ANKLE FRACTURES

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ANKLE FRACTURES

• Anatomy, biomechanics, clinical evaluation,
  radiological evaluation, classification,
  treatments and complications of ankle fractures.

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ANATOMY

• The ankle is a complex joint consisting of three
  distinct functional articulations.
• Tibia and fibula
• Tibia and talus
• Fibula and talus
• Each of these articulations are reinforced by a
  group of ligaments

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ANATOMY CONT.

• The tibia and fibula form a mortise which
  provides a constrained articulation for the
  talus.
• The articular surface of the distal tibia
  (plafond) and the mortise is wider superiorly and
  anteriorly to accommodate the wedge shaped talus.
• This provides some intrinsic stability especially
  during weight bearing.

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ANATOMY CONT.

• Ankle stability is provided by a combination of
  three factors.
• Bony architecture
• The joint capsule
• Ligamentous structures (three distinct groups)
• Syndesmotic ligaments
• Medial collateral ligaments
• Lateral collateral ligaments

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Syndesmotic Ligaments

• Comprised of 4 ligaments
• Anterior tibiofibular
• Posterior tibiofibular
• Transverse tibiofibular
• Interosseous

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Medial Collateral

• Superficial and deep Deltoids
• Posterior tibiotalar
• Tibiocalcaneal
• Tibionavicular

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Lateral Collateral

• Anterior Talofibular ligament (weakest)
• Posterior Talofibular ligament
• Calcaneofibular Ligament

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Tendons and Neurovascular Structures

• Thirteen Tendons, two major arteries and veins,
  and five nerves cross the ankle joint
• Four groups of Tendons
• Posterior
• Achilles and Plantaris
• Tibialis Posterior
• Flexor Digitorum Longus
• Flexor Hallucis Longus
• Innervated by Tibial Nerve

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Tendons and Neurovascular Structures

• Anterior
• Tibialis Anterior
• Extensor Digitorum Longus
• Extensor Hallucis Longus
• Peroneus Tertius
• Innervated by Deep Peroneal nerve
• Peroneus Longus and Brevis
• Innervated by Superficial Peroneal nerve

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Neurovascular Bundles

• Anterior N/V bundle
• Anterior Tibial artery and Deep Peroneal nerve
• Lies anterior between the EHL and Tib. Ant..
• Superficial Sensory Nerves
• Saphenous nerve-ant. to med. malleolus
• Superficial Peroneal nerve-ant to midline dorsal
  foot
• Sural nerve-post to the fibula

• Posterior N/V bundle

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Ankle Biomechanics

• A lateral talar shift of 1mm will decrease
  surface contact by 40 and a 3 mm shift results
  in a gt60 decrease.
• The fibula is essential to providing lateral
  stability, an maintaining congruency between the
  talus and the plafond.
• A minimum of 10 degrees of dorsiflexion and 20
  degrees of plantarflexion are required for normal
  gait.

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Clinical Evaluation

• Assess the neurovascular status
• Assess the condition of the soft tissues
• Always palpate proximal and midshaft fibula for
  tenderness
• Reduce a dislocated ankle immediately to prevent
  pressure or impaction injuries to the talar dome

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Radiographic Evaluation

• AP-Look for talar shift (medial joint widening)
  and syndesmotic disruption
• Lateral- The dome of the talus should be centered
  under the tibia and congruous with the tibial
  plafond. Also posterior malleolus fxs can be
  identified.
• Mortise- Taken in 15-20 degrees of int rotation
  to offset the rotation of the malleoli. You
  should see a symmetric joint space on all sides.

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Classifications-Lauge-Hansen

• Four patterns, based on pure injury sequences,
  each subdivided into stages of increasing
  severity
• System takes into account (1) the position of the
  foot at the time of injury (2) the direction of
  the deforming force.
• Based on cadaveric studies
• The patterns may not always reflect clinical
  reality.

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Supination-adduction (SA)

• Accounts for 10-20 of malleolar fxs
• The only type assoc. with medial displacement of
  the talus
• I. Fibula fx transverse
• II. Med. Malleolus vertical fx or disruption

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Supination-external rotation (SER)

• Accounts for 40-75 of malleolar fxs
• I. Disruption of ant talofibular ligament
• II. Spiral oblique fx fibula
• III. Disruption PTF lig or post malleolar fx
• IV. Deltoid disruption or Med malleolar fx

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Pronation-abduction (PA)

• Accounts for 5-20 of malleolar fxs
• I. Transverse fx med malleolus or rupture of
  deltoid
• II. Rupture of sydesmotic lig or avulsion fx
• III. Transverse or short oblique fibular fx at or
  above joint line

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Pronation-external rotation (PER)

• Accounts for 5-20 of malleolus fxs
• I. Transverse fx med malleolus or rupture of
  deltoid
• II. Disruption of ant tibiofibular lig with or
  without avulsion fx
• III. Spiral fx above level of syndesmosis (3-5cm
  proximal)
• IV. Rupture of post tib/fib lig or post malleolus

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Classifications-Weber

• Types A,B, and C
• Based o the level of the fibular fx the more
  proximal, the greater the risk of syndesmotic
  disruption and associated instability
• A. Fx below the level of the syndesmosis,
  avulsion fx resulting from supination of foot.
• B. Oblique or spiral fx caused by ext rotation,
  begins near or at the level of the sydesmosis
• C. Fx of fibula above the syndesmosis with
  almost always assoc med malleolus fx

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Weber Classification
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Fracture Variants

• Maisonneuve fracture- originally described as and
  ankle injury with a fracture of the proximal
  third of the fibula. An external rotation-type
  injury. Resemble PER fxs.
• Curbstone fracture-avulsion fx off the posterior
  tibia produced by a tripping mechanism.
• Leforte-Wagstaffe fracture-anterior fibular
  tubercle avulsion fracture by the anterior
  tibiofibular ligament, usually associated with
  SER fx patterns.
• Tilaux-Chaput fracture-avulsion of anterior
  tibial margin by the ant tibiofibular ligament
  counterpart to the LeForte-Wagstaffe fx.

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Pediatric Classification-Dias and Tachjian

• Lauge-Hansen principles correlated with the
  Salter-Harris classification
• Typology simplified by noting the direction of
  physeal displacement, Salter-Harris type, and
  location of the metaphyseal fragment.
• The four types of classification aids in
  determining the proper maneuver for closed
  reduction.

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Supination-inversion (SI)

• Grade I- adduction forces avulse the distal
  fibular epiphysis (Salter I or II)
• Grade II- tibial fx, usually SH III or IV
• Require ORIF if displaced
• High rate of growth disturbances

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Supination-plantar flexion (SPL)

• The plantarflexion force displaces the epiphysis
  directly posteriorly, resulting in a SH I or II
  fx. Fibular fxs are not described with this
  mechanism.

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Supination-external rotation (SER)

• Grade I- the external rotation force results in a
  SH II fx of the distal tibia. Distal fragment is
  displaced post.
• Grade II- with further external rotation, a
  spiral fx of fibula is produced.

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Pronation-eversion-external rotation (PEER)

• A SH I or II fx of the distal tibia occurs
  simultaneously with a transverse fibular fx. A
  Thurston-Holland fragment, when present is
  lateral or posterolateral.

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Juvenile Tillaux fracture

• A SH type III fx involving the anterolateral
  distal tibia. This takes place in children ages
  10-14 when the physis is not yet completely
  closed.

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Triplane fractures

• A group of fractures that have in common the
  appearance of a SH III fx on the AP x-ray and a
  SH II fx on lateral x-ray.

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Treatment

• Incidence of posttraumatic arthritis in the ankle
  is greater than 90 for displaced fxs and less
  than 10 for those with accurate stable reduction
• The goal of treatment is to restore the ankle
  joint anatomically. Fibular length and rotation
  must be restored to obtain an anatomic reduction.

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Closed Treatment

• Only undisplaced, stable fracture patterns with
  an intact syndesmosis can be treated closed.
• If anatomic reduction is achieved with closed
  manipulation, a short leg cast can be placed for
  4-6 weeks.
• All fxs should be reduced as well as possible in
  the emergency room, regardless of eventual
  treatment.

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Open Treatment

• ORIF is indicated for failure to obtain or
  maintain a closed reduction.
• Widened mortise greater than 1-2 mm should be
  reduced and fixed if it cannot be stabilized with
  closed means.
• ORIF should be carried out immediately, or, if
  the soft tissue is in question,wait 4-7 days
  until swelling subsides.

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Open Treatment of the Fibula

• Restoration of fibular length and rotation is
  essential in obtaining an accurate reduction.
• The fibula is generally held with an
  interfragment screw and a 1/3 tubular plate.
• Fractures up to the midshaft should be fixed.
• Fibula fxs above the syndesmosis generally
  require a syndesmotic screw. Cottons test can be
  performed to test for the integrity of the
  sydesmotic ligament.
• The syndesmotic screw is placed 1.5-2.0cm above
  the joint under max dorsiflexion.

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Treatment of the Medial and Posterior Malleoli

• Medial malleolar fxs can be held with one or two
  cancellous screws perpendicular to the fx line or
  with tension bands
• Indication for fixation of the posterior
  malleolus are involvement of gt25 of the
  articular surface, gt2 mm displacement, or
  persistent posterior subluxation of the talus.

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Treatment of Open Fractures

• These require immediate irrigation and
  debridement in the operating room.
• Stable fixation is important prophylaxis against
  infection and helps soft tissue healing.
• Reports have shown that immediate internal
  fixation can be done with a low incidence of
  infection
• Avoid use of a tourniquet, closed surgical
  incisions, and leave open wounds open.
• Repeat debridement every 2-3 days until the wound
  is clean, then delayed closure can be performed.

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Complications

• Nonunion-rare usually the medial malleolus when
  treated closed.
• Malunion
• Wound problems
• Infection-lt2 of closed fxs leave implants alone
  when stable, even with deep infection.
• Posttraumatic arthritis-seen with 10 of
  anatomically reduced fxs and 90 of malreduced
  fxs usually seen by 18 months
• Reflex sympathetic dystrophy
• Compartment syndrome of foot