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					Dr. Sandeep Gurung
 Injuries to the foot can have a dramatic impact on the
  overall health, activity, and emotional status of
  patients.
 More attention and aggressive management needs to
  be given to foot injuries to improve the outcome of
  multiply injured patients.
 The midfoot is described as the section of the foot
  distal to Chopart's joint line and proximal to Lisfranc's
  joint line.
Five bones comprise
the midfoot
• navicular

• cuboid and
•medial, middle, and lateral
cuneiforms .
•There is no bony weight-
bearing contact with the
ground in this area in the
normal foot structure.
•it is also relatively immobile
compared to the rotatory and
accommodative functions of
the hindfoot and forefoot.
 The stability or resistance to movement in these
  articulations is due in large part to the numerous dense
  plantar ligaments, which tightly bind the osseous
  structures in the midfoot together.
 These ligaments also carry over to the hindfoot and medial
  forefoot providing strong mechanical links between the
  three sections of the foot.
 The strength and stability of the whole structure is
  dependent on the tensile strength of the plantar-based
  intersegmental ties between the osseous structures.
 The only motor unit to completely insert into the
  midfoot is the tibialis posterior.
 Its multiple insertions on the plantar surface of the
  midfoot bones are intertwined with the plantar
  ligamentous structures to provide dynamic
  support and mechanical overload protection.
 Its attachment to all five bones of the midfoot
  ensures movement as a unit.
 This inherent stability is important for normal foot
    function.
    The medial arch provides a protective conduit and alcove
    for the neurovascular structures and intrinsic musculature
    of the plantar aspect of the foot.
   These muscles are extremely important to the function and
    stability of the weight-bearing surfaces of the forefoot.
   As a rigid beam, the midfoot solidly binds the forefoot to
    the hindfoot through the full arc of subtalar motion.
   During weight-bearing, the midfoot acts as a mechanical
    actuator transmitting the rotational motion of the hindfoot
    complex to the forefoot .
 The midfoot, because of its axial rigidity, is also responsible
  for the weight-bearing relationship of the hindfoot to the
  forefoot.
 Relative changes in the position of the medial and lateral
  aspects of the midfoot can lead to significant distortions in
  forefoot/hindfoot alignment.
 The midfoot is not totally without the potential to move.
  This motion is small compared to the motion of the
  subtalar complex and metatarsophalangeal joints, but it
  plays a role in shock absorption during weight-bearing.
 The functional descriptive is that of a leaf spring that
  provides essential dampening and recoil of repetitive
  loading forces.
In treating midfoot injuries
 Stability is of paramount importance.
 The structural integrity of the five bones and their positional
  relationship to each other are key to retaining midfoot function.
 Secondly, maintenance of the normal relationship of the weight-
  bearing surfaces of the hindfoot to the forefoot should be
  considered.
 This requires attention to the maintenance of talonavicular,
  calcaneocuboid, and fifth tarsometatarsal joint motions. The
  least important consideration is to maintain the articular
  integrity of the surfaces between these five bones. They should
  be readily sacrificed for the restoration of bony stability and the
  preservation of the major end articular surfaces.
 Injuries to midfoot vary from minor sprain, often
  incorrectly labelled as ankle sprain, to severe fracture
  dislocations which can threaten the survival of the
  foot.
 Isolated injuries are rare, fractures in this region
  should be assumed to be combination fractures or
  fracture subluxation until proved otherwise.
Main and Jowett classified midfoot injuries based on the
  mechanism of injury
 Medial stress injury caused by violent inversion of
  the foot and vary in severity from sprains of the mid
  tarsal joint to subluxation or fracture subluxation of
  the talonavicular or mid tarsal joint.
 Longitudinal stress injuries are the most common.
  They are caused by a severe longitudinal force with the
  foot in planterflexion. Result in navicular fracture and
  subluxation of the mid tarsal joint.
 Lateral stress injuries usually due to fall in which the
  foot is forced into valgus. Injuries include fracture and
  fracture subluxations of the cub0id and the anterior
  end of the calcaneum as well as avulsion injuries on
  the medial side of the foot.
 Planter stress injuries result from falls in which the
  foot is twisted and trapped under the body; they
  usually present as dorsal avulsion injuies or #
  subluxation of the calcaneocuboid joint.
 Crush injuries usually cause open comminuted # of
  the mid tarsal region.
C/F
 The foot is bruised and swollen.
 Tenderness is usually diffuse across the mid foot.
 A medial mid tarsal dislocation looks like an acute
  clubfoot and a lateral dislocation produces a valgus
  deformity.
 An attempt at movement is painful.
 It is important to exclude distal ischemia or a
  compartmental syndrome.
NAVICULAR FRACTURES
 The    navicular is the keystone of the medial
  longitudinal arch of the foot.
 It is wider dorsally and medially than plantarly and
  laterally.
 medial prominence, known as the navicular tuberosity,
  provides the interim attachment point for the
  posterior tibialis on its medial inferior surface.
 Proximally, the articular surface is concave and
  articulates with the talus. This joint enjoys a
  significant arc of motion .
 distal articular surfaces of the navicular have three
  separate, broad facets that articulate with each of the three
  cuneiforms. These joints provide little motion.
 Laterally the navicular appears to rest on the dorsal medial
  aspect of the cuboid with a variable articular surface.
 Perfusion is abundant along the periphery, but it is
  relatively avascular centrally.
 Anatomic variants to be aware of when viewing the
  navicular involve the shape of the tuberosity and the
  presence of an accessory navicular (os tibiale externum).
 These are present up to 25% of
  the time and 90% are bilateral.
 Clinically      the     accessory
  navicular can be seen as a medial
  prominence on the foot.
 It can be present in one of these
  forms: a fused elongation of the
  normal tuberosity, a bone island
  with a flat synchondrotic joint
  separating it from the navicular
  tuberosity proper, or as a true os
  separated completely from the
  navicular.
 All three variants are completely
  within the substance of the
  posterior tibialis tendon.
 Injury may be sports related, secondary to a fall from a
  height, or due to a motor vehicle collision.
 Because of the cross interaction of the surrounding
  bony and soft tissue structures, injury to adjacent
  structures is likely and must be carefully ruled out
  where a navicular injury is found.
 Recognition of navicular injuries ranges from obvious
  midfoot deformity and loss of function to subtle
  chronic pain and local tenderness.
 The contour of two thirds of the navicular is readily
  palpable in the foot. Following injury, local tenderness
  to palpation, ecchymosis, or local edema warrants
  further investigation.
 As with any foot injury, anteroposterior, lateral, medial
  oblique, and lateral oblique x-ray views should be
  obtained to ascertain the extent of injury to the
  navicular, as well as rule out collateral damage.
 If the patient is at all ambulatory, the initial films
  should be weight-bearing, single-leg stance if possible,
  to fully appreciate any ligamentous instability.
Fracture classification
Three basic types with a
subclassification     for  body
fractures       suggested    by
sangeorzan.
a) Avulsion type # can involve
    either the talonavicular or
    naviculocuneiform
    ligaments.
b) Tuberosity # are usually
    traction type injuries with
    disruption of the tibilais
    posterior insertion.
c) A type 1 dody #splits the
    navicular into dorsal and
    palnter segment.
d) A type 2cleaves into medial
    and lateral segment.
e) A type 3 comminuted #
TREATMENT
 The two criteria most important in obtaining a satisfactory outcome are
  maintenance or restoration of the medial column length and the
  articular congruity of the talonavicular joint.
 Closed management of navicular #
Indications
  <2-mm displacement of the talonavicular joint surface .
  No evidence of midfoot instability with weight-bearing or stress views .
  No loss of bony length .
Treatment
  Short leg non weight-bearing cast for 6 to 8 weeks .
  Recheck stability with stress views at 10 days from injury .
  Progressive weight-bearing in protective brace until asymptomatic .
 Surgical intervention should be considered for any
  unstable injury or fracture resulting in loss of position
  or loss of articular congruity.
 Problems in the near term from navicular fractures
  include nonunion of the fracture fragments, arthritic
  degeneration, late instability, loss of normal foot
  alignment through bony resorption, or collapse and
  avascular necrosis.
 Avascular necrosis can be evident as early as 8 weeks
  from injury and is usually centrally located in the
  navicular.
NAVICULAR STRESS FRACTURES
 frequent causes of arch pain in athletes.
 Because many of these fractures are not clearly
  identified on routine radiographs, a high index of
  suspicion is necessary for accurate diagnosis.
 The midfoot may be tender over the navicular, and the
  foot may be irritable with eversion and inversion
  stress.
 Radiographs may be normal initially, but a bone scan
  frequently is positive, and tomograms, CT, or MRI may
  confirm the diagnosis
 Quirk recommended the following treatment:
1.   At the time of initial diagnosis, all patients should
 be placed in a below-knee, non–weight bearing cast for
 6weeks.
2. If tenderness is still located over the navicular after 6
 weeks of non–weight bearing immobilization, another
 cast is applied for 2 weeks.
3. If treatment is successful, the patient is allowed to
 return to previous activity gradually under supervision.
NAVICULAR DISLOCATION
 Outside of the neuropathic foot, isolated dislocation
  or subluxation of the navicular is rare.
 When it does occur the navicular can be found either
  medial and plantar to its normal position in the case of
  neuropathic instability or dorsal as occurs with acute
  trauma.
 The trauma mechanism appears to be an initial
  hyperplantar flexion of the forefoot with subsequent
  axial loading.
 Dislocation in the neuropathic foot appears to be the
  result of motor pull with ligamentous failure.
 To maintain proper midfoot alignment, anatomic
  reduction and stabilization is required.
 Open reduction is usually necessary to restore both
  navicular position and articular congruity.
 use of wires and screws to maintain reduction .
CUBOID INJURIES
 The cuboid is the sole osseous structure of the midfoot
  considered part of the lateral support column of the foot .
 Its saddle-shaped articulation with the calcaneus acts as a
  stress valve for the imperfectly matched movements of the
  talonavicular and subtalar joints.
 Distally the cuboid provides separate articular facets for
  each of the fourth and fifth metatarsals.
 There are variable articular surfaces on the dorsomedial
  aspect of the cuboid where the navicular and lateral
  cuneiform come into contact with the cuboid.
 It is important to realize that the cuboid-metatarsal
  articulations are more important to overall foot function
  than the calcaneocuboid articulation.
 These tarsometatarsal joints provide for nearly all of the
  dorsal and plantar motion of the lateral column of the foot.
 The peroneus longus courses along the lateral and plantar
  surfaces of the cuboid on its way to the base of the first
  metatarsal.
 The importance of the cuboid in the overall function of
  the foot lies primarily in its structural position as a lateral
  column spacer secondarily in the function of the fourth
  and fifth tarsometatarsal joints and thirdly in
  calcaneocuboid joint motion.
 Injury to the cuboid can occur as an isolated entity, but it is
  usually seen in association with injuries to the
  talonavicular joint, with injuries to other midfoot
  structures, or in conjunction with complex Lisfranc joint
  injuries.
 A small medial or dorsal avulsion fracture of the navicular
  is considered a sign of a possible cuboid injury.
 Injuries to the cuboid can occur with as little force as an
  ankle twist or as part of a high-energy multitrauma event.
  As with any foot injury, cuboid fracture can occur with a
  direct blow.
 Presentation of a cuboid injury can range from subtle to
  severe distortion of the foot anatomy.
 Dorsolateral pain swelling and ecchymosis over the lateral
  midfoot should raise suspicion of a cuboid injury.
 Plain x-rays, especially a medial oblique view, can be
  extremely helpful in assessing cuboid injury.
 Complete isolated dislocation is extremely rare and is most
  likely the result of a direct, medially applied force followed
  by axial loading or abduction of the foot. The position of
  the dislocated cuboid is always plantar and medial.
 Cuboid fractures can be classified into avulsion or
  compression types.
 Small avulsions may occur with inversion-type ankle
  sprains and generally respond to conservative treatment.
 Compression, or “nutcracker,” fractures of the cuboid
  are associated with Lisfranc and midtarsal disruptions.
  Most are minimally displaced and can be treated in a non–
  weight bearing cast for 4 weeks followed by weight bearing
  casts for 4 weeks. A well-molded arch support often is used
  afterward.
 For severe displacement with shortening of the lateral
  column, consideration should be given to open reduction
  and internal fixation with bone grafting.
INJURY TO THE OS PERONEUM
 The os peroneum is a sesamoid bone lying within the
  substance of the peroneus longus tendon.
 It can be found at the level of the cuboid tunnel where
  the peroneus longus tendon passes under the cuboid
  or at the level of the calcaneocuboid joint.
 present in 5% to 14% of the population and the
  majority are bilateral and symmetric .
 caused by a direct blow or supination and
  plantarflexion forces .
 Patients usually present with lateral ankle pain on
  weight-bearing resistant to conservative measures.
 Tenderness can be localized to the plantar lateral
  aspect of the foot proximal to the base of the fifth
  metatarsal.
 Resistance to peroneus longus motion also causes
  pain.
 A medial oblique x-ray view will usually reveal the
  presence of the os peroneum.
 Treatment     consists of
  non-weight-bearing in a
  cast for a minimum of 6
  weeks       and       then
  progressive         weight-
  bearing in a cast until
  asymptomatic.
 Despite these measures, a
  painful fibrous union can
  occur, which is best
  treated with excision of
  the bone fragments .
 Wide displacement of the
  fragments         indicates
  disruption       of     the
  peroneus longus tendon,
  which      would      need
  surgical repair.
CUNEIFORM INJURIES
 The three cuneiform bones sit in the middle of the
  medial column of the foot and provide the rigid
  support for the medial longitudinal arch.
 They constitute the apex of the transverse arch .
 All are wedge shaped along the axial axis. The medial
  cuneiform has a plantar base and a dorsal crest. The
  middle and lateral cuneiforms are reversed.
 Proximally,    each cuneiform articulates with
  approximately one third of the distal navicular. Each
  cuneiform articulates with its respective metatarsal
  distally.
 Disruption of the position of any of the three
  cuneiform bones is a rare injury .
 Commonly, cuneiform injuries are seen in conjunction
  with tarsometatarsal joint injuries.
 Whether injury to the cuneiform results in a fracture
  or fracture dislocation, it is usually the result of
  indirect axial loading of the bone.
 Medial cuneiform instability usually occurs with
  seemingly minimal energy.
 Localized tenderness over the cuneiform region, pain
  in the midfoot with weight-bearing, or discomfort with
  motion through the tarsometatarsal joints can signify
  injury to these bones.
 Anteroposterior, lateral, and oblique x-ray views
  should be obtained to assess the extent of injury and
  check for injury to adjacent structures. These should
  be obtained with single-leg weight-bearing, if possible.
 In treating cuneiform injuries it is the presence of
  instability or the loss of position of the individual bones,
  which requires aggressive treatment.
 The use of closed reduction techniques can be employed
  with isolated dorsal dislocation of the middle and lateral
  cuneiforms when there is no evidence of adjacent injury.
 Longitudinal traction is applied to the affected ray and
  with direct dorsal pressure a reduction is attempted.
  Successful stable, anatomic reduction can be treated with a
  non-weight-bearing short leg cast holding the foot in a
  neutral, plantigrade position .
 Nonanatomic reduction        or continued instability
  should be treated with open reduction and pin or
  screw fixation into adjacent stable structures.
 Instability of the medial cuneiform requires internal
  fixation even if closed anatomic reduction is obtained
  through traction .
TARSO METATARSAL INJURIES
 The area known as Lisfranc's joint represents the transition
    between the midfoot and forefoot.
   It consists of the three cuneiform-metatarsal articulations
    and the two cuboid-metatarsal articulations of the fourth
    and fifth rays.
    The alignment and stability of this joint line is critical for
    normal function of the foot.
   The medial to lateral cascade of the distal articular surfaces
    of the cuneiforms and cuboid provide for the transverse
    arch of the foot.
   The metatarsals, with the distal heads placed for forefoot
    weight-bearing, comprise the distal half of the longitudinal
    arch.
The osseous alignment of this joint
•The first articulation is a broad surface,
usually 3 cm deep, and with a broad
plantar base and dorsal apex.
• The second and third are much smaller
and triangular in shape with the apex
plantar.
• The second is recessed from the first by
approximately 1 cm and from the third
by 0.5 cm.
•The fourth and fifth are more
trapezoidal in shape and lie in a separate
plane plantar and lateral to the joints of
the medial column.
• The inherent stability of this region is
due in part to the recessed second
metatarsal base but even to a greater
degree to the numerous strong
ligamentous attachments across each
tarsometatarsal joint and between each
ray.
 Injuries of the tarsometatarsal articulation encompass
  a wide spectrum ranging from mild sprains or subtle
  subluxations to widely displaced debilitating injuries .
 It is important to recognize and treat these injuries
  early and aggressively for best results.
 High suspicion for this type of injury should be
  present following motor vehicle trauma.
 Two mechanisms of injury are described.
•A direct loading of the joint complex along the
dorsal surface in the manner of a crush injury or
an object falling on a stationary foot can result in
ligamentous or bony disruption anywhere along
the joint line.
•Indirect loading is a more common
mechanism and can produce significant
disruption of the whole complex. It is
characterized by longitudinal loading of a
plantarflexed foot .
•This causes hyperplantarflexion across the long
axis of the foot, disrupting first the dorsal
ligaments and then the plantar ligaments with a
variable extent of bony injury.
•The resulting pattern again is dependent on the
amount of force and the presence of secondary
forces acting about the long axis of the foot. This
is the most common mechanism for sports
injuries
•Fractures of the cuneiforms, cuboid, and or
metatarsals are common.
    EVALUATION
•Any injury resulting in midfoot tenderness
and swelling merits a careful physical and
radiographic examination.
•Although     grossly displaced     fracture-
dislocations are obvious on examination, care
should be taken with subtle injuries to
palpate each articulation for tenderness and
swelling, especially the medial cuneiform–
first metatarsal joint, which often appears
nondisplaced on radiographs.
•“rotation test,” in which stressing the second
tarsometatarsal joint by elevating and
depressing the second metatarsal head
relative to the first metatarsal head elicits
pain at the Lisfranc joint.
•The presence of plantar ecchymosis is also
suggestive of ligamentous injury.
•The inability to bear weight on the foot is
another sign of potential instability.
 X-ray evaluation is crucial in the diagnosis and treatment of this
    injury.
    It is used to assess the stability of the joint and to catalog the
    presence of collateral injuries.
   If possible at the time of presentation, weight-bearing films of
    the foot in an anteroposterior, lateral, and 30-degree medial
    oblique position should be obtained.
   If the patient is unable to bear weight because of pain or the
    presence of other injuries non-weight-bearing films are still
    useful as a preliminary evaluation.
    If the radiograph reveals no displacement, and the patient
    cannot bear weight, a short leg cast should be used for 2 weeks,
    and the radiographs should be repeated with weight bearing.
Evaluation should be directed to the
following areas:
i.   The medial shaft of the second metatarsal
     should be aligned with the medial aspect of
     the     middle     cuneiform     on     the
     anteroposterior view.
ii. The medial shaft of the fourth metatarsal
     should be aligned with the medial aspect of
     the cuboid on the oblique view
iii. The first metatarsal–cuneiform articulation
     should have no incongruency.
iv. A “fleck sign” should be sought in the
     medial cuneiform–second metatarsal space.
     This represents an avulsion of the Lisfranc
     ligament.
v. The naviculocuneiform articulation should
     be evaluated for subluxation.
vi. A compression fracture of the cuboid
     should               be             sought.
CLASSIFICATION
 Myerson's modification of the original classification
  of Quénu and Küss and Hardcastle .
 Type A Injuries
       Type A injuries involve displacement of all five
  metatarsals with or without fracture of the base of the
  second metatarsal.
       The usual displacement is lateral or dorsolateral,
  and the metatarsals move as a unit. These injuries are
  referred to as homolateral.
 Type B Injuries
      In type B injuries, one or more articulations remain
 intact.
      Type B1 injuries are medially displaced, sometimes
 involving the intercuneiform or naviculocuneiform joint.
      Type B2 injuries are laterally displaced and may
 involve the first metatarsal–cuneiform joint.
 Type C Injuries
      Type C injuries are divergent injuries and can be
 partial (C1) or complete (C2).
      These generally are high-energy injuries, associated
 with significant swelling, and prone to complications,
 especially compartment syndrome.
TREATMENT
 The key to successful outcome in Lisfranc injuries is
  anatomical alignment of the involved joints.
 Closed, nondisplaced (<2 mm) injuries can be treated with
  a non–weight bearing cast for 6 weeks followed by a weight
  bearing cast for an additional 4 to 6 weeks. Repeat
  radiographs should be obtained to ensure that no
  displacement is occurring in the cast.
 Displaced fractures should be treated operatively .
 Closed reduction, using finger traps and countertraction,
  can be successful if displacement is not severe. Fixation
  should be used to maintain the reduction.
  COMPLICATION
•Compartment syndrome, although
rare and usually seen only with higher
energy fracture-dislocations, can cause
severe, difficult-to-treat clawing of the
toes and chronic pain.
•individual compartments can be
difficult to assess, and clinical
suspicion alone is enough to warrant
decompression.
•long medial incision to decompress
the abductor hallucis and deep
compartments of the foot, including
the calcaneal compartment.
•In addition, two incisions—one
between the second and third and one
between the fourth and fifth
metatarsals—are used for the dorsal
intrinsic compartments.
 incomplete reduction
 loss of reduction
 post-traumatic arthropathy
 missed or delayed diagnosis
      If the injury is recognized within 6 weeks of onset,
 anatomic reduction and stabilization is the treatment
 of choice.
      After 6 weeks, anatomic reduction is difficult and
 the results are poor. These injuries are best treated
 with medial column fusion when the patient is
 symptomatic
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