Ankle Fracture

AnatomyDislocated Ankle

 

Bony

- 90% load through plafond to talus

- 10% load through lateral talofibular articulation

 

Ligaments

 

A.  Lateral Ligament Complex

 

ATFL (Anterior Talo-Fibular Ligament) 

- tight in plantar flexion

 

CFL (Calcaneo-fibular ligament)

- slopes down & back

- tight in dorsiflexion

 

PTFL (Posterior Talofibular Ligament)

- scissors with Posterior Tibiofibular Ligament

 

B.  Medial Ligaments

 

Superficial Deltoid (SDL)

- origin medial tibia

- broad insertion talus / calcaneum / navicular

- resists hindfoot eversion

 

Deep Deltoid (DDL) 

- tibiotalar

- key to stability / primary stabiliser of ankle

- resists talus ER

- if divided get abnormal ER of talus in plantar flexion

 

C.  Syndesmosis

 

Interosseous Ligament

- between AITFL and PITFL (anterior inferior and posterior inferior tibio-fibular ligament)

 

Biomechanics

  

ROM

- DF = 30°

- PF = 45°

- Rolls & slides to produce DF/PF

 

Plantarflexion

- deltoid ligament acts as a checkrein

- prevents ER of talus

- causes 5° IR talus

 

Dorsiflexion

- talus wider anteriorly 2.5 mm

- fibula moves laterally & ER to accommodate

 

Ramsey 1976

- 1mm talus shift = Contact area decreased by 40%

- non-physiological study

- jammed wedges in intact ankle

 

Ankle Fracture Classification 

 

No system prognostic

 

1.  Weber ABC

 

A.  Fracture distal to syndesmosis

- stable / avulsion type fracture

- FWB

 

Weber A

 

B.  Fracture at level of syndesmosis

- syndesmosis intact

- ORIF if medial structures not intact

- xray below demonstrates Weber B with rupture deltoid ligament

- ankle unstable

 

Ankle Weber B Fracture

 

C.  Fracture above level syndesmosis

- syndesmosis at risk / must assume is torn

- medial structures often torn

 

Ankle Weber C Fracture

 

2.  Lauge-Hansen 1950

 

Two part 

 

1.  Position of talus

- supination tenses lateral structures

- pronation tenses medial structures

 

2.  Direction of force

- rotation or translational injury

 

A. Supination-Adduction

Stage 1: Transverse fracture of lateral malleolus at or below the level of anterior talo-fibular ligament (Weber B) 

Stage 2: Vertical fracture of medial malleolus (often a marginal impaction at medial edge of plafond)

 

Ankle Fracture Supination Adduction

 

B.  Supination-External Rotation (Most common - up to 85% all injuries)

Stage 1: Rupture of AITFL

Stage 2: Short oblique fracture of the lateral malleolus (Weber B) (stable)

Stage 3: Rupture of PITFL / fracture of posterior malleolus of tibia

Stage 4: Transverse fracture of medial malleolus (unstable) 

 

Ankle Fracture Supination ER

 

C. Pronation-Abduction (Less than 5% of ankle fractures)

Stage 1: Rupture of the deltoid ligament or transverse fracture of the medial malleolus

Stage 2: Rupture of the anterior and posterior inferior tibiotalofibular ligaments or bony avulsion

Stage 3: Proximal fibula fracture (often butterfly)

 

Ankle Pronation Abduction

 

D. Pronation-External Rotation

Stage 1: Rupture of the deltoid ligament or transverse fracture of the medial malleolus

Stage 2: Rupture of the anterior inferior tibiotalofibular ligaments or bony avulsion

Stage 3: Spiral/Oblique fracture of the fibula above the level of the syndesmosis        

Stage 4: Rupture of the posterior inferior tibiofibular ligament or fracture of the posterior malleolus

 

Ankle Fracture Pronation External Rotation

 

X-ray assessment

 

3 standard views

 

AP, lateral and mortise

 

Ankle AP XrayAnkle Mortise View

 

Mortise

 

Technique

- foot internally rotated

- AP projection

- should be symmetrical clear space around talus

 

Ankle Mortise View

 

1.  Lateral talar shift / increased medial clear space

- medial clear space > superior clear space

- should be < 4mm

- indicates injury to medial structures

- instability

 

Ankle Fracture Increased Medial Clear SpaceAnkle Fracture Increased Medial Clear Space 2

 

2.  Tibia / fibular overlap < 1mm / syndesmotic injury

 

Ankle Fracture Syndesmosis WidenedAnkle Diastasis

 

Incidence

 

Unimalleolar 70%

Bimalleolar 25%

Trimalleolar 7%

Open 2%

 

Management

 

Principles

 

Reduction

- protects skin medially

- conscious sedation in emergency department

- well moulded POP

- unstable ankles need monitoring for loss of reduction

- can need external fixation to maintain position

 

Ankle Fracture Severely Dislocated Dislocated Ankle Lateral

 

Timing

- operate when swelling reduced

- usually < 6 hours or 6 days

- higher risk with bimalleolar / 2 incision operations

- risk not being able to close wounds / infection

 

Long term results rely on

- reduction of talus under tibia

- mechanical stability

- degree of chondral damage

 

Medial ligament injury is the key to management

 

1.  Isolated Lateral Malleolar / Weber B Fracture

 

Ankle Fracture Isolated Weber BIsolated Fibula Fracture 3 mm displaced

 

Definition

- no medial fracture / no complete deep deltoid injury

- no increased medial clear space

- no instability on stress ER views

- no syndesmotic injury

 

Pathology

 

85% have no medial injury

- by definition have no talar shift 

 

LM displacement not important if medial side not injured

- Biomechanical studies show Talus doesn't follow LM when axially loaded if medial ligament  intact 

- Doesn't lead to altered biomechanics

 

There is no external rotation of the distal fragment 

- its relationship to the talus is fixed

- the proximal fragment is internally rotated

- again, this does not alter the biomechanics

 

Diagnostic Dilemma / Is the deltoid ligament intact?

 

Examination

 

A.  Non tender / no bruising

- is intact

- non operative management

 

B.  Tender / bruising

- may be partially injury sprained / or completely ruptured and unstable

- inconclusive

 

Lateral BruisingMedial bruising

 

Xray

 

1.  Mortise view

- any increased clear space

- ORIF

 

2.  Stress views

 

Option A:  Gravity Stress View

- Patient lies injured side down, cross table xray

- see if medial clear space opens

 

Option B:  Valgus view

- lead gloves

- can be painful as patient has acute injury

 

Option C:  EUA

 

Results of Isolated Weber B Fibular Fracture

 

Results of surgical and non surgical management equally good

- Talus is stable if medial ligament is intact

- If  < 3mm fibula displacement, nil poor outcome

 

Non operative

- Kristensen and Hansen etal

- 95% good outcome non operatively

- no salvage operations required for post-traumatic arthritis

 

Operative

- 1-3% chance of serious infection

- more long term swelling

 

Management

 

Cast in Internal Rotation to reduce the deformity

 

2.  Bi Malleolar Injury

 

Types

 

A.  Medial Malleolus and Lateral Malleolus Fractured

 

Ankle Fracture Bimalleolar

 

B.  Deltoid tear + Lateral Malleolus Fractured

 

Ankle Fracture Weber B + Deltoid Ligament

 

If have talar shift, then by definition bi-malleolar injury

- must be an interruption to medial structures

 

Results

 

Superior results with operative management

- able to obtain and maintain anatomical reduction

- 90% good results

 

Closed treatment

- for elderly or medically unfit

- acceptable reduction / ankle internally rotated

- 60% good results

 

Surgery

 

1.  Weber B + Medial Malleolus fracture

 

Fibula

- interfragmentary lag screw

- derotation 1/3 tubular plate

 

Medial malleolus (dependant on fragment size)

- 2 partially threaded lag screws

- 1 screw and one k wire

- TBW

 

Screen syndesmosis

- should be stable with Weber B

- stress view (ER and dorsiflexion)

- cotton test (clamp on fibula and attempt to open syndesmosis under II)

 

Ankle Fracture Bimalleolar ORIFAnkle Fracture Bimalleolar ORIF

 

2.  Weber B + Deltoid Ligament

 

Ankle Weber B Deltoid Ligament InjuryAnkle Weber B Deltoid Ligament ORIF

 

A.  Manage Fibula as above

- ensure joint fully reduced

 

Ankle Fracture Fibula ORIF Increased Medial Clear Space

 

B.  Medial clear space remains open

- ensure fibular out to length and anatomical

- assess syndesmosis intact / reduce and fix

- if remains open, must be suspicious of OCD fragment or deltoid ligament blocking medial reduction

- may need to open medially

 

No evidence that repair of medial ligament improves results

 

3.  Tri-Malleolar Fracture

 

Posterior malleolus

 

Anatomy

- avulsion of PITFL

 

Ankle Fracture Small Posterior Malleolus Xray

 

Ankle instability results if

- > 1/3 articular surface (>30%)

- displacement of > 2mm 

- risk posterior subluxation of the tibio-talar joint

 

Issue

- these can be highly unstable and require external fixation

 

Trimalleolar UnstableTrimalleolar Unstable

 

Ankle External Fixator APAnkle External Fixator Lateral

 

Indications to ORIF posterior malleolus

- usually get anatomical reduction after plating of LM

- ORIF if > 30% and > 2mm displaced

 

 Ankle Fracture Large Posterior Malleolus XrayAnkle Fracture Large Posterior Malleolus CT

 

Surgical Options

 

1.  Posterolateral approach to fibula

- enable AP clamp to reduce and hold fracture

- anterolateral approach

- front to back screws

 

2.  Formal posterolateral approach

- patient lateral or prone

- PA screws or buttress plate

 

Posterior Malleolus LargePosterior tibial buttress plate

 

Ankle Fracture Trimalleolar ORIFAnkle Fracture Trimalleolar ORIF Lateral

 

4.  Syndesmosis Injury

 

Ankle Fracture Clear Syndesmotic Injury

 

Definition

 

Disruption of syndesmosis between level of fracture and plafond

- distal tibia and fibular not connected and stable

 

Situations

 

A.  Weber C fracture

- extremely high risk

- almost always safer to ORIF

 

Ankle Weber C Syndesmotic InjuryAnkle Weber C Syndesmotic Screw

 

B.  Weber B fracture + medial column injury

- occasionally syndesmotic injury

- check intraoperatively

 

C.  Maisonnerve injury

- high fibula fracture

- medial clear space opening / deltoid injury

- need diastasis screw

 

Ankle Fracture Maisonnerve InjuryAnkle Fracture Maisonnerve Proximal Fibula

 

D.  Isolated Injury

 

Ankle DiastasisORIF Diastasis

 

Intraoperative tests

 

Cotton test

Stress test

 

Management

 

Reduction technique

- foot in neutral, clamp across medial and lateral malleolus

- don't reduce in plantarflexion as posterior talus is more narrow

- don't over reduce the joint

- check symmetrical joint space on mortise view

 

Diastasis Screw Fixation technique

 

1.  With other LM / MM fracture

- 1 or 2 screws

- 3 or 4 cortices

- 3.5 or 4.5 mm

- at level of epiphyseal scar

 

Ankle Fracture Diastasis Screw

 

2.  High Weber C fibula / Maisonnerve

- don't have to plate fibula

- ensure fibula out to length

- usually 2 screws
 

Post op

 

Need screw in for 8 - 10 weeks

- need to await ligament healing

- NWB

- usually remove screw as will break

 

Ankle Broken Diastasis Screws

 

5.  Medial Malleolar Fractures

 

Medial Malleolus Fracture

 

Management

 

Displaced

- ORIF

- 20% risk of non union

 

Undisplaced

- can usually manage in cast

- still small risk of non union

 

Fixation

 

A.  Large fragment

- 2 x screws

 

Ankle Fracture Medial Malleolus 2 Screws

 

B.  Small fragment

- screw + K wire

- TBW

 

Ankle Fracture Medial Malleolus TBW

 

C.  Plate

- vertical fractures

 

Medial Malleolus Plate

 

6.  Open Ankle Fractures

 

Presentations

 

Compound Ankle Fracture

 

Clean & Closeable wound

- wound usually medial

- washout / ORIF / close

 

Dirty wound / wounds need skin cover

- external fixation

- wound management

- ORIF later

 

7.  DM

 

Risks

- amputation (6% open, 40% closed)

- infection

- malunion / non union / delayed union

 

Increased in patient with neuropathy and PVD

 

Management

- increase fixation

- double NWB times

- leave sutures in for twice as long

 

8.  Elderly / Osteoporotic

 

Issue

- bone very poor

- good fixation difficult

 

Ankle Fracture OsteoporoticAnkle Osteoporotic Fixation

 

Complication

 

Non-union 

- uncommon

- Improve for up to 9 yrs

 

Medial Malleolus Non union

 

Swelling 

- worse after ORIF 

- continues > 3/12

 

Fibula malunion 

- decreases tibiotalar contact by 30%

- correction <4 years = Good results

 

Infection 1-4%

 

Missed fractures

- plafond fractures

- chondral lesions (50%)

- anterior process calcaneum

 

RSD

 

Stiffness

 

OA

 

Ankle OA Post ORIF