and view all the answers

At what diastasis measurement in mm is a lisfranc injury considered unstable?

2 mm. Signup and view all the answers

What is the most accepted diagnostic measure to determine if a lisfranc injury is unstable?

1 mm greater diastasis than the contralateral limb on a weight-bearing radiograph. Signup and view all the answers

After successful ORIF, what percentage of patients still develop arthritis?

25%. Signup and view all the answers

Which is worse for a lisfranc injury?

Medial column Signup and view all the answers

When do you need surgery for a lisfranc injury?

Gross displacement of more than 2 mm or 'Fleck-sign' to 2nd met base. Signup and view all the answers

What is considered the 'Lisfranc ligament'?

Interosseous between the medial cuneiform and the 2nd metatarsal. Signup and view all the answers

What fraction of the strength do dorsal ligaments have compared to the Lisfranc ligament?

1/3. Signup and view all the answers

Put these lisfranc ligaments in order from largest to smallest:

Interosseous = Largest Dorsal = Medium Plantar = Smallest Signup and view all the answers

Is there a ligament between the 1st and 2nd metatarsals interosseously?

No. Signup and view all the answers

What classification explains soft tissue injury in closed fractures?

Tscherne. Signup and view all the answers

What is Tscherne Grade 0?

Minimal soft tissue damage + simple fracture. Signup and view all the answers

What does Tscherne Grade 1 indicate?

Superficial abrasion + mild fracture pattern. Signup and view all the answers

What characterizes Tscherne Grade 2?

Deep abrasion + severe fracture pattern. Signup and view all the answers

What is Tscherne Grade 3?

Extensive skin contusion, compartment syndrome, severe damage to muscle with fracture. Signup and view all the answers

Match the historical classifications of Lisfranc Injury:

Quenu and Kuss = 1st classification Hardcastle = 2nd classification with several grades Signup and view all the answers

What classification is graded by degree of diastasis for Lisfranc injuries?

Myerson. Signup and view all the answers

What is Grade 3 in Myers classification?

5 mm between 1st & 2nd met bases + longitudinal arch height loss. Signup and view all the answers

What classification has prognostic value and compares 1st from 2nd metatarsal bases?

Nunley & Vertullo. Signup and view all the answers

What is Stage 1 Nunley & Vertullo?

Pain only at the Lisfranc complex and increased uptake on bone scan, with negative radiographic findings. Signup and view all the answers

What is Stage 2 Nunley & Vertullo?

Lisfranc diastasis between 1st and 2nd mets of 1-5 mm greater than that of contralateral side, without loss of midfoot arch height. Signup and view all the answers

At what amount of diastasis does it cause the longitudinal midfoot arch to drop?

≥ 5 mm. Signup and view all the answers

Which stages of Nunley & Vertullo need surgical treatment?

Stages 2 & 3. Signup and view all the answers

What characterizes Stage 3 Nunley & Vertullo?

Diastasis >5 mm + loss of midfoot arch height. Signup and view all the answers

What should be evaluated on radiographs for lisfranc injuries?

Medial margins alignment, lateral margin alignment, and the 4th met to cuboid alignment. Signup and view all the answers

What is a classic sign when an uninterrupted line cannot be drawn along the dorsal surface of the foot?

Step-off sign. Signup and view all the answers

What is the anteater sign?

Avulsion fracture at distal medial cuboid. Signup and view all the answers

What imaging modality is the best for assessing the lisfranc ligament according to Rettedal?

Ultrasound. Signup and view all the answers

At what diastasis mm can suggest the lisfranc ligament is torn?

1.3 mm. Signup and view all the answers

X-rays reliably pick up mal-alignment of 1 to 2 mm.

False Signup and view all the answers

If displaced > 2 mm, what type of intervention is needed?

ORIF with plate fixation. Signup and view all the answers

Does the severity of soft tissue injury play a role in operative management?

Yes, it has a negative impact. Signup and view all the answers

Is percutaneous reduction effective for lisfranc injuries?

Not really in comparison to ORIF. Signup and view all the answers

What is the optimal method of treatment for purely ligamentous lisfranc injuries?

Partial Primary Arthrodesis. Signup and view all the answers

What are the benefits of percutaneous versus ORIF?

Get back to sports a lot sooner (12 weeks), but often requires secondary surgery. Signup and view all the answers

Is there a significant difference in function between ORIF and Partial Primary Arthrodesis?

Not really. Signup and view all the answers

What does Rammelt suggest about the timing for delayed arthrodesis?

Found out you can even wait 36 months before doing the partial arthrodesis. Signup and view all the answers

What is the landmark study looking at Partial Primary Arthrodesis versus ORIF?

Coetzee study. Signup and view all the answers

What is the mainstay surgical treatment for a displaced lisfranc injury?

Primary Partial Arthrodesis. Signup and view all the answers

What test is a reliable indicator of functional strength?

Hops test. Signup and view all the answers

What is your first step if a patient presents with plantar bruising, a painful piano key test, and midfoot swelling?

Obtain weight-bearing radiographs. Signup and view all the answers

What is a complication of ORIF?

DJD in respective joints Signup and view all the answers

What is a complication of Partial Primary Arthrodesis?

DJD in adjacent joints Signup and view all the answers

What is the conclusion regarding conservative management of Lisfranc fracture dislocations?

Little place for conservative management. Signup and view all the answers

What is crucial to fix in lisfranc injuries to prevent post-traumatic arthritis?

The 1st, 2nd, and 3rd metatarsals. Signup and view all the answers

What is the takeaway regarding lisfranc injuries?

Commonly misdiagnosed (20%). Signup and view all the answers

Study Notes

Mechanism of Injury (MOI)

Excessive plantar flexion (PF) and abduction forces can lead to Lisfranc injuries.
Two key mechanisms:
- Ankle equinus and MPJ PF with the joint engaged along a long lever arm, causing dorsal displacement upon missing a step.
- External rotation on a pronated forefoot resulting in the most unstable injuries.

Lisfranc Injury Characteristics

The 2nd metatarsal commonly dislocates or fractures, leading to lateral movement.
External rotation and a pronated forefoot are responsible for substantially unstable Lisfranc ligamentous injuries.
Axial loading of a plantar-flexed foot can cause the midfoot to buckle dorsally, due to weaker dorsal ligaments.

Prevalence and Diagnosis

About 20% of Lisfranc injuries are initially unrecognized or misdiagnosed.
A key sign is ecchymosis on the plantar surface of the midfoot, often accompanied by midfoot edema and pain upon heel raise.

Clinical Tests and Diagnostic Criteria

The Piano Key Test assesses lisfranc injuries through pain induced by toe movement.
Diastasis of ≥2mm between the medial cuneiform and base of the 2nd metatarsal indicates an unstable Lisfranc injury when non-weight bearing.
The most accepted diagnostic measure involves a 1mm greater diastasis than the contralateral limb on weight-bearing radiographs.

Treatment and Long-term Outcomes

Up to 25% of patients develop arthritis after successful open reduction and internal fixation (ORIF).
Surgical intervention is required for gross displacement exceeding 2mm or "fleck-sign" present at the base of the 2nd metatarsal.
The Lisfranc ligament, located interosseously between the medial cuneiform and 2nd metatarsal, is considered strong.

Ligament Strength Comparison

Dorsal ligaments possess only one-third the strength of the Lisfranc ligament, making them the weakest in the midfoot.
Lisfranc ligaments rank in strength as: interosseous > plantar > dorsal.

Lisfranc Injury Classifications

Historical classifications include Quenu and Kuss, and Hardcastle, describing varying degrees of injury incongruity.
Myerson classification focuses on diastasis degree for Lisfranc injuries, with a Grade 3 indicating significant changes.

Imaging and Assessment

Radiographs should demonstrate alignment in three key anatomical relationships to distinguish lisfranc injuries accurately.
A "step-off" sign indicates disruption when a straight line cannot be drawn across the dorsal surface of the foot.
Ultrasound is noted as an effective imaging modality for assessing the Lisfranc ligament.

Treatment Choices

Primary Partial Arthrodesis (PPA) shows favorable outcomes for purely ligamentous injuries, as it allows quicker recovery with fewer complications compared to ORIF.
Risks of degenerative joint disease (DJD) exist for both surgical approaches, though complications differ based on treatment type.

Special Considerations and Misdiagnosis

Lisfranc injuries are often misdiagnosed due to subtle presentation and require careful evaluation of non-weight-bearing radiographs.
Purely ligamentous injuries present unique challenges, and conservative management is typically ineffective in cases of diastasis over 2mm.

Conclusion

Management of Lisfranc injuries is complex due to the risk of long-term complications, and surgical intervention is necessary for significant displacement.
Understanding the mechanics, classifications, and treatment options is vital for improving patient outcomes and avoiding misdiagnosis.

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Description

Explore essential concepts related to Lisfranc injuries through these flashcards. Gain insights into the mechanisms of injury and key forces at play, enhancing your understanding of this critical topic in orthopedic medicine.