Download Lisfranc Fracture Dislocation

LISFRANC FRACTURE-DISLOCATION
“Napoleon at Mont St. Bernard”, Jacques-Louis David, 1800, Oil on Canvas, Musee du Louvre,
Paris.
This is Jacques-Louis David’s immortal depiction of a young Napoleon Bonaparte, portrayed
shortly after be burst onto the European scene in 1797 to save a France that was in total
disarray. Torn by revolution and under attack from virtually all her European neighbours there
appeared to be no hope. Napoleon however not only rescued France from the excesses of the
revolution, he swiftly overcame all her foreign enemies then came to dominate the rest of Europe
to an extent not previously matched since the days of the Roman Empire. To many a Frenchman
he was France’s greatest hero, since Charlemagne. David’s panting inspired admiration and
awe to all Frenchmen of his day, all except perhaps for one of his field surgeons named Jacques
Lisfranc. He would have no doubt felt somewhat apprehensive for his general lest he fall off
backwards from his horse if he persisted in this striking pose. With a foot left in the stirrup
Napoleon would have been a fair bet for a severe “Lisfranc” type injury to his forefoot which in
those times may well have meant that his field surgeon would have had to perform one of his
famous forefoot amputations!
LISFRANC FRACTURE-DISLOCATION
Introduction
Lisfranc (i.e. tarso-metatarsal) fracture-dislocation injuries of the forefoot are uncommon and
usually require a significant force to produce them.
There is usually disruption to the “keystone” second metatarsal bone with associated lateral
displacement of the metatarsal bones, but lesser degrees of injury can occur and these can be
difficult to detect on plain radiography.
History
Jacques Lisfranc (1790-1847) was a field surgeon in Napoleon Bonaparte's army. He developed
a new amputation technique to treat forefoot gangrene caused by frostbite, (he was serving on
the Russian front).
His technique involved a cutting a route through a series of joints (the tarso-metatarsal array) to
avoid having to cut through bone, thus decreasing the time taken for an amputation. This route
became known as the Lisfranc joint.
Fracture-dislocations of the metatarsal bases in this region today have become known as
Lisfranc fracture-dislocations.
Anatomy
The Tarsometatarsal Articulations
Left: Lisfranc’s joint (Gray’s Anatomy). Right: Radiological demonstration of the forefoot
(Lisfranc) joint line shown in red. The hindfoot joint line (in yellow) is sometimes referred to as
Chopart’s joint
The tarso-metatarsal joints are sometimes collectively referred to as Lisfranc’s joint. It divides
the mid-foot from the forefoot.
These are synovial joints of approximately plane variety with articulations as follows:
●
The first metatarsal articulates with the medial cuneiform
●
The second metatarsal is recessed between the medial and lateral cuneiforms, articulating
between them and with the intermediate cuneiform proximally.
●
The third metatarsal articulates with the lateral cuneiform.
●
The fourth metatarsal articulates with the lateral cuneiform and the cuboid.
●
The fifth metatarsal articulates with the cuboid alone.
The joints lie in a continuous line joining the tubercle of the fifth metatarsal bone to the
tarsometatarsal joint of the great toe, with the exception of the joint between the second
metatarsal and the intermediate cuneiform bone, which lies 2-3 mm proximal to the line of the
others.
The second metatarsal acts as an important “locking keystone” for the whole complex.
If the base of the second metatarsal fractures, subluxation/ dislocation of the rest of the joint
complex is likely.
Mechanism
Lisfranc injuries are usually the result of significant force.
They may occur by (as illustrated above):
A
A fall onto the plantar flexed foot
B
A direct blow on the heel, in the kneeling position
C
Crush injuries
D
Forced inversion or eversion of the forefoot.
Complications
The major complications of this injury include:
●
Due to the severe forces required, there may be associated vascular compromise,
especially at the dorsalis pedis medial / medial plantar anastomosis.
An important branch of the dorsalis pedis artery passes between the first and second
metatarsals to form the plantar arch (1, see below).
Trauma to this vessel can cause significant haemorrhage leading to a compartment
syndrome or less commonly vascular compromise of the forefoot.
●
Fracture of the “keystone” base of the second metatarsal (2, 3 below) will allow lateral
drift (4) of the 3rd, 4th and 5th metatarsals. The first metatarsal may drift medially (5) with
the medial cuneiform (6).
This can result in significant long term biomechanical problems if inadequately
treated.
●
Secondary degenerative arthritis changes are common due to damage to articular
cartilage.
●
Associated fractures of the tarsal bones (navicular, cuboid and cuneiforms are also
common.
Clinical Features
1.
Pain is usually severe in the region of the forefoot.
2.
In lesser injuries there may be a clue given by the inability to weight bear on the toes.
3.
There is usually significant swelling/ bruising and tenderness (see below).
4.
There may be compartment syndrome and/or direct vascular compromise of the foot.
5.
There may be frank mid-foot deformity and instability in the more severe injuries.
Extensive mid-foot swelling and bruising of the left foot of a young male who had sustained a
Lisfranc type fracture of his forefoot. This extent and location of bruising is strongly suggestive
of a significant mid-foot fracture -dislocation type injury.
Investigations
Plain radiography
Three standard plain x-ray views:
●
A-P
●
Lateral
●
A 45 degree oblique view
Normal radiology:
Normally the first four metatarsal should each line up with their respective tarsal articulations on
both A-P and oblique views as follows:
●
Lateral border of First metatarsal → Lateral border of the medial cuneiform
●
Medial border of Second metatarsal → Medial border of middle cuneiform
●
Medial and lateral borders of Third metatarsal → Medial and lateral borders of the lateral
cuneiform
●
Medial border of the Fourth metatarsal → Medial border of cuboid.
●
Lateral margin of the Fifth metatarsal should not project more than 3 mm lateral to
cuboid on oblique views.
Major disruptions are easily diagnosed on plain x-ray, but lesser degrees of injury can be subtle
and so difficult to detect.
Look especially for abnormalities in the normal alignments of the midfoot bones:
●
The most constant and reliable radiographic sign will be separation between the base of
the 1st and 2nd metatarsals.
This is strongly suggestive of subluxation.
●
Another important clue in more subtle injuries can be the lateral displacement of the base
of the 5th metatarsal with respect to the cuboid, (as shown in the second set of x-rays
below).
●
A fracture of the “keystone” base of the second metatarsal is also very suggestive of
more extensive disruption of Lisfranc’s joint.
This may be obvious, or take the form of a more subtle chip or avulsion types fracture as
below, left.
Above Left: A fracture of the “keystone” base of the second metatarsal is also very suggestive of
more extensive disruption of Lisfranc’s joint. This may be obvious, or take the form of a more
subtle chip or avulsion types fracture.
Generally the best view for this
injury will be the A-P. In fact
however severe injury can exist,
with very little evidence of it seen
on the other views of the lateral
and oblique projections, (as
demonstrated above middle, right
and left opposite), in a 21 year old
male.
A-P and oblique views showing dislocation of the bases of metatarsals, II-V. This is not as
obvious as in the case shown previously , however the clue is the extreme lateral displacement of
the Vth metatarsal with respect to the cuboid bone. The second x-ray on the right shows
confirmatory wide disruption of the second metatarsal on the second view. This is sometimes
called a “divergent” type injury where the metatarsals diverge - as opposed to a “homovergent”
type injury where all the metatarsals are displaced in the same direction.
Note that fractures of the second metacarpal base are virtually pathognomonic of occult
Lisfranc fractures.
If a suspicious fracture is present but alignment appears normal then a spontaneously
reduced Lisfranc injury may have occurred.
CT scan
●
CT scan is required in lesser degrees of injury, when plain radiology is inconclusive, but
injury to the midfoot is suspected on clinical grounds.
●
CT scan is also needed to more fully define the extent of injury, which plain x-rays do
not adequately demonstrate.
MRI
This is a further imaging alternative, particularly in cases where it is more desirable to avoid
radiation, as in children or pregnant women.
Management
1.
Analgesia:
●
Opioid analgesia will usually be required.
2.
Splint/ Elevate.
3.
Surgery:
●
Good reduction is essential to avoid longer term degenerative changes and
chronic biomechanical problems and ORIF is usually required.
●
Reduction of significant injuries should be urgent because of the risk of vascular
impairment.
●
In more minor injuries reduction may be possible with closed axial traction of the
metatarsals and pressure over the bases.
Disposition
All suspected Lisfranc type injuries should be referred to the orthopaedic Unit.
References
1.
McRae R, Practical Fracture Treatment, Churchill -Livingstone, 3rd ed p.359.
2.
Riyad B Abu-Laban & Kendall Ho; Ankle & Foot Injuries in Rosen’s Emergency
Medicine 7th ed, 2010.
Dr J. Hayes
Reviewed February 2013.