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10/26/2018 0 Comments

LisFranc Fracture

Introduction

Disruption between the articulation of the medial cuneiform and base of the second metatarsal
- Disruption of the TMT joint complex
- Injury to 2nd metatarsal àDisruption of other metatarsals
May take form of purely ligamentous injuries or fracture-dislocations
- Ligamentous vs. bony injury pattern has treatment implications
More common in males in their 30s
Missed injuries can result in progressive foot deformity, chronic pain and dysfunction
- Tarsometatarsal fracture-dislocations are easily missed (up to 30% on initial visits) and diagnosis is critical

Mechanism & Pathoanatomy

Mechanism = indirect rotational forces and axial load through hyperplantar flexed forefoot
- Hyperflexion/compression/abduction moment exerted on forefoot and transmitted to the TMT articulation
- Metatarsals displaced in dorsal/lateral direction
- Think of a running back trying to push through lineman or sprinter

Anatomy

Midfoot:
- Medial, Intermediate (Middle), Lateral Cuneiform
- Navicular
- Cuboid
Lisfranc joint complex consists of three articulations:
- 1) Tarsometatarsal articulation
- 2) Intermetatarsal articulation
- 3) Intertarsal articulations
Ligaments
- Lisfranc ligament
  - Stabilizes 2nd metatarsal and maintenance of the midfoot arch
  - Interosseous ligament that goes from medial cuneiform to base of 2nd metatarsal on plantar surface
- No direct ligamentous attachment between first and second metatarsal

Physical Exam

Symptoms
- Severe pain and inability to bear weight
PE
- Medial plantar bruising with swelling throughout midfoot
- Tenderness over tarsometatarsal joint
- Pain with pronation and passive abduction of the midfoot
- *Instability test
  - Grasp metatarsal heads and apply dorsal force to forefoot while other hand palpates the TMT joints
  - Dorsal subluxation suggests instability
  - If first and second metatarsals can be displaced, global instability is present, and surgery is required
  - When plantar ligaments are intact, dorsal subluxation does not occur with stress exam and injury may be treated nonoperatively
- Evaluate for compartment syndrome!

Imaging

Radiographs
- AP, lateral, oblique views
- Stress -> may be helpful to show instability when non-weight bearing radiographs are normal and there is high suspicion
- Weight-bearing with comparison view
- 5 critical radiographic signsthat indicate presence of midfoot instability
  - 1) Discontinuity of a line drawn from the medial base of the 2nd metatarsal to the medial side of the middle cuneiform (diagnostic)
  - 2) Widening of the interval between the 1st and 2nd metatarsal
    - Fleck sign= bony fragment in 1st intermetatarsal space àAvulsion of Lisfranc ligament from base of 2nd metatarsal (diagnostic)
  - 3) Dorsal displacement of the proximal base of the 1st or 2nd metatarsal
  - 4) Medial side of the base of the 4th metatarsal does not line up with medial side of cuboid
  - 5) Disruption of the medial column line (line tangential to the medial aspect of the navicular and the medial cuneiform)
CT scan
- Useful for diagnosis and preoperative planning
MRI
- Can be used to confirm presence of purely ligamentous injury

Treatment

Nonoperative
- Posterior splint and non-weightbearing for sprains and non-displaced fractures
  - No displacement on weight-bearing and stress radiographs and no evidence of bony injury on CT (usually dorsal sprains)
- Cast immobilization for 8 weeks
Operative
- ORIF
- Any evidence of instability (> 2mm shift)
- Favored in bony fracture dislocations as opposed to purely ligamentous injuries
- Primary arthrodesis
  - Purely ligamentous arch injuries
  - Primary arthodesis is an alternative to ORIF in patients with any evidence of instability with possible benefits

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10/25/2018 0 Comments

Patellar Dislocation

Background

Typically occurs with trauma to an extended knee with externally rotated foot (quick pivoting in basketball, football and soccer)
Acute dislocation occurs with traumatic injury, M=F, may see hemarthrosis
Chronic dislocation or patholaxity seen more commonly in women
- Ehlers-Danlos syndrome
- Typically, little or no swelling; painless
- Recurrent subluxation episodes with each flexion movement
May occur from a direct blow (ex. helmet to knee collision in football; knee-knee collision in basketball)
- Usually on noncontact twisting injury with the knee extended and foot externally rotated
- Patient will usually reflexively contract quadriceps thereby reducing the patella
Common associated fractures
- Medial patella facet
- Lateral femoral condyle

Clinical Features

Patella is usually displaced laterally
Knee is held in flexion
Acute dislocation usually associated with a large hemarthrosis
- Absence of swelling supports ligamentous laxity and chronic dislocation mechanism

Evaluation

Clinical diagnosis
May consider pre-reduction x-ray if concern for fracture (not required)

Management

Reduction = Relocation with lateral pressure on dislocated patella
Do NOT need x-rays prior to reduction
- Consider XR following reduction to rule out fracture or loose body
Rarely need any sedation (sub-dissociative dose ketamine ?)
Option #1:
- Mild flexion of hip (20-30 degrees by raising head of bed, not by propping the leg up off the bed) to relax quadriceps
- Slowly extend and slightly hyperextend the knee and slide patella back into place.
Option #2
- One provider applies slow downward pressure over the quads. This stretches out the muscle and slowly straightens the leg
- At the same time, second provider pulls gentle traction of the patella outward while rotating the patella back over from lateral to anterior

Disposition

Obtain ortho consult if unable to reduce or fracture/loose bodies seen on post-reduction x-ray
Otherwise may be discharged with ortho follow-up in 1-2 weeks
Non-Operative:
- NSAIDS, activity modification, and physical therapy
- Knee immobilizer for comfort (short-term)
- Quad strengthening exercises
- Core and hip strengthening to improve limb positioning and balance (hip abductors, gluteals, and abdominals)
Consider knee aspiration for tense effusion
- Positive fat globules indicates fracture

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From the J. Lee Garvey Innovation Studio in the
Department of Emergency Medicine
Carolinas Medical Center
Charlotte, NC

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LisFranc Fracture

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