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Not medical advice. Verify clinically important information against current local guidance.

Open Reduction and Internal Fixation of Ankle Fracture

Operative SurgeryFoot & Ankle
Foot & AnkleIntermediateCore Procedure

Open Reduction and Internal Fixation of Ankle Fracture

Operative technique for ORIF of ankle fractures — the fibula-first fixation sequence, lateral and medial exposures with their danger structures, syndesmotic assessment under fluoroscopy, and posterior malleolar fixation. advanced orthopaedic operative-surgery guide.

Procedure console
55 min
Read
0
Sections
intermediate
Level
Peer-reviewed · 2026-06-20
High-yield overview

Restore the mortise · Fix the fibula first · Assess the syndesmosis last

foot-ankleSubspecialty
60–90 minTypical duration
FMSPFixation sequence
42%Tibiotalar contact lost per 1mm of talar shift
Critical Must-Knows
  • Indications for ORIF: a Weber B with talar shift greater than 1mm or a positive stress test, ALL Weber C (the syndesmosis is always injured), bimalleolar, and trimalleolar fractures with a posterior fragment greater than 25-33% or any posterior talar subluxation.
  • Restore fibular length first. As little as 1mm of lateral talar shift cuts tibiotalar contact area by 42% (Ramsey and Hamilton, 1976); shortening, lateral shift and external rotation all raise peak contact pressures (Thordarson, 1997).
  • Assess the syndesmosis ONLY after all bony fixation is complete, with the ankle dorsiflexed and in neutral rotation under fluoroscopy — syndesmotic malreduction is the number-one cause of poor outcomes and is found in up to half of cases on CT (Gardner, 2006; Sagi, 2012).
  • Fix the posterior malleolus for a fragment greater than 25-33% OR any posterior talar subluxation — subluxation matters more than size, and CT is essential because plain films underestimate the fragment by about 30%.
  • Respect the soft-tissue envelope: operate only once the wrinkle sign is positive (delay 5-14 days if swollen). Operating through swollen tissue carries a 20-30% wound-complication rate versus 2-5% with recovered soft tissues.

When & Why


Indication. Operative fixation is reserved for the unstable ankle fracture — one in which the talus has shifted or is likely to shift out of the mortise. The decision rests on the Weber level, the Lauge-Hansen mechanism, and the radiographic markers of instability, not on the patient's pain alone. Absolute indications

  • Weber B with instability — talar shift greater than 1mm, a medial clear space greater than 4mm, or a positive external-rotation stress test.
  • All Weber C fractures — the syndesmosis is injured by definition, so ORIF plus syndesmotic fixation is required.
  • Bimalleolar fractures — unstable by definition; both malleoli are fixed.
  • Trimalleolar fractures — fix the lateral and medial malleoli, and the posterior malleolus if it is greater than 25-33% of the articular surface or there is any posterior talar subluxation.
  • Open fractures — urgent irrigation, debridement and fixation.
  • Irreducible dislocations (interposed periosteum or tendon) and neurovascular compromise — urgent reduction. Relative indications include a Weber A with significant displacement or rotation, an isolated medial malleolus displaced greater than 2mm, the young active patient (lower threshold to operate), and failure of non-operative care (displacement or loss of reduction in a cast). Contraindications. Absolute: active infection, or severe peripheral vascular disease with no healing potential. Relative: major medical comorbidity, the non-ambulatory patient, severe neuropathy with Charcot risk, and — critically — a poor soft-tissue envelope, for which surgery is delayed, not abandoned.
Weber B is the grey zone

About half of Weber B fractures have a syndesmotic injury. A Weber B with medial tenderness, a medial clear space greater than 4mm, or a positive stress test is unstable and needs surgery — so stress-test every Weber B you are tempted to treat conservatively.

Soft-tissue timing — the wrinkle sign

If the skin wrinkles over the ankle with passive dorsiflexion, the soft tissues have recovered and it is safe to proceed. If the skin is tense and will not wrinkle, delay surgery 5-14 days with elevation and ice. Operating through swollen tissue drives a 20-30% wound-complication rate, against 2-5% once the wrinkle sign is positive.

Consent. Counsel the patient that union is greater than 95% with adequate fixation, return to most activities takes 3-6 months, and 80-90% achieve good-to-excellent function after anatomic reduction — but post-traumatic arthritis develops in 15-40% by 10 years (higher with any residual incongruity). Common risks are symptomatic hardware (10-30%), stiffness (10-20%) and permanent swelling (20-30%); less common are infection (2-5% in closed fractures), nerve injury (usually temporary), DVT/PE (1-2% with prophylaxis) and syndesmotic malreduction (up to 50% in some series). Alternatives are non-operative care (Weber A, a truly stable Weber B, the elderly non-ambulatory patient) or bridging external fixation for severe soft-tissue injury.

Global practice and the elderly pathway

Operative indications are consistent across AAOS and UK BOAST/BOFAS guidance — unstable Weber B/C, bimalleolar and displaced trimalleolar fractures, with stress-confirmed instability and timing built around the soft-tissue envelope. For adults over 60 with unstable fractures, the UK Willett AIM trial (2016) showed close-contact casting gives 6-month function equivalent to ORIF with far fewer wound complications — increasingly reflected in elderly-fracture pathways worldwide.

Setup. Supine on a radiolucent table with a bump under the ipsilateral hip to internally rotate the leg 15-30 degrees and bring the lateral malleolus up. Thigh tourniquet. Position the contralateral leg so the C-arm can reach a true mortise view. Plan the fixation sequence: Fibula, Medial malleolus, Syndesmosis, Posterior malleolus (FMSP).

The Operation


The goal is to restore the ankle mortise anatomically: fix the fibula first to restore length and rotation, then the medial malleolus, then assess and fix the syndesmosis, and finally the posterior malleolus if indicated. The exposures are laid out step by step below (and in depth on the approach to the fibula and medial approach to the ankle pages).

Trimalleolar ankle fracture before and after ORIF
Trimalleolar ankle fracture (left) treated by open reduction and internal fixation (right): a lateral fibular plate and a medial malleolar screw restoring the ankle mortise.Credit: Chaim Mintz via Wikimedia Commons (CC BY-SA 4.0)

Operative sequence

Step 1Position, setup & fluoroscopy
  • Supine, radiolucent table, bump under the ipsilateral hip for 15-30 degrees of internal rotation (brings the lateral malleolus up).
  • Thigh tourniquet at 250-300mmHg — never a calf tourniquet (peroneal nerve risk); pad all pressure points (fibular head, malleoli, heel).
  • Test EVERY fluoroscopic view before prepping — AP, mortise (15-20 degrees internal rotation) and lateral. The C-arm comes from the contralateral side; repositioning a prepped patient is difficult.
Step 2Lateral approach — expose the fibula
  • Mark the incision POSTERIOR to the fibular shaft. Staying posterior protects the superficial peroneal nerve, which emerges from the anterior compartment 10-12cm proximal to the lateral malleolus tip and runs anterolaterally.
  • An 8-10cm incision centered on the fracture, from about 8-10cm proximal to the tip distally to the joint line.
  • Careful subcutaneous dissection; if a superficial peroneal nerve branch is seen, protect it with a vessel loop — never divide it.
  • The sural nerve lies 1.5-2cm posterior to the fibula at the joint level with the lesser saphenous vein — avoid excessive posterior dissection.
  • Incise the periosteum longitudinally and elevate subperiosteally to protect the peroneal tendons in the retromalleolar groove.
Step 3Reduce and fix the fibula
  • Clear the fracture of interposed tissue; assess the pattern (spiral, oblique, comminuted).
  • Reduction goals: restore length (compare to the contralateral side — 2mm shortening is unacceptable), correct rotation (use the posterior malleolar fragment as a guide), and achieve an anatomic reduction.
  • Spiral or long oblique: a lag screw perpendicular to the fracture line plus a lateral neutralization plate (lag screw outside the plate if the spiral is greater than twice the fibular diameter, through the plate if shorter).
  • Short oblique: a posterolateral antiglide (buttress) plate — biomechanically superior to a lateral plate.
  • Comminuted: bridge plating; do NOT strip periosteum and devascularise fragments.
Step 4Confirm fibular reduction on fluoroscopy
  • Mortise and lateral views: tibiofibular clear space less than 6mm; tibiofibular overlap greater than 6mm on AP and greater than 1mm on mortise; confirm length and rotation against the contralateral side.
  • If the medial clear space stays greater than 4mm after anatomic fibular fixation, the deltoid is torn or the syndesmosis is injured.
Step 5Medial approach — expose the medial malleolus
  • Incision 5-7cm just POSTERIOR to the subcutaneous tibial border — staying posterior protects the saphenous vein and nerve anteriorly.
  • Identify and protect the saphenous structures; incise the periosteum.
  • Clear any interposed deltoid ligament from the fracture site — the commonest cause of a medial malleolus that will not reduce.
  • Stay anterior to avoid the posterior tibial neurovascular bundle in the tarsal tunnel (Tom, Dick, And Nervous Harry).
Step 6Fix the medial malleolus
  • Reduce with a pointed reduction clamp; verify articular reduction (a step greater than 1mm is unacceptable).
  • Standard fixation: two PARALLEL 4.0mm partially-threaded cancellous screws — partially threaded so the threads engage only the far fragment and compress. Entry at the malleolar tip, directed posterolaterally into the best metaphyseal bone.
  • Keep the screws parallel — convergent screws spread the fracture, divergent screws lose purchase.
  • A vertical (supination-adduction) fracture may need a buttress or antiglide plate; comminuted or osteoporotic bone needs buttress plating. A tension-band wire is an alternative for a transverse fragment.
Step 7Assess the syndesmosis (after ALL bony fixation)
  • Perform the external rotation stress test ONLY once the fibula and medial side are fixed — you cannot assess the syndesmosis with unstable malleoli.
  • Ankle dorsiflexed (the talus is widest anteriorly), neutral rotation; apply an external rotation force and watch under fluoroscopy.
  • Abnormal: tibiofibular clear space greater than 6mm, loss of overlap, or medial clear space greater than 4mm. Cotton (hook) test: lateral traction on the talus should not displace it more than 2mm.
  • Weber C: always assess (the syndesmosis is injured by definition). Weber B: assess if there is any doubt (50% have syndesmotic injury).
Step 8Syndesmotic fixation (if unstable)
  • Apply a large pointed reduction clamp from fibula to tibia, 2-3cm proximal to the joint, in the AP direction.
  • CRITICAL: ankle in full dorsiflexion and neutral rotation. The talus is 2-4mm wider anteriorly, so dorsiflexion seats the fibula anatomically in the incisura; plantarflexion overtightens it, and internal rotation malreduces the fibula posteriorly.
  • Two 3.5mm cortical screws engaging 3-4 cortices, or a suture-button device. Confirm reduction on fluoroscopy BEFORE definitively fixing.
Step 9Posterior malleolus (if indicated)
  • Indication: a fragment greater than 25-33% of the articular surface OR any posterior talar subluxation. Subluxation is the more important trigger — a 20% fragment with posterior shift still needs fixation.
  • Indirect technique: A-P lag screws (3.5mm or 4.0mm) through the lateral approach — faster and less dissection, but no direct visualisation; confirm no joint penetration on lateral fluoroscopy.
  • Direct technique: a posterolateral approach with a buttress plate — better reduction but more dissection, prone positioning, and sural-nerve risk.
Step 10Final fluoroscopic assessment
  • Run the MORTISE checklist (below): medial clear space less than 4mm and symmetric; tibiofibular clear space less than 6mm; overlap greater than 6mm AP and greater than 1mm mortise; no talar subluxation; articular congruence; all screws out of the joint; posterior malleolus reduced.
  • Compare to the contralateral side and document every image.
  • DO NOT accept a malreduction — revise immediately. Delayed revision has worse outcomes.
Step 11Closure and immediate aftercare
  • Copious irrigation (at least 3L), meticulous hemostasis, close the periosteum if possible, then a layered tension-free skin closure.
  • A well-padded posterior slab or bulky Jones dressing; elevate the leg above heart level; DVT prophylaxis per risk.
Medial clear space
Normal
Less than 4mm (equal to the superior joint space)
Abnormal
Greater than 4mm
Tibiofibular clear space
Normal
Less than 6mm on every view
Abnormal
Greater than 6mm
Tibiofibular overlap (AP)
Normal
Greater than 6mm
Abnormal
Less than 6mm
Tibiofibular overlap (mortise)
Normal
Greater than 1mm
Abnormal
Less than 1mm
Intra-operative fluoroscopic parameters (MORTISE)
MeasurementNormalAbnormal
Medial clear spaceLess than 4mm (equal to the superior joint space)Greater than 4mm
Tibiofibular clear spaceLess than 6mm on every viewGreater than 6mm
Tibiofibular overlap (AP)Greater than 6mmLess than 6mm
Tibiofibular overlap (mortise)Greater than 1mmLess than 1mm
Superficial peroneal nerve

Emerges from the anterior compartment 10-12cm proximal to the lateral malleolus tip and runs anterolaterally. Place the fibula incision POSTERIOR to the shaft; protect any branch with a vessel loop.

Sural nerve

Lies 1.5-2cm posterior to the fibula at the joint level with the lesser saphenous vein. At risk in the posterolateral approach — avoid excessive posterior dissection.

Saphenous vein and nerve

Anterior to the medial malleolus with the great saphenous vein. Place the medial incision POSTERIOR to the subcutaneous tibial border and protect them anteriorly.

Posterior tibial neurovascular bundle

Posterior to the medial malleolus in the tarsal tunnel (Tom, Dick, And Nervous Harry). Stay anterior with the medial approach and avoid posterior dissection.

Peroneal tendons

Lie directly posterior to the fibula in the retromalleolar groove. Subperiosteal dissection and posterior retractors protect them during plating.

Lag screw technique for the spiral fibula

Drill a 3.5mm glide hole in the near cortex and a 2.5mm thread hole in the far cortex. The screw must be perpendicular to the FRACTURE LINE, not the bone axis — that is what gives compression across the fracture. Add a neutralization plate to protect the lag screw from rotational and bending forces.

Why dorsiflexion matters for the syndesmosis

The talus is 2-4mm wider anteriorly than posteriorly. Dorsiflexing the ankle brings the wider anterior talus into the mortise and forces the fibula into its anatomic position in the incisura. Reduce the syndesmosis in plantarflexion and you overtighten it — the patient loses dorsiflexion post-operatively.

The interposed deltoid

The commonest reason a medial malleolus fracture will not reduce is interposed deltoid ligament pulled into the fracture gap. Always inspect the fracture site and clear any interposed soft tissue before you reduce — direct visualisation is essential.

Never accept a malreduction

If any fluoroscopic parameter is outside range, revise immediately — do not leave the operating theatre hoping it will settle. A non-true mortise view can give falsely abnormal readings, so first confirm 15-20 degrees of internal rotation and compare with the contralateral side; if it is genuinely malreduced, take the fixation down and redo it. Delayed revision has worse outcomes.

Syndesmotic malreduction — the number-one cause of poor outcomes

Up to half of syndesmotic fixations are malreduced on CT and plain films miss most of them. Reduce under direct vision where possible, scrutinise the intra-operative imaging, and have a low threshold for a post-operative CT with contralateral comparison in higher-risk injuries.

Aftercare & Complications


Rehabilitation | Phase | Timing | Immobilisation / weight-bearing | Therapy | |-------|--------|----------------------------------|---------| | Protection | 0–2 weeks | Splint or Jones dressing, non-weight-bearing, elevation | None — rest | | Early ROM | 2–6 weeks | Removable boot, non-weight-bearing | Wound check at 2 weeks; gentle active ROM out of the boot | | Progressive WB | 6–12 weeks | Progress to full weight-bearing as tolerated | ROM, light strengthening | | Strengthening | 12+ weeks | Return to activities | Physiotherapy, proprioception, sport-specific work | Most patients return to desk work by about 6 weeks and heavier activity by 3-6 months. Syndesmotic screws are removed by some surgeons at around 12 weeks (controversial — outcomes are similar with or without removal); suture-buttons do not require removal. Complications

Wound dehiscence or infection (2-5%)
Recognition
Erythema, drainage, wound breakdown within 2-4 weeks
Prevention
Wait for the wrinkle sign, minimise soft-tissue trauma, peri-operative antibiotics
Management
Superficial: oral antibiotics and wound care. Deep: debridement, IV antibiotics, hardware removal if loose
Syndesmotic malreduction (up to 50%)
Recognition
Persistent lateral pain, instability, widened mortise on follow-up, clear space greater than 6mm
Prevention
Stress test AFTER bony fixation, anatomic fibular reduction first, dorsiflexed neutral-rotation clamp
Management
Revision ORIF with syndesmotic correction — outcomes worse with delayed revision
Symptomatic hardware (10-30%)
Recognition
Lateral pain over the plate, footwear difficulty, palpable hardware
Prevention
Low-profile plates, countersink screw heads, counsel the patient pre-operatively
Management
Removal after union confirmed (minimum 12 months). Suture-button needs no removal
Post-traumatic arthritis (15-40% at 10 years)
Recognition
Progressive pain and stiffness, joint-space narrowing, osteophytes
Prevention
Anatomic reduction (step less than 1mm), restore fibular length within 2mm
Management
Conservative first; debridement, osteophyte excision, fusion or arthroplasty for severe disease
Malunion (fibular shortening or rotation)
Recognition
Talar shift on weight-bearing films, valgus tilt, medial clear space greater than 4mm
Prevention
Restore length within 2mm, correct rotation using the posterior malleolar fragment
Management
Corrective fibular osteotomy — can improve outcomes even years later
Non-union (less than 5%)
Recognition
Pain and motion at the fracture site beyond 6 months, lucency around hardware
Prevention
Stable fixation, address smoking, diabetes and nutrition
Management
Revision ORIF with bone grafting
Ankle fracture ORIF complications — recognition, prevention, management
ComplicationRecognitionPreventionManagement
Wound dehiscence or infection (2-5%)Erythema, drainage, wound breakdown within 2-4 weeksWait for the wrinkle sign, minimise soft-tissue trauma, peri-operative antibioticsSuperficial: oral antibiotics and wound care. Deep: debridement, IV antibiotics, hardware removal if loose
Syndesmotic malreduction (up to 50%)Persistent lateral pain, instability, widened mortise on follow-up, clear space greater than 6mmStress test AFTER bony fixation, anatomic fibular reduction first, dorsiflexed neutral-rotation clampRevision ORIF with syndesmotic correction — outcomes worse with delayed revision
Symptomatic hardware (10-30%)Lateral pain over the plate, footwear difficulty, palpable hardwareLow-profile plates, countersink screw heads, counsel the patient pre-operativelyRemoval after union confirmed (minimum 12 months). Suture-button needs no removal
Post-traumatic arthritis (15-40% at 10 years)Progressive pain and stiffness, joint-space narrowing, osteophytesAnatomic reduction (step less than 1mm), restore fibular length within 2mmConservative first; debridement, osteophyte excision, fusion or arthroplasty for severe disease
Malunion (fibular shortening or rotation)Talar shift on weight-bearing films, valgus tilt, medial clear space greater than 4mmRestore length within 2mm, correct rotation using the posterior malleolar fragmentCorrective fibular osteotomy — can improve outcomes even years later
Non-union (less than 5%)Pain and motion at the fracture site beyond 6 months, lucency around hardwareStable fixation, address smoking, diabetes and nutritionRevision ORIF with bone grafting

Viva & Exam Focus


Mnemonic

MORTISEMORTISE — fluoroscopic parameters to confirm reduction

M
Medial clear space
Less than 4mm, equal to the superior joint space
O
Overlap of tibiofibula
Greater than 6mm on AP, greater than 1mm on mortise
R
Rotation of the fibula
Assess on the lateral view
T
Tibiofibular clear space
Less than 6mm on every view
I
Integrity of the posterior malleolus
Reduced, no step
S
Subluxation
No anterior or posterior talar shift
E
Equal joint space
Symmetric throughout the mortise
Mnemonic

FMSPFMSP — the fixation sequence

F
Fibula first
Restore length and rotation
M
Medial malleolus next
Restore the articular surface
S
Syndesmosis assessment
Stress test after bony fixation only
P
Posterior malleolus
If greater than 25-33% or any posterior subluxation

Clinical Decision Scenarios

Practise clinical reasoning and management decisions out loud

Viva scenarioStandard
Clinical prompt

“A 45-year-old woman presents after a twisting injury to her ankle. X-rays show a Weber B fracture with 2mm medial clear space widening. The soft tissues are significantly swollen. How would you manage this patient?”

Viva scenarioStandard
Clinical prompt

“You are fixing a Weber C fracture. After reducing and plating the fibula, you apply a syndesmotic reduction clamp. The registrar questions why you are dorsiflexing the ankle. Explain your rationale and describe your syndesmotic fixation technique.”

Viva scenarioStandard
Clinical prompt

“On your post-operative mortise view, you notice the tibiofibular clear space measures 7mm despite what appeared to be good intraoperative reduction. The fibular plate position looks good. What are your thoughts and what would you do?”

Exam day cheat sheet
Ankle fracture ORIF — exam-day essentials

Classification

  • Weber A/B/C by fibula level versus the syndesmosis: A = below (stable), B = at level (variable), C = above (unstable, always fix the syndesmosis)
  • Lauge-Hansen by mechanism: SER ~60% (commonest), SA ~20%, PER ~10%, PA ~5%
  • Examiners expect you to correlate both: 'This is a Weber B, or SER Stage II, injury'
  • Weber B is the grey zone — 50% have syndesmotic injury, so stress test every one

Critical measurements (MORTISE)

  • Medial clear space less than 4mm (equal to the superior joint space)
  • Tibiofibular clear space less than 6mm
  • Tibiofibular overlap greater than 6mm on AP, greater than 1mm on mortise
  • 1mm of lateral talar shift cuts tibiotalar contact area by 42% (Ramsey and Hamilton) — restore fibular length and prevent any talar shift
  • Always obtain a TRUE mortise view (15-20 degrees internal rotation) for accurate measurements

Fixation sequence (FMSP)

  • Fibula first — restore length and rotation using the posterior malleolar fragment as a guide
  • Medial malleolus next — remove interposed deltoid, articular reduction with step less than 1mm
  • Syndesmosis assessment — stress test AFTER bony fixation (cannot assess with unstable malleoli)
  • Posterior malleolus if greater than 25-33% OR posterior subluxation (subluxation matters more than size)

Syndesmotic fixation keys

  • Ankle DORSIFLEXED (talus 2-4mm wider anteriorly — forces anatomic reduction)
  • NEUTRAL rotation (internal rotation malreduces the fibula posteriorly)
  • Clamp 2-3cm proximal to the joint in the AP direction (not medial-lateral)
  • Confirm reduction on fluoroscopy BEFORE definitive fixation
  • Screws versus suture-button both effective — suture-button needs no removal

Danger structures

  • Superficial peroneal nerve: 10-12cm proximal to the tip, runs anteriorly (incise POSTERIOR to the fibula)
  • Saphenous vein/nerve: anterior to the medial malleolus (incise POSTERIOR to the tibial border)
  • Sural nerve: 1.5-2cm posterior to the fibula at the joint level (posterolateral approach risk)
  • Posterior tibial NV bundle: posterior to the medial malleolus in the tarsal tunnel
  • Peroneal tendons: directly posterior to the fibula — subperiosteal dissection protects them

Soft-tissue timing

  • Wrinkle sign must be positive before surgery — skin wrinkles with ankle dorsiflexion
  • If swollen, delay surgery 5-14 days with elevation and ice
  • Operating through swollen tissue: 20-30% wound complication rate
  • Operating after soft-tissue recovery: 2-5% wound complication rate
  • Ankle soft tissues are unforgiving — be patient with timing

Complications

  • Syndesmotic malreduction: number-one cause of poor outcomes, up to 50% in some series
  • Wound dehiscence: 2-5% with proper timing, never close under tension
  • Hardware symptoms: 10-30%, counsel pre-operatively, removal after union confirmed
  • Post-traumatic arthritis: 15-40% at 10 years, correlates with reduction quality
  • Non-union: less than 5%, address smoking, diabetes and nutrition

Exam pearls

  • Always give BOTH Weber and Lauge-Hansen — examiners expect correlation
  • Syndesmotic malreduction is the top exam talking point — know how to prevent and recognise it
  • Posterior malleolus: know the 25% versus 33% debate but stress that subluxation matters more than size
  • Describe stress testing precisely: external rotation force with the ankle dorsiflexed, looking for tibiofibular widening greater than 6mm
  • Lag screw: glide hole in the near cortex, thread hole in the far cortex, perpendicular to the fracture line
  • Elderly unstable fractures: close-contact casting is an evidence-based alternative to ORIF (Willett AIM trial)

Background & Evidence


Epidemiology. Ankle fractures are an increasing problem in adults (Court-Brown, 1998), driven by an ageing, osteoporotic population — bimodal distribution, with young high-energy men and older low-energy women. The Lauge-Hansen mechanism predicts the associated injuries: supination-external-rotation (SER) is by far the commonest (~60%), then supination-adduction (SA ~20%), pronation-external-rotation (PER ~10%) and pronation-abduction (PA ~5%). Pathoanatomy. The ankle is a mortise — the tibial plafond, medial and lateral malleoli form a box around the talus, which is 2-4mm wider anteriorly than posteriorly (the basis for dorsiflexed syndesmotic reduction). Stability depends on the ring of bones and ligaments: a single break in the ring may be stable, but two breaks (e.g. a high fibula fracture plus a medial malleolus/deltoid injury) make it unstable. The syndesmosis (AITFL, PITFL, interosseous ligament, inferior transverse ligament) holds the fibula in the incisura fibularis; the deltoid (superficial and deep) resists eversion and talar lateral shift.

A
Fibula level
Below the syndesmosis
Syndesmosis
Intact
Stability
Stable
Treatment
Usually non-operative
B
Fibula level
At the syndesmosis level
Syndesmosis
Variable (50% injured)
Stability
Variable — stress test
Treatment
ORIF if displaced or unstable
C
Fibula level
Above the syndesmosis
Syndesmosis
Always injured
Stability
Unstable
Treatment
ORIF plus syndesmotic fixation
Weber classification — fibula level, syndesmosis, stability
TypeFibula levelSyndesmosisStabilityTreatment
ABelow the syndesmosisIntactStableUsually non-operative
BAt the syndesmosis levelVariable (50% injured)Variable — stress testORIF if displaced or unstable
CAbove the syndesmosisAlways injuredUnstableORIF plus syndesmotic fixation
SER
Frequency
~60%
Foot position
Supinated
Force
External rotation
Injury sequence
AITFL, then spiral fibula, then PITFL/posterior malleolus, then medial malleolus/deltoid
SA
Frequency
~20%
Foot position
Supinated
Force
Adduction
Injury sequence
Transverse lateral malleolus, then vertical medial malleolus
PER
Frequency
~10%
Foot position
Pronated
Force
External rotation
Injury sequence
Medial malleolus/deltoid, then AITFL, then spiral fibula above the syndesmosis, then PITFL
PA
Frequency
~5%
Foot position
Pronated
Force
Abduction
Injury sequence
Medial malleolus/deltoid, then AITFL/syndesmosis, then comminuted fibula
Lauge-Hansen classification — mechanism and injury sequence
TypeFrequencyFoot positionForceInjury sequence
SER~60%SupinatedExternal rotationAITFL, then spiral fibula, then PITFL/posterior malleolus, then medial malleolus/deltoid
SA~20%SupinatedAdductionTransverse lateral malleolus, then vertical medial malleolus
PER~10%PronatedExternal rotationMedial malleolus/deltoid, then AITFL, then spiral fibula above the syndesmosis, then PITFL
PA~5%PronatedAbductionMedial malleolus/deltoid, then AITFL/syndesmosis, then comminuted fibula
Know BOTH systems for the exam

Weber tells you WHERE (the anatomic level) and predicts syndesmotic status; Lauge-Hansen tells you HOW (the mechanism) and predicts associated injuries. Examiners expect you to correlate them: "This is a Weber B, or SER Stage II, injury."

Key evidence.

  • 1mm of lateral talar shift reduces tibiotalar contact area by about 42% (Ramsey and Hamilton, 1976); fibular shortening, lateral shift and external rotation each raise peak talar contact pressures, shortening being the most deleterious (Thordarson, 1997).
  • Syndesmotic malreduction occurs in roughly half of cases on CT and is largely undetected by plain radiographs (Gardner, 2006); malreduction correlates with significantly worse functional scores at 2 years (Sagi, 2012).
  • Suture-button versus screw: similar malreduction and functional outcomes; the suture-button maintains reduction better over time and needs no routine removal (Kortekangas, 2015).
  • Posterior malleolus: open fixation of the fragment with its intact PITFL gives outcomes at least equivalent to a syndesmotic screw (Miller, 2009).
  • In adults over 60 with unstable fractures, close-contact casting gives 6-month function equivalent to surgery with far fewer wound complications (Willett AIM trial, 2016).

References


Evidence

Changes in tibiotalar area of contact caused by lateral talar shift

Level V (biomechanical)
Ramsey PL, Hamilton W • J Bone Joint Surg Am (1976)
Key Findings:
  • Classic cadaveric study of talar shift in the ankle mortise
  • As little as 1mm of lateral talar shift reduced the tibiotalar contact area by approximately 42%
  • Established the biomechanical rationale for anatomic mortise reduction
Clinical implication: Even minor talar shift after an ankle fracture dramatically reduces tibiotalar contact area and concentrates load — the foundation for insisting on anatomic reduction of fibular length and the mortise.
Verify on PubMed (PMID 1262367)
Evidence

The effect of fibular malreduction on contact pressures in an ankle fracture malunion model

Level V (biomechanical)
Thordarson DB, Motamed S, Hedman T, Ebramzadeh E, Bakshian S • J Bone Joint Surg Am (1997)
Key Findings:
  • Cadaveric model: fibular shortening, lateral shift and external rotation each shifted load to the mid- and posterolateral talar dome
  • Peak contact pressures reached 4.1 MPa, highest with maximal shortening and with combined deformities
  • Shortening was the most deleterious single deformity
Clinical implication: Restoring fibular length, rotation and translation is biomechanically essential — any residual malreduction concentrates load laterally and predisposes to post-traumatic arthritis.
Verify on PubMed (PMID 9409794)
Evidence

Malreduction of the tibiofibular syndesmosis in ankle fractures

Level III
Gardner MJ, Demetrakopoulos D, Briggs SM, Helfet DL, Lorich DG • Foot Ankle Int (2006)
Key Findings:
  • In 25 patients with operatively fixed syndesmotic injuries, postoperative CT showed incongruity of the fibula in the incisura in 13 of 25 (52%), averaging 3.6mm (range 2.0-8.0mm)
  • Plain radiographs detected only 6 of these (sensitivity 31%, specificity 83% versus CT)
  • In 77% of malreductions the fibula was internally rotated or anteriorly translated
Clinical implication: Plain films grossly under-detect syndesmotic malreduction. Reduce under direct vision, scrutinise intraoperative imaging, and consider postoperative CT with contralateral comparison in higher-risk injuries.
Verify on PubMed (PMID 17054878)
Evidence

The functional consequence of syndesmotic joint malreduction at a minimum 2-year follow-up

Level II
Sagi HC, Shah AR, Sanders RW • J Orthop Trauma (2012)
Key Findings:
  • Bilateral CT in 68 patients: 27 (39%) were malreduced versus the uninjured side at 2 years
  • Open syndesmotic reduction was malreduced in only 15% versus 44% with closed reduction
  • Malreduced patients had significantly worse SMFA and Olerud-Molander scores (P less than 0.05)
Clinical implication: Anatomic syndesmotic reduction is the single strongest modifiable predictor of outcome; direct open reduction substantially lowers the malreduction rate compared with clamp-and-shoot closed reduction.
Verify on PubMed (PMID 22357084)
Evidence

Posterior malleolar stabilization of syndesmotic injuries is equivalent to screw fixation

Level II
Miller AN, Carroll EA, Parker RJ, Helfet DL, Lorich DG • Clin Orthop Relat Res (2009)
Key Findings:
  • 31 unstable fractures with MRI-confirmed syndesmotic injury and intact PITFL
  • Open posterior malleolar fixation (capturing the PITFL footprint) gave FAOS outcomes equivalent to syndesmotic screws
  • Reduction was maintained at minimum 12-month follow-up
Clinical implication: When a posterior malleolar fragment carries the PITFL, fixing it can directly restore syndesmotic stability and may avoid a separate trans-syndesmotic implant.
Verify on PubMed (PMID 19798540)
Evidence

TightRope versus syndesmotic screw fixation: accuracy and maintenance of reduction assessed with bilateral CT

Level I
Kortekangas T, Savola O, Flinkila T, et al • Injury (2015)
Key Findings:
  • RCT of 43 Weber C/PER fractures: suture-button (n=21) versus single 3.5mm tricortical screw (n=22)
  • No significant difference in malreduction, function (Olerud-Molander, FAOS) or osteoarthritis at 2 years
  • Follow-up CT showed reduction was better maintained with the suture-button (3 malreduced with screw versus 1 with TightRope)
Clinical implication: Suture-button and screw fixation are both acceptable; the dynamic suture-button maintains reduction at least as well over time and avoids routine hardware removal.
Verify on PubMed (PMID 25769201)
Evidence

Close contact casting versus surgery for initial treatment of unstable ankle fractures in older adults (AIM trial)

Level I
Willett K, Keene DJ, Mistry D, et al • JAMA (2016)
Key Findings:
  • Multicentre RCT of close-contact casting versus ORIF for unstable ankle fractures in adults over 60
  • Equivalent Olerud-Molander Ankle Score at 6 months in the intention-to-treat analysis
  • Significantly fewer wound complications in the casting group
Clinical implication: In selected older adults with unstable ankle fractures, close-contact casting is a reasonable evidence-based alternative to ORIF — the basis for modern elderly-fracture pathways.
Verify on PubMed (PMID 27727383)

Further reading 1. Court-Brown CM, McBirnie J, Wilson G. Adult ankle fractures — an increasing problem? Acta Orthop Scand. 1998;69(1):43-47. 2. Michelson JD. Fractures about the ankle. J Bone Joint Surg Am. 1995;77(1):142-152. 3. Egol KA, Pahk B, Walsh M, et al. Outcome after unstable ankle fracture: effect of syndesmotic stabilization. J Orthop Trauma. 2010;24(1):7-11. 4. Donken CC, Al-Khateeb H, Verhofstad MH, et al. Surgical versus conservative interventions for treating ankle fractures in adults. Cochrane Database Syst Rev. 2012;(8):CD008470. 5. van den Bekerom MP, Haverkamp D, Kloen P. Biomechanical and clinical evaluation of posterior malleolar fractures: a systematic review of the literature. J Trauma. 2009;66(1):279-284.

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Procedure console
55 min
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Sections
intermediate
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Peer-reviewed · 2026-06-20
Procedure info
Level
intermediate
Read time
55 min
Updated
2026-06-20
SURGICAL APPROACHES USED
Approach to the Fibula (Lateral, Peroneal-Protecting)Medial Approach to Ankle (Medial Malleolus)
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