Anterolateral Approach to Ankle

Why Anterolateral Approach Dominates Ankle Surgery

The anterolateral approach is the gold standard for ankle arthrodesis and provides the most versatile access to the anterior ankle joint. Its dominance stems from three key advantages:

1. Safe Neurovascular Anatomy: The approach exploits the internervous plane between tibialis anterior (deep peroneal nerve) and extensor digitorum longus (superficial peroneal nerve). The major neurovascular bundle (dorsalis pedis artery + deep peroneal nerve) stays safely MEDIAL to the approach - protected by intact tibialis anterior tendon.

2. Optimal Joint Visualization: Direct anterior approach to the tibiotalar joint allows:

• 360° joint preparation: Curette cartilage from anterior tibia, talus, and medial/lateral gutters
• Accurate positioning: Assess ankle alignment (valgus/varus, dorsiflexion/plantarflexion, rotation) under direct vision
• Hardware placement: Antegrade tibiotalar screws easily inserted anterior-to-posterior

3. Extensile Without Consequences: Can extend proximally (access tibial plafond, syndesmosis) or distally (talar neck, subtalar joint) without crossing new neurovascular territories.

Historical Context:

• 1970s-1980s: Ankle arthrodesis via lateral approach (transfibular - requires fibula osteotomy, high non-union)
• 1990s: Anterolateral approach popularized (Scranton) - lower non-union, better alignment control
• 2000s-Present: Anterolateral remains standard (arthroscopic ankle fusion emerging as alternative for selected cases)

Global Practice Pattern: Across registries and national series, total ankle replacement rates have risen steadily over the past two decades while ankle fusion rates have remained relatively static, yet fusion stays the preferred option for younger, high-demand and post-traumatic patients, those with talar AVN, and as a salvage for failed replacement. The anterior or anterolateral interval is the most widely used open exposure for tibiotalar fusion worldwide; arthroscopic ankle fusion is an established minimally invasive alternative in suitable, well-aligned ankles.

Primary Indications

1. Ankle Arthrodesis (Most Common Indication)

End-Stage Ankle Arthritis:

• Post-traumatic: Pilon fracture sequelae, talar fracture malunion/AVN (50% of all ankle fusions)
• Primary osteoarthritis: Rare (<5%) - unlike hip/knee (ankle cartilage thinner, less susceptible to OA)
• Inflammatory arthropathy: Rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis
• Neuropathic arthropathy (Charcot): Relative indication - high non-union risk (50%), consider fusion with bone graft

Failed Ankle Replacement:

• Aseptic loosening, infection (staged - explant then fusion), instability
• Massive bone loss (consider structural allograft + fusion)

2. Syndesmotic Pathology

Acute Syndesmotic Injury:

• Weber C ankle fracture with syndesmotic disruption (posterior malleolus fixation via anterolateral approach)
• Isolated syndesmotic injury (high ankle sprain requiring ORIF - suture button vs screws)

Chronic Syndesmotic Instability:

• Failed repair, persistent diastasis (revision fixation, arthroscopic debridement + ORIF)

3. Intra-articular Ankle Pathology

Talar Osteochondral Lesions (OCL):

• Anterolateral talar dome lesions (lesions >15mm diameter - too large for arthroscopy)
• Failed arthroscopic treatment (persistent pain, large lesion)
• Technique: Debridement + microfracture, osteochondral autograft transfer (OATS), allograft

Anterior Ankle Impingement:

• "Footballer's ankle" - anterior osteophyte (tibia + talus) causing impingement
• Debridement via anterolateral approach (remove spurs, synovectomy)

4. Fracture Fixation

Pilon Fractures (Anterolateral Fragment):

• Anterolateral plafond fragment ORIF (buttress plate via anterolateral approach)
• Can combine with anteromedial approach (two-incision technique)

Posterior Malleolus Fractures:

• Large posterior malleolus (>25% joint surface) via anterolateral approach
• Alternative to posterior approach (lower wound complication rate)

Contraindications

Absolute:

• Active Infection: Deep ankle infection, osteomyelitis (staged treatment - debridement, antibiotics, delayed fusion)
• Severe Peripheral Arterial Disease: Ankle-brachial index under 0.5 (critical limb ischemia - revascularize first or accept non-union risk)

Relative:

• Young Active Patients: Ankle replacement emerging alternative (<60 years, moderate activity level)
• Neuropathic Arthropathy: Charcot ankle (non-union risk 50% - consider extended fusion to midfoot)
• Smoking: Triple non-union risk (counsel cessation 6 weeks pre-op, restart 12 weeks post-op)
• Diabetes: Poor glycemic control (HbA1c >8%) - delay surgery until optimized
• Obesity: BMI >40 increases wound complications 3× (optimize weight preop)
• Adjacent Joint Arthritis: Subtalar or midfoot arthritis may progress post-fusion (counsel patient - may need future fusions)

Clinical Assessment

History - Mechanism and Progression:

• Post-traumatic: Prior pilon/ankle/talar fracture (most common - 50-60% of ankle fusions)
• Inflammatory: RA, psoriatic arthritis (bilateral ankle involvement suggests systemic disease)
• Functional Limitation: Pain with ambulation, distance (e.g., "cannot walk >100m without severe pain")
• Failed Conservative Management: Bracing (AFO - ankle-foot orthosis), NSAIDs, intra-articular injections

Physical Examination:

Inspection:

• Gait: Antalgic (pain-avoidance), stiff ankle (limited motion compensated by midfoot/subtalar motion)
• Alignment: Varus vs valgus deformity (assess from behind - hindfoot alignment)
• Swelling: Chronic effusion (synovitis), edema (venous insufficiency - wound healing concern)
• Skin: Scars from prior surgery (plan incision to avoid crossing old scars), ulcers (vascular insufficiency), sinuses (infection)

Palpation:

• Tenderness: Anterior ankle joint line (tibiotalar arthritis), medial/lateral gutters (osteophytes)
• Subtalar motion: Assess subtalar ROM (if subtalar also arthritic, may need subtalar fusion simultaneously)
• Midfoot motion: Assess Chopart/Lisfranc joints (compensatory motion post-ankle fusion will stress these joints)

Range of Motion:

• Ankle dorsiflexion/plantarflexion (normal 20° DF, 50° PF - arthritis typically 0-10° DF, 10-20° PF)
• Subtalar inversion/eversion (assess if arthritic - crepitus, limited ROM, pain)
• Hindfoot alignment: Varus vs valgus (measure - >10° deformity needs correction during fusion)

Neurovascular Examination (MANDATORY):

• Dorsalis pedis pulse: Palpate (if absent - get ankle-brachial index, consider vascular consult)
• Posterior tibial pulse: Medial malleolus (assess posterior tibial artery integrity)
• Deep peroneal nerve: EHL function (great toe dorsiflexion), sensation first web space
• Superficial peroneal nerve: Sensation dorsum of foot (lateral 4 toes)
• Tibial nerve: FHL function (great toe plantarflexion), sensation plantar foot

Imaging Essentials

Radiographs (Weight-Bearing MANDATORY):

AP Ankle (Standing):

• Joint space narrowing (arthritis - normal 2-3mm, arthritic <1mm or bone-on-bone)
• Varus/valgus deformity (measure tibiotalar angle - normal 90±5°, >10° deformity needs correction)
• Osteophytes (anterior tibial/talar spurs - anterior impingement)

Lateral Ankle (Standing):

• Anterior/posterior translation (instability)
• Dorsal osteophytes (footballer's ankle - anterior impingement)
• Tibiotalar angle (normal tibia 80-90° relative to talus)

Mortise View:

• Joint space symmetry (medial/lateral/superior - asymmetry suggests ligamentous injury)
• Talar tilt (varus/valgus instability)

Hindfoot Alignment View (Saltzman):

• Assess hindfoot valgus/varus (critical for fusion positioning)
• Measure from tibial mechanical axis to heel center (valgus >10mm medial or varus >10mm lateral = deformity)

Full Length Leg Alignment (If Deformity):

• Hip-knee-ankle (HKA) axis (assess for tibial deformity contributing to ankle varus/valgus)
• May need tibial osteotomy simultaneously if deformity proximal to ankle

CT Scan (Fusion Planning):

• Bone Quality: Assess for cysts, AVN (talus), sclerosis (bone stock for screw purchase)
• Deformity Assessment: 3D reconstruction (plan osteotomy if severe varus/valgus)
• Hardware Planning: Measure screw trajectory (anterolateral talus to posterior tibia - avoid neurovascular structures)

MRI (Selected Cases):

• Talar AVN: Assess talar body viability (if AVN - may need structural bone graft or talectomy + tibiocalcaneal fusion)
• Soft Tissue Pathology: Deltoid ligament injury, spring ligament insufficiency (affects hindfoot alignment)

Surgical Planning Decision Points

Arthrodesis vs Arthroplasty Debate:

The Evidence:

• TARVA RCT (Goldberg et al, Ann Intern Med 2022): in 303 patients aged 50-85, ankle replacement and fusion gave broadly equivalent patient-reported outcomes (MOXFQ) at 1 year; complication profiles differed (TAR more wound/nerve problems, fusion more VTE and non-union, symptomatic non-union ~7%).
• Pooled outcome data (Haddad et al, JBJS Am 2007): intermediate AOFAS scores similar between procedures; second-generation implant survival ~78% at 5 yr.
• General principle (not a single-country guideline): fusion favoured for younger, high-demand and post-traumatic patients where durability matters; replacement increasingly chosen for older, lower-demand patients where preserving motion may aid function.

Fusion Position - The Critical Decision:

Optimal Ankle Fusion Position (Buck, JBJS Am 1987):

• Sagittal Plane: Neutral dorsiflexion (0-5° DF) - allows toe clearance in swing phase, prevents knee hyperextension; talus translated slightly posteriorly under the tibia
• Coronal Plane: Slight hindfoot valgus (0-5°) - mimics normal hindfoot alignment, prevents lateral column overload, gives more normal gait on uneven ground
• Axial Plane: 5-10° external rotation (match contralateral foot progression angle)

Why Position Matters:

• Varus malunion (most common error): Lateral column overload, fifth metatarsal stress fractures (20%), painful lateral midfoot arthritis
• Valgus malunion: Medial column overload, tibialis posterior dysfunction, less common (easier to correct intraop)
• Plantarflexion malunion: Knee hyperextension gait (quadriceps strain), toe drag (trip risk)
• Dorsiflexion malunion: Shortened stride (flexed knee gait), calcaneal stress (plantar fasciitis)

Essential Instrumentation

Standard Orthopaedic Set:

• Scalpel (15 blade - smaller incision)
• Self-retaining retractor (small Weitlaner)
• Army-Navy retractors
• Hohmann retractors (joint distraction, retraction)
• Electrocautery (bipolar preferred - less nerve thermal injury)

Ankle Fusion-Specific Instruments:

Joint Preparation:

• Curettes: Remove articular cartilage (straight and curved - 10mm, 15mm sizes)
• Osteotomes: Flat (10mm, 15mm) - remove subchondral bone plate, create bleeding bone
• Sagittal Saw: Flat cuts (remove bone to correct deformity, prepare fusion surfaces)
• Rongeurs: Remove osteophytes, anterior impingement bone

Distraction and Positioning:

• Lamina Spreaders: Distract ankle joint (allows cartilage removal from medial/lateral gutters)
• K-wires: 2.0mm for provisional fixation (hold fusion position while checking alignment)
• External Fixator (Optional): Distraction across ankle (facilitates joint prep if severe deformity or bone loss)

Fluoroscopy:

• C-arm (MANDATORY - intraop imaging for alignment, screw position)
• AP, lateral, mortise views (check fusion position before final fixation)

Implant Selection

Screw Fixation (Most Common):

Configuration Options:

1. Three-Screw Technique (Gold Standard):

   • 2× anterolateral tibiotalar screws (6.5mm or 7.0mm partially threaded cannulated)
   • 1× medial tibiotalar screw (medial malleolus to talar body - "home-run" screw)
   • Rationale: multiple crossed compression screws give a rigid, well-distributed construct; rigid compressive fixation across the prepared surfaces is the biomechanical priority

2. Two-Screw Technique:

   • 2× crossing screws (anterolateral tibia to posteromedial talus, anteromedial tibia to posterolateral talus)
   • Adequate for most fusions (slightly less rigid than three-screw)

Screw Specifications:

• Diameter: 6.5mm or 7.0mm partially threaded cannulated screws
• Thread: Partially threaded (16-32mm thread length - compression across fusion site)
• Length: 60-80mm (measure on lateral fluoro - tibia to talar body)
• Material: Titanium (MRI compatible) or stainless steel

Plate Fixation (Alternative):

Anterior Ankle Plate:

• Low-profile anatomic plate (crosses anterior tibiotalar joint)
• Screws into tibia proximally, talus distally (4-6 screws each side)
• Indications: Severe bone loss (plate provides structural support), revision fusion, talar AVN
• Complications: Higher wound breakdown (10-15% vs 5% screws), prominence (may need removal)

Blade Plate or Intramedullary Nail:

• Reserved for tibiotalocalcaneal fusion (pantalar fusion - ankle + subtalar simultaneous)
• Not standard for isolated ankle fusion

Bone Graft (If Needed):

Autograft:

• Iliac crest: Gold standard (highest fusion rate), 10cc morselized cancellous bone
• Distal tibia: Local harvest (metaphyseal cancellous bone - 5cc volume, less morbidity than iliac crest)

Allograft:

• Cancellous chips or DBM (demineralized bone matrix)
• Indications: Revision fusion, bone void (cysts, AVN)

Structural Graft (Severe Bone Loss):

• Femoral head allograft (tricortical - restores height if talar collapse)
• Indications: Talar AVN, revision fusion with massive bone loss

Standard Positioning - Supine

Setup:

1. Patient Position: Supine on OR table, operative leg on radiolucent leg holder OR bump under ipsilateral hip
2. Hip Positioning: Small bump (10cm) under ipsilateral hip (internally rotates leg - brings ankle anterior for exposure)
3. Knee Position: Flexed 20-30° (relaxes gastrocnemius - easier ankle dorsiflexion)
4. Heel Support: Free-hanging (heel off table) OR on bump (allows ankle plantarflexion/dorsiflexion freedom)
5. Tourniquet: Upper thigh pneumatic tourniquet (inflated to 300mmHg - exsanguinate with Esmarch first)

Advantages:

• Surgeon Ergonomics: Seated or standing position (surgeon comfort)
• Fluoroscopy Access: C-arm lateral position (parallel to table), AP (perpendicular)
• Bilateral Access: If needed for contralateral comparison or bilateral surgery

Disadvantages:

• Limited Posterior Access: Cannot access posterior malleolus or posterior talus easily (use alternative positioning if needed)

Alternative Positioning - Lateral Decubitus

Setup (If Concomitant Fibula Osteotomy or Lateral Ankle Surgery):

1. Patient lateral decubitus, operative side up
2. Beanbag stabilization, kidney rests
3. Allows simultaneous lateral and anterior approaches

Rarely Used for Isolated Anterolateral Approach (supine is standard).

Tourniquet Considerations

Standard Practice:

• Upper thigh tourniquet (300mmHg), exsanguinate with Esmarch
• Bloodless field (improves nerve identification, reduces blood loss)
• Safe time limit: 2 hours (most ankle fusions under 90 minutes)
• Release tourniquet BEFORE closure (achieve haemostasis - prevents postop haematoma)

No Tourniquet Alternative:

• PAD patients (arterial insufficiency), sickle cell disease
• Requires meticulous haemostasis with bipolar cautery

Surface Landmarks

Palpable Structures (Mark Preoperatively):

1. Tibialis Anterior Tendon: Most medial dorsal ankle tendon (ask patient to dorsiflex ankle - tendon prominent)
2. Extensor Hallucis Longus (EHL): Medial to EHL = dorsalis pedis artery pulse
3. Lateral Malleolus: Distal fibula - lateral reference
4. Ankle Joint Line: Palpate anterior ankle (tibiotalar joint 1cm proximal to talar neck)

Incision Planning:

• Position: 2cm LATERAL to tibialis anterior tendon (stay lateral to dorsalis pedis artery)
• Proximal Start: 8-10cm proximal to ankle joint (allows access to distal tibia)
• Distal End: Talar neck (allows access to talus for fusion prep, screw insertion)
• Direction: Slightly curved (follows anterior tibial contour), longitudinal

Anatomic Intervals

The Internervous Plane:

• Medial: Tibialis anterior muscle/tendon (innervated by deep peroneal nerve)
• Lateral: Extensor digitorum longus (EDL) muscle/tendon (innervated by superficial peroneal nerve)
• True Internervous Plane: TA (deep peroneal) vs EDL (superficial peroneal) - different nerves = no motor denervation

Key Anatomic Relationship: The dorsalis pedis artery + deep peroneal nerve run BETWEEN tibialis anterior and EHL (medial to the surgical field). By staying lateral to TA tendon and working in the TA-EDL interval, the major neurovascular bundle stays protected medially.

Critical Neurovascular Anatomy

Superficial Peroneal Nerve (SPN):

• Course: Runs in lateral compartment (innervates peroneus longus and brevis), then pierces deep fascia 10-12cm proximal to ankle joint (emerges between peroneus brevis and EDL)
• Branches:
  • Medial dorsal cutaneous nerve: Crosses medially (innervates medial dorsal foot)
  • Intermediate dorsal cutaneous nerve: Crosses laterally (innervates lateral dorsal foot - 4th web space)
• Surgical Relevance: SPN cutaneous branches frequently lie within the anterolateral field (in cadaveric mapping, lateral to EDL in ~32% and between EHL and EDL in ~24% - Solomon 2006) - MUST identify and protect with a vessel loop
• Injury Consequences: Painful dorsal-foot neuroma if a branch is divided, sensory loss over the dorsum of the foot, and a risk of complex regional pain syndrome (CRPS)

Deep Peroneal Nerve (DPN):

• Course: Runs with anterior tibial artery (becomes dorsalis pedis artery at ankle joint) - MEDIAL to surgical field
• Position: Between tibialis anterior and EHL tendons at ankle level (palpate DP pulse - nerve is just lateral to artery)
• Branches:
  • Motor: EHL, EDL, tibialis anterior (all supplied PROXIMAL to ankle - safe)
  • Sensory: First web space (between great toe and second toe)
• Surgical Relevance: Safe if stay lateral to TA tendon - approach does NOT cross DPN
• Injury: Rare (<1%) - would require dissection medial to TA tendon (technical error)

Dorsalis Pedis Artery:

• Course: Continuation of anterior tibial artery at ankle joint, runs between TA and EHL tendons
• Position: Palpable pulse on dorsum of foot (medial midfoot - between TA and EHL)
• Surgical Relevance: MEDIAL to surgical field - protected by TA tendon (do NOT dissect medial to TA)
• Injury: Rare (<1%) if stay in proper interval - would cause foot ischemia (emergency vascular repair)

Extensor Retinaculum Anatomy

Superior Extensor Retinaculum:

• Transverse band at distal tibia (10cm proximal to ankle joint)
• Holds tendons close to tibia (prevents bowstringing)
• Surgical approach: Usually proximal to this - not divided

Inferior Extensor Retinaculum:

• Y-shaped band at ankle joint level (stem crosses anterolateral ankle, bifurcates into superior and inferior limbs)
• Creates compartments for tendons:
  • Medial compartment: TA tendon
  • Middle compartment: EHL tendon + NV bundle (DP artery, DPN)
  • Lateral compartment: EDL tendons
• Surgical Approach: MUST divide inferior retinaculum longitudinally to expose ankle joint capsule (release TA-EDL interval)

Ankle Joint Capsule

Anterior Capsule:

• Thin fibrous layer (attaches to anterior tibia, anterior talus)
• Weak anteriorly (compared to robust medial/lateral collateral ligaments)
• Surgical approach: Incise longitudinally (exposes tibiotalar joint space for fusion prep)

Synovium:

• Lines joint capsule (inflamed in arthritis - thickened, hypervascular)
• Remove during fusion (improves bone contact)

Step 1: Skin Incision and Superficial Dissection

Incision:

• Mark Landmarks: Palpate TA tendon (most medial dorsal tendon), mark incision 2cm LATERAL to TA
• Incision Line: 8-10cm longitudinal, starting 10cm proximal to ankle joint, extending to talar neck
• Avoid Medial: Do NOT make incision medial to TA (risks dorsalis pedis artery)

Skin Incision:

• 15 blade scalpel, incise through dermis
• Subcutaneous dissection (3-5mm depth to deep fascia)
• Identify superficial veins (greater saphenous vein more medial - should not be in field)

Identify Superficial Peroneal Nerve (CRITICAL STEP):

During subcutaneous dissection (before incising deep fascia):

1. Look for SPN: Small white nerve (2-3mm diameter) emerging through fascia 10-12cm proximal to ankle
   • Intermediate dorsal cutaneous branch crosses field obliquely (radial to ulnar as travels distally)
2. If Identified: Place vessel loop around nerve, gentle retraction throughout case (protect from stretch/laceration)
3. If Not Seen: Assume it's nearby - stay alert during fascial incision, minimize subcutaneous retraction

Step 2: Deep Fascial Incision and Interval Development

Incise Deep Fascia:

1. Identify deep fascia (white glistening layer deep to subcutaneous fat)
2. Incise fascia longitudinally (parallel to incision) - full length of incision
3. SPN may pierce fascia at this level (if emerges during fascial incision - vessel loop it immediately)

Identify Tibialis Anterior Tendon:

• Most medial dorsal ankle tendon (ask anesthesia to passively dorsiflex foot - TA contracts)
• Firm white cord (tendon prominent at ankle level)

Identify Extensor Digitorum Longus (EDL):

• Lateral to TA (4 separate tendons to lateral 4 toes)
• Less prominent than TA (thinner tendons)

Develop Interval:

1. Identify Interval: Fat stripe between TA (medial) and EDL (lateral)
2. Blunt Dissection: Elevator or blunt scissors (separate muscles)
3. Retract: TA tendon MEDIAL (protects DP artery + DPN), EDL LATERAL (exposes anterior ankle joint capsule)

What You Should See:

• TA tendon retracted medially (you should NOT see DP artery - it's medial to TA, protected)
• EDL tendons retracted laterally
• Deep: Anterior ankle joint capsule (thin white layer covering tibia and talus)

Step 3: Divide Extensor Retinaculum and Expose Joint Capsule

Identify Inferior Extensor Retinaculum:

• Y-shaped band at ankle level (crosses anterior ankle obliquely)
• Creates tendon sheaths (prevents bowstringing)

Divide Retinaculum:

1. Incise longitudinally (parallel to tendons) - between TA and EDL compartments
2. Release superior and inferior limbs (exposes ankle joint capsule fully)
3. Protect tendons (stay between TA and EDL - avoid cutting tendons)

Expose Joint Capsule:

• Thin fibrous layer (attaches tibia to talus)
• May be thickened if chronic arthritis (synovitis)
• Osteophytes visible (anterior tibial/talar spurs - remove with rongeur)

Remove Anterior Osteophytes (If Present):

• Rongeur or osteotome (remove anterior tibial/talar spurs)
• Improves joint visualization
• Debride synovium (hypervascular - cauterize with bipolar)

Step 4: Capsulotomy and Joint Exposure

Incise Ankle Joint Capsule:

1. Longitudinal capsulotomy (midline of anterior tibiotalar joint)
2. Extend proximal (onto anterior tibia) and distal (onto talar neck)
3. Elevate capsular flaps (medial and lateral - exposes joint 360°)

Distract Ankle Joint:

• Lamina spreader or small Hohmann retractors (lever tibia up, talus down)
• Opens joint space (visualizes articular surfaces - tibia and talus)

What You Should See:

• Tibia: Distal tibial articular surface (plafond) - normally smooth, arthritic shows eburnation (polished bone), sclerosis, cartilage loss
• Talus: Talar dome - normally convex, smooth, arthritic shows flattening, osteophytes, cysts
• Medial Gutter: Medial tibiotalar joint (between medial malleolus and medial talus)
• Lateral Gutter: Lateral tibiotalar joint (less accessible from anterolateral approach)

Step 5: Joint Preparation for Fusion

Cartilage Removal:

Principle: Remove ALL articular cartilage and subchondral bone plate to bleeding cancellous bone (allows bone-to-bone contact for fusion).

Technique:

1. Curettes: Curette tibial and talar articular surfaces (remove cartilage)

   • Straight curettes (10mm, 15mm) for plafond and dome
   • Curved curettes for medial/lateral gutters
   • Goal: Expose bleeding subchondral bone (fish-scale appearance)

2. Osteotomes: Flat osteotomes (10mm) to remove subchondral bone plate

   • Sclerotic bone (hard white bone) resists fusion - remove 2-3mm
   • Stop when bleeding cancellous bone visible (punctate bleeding - "paprika sign")

3. Sagittal Saw (If Deformity Correction Needed):

   • Varus Deformity: Remove lateral tibia wedge (opens lateral joint space, closes medial) - corrects to 5° valgus
   • Valgus Deformity: Remove medial tibia wedge
   • Plantarflexion: Remove anterior tibia wedge (brings ankle into neutral dorsiflexion)

Gutter Debridement:

• Medial gutter: Curette between medial malleolus and medial talus (remove cartilage, synovium)
• Lateral gutter: Harder to access from anterolateral (may need mini-incision laterally if severe lateral arthritis)

Bone Graft Preparation (If Using):

• Harvest iliac crest autograft (10cc morselized cancellous) OR use allograft chips
• Pack graft into fusion site (medial/lateral gutters, central contact zone)

Step 6: Provisional Fusion Positioning

Restore Anatomic Position:

Sagittal Plane:

• Ankle NEUTRAL dorsiflexion (0-5° DF)
• Check: Lateral fluoroscopy (tibiotalar angle 90°)

Coronal Plane:

• Hindfoot 5-7° VALGUS (relative to tibial axis)
• Check: AP fluoroscopy (measure hindfoot alignment)
• Examiner tip: "Match contralateral normal foot if available"

Axial Plane:

• 5-10° external rotation (match contralateral foot progression angle)
• Check: Patient supine, both feet visible - compare foot rotation angles

Provisional K-wire Fixation:

1. Place 2.0mm K-wires (anterolateral tibia into talus - parallel to intended screw trajectories)
2. Check fluoroscopy (AP, lateral, mortise):
   • Ankle position acceptable? (neutral DF, 5° valgus, 10° ER)
   • Joint surfaces apposed? (no gap - may need further bone resection)
   • K-wire position safe? (avoid neurovascular structures posteriorly)

Adjustments: If position incorrect:

• Remove K-wires
• Adjust bone cuts (saw) or manipulation
• Re-insert K-wires and re-check fluoro

Step 7: Definitive Screw Fixation

Three-Screw Technique (Gold Standard):

Screw 1: Anterolateral Tibiotalar Screw (Lateral Column)

1. Entry point: Anterolateral distal tibia (2-3cm proximal to joint, 1cm anterior to fibula)
2. Trajectory: Aim posteromedial into talar body (cross fusion site obliquely)
3. Drill: 3.2mm guidewire (over K-wire if cannulated system), check lateral fluoro (wire should cross fusion site, end in posterior talus)
4. Measure: Depth gauge over wire (typical length 65-75mm)
5. Cannulated drill: 4.5mm (over wire - pilot hole for 6.5mm screw)
6. Insert: 6.5mm partially threaded cannulated screw (16-32mm thread crosses fusion site)
7. Tighten: Compresses tibia to talus (closes fusion gap)

Screw 2: Anterolateral Tibiotalar Screw (Medial Column)

1. Entry point: Anteromedial distal tibia (2-3cm proximal to joint, 1cm lateral to medial malleolus)
2. Trajectory: Aim posterolateral into talar body (cross fusion site - opposite direction from Screw 1)
3. Technique: Same as Screw 1 (guidewire, drill, measure, insert)
4. Screw Crossing: Screws should cross DISTAL to tibiotalar joint (inside talus - creates triangular construct)

Screw 3: Medial Malleolar Screw (Optional - Gold Standard Includes This)

1. Entry point: Medial malleolus (mini-incision medial ankle if needed, OR percutaneous)
2. Trajectory: Medial malleolus into talar body (lateral direction)
3. Length: Shorter screw (45-55mm typical)
4. Compression: Compresses medial side of joint

Fluoroscopy Check (CRITICAL):

• AP View: All screws within bone (no cortical perforation), crossing at fusion site
• Lateral View: Screws crossing fusion site, NO posterior talar penetration (posterior neurovascular structures), thread across fusion site
• Mortise View: Screws within medial/lateral columns (not exiting)

Screw Position Errors to Avoid:

• Too short: Thread doesn't cross fusion site (no compression)
• Too long: Posterior talar penetration (FHL tendon, posterior tibial NV bundle injury)
• Wrong trajectory: Misses talus (enters subtalar joint), exits medially/laterally

Step 8: Final Checks and Closure

Remove K-wires:

• Provisional K-wires removed (screws provide definitive fixation)

Assess Stability:

• Manual stress (varus/valgus, AP drawer) - fusion site should be rigid (no motion)

Haemostasis:

• Release tourniquet (identify bleeding vessels)
• Bipolar cautery (coagulate vessels)
• Ensure DP pulse present (palpate - confirms artery intact)

Capsular Closure:

• Re-approximate joint capsule (2-0 Vicryl simple interrupted sutures)
• Not critical (ankle fused - capsule won't heal) but reduces dead space

Extensor Retinaculum:

• Re-approximate if possible (2-0 Vicryl)
• Often not possible (tissue attenuated from chronic arthritis) - not critical

Deep Fascia:

• 2-0 Vicryl interrupted (close fascial layer - reduces tension on skin)

Subcutaneous:

• 3-0 Vicryl interrupted (invert skin edges, meticulous haemostasis)
• Anterior ankle has thin skin (high wound complication risk 10-15%)

Skin:

• 4-0 Nylon interrupted vertical mattress sutures (stronger than subcuticular for ankle - allows individual suture removal if wound issues)
• Alternative: 4-0 Monocryl subcuticular (better cosmesis but all-or-nothing removal)

Dressing:

• Sterile gauze, cotton padding (generous - absorb drainage)
• Posterior splint (short leg - knee free, ankle neutral, well-padded)
• Elevate leg postop (reduce swelling, prevent haematoma)

Pre-Closure Verification

Fluoroscopy Final Check:

• AP: Hindfoot alignment 5-7° valgus, screws within bone
• Lateral: Ankle neutral dorsiflexion (0-5° DF), screws crossing fusion site, NO posterior penetration
• Mortise: Joint surfaces apposed (no gap), screws positioned correctly

Fusion Position:

• Sagittal: Neutral dorsiflexion (0-5° DF)
• Coronal: 5-7° valgus hindfoot
• Axial: 5-10° external rotation (match contralateral)

Neurovascular:

• Dorsalis pedis pulse present (palpate - confirms artery intact)
• Superficial peroneal nerve intact (no visible injury - was protected with vessel loop)

Haemostasis:

• Tourniquet deflated, bleeding controlled
• No active bleeding from bone or soft tissue

Layer-by-Layer Closure

Deep Layers:

1. Capsule: 2-0 Vicryl × 3-4 interrupted (re-approximate capsular edges)
2. Extensor Retinaculum: 2-0 Vicryl × 2-3 (if tissue adequate)
3. Deep Fascia: 2-0 Vicryl × 4-5 interrupted

Superficial Layers: 4. Subcutaneous: 3-0 Vicryl × 8-10 interrupted (invert edges, meticulous haemostasis) 5. Skin: 4-0 Nylon vertical mattress × 10-12 (or 4-0 Monocryl subcuticular)

Splint:

• Posterior short leg splint (plaster or fiberglass)
• Ankle neutral position
• Well-padded (prevent pressure sores - heel, malleoli)
• Non-weight-bearing instructions

Intraoperative Complications

Superficial Peroneal Nerve Injury (10-15%)

• Mechanism: Not identified during subcutaneous dissection, divided during fascial incision, or stretched during retraction
• Presentation: Cannot test intraop (patient asleep), postop sensory loss dorsum of foot (lateral 4 toes)
• Management:
  • If recognized intraop (nerve cut): Primary repair (microsurgical 8-0 nylon, nerve ends approximated)
  • If recognized postop: Observation 3-6 months (many improve - neuropraxia), persistent = neuroma excision + nerve burial
• Prevention: Active search for SPN during subcutaneous dissection, vessel loop protection

Dorsalis Pedis Artery Injury (<1%)

• Mechanism: Dissection medial to TA tendon (technical error), overly aggressive medial retraction
• Presentation: Loss of DP pulse, foot ischemia
• Management: Emergency vascular repair (primary repair vs vein graft) - consult vascular surgery
• Prevention: Stay lateral to TA tendon, never dissect medial to TA

Deep Peroneal Nerve Injury (<1%)

• Mechanism: Same as DP artery (nerve runs with artery - injury together)
• Presentation: Postop weakness EHL/EDL (foot drop), sensory loss first web space
• Management: Usually neuropraxia (observation), EMG at 6 weeks
• Prevention: Respect TA tendon boundary (do NOT cross medially)

Malposition (5-10%)

• Mechanism: Inadequate intraop fluoroscopy, failure to check alignment in all planes
• Presentation: Postop X-ray shows varus/valgus, excessive dorsiflexion/plantarflexion
• Consequences:
  • Varus: Lateral column overload (5th metatarsal stress fracture, lateral midfoot pain)
  • Valgus (excessive >10°): Medial column overload (less common)
  • Plantarflexion: Knee hyperextension, quadriceps fatigue
• Management: If severe (>10° varus, >20° plantarflexion): Revision fusion (osteotomy through fusion site, re-align, re-fix)
• Prevention: Systematic fluoroscopy (AP, lateral, mortise), check ALL planes before final fixation

Early Postoperative Complications (0-6 weeks)

Wound Complications (10-15%)

• Mechanism: Anterior ankle thin skin (poor soft tissue coverage), vascular compromise (PAD, diabetes), excessive swelling
• Presentation: Wound edge necrosis, dehiscence, exposed hardware
• Risk Factors: Smoking (3× risk), diabetes, PAD, obesity
• Management:
  • Superficial dehiscence: Local wound care (dressings, VAC therapy if needed)
  • Deep dehiscence (hardware exposed): Flap coverage (reverse sural artery flap, free flap) + continue antibiotics
  • Infection (hardware contaminated): Debridement, retain hardware if stable + IV antibiotics
• Prevention: Meticulous tissue handling, avoid excessive tension on skin closure, elevation postop, smoking cessation

Infection (5-10%)

• Presentation: Wound erythema, drainage, pain, fevers (usually 7-21 days postop)
• Organisms: Staph aureus (70%), Strep species, polymicrobial (diabetes)
• Diagnosis: Wound culture, blood cultures, CRP/ESR
• Management:
  • Superficial (skin/subcutaneous): Oral anti-staphylococcal antibiotics (e.g. flucloxacillin/dicloxacillin, or cefalexin) for ~7-14 days, guided by culture and local antimicrobial guidelines
  • Deep (bone/hardware): Surgical debridement + hardware retention (if fusion stable and hardware not loose) + a prolonged course of IV/oral antibiotics (typically ~6 weeks for implant-associated infection), per local protocol and microbiology advice
  • Severe (osteomyelitis, loose hardware): Hardware removal, external fixation, delayed revision fusion
• Prevention: Prophylactic IV antibiotic at induction (a first-generation cephalosporin such as cefazolin, with cover adjusted per local guidelines/MRSA status), minimally traumatic technique

Compartment Syndrome (<1%)

• Mechanism: Postop haematoma (anterior compartment), excessive swelling (tight splint)
• Presentation: Pain out of proportion, tense anterior leg, pain with passive toe flexion
• Management: EMERGENCY fasciotomy (release all four leg compartments)
• Prevention: Loose splint, elevate leg, educate patient (return if severe pain)

Late Postoperative Complications (>6 weeks)

Non-union (5-15%)

• Mechanism: Inadequate bone contact (gap at fusion site), smoking (vasoconstriction impairs healing), diabetes, talar AVN (poor blood supply)
• Presentation: Persistent pain at fusion site (3-6 months postop), pain with ambulation
• Diagnosis: X-ray at 3-6 months (no bridging bone across fusion site), CT (confirms non-union - gap visible on coronal/sagittal)
• Management:
  • Asymptomatic non-union: Observation (some patients function well despite non-union)
  • Symptomatic: Revision fusion (remove hardware, freshen bone surfaces, bone graft, re-fix with screws ± plate)
• Prevention: Smoking cessation (6 weeks pre-op, restart 12 weeks post-op), optimize diabetes (HbA1c <7%), adequate bone contact intraop, bone graft if AVN/cysts

Malunion (5-10%)

• Mechanism: Healed in wrong position (varus/valgus, dorsiflexion/plantarflexion)
• Presentation: Abnormal gait, foot pain (lateral column if varus, medial column if valgus)
• Diagnosis: Weight-bearing X-rays (measure alignment), compare to contralateral
• Management:
  • Mild (<5° varus) and asymptomatic: Observation, orthotic support
  • Severe (>10° varus) or symptomatic: Corrective osteotomy (cut through fusion, re-align, re-fix)
• Prevention: Intraop fluoroscopy checks (systematic - all planes), match contralateral foot alignment

Adjacent Joint Arthritis (30% at 10 years)

• Mechanism: Ankle fusion eliminates tibiotalar motion - subtalar and midfoot joints compensate (increased stress = accelerated arthritis)
• Presentation: Heel pain (subtalar arthritis), midfoot pain (talonavicular, calcaneocuboid arthritis)
• Diagnosis: Weight-bearing X-rays (subtalar joint narrowing, midfoot arthritis)
• Management:
  • Conservative: NSAIDs, orthotic support, activity modification
  • Surgical: Subtalar fusion (if subtalar arthritic), triple arthrodesis (if hindfoot globally arthritic)
• Prevention: None (inevitable consequence of fusion - counsel patient preop)

Hardware Complications

• Prominent Screws: Screw heads irritate soft tissue (anterior ankle)
  • Management: Hardware removal (>12 months postfusion - bone healed)
• Screw Breakage: Rare (if non-union, screws fail from cyclical loading)
  • Management: Revision fusion (remove broken hardware, re-fuse)

Immediate Postoperative Care (Day 0-2)

Recovery Room:

• Neurovascular check (DP pulse, deep peroneal nerve function - cannot test EHL/EDL immediately due to pain/swelling)
• Pain control: Popliteal nerve block (sciatic block - 12-18 hour analgesia), oral opioids (oxycodone 5-10mg Q4h PRN)
• X-ray (AP, lateral, mortise ankle - confirm hardware position, alignment)

Ward Care:

• Elevation: Leg elevated above heart level (24-48 hours - CRITICAL for swelling reduction)
• Cryotherapy: Ice packs 20 min Q2h (reduces swelling, pain)
• DVT Prophylaxis: Enoxaparin 40mg SC daily (continue until mobile) OR rivaroxaban 10mg PO daily
• Splint: Posterior short leg splint (ankle neutral, well-padded)

Discharge Criteria (Day 1-2):

• Pain controlled (NRS under 4 out of 10 on oral meds)
• Neurovascularly intact (DP pulse palpable)
• Safe mobilization (crutches non-weight-bearing - patient independent)
• Understands NWB restrictions (6-12 weeks)

Outpatient Follow-up Protocol

Week 2:

• Wound Check: Remove dressing, assess for infection (erythema, drainage), dehiscence
• Suture Removal: If interrupted nylon (vertical mattress), remove alternate sutures; if subcuticular, leave (absorbable)
• X-ray: AP and lateral ankle (assess hardware position - ensure no early loosening/migration)
• Splint Change: Re-apply posterior splint (or transition to CAM boot if wound healthy)
• Weight-Bearing: Continue NWB (crutches)

Week 6:

• X-ray: AP, lateral, mortise ankle (assess early fusion - trabecular bridging may be visible)
• Clinical Exam: ROM (ankle fused - no motion), tenderness at fusion site
• Transition to CAM Boot: If wound healed, remove splint, apply CAM boot (controlled ankle motion - but ankle fused so ROM N/A)
• Weight-Bearing: Continue NWB OR begin toe-touch weight-bearing (TTWB 10-20kg) if early radiographic healing

Week 12:

• X-ray: AP, lateral, mortise + weight-bearing (assess fusion progress - expect 50-70% bridging)
• CT Scan (If Uncertain): If X-ray equivocal (patient still painful, X-ray not clearly fused) - CT confirms bridging bone
• Weight-Bearing Progression:
  • Fusion progressing: Advance to partial weight-bearing (PWB 50% body weight with crutches)
  • Fusion solid: Advance to weight-bearing as tolerated (WBAT) with CAM boot

Month 6:

• X-ray: Weight-bearing AP and lateral (confirm solid fusion - 3/4 cortices bridged)
• CT Scan: If X-ray shows non-union (gap at fusion site, no bridging bone) - confirms non-union diagnosis
• Weight-Bearing: Full weight-bearing (FWB) in regular shoes (if fusion solid)
• Return to Activity: Unrestricted activities (fusion healed - no restrictions)

Month 12+:

• Final X-ray: Confirm mature fusion, assess adjacent joint health (subtalar, midfoot)
• Hardware Removal: Consider if symptomatic (prominent screws causing pain) - remove >12 months postfusion (fusion mature)

Physiotherapy Protocol

Phase 1 (Weeks 0-6): Protection

• Goals: Protect fusion site, prevent DVT, maintain upper body/contralateral leg strength
• Exercises:
  • Toe wiggling (prevent stiffness in toes)
  • Knee ROM (prevent stiffness - flexion/extension exercises)
  • Contralateral leg strengthening (prepare for crutch ambulation)
• Restrictions: NWB (no weight on operative leg), ankle immobilized (splint/boot)

Phase 2 (Weeks 6-12): Progressive Weight-Bearing

• Goals: Begin loading fusion site (stimulates bone healing), restore gait
• Exercises:
  • Toe-touch weight-bearing (10-20kg) with crutches (gradual load)
  • Progress to partial weight-bearing (50%) at 8-10 weeks if X-ray shows healing
  • Gait training (reduce limp - normalize gait pattern with CAM boot)
• Restrictions: CAM boot until fusion confirmed (12 weeks minimum)

Phase 3 (Months 3-6): Return to Function

• Goals: Full weight-bearing, independent ambulation, shoe transition
• Exercises:
  • WBAT in CAM boot (progress to FWB)
  • Transition to regular shoes (supportive - cushioned heel, rocker sole helpful)
  • Functional training (stairs, uneven ground, long-distance walking)
• Restrictions: No running/jumping until fusion confirmed solid (CT if needed)

Phase 4 (Months 6-12): Full Activity

• Goals: Unrestricted activities, optimize adjacent joint function (subtalar, midfoot)
• Exercises:
  • Subtalar strengthening (inversion/eversion with Theraband - compensates for lost ankle motion)
  • Balance training (single-leg stance - improves proprioception)
  • Return to sport (low-impact OK - cycling, swimming; high-impact with caution - running may stress midfoot)

Functional and Return-to-Activity Considerations

Rehabilitation Access: A structured, supervised physiotherapy programme improves gait re-education and adjacent-joint conditioning after fusion. Funding and access vary by health system and insurance/compensation status; engage the patient's local pathway early. Refer smokers to a recognised smoking-cessation service preoperatively, given the dominant effect of smoking on non-union.

Return to Work (typical guidance):

• Sedentary: 3-6 months (desk-based, no prolonged standing/walking)
• Light Manual: 6-9 months (occasional standing, light duties)
• Heavy Manual: 12+ months (some patients do not return to heavy labour - a fused ankle limits agility and endurance)

Driving:

• Right ankle fusion (or left-side-drive equivalent of the pedal foot): approximately 6-12 months - requires safe, reliable emergency braking; subtalar/midfoot compensate but reaction times are slower
• Non-pedal-foot fusion: earlier return (~3-6 months) where transmission/vehicle adaptation allows the unaffected foot to control the pedals
• Advise the patient preoperatively to arrange transport and to confirm requirements with their licensing authority and insurer

Permanent Impairment: Ankle fusion produces a permanent loss of tibiotalar motion. Counsel patients preoperatively about the functional trade-off and any occupational or disability-support implications relevant to their setting.