Anatomy
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
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
C. Fracture above level syndesmosis
- syndesmosis at risk / must assume is torn
- medial structures often torn
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)
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)
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)
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
X-ray assessment
3 standard views
AP, lateral and mortise
Mortise
Technique
- foot internally rotated
- AP projection
- should be symmetrical clear space around talus
1. Lateral talar shift / increased medial clear space
- medial clear space > superior clear space
- should be < 4mm
- indicates injury to medial structures
- instability
2. Tibia / fibular overlap < 1mm / syndesmotic injury
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
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
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
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
- 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
B. Deltoid tear + Lateral Malleolus Fractured
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)
2. Weber B + Deltoid Ligament
A. Manage Fibula as above
- ensure joint fully reduced
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
Fibular plate versus nail
Walsh et al Foot Ankle Surg 2022
- meta-analysis of RCTs of plate versus fibular nail
- no difference in outcome or healing rates
- reduction in complications with nail
3. Tri-Malleolar Fracture
Posterior malleolus
Anatomy
- avulsion of PITFL
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
Indications to ORIF posterior malleolus
- usually get anatomical reduction after plating of LM
- ORIF if > 30% and > 2mm displaced
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
4. Syndesmosis 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
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
D. Isolated Injury
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
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
5. Medial Malleolar Fractures
Management
Displaced
- ORIF
- 20% risk of non union
Undisplaced
- can usually manage in cast
- still small risk of non union
Approaches
AO posteromedial approach ankle
Fixation
A. Large fragment
- 2 x screws
B. Small fragment
- screw + K wire
- TBW
C. Plate
- vertical fractures
6. Open Ankle Fractures
Presentations
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
Complication
Non-union
- uncommon
- Improve for up to 9 yrs
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
Osteoarthritis
Swierstra et al EFORT Open Rev 2022
- systematic review
- overall incidence of post-traumatic OA 25%
Beak et al Foot Ankle Int 2022
- risk factors for OA in 330 patients
- fracture dislocations / posterior malleolar fractures / malreduction
