Triple Arthrodesis

1. Clinical Overview

Summary

The Triple Arthrodesis is the definitive salvage procedure for severe, rigid hindfoot deformity and pan-talar arthritis. It involves the surgical fusion of three critical hindfoot joints: the Subtalar (Talocalcaneal), Talonavicular, and Calcaneocuboid joints. By converting the hindfoot into a stable, rigid, plantigrade platform, this procedure eliminates pain, corrects fixed deformity, and provides a stable base for ambulation. [1,2]

The operation represents a trade-off: immediate pain relief and deformity correction are achieved at the cost of hindfoot motion and eventual adjacent joint degeneration. The procedure is indicated when single-joint fusions would be inadequate, typically in cases of multi-joint arthritis, severe post-traumatic deformity, or end-stage inflammatory arthropathy. [3]

Modern orthopaedic practice questions whether all three joints require fusion, leading to the evolution of the "Double Arthrodesis" (subtalar plus talonavicular) which preserves the lateral column and may reduce non-union rates while achieving similar clinical outcomes. [4,5]

Key Facts

The Three Joints:

1. Subtalar (ST) Joint: Articulation between talus and calcaneus. Primary motion: inversion and eversion (hindfoot coronal plane motion). Contributes approximately 50% of hindfoot motion. [6]
2. Talonavicular (TN) Joint: The "Acetabulum Pedis"

• the spherical head of the talus articulates with the concave socket formed by the navicular and spring ligament complex. Primary motion: triplanar rotation. Accounts for approximately 40% of hindfoot motion and is the key to hindfoot flexibility. [7]

3. Calcaneocuboid (CC) Joint: Lateral column articulation. Primary motion: minimal gliding. Provides lateral column stability and serves as a buttress against forefoot abduction. [8]

Biomechanical Principles:

• Normal hindfoot motion: 20-30° of inversion/eversion at subtalar joint
• Triple arthrodesis eliminates 90-100% of hindfoot motion
• Ankle joint compensates by increasing rotational stress 3-4 fold
• Loss of shock absorption mechanism accelerates adjacent joint wear [9,10]

The Double vs Triple Debate: Contemporary evidence suggests that isolated calcaneocuboid arthritis is rare, and fusion of this joint may not be necessary for deformity correction in many cases. Double arthrodesis (ST + TN) preserves lateral column length, potentially reduces non-union rates (particularly at the CC joint), and may decrease the incidence of sural nerve complications. [4,11]

Long-Term Sequelae:

• Adjacent ankle arthritis develops in 50-100% of patients over 10-20 years
• Midfoot arthritis occurs in 30-40% of patients
• Despite arthritic changes, patient satisfaction remains high (80-90%) due to pain relief and functional improvement [12,13]

Clinical Pearls

"Position is Everything": The fused hindfoot cannot accommodate or compensate for malposition. Varus malposition results in lateral column overload, recurrent ankle sprains, and 5th metatarsal stress fractures. Excessive valgus causes lateral impingement and peroneal tendinopathy. The target position is 5-7° of valgus (measured on AP standing radiographs), neutral dorsiflexion, and neutral rotation relative to the tibia. [14,15]

"The Talonavicular Joint is the Key": The TN joint is the most important articulation in the hindfoot complex. It is also the most prone to non-union (5-15% non-union rate) due to its spherical geometry, high rotational forces, and relatively poor vascularity. Meticulous preparation and robust fixation are essential. [16,17]

"The Peg Leg Effect": Pre-existing ankle stiffness is a relative contraindication. If the ankle has less than 10° of motion, performing a triple arthrodesis creates a functional "pantalofusion" effect, severely limiting gait and requiring rocker-bottom shoes. Consider pantalar fusion or total ankle replacement with hindfoot fusion in these cases. [18]

"Smoking is the Enemy": Smoking increases non-union risk by 3-5 fold and wound complications by 2-3 fold. Patients must achieve complete smoking cessation for at least 6-8 weeks preoperatively. Consider adjunctive bone stimulation in high-risk patients. [19,20]

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2. Epidemiology

Patient Demographics

Triple arthrodesis is most commonly performed in:

• Adults aged 40-65 years (peak incidence)
• Slight female predominance (60:40) due to higher incidence of inflammatory arthritis and PTTD
• Bilateral procedures in 10-15% of cases, particularly in rheumatoid arthritis and hereditary neuropathies [21]

Indications

Primary Indications:

End-Stage Posterior Tibial Tendon Dysfunction (PTTD):

• Stage 3: Rigid flatfoot deformity with fixed hindfoot valgus
• Stage 4: Rigid flatfoot with associated ankle valgus/deltoid ligament incompetence
• Most common indication, representing 30-40% of all triple arthrodeses [22]

Cavovarus Deformity:

• Charcot-Marie-Tooth disease (hereditary motor sensory neuropathy)
• Post-traumatic contracture
• Residual clubfoot deformity
• Represents 20-25% of indications [23]

Post-Traumatic Arthritis:

• Calcaneal fracture malunion with subtalar arthritis
• Talus fracture sequelae
• Lisfranc injury with hindfoot involvement
• Multiple crush injuries affecting all three joints
• Represents 15-20% of indications [24]

Inflammatory Arthropathy:

• Rheumatoid arthritis with pan-talar destruction
• Psoriatic arthritis
• Ankylosing spondylitis
• Represents 10-15% of indications [25]

Other Indications:

• Failed tarsal coalition excision with persistent pain
• Neuromuscular disorders (polio, cerebral palsy) - Lambrinudi modification
• Post-infectious arthritis (septic arthritis sequelae)
• Avascular necrosis of the talus
• Neuropathic arthropathy (Charcot) - controversial due to high failure rate [26]

Contraindications

Absolute Contraindications:

• Active infection (hardware will fail; requires two-stage procedure)
• Severe peripheral vascular disease (ABI less than 0.5, non-palpable pulses)
• Inadequate soft tissue envelope (exposed bone, radiation damage)
• Medical unfitness for surgery (ASA IV-V)
• Patient non-compliance with non-weight-bearing restrictions

Relative Contraindications:

• Ankle arthritis (consider pantalar fusion or TAR + hindfoot fusion)
• Ankle stiffness less than 10° motion (functional pantalofusion effect)
• Active smoking (must cease 6-8 weeks pre-op)
• Uncontrolled diabetes (HbA1c > 8.5%)
• Neuropathy (Charcot risk, consider internal/external fixation)
• Age less than 18 years (physeal considerations)
• Obesity (BMI > 40, increased non-union risk)
• Workers' compensation claims (lower satisfaction scores) [27,28]

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3. Pathophysiology

Biomechanics of the Normal Hindfoot

The hindfoot functions as a dynamic torque converter, transforming rotational forces from the leg into triplanar motion of the foot. The three joints work in concert:

Subtalar Joint:

• Axis oriented 42° to horizontal, 16° medial to midline
• Inversion/eversion: 20-30° total motion
• Coupled with internal/external tibial rotation
• Critical for walking on uneven ground [29]

Talonavicular Joint:

• "Universal joint" of the foot
• Triplanar motion: dorsiflexion/plantarflexion, abduction/adduction, supination/pronation
• Transmits 80% of body weight from talus to midfoot
• Spring ligament provides plantar support [30]

Calcaneocuboid Joint:

• Predominantly gliding motion
• Stabilizes lateral column
• Acts as buttress against forefoot abduction
• Minimal isolated motion [31]

Biomechanical Consequences of Fusion

Loss of Shock Absorption: Normal hindfoot motion dissipates 30-40% of ground reaction forces through joint motion. After triple arthrodesis, these forces are transmitted directly to the ankle joint, increasing contact stress by 200-300%. [9,32]

Compensatory Ankle Motion: The ankle attempts to compensate for lost hindfoot motion by increasing rotational excursion. Talar dome shear stress increases 3-4 fold, accelerating cartilage degeneration. [10]

Gait Alterations:

• Decreased stride length (10-15%)
• Reduced walking speed (15-20%)
• Increased energy expenditure (20-30%)
• Loss of terrain accommodation
• Altered muscle firing patterns [33]

Adjacent Joint Degeneration:

• Ankle arthritis: 50-100% radiographic prevalence at 10-20 years
• Midfoot arthritis: 30-40% prevalence
• First MTP joint: increased stress and hallux rigidus [12,13]

Deformity Patterns and Correction Strategies

Planovalgus Deformity (Flatfoot):

• Pathoanatomy: Talonavicular subluxation/dislocation, subtalar eversion, forefoot abduction
• Correction: Medial column shortening (resect wedge from TN joint), subtalar correction, maintain lateral column length
• Goal: Restore medial longitudinal arch, align heel to 5-7° valgus [34]

Cavovarus Deformity (High Arch):

• Pathoanatomy: Subtalar inversion, plantarflexed first ray, forefoot adduction
• Correction: Lateral column shortening (resect wedge from CC joint), subtalar de-rotation, consider first ray dorsiflexion osteotomy
• Goal: Plantigrade foot, tripod weight-bearing, neutral hindfoot alignment [35]

Equinus Contracture (Lambrinudi):

• Pathoanatomy: Dorsiflexion weakness (drop foot), ankle plantarflexion contracture
• Correction: Anterior wedge resection from talus, fuse foot in relative plantarflexion (10-15°) to compensate for ankle position
• Goal: Foot clearance in swing phase, stable stance [36]

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4. Clinical Assessment

History

Pain Characteristics:

• Location: Hindfoot (subtalar, TN, CC joints)
• Character: Deep, aching, mechanical (worse with activity)
• Severity: Assess impact on function, use validated scores (AOFAS, FADI)
• Duration: Typically long-standing (years)
• Previous treatments: Orthotics, injections, previous surgeries

Functional Impact:

• Walking distance limitation
• Terrain limitations (flat surfaces only)
• Footwear restrictions
• Impact on work/activities of daily living
• Use of walking aids

Medical History:

• Inflammatory conditions (RA, psoriatic arthritis, ankylosing spondylitis)
• Neurological conditions (CMT, cerebral palsy, polio)
• Diabetes and neuropathy
• Vascular disease
• Smoking history (pack-years)
• Previous foot/ankle trauma or surgery

Physical Examination

Inspection:

• Alignment: Observe from behind (hindfoot valgus/varus angle)
• Deformity: Flatfoot vs cavus, forefoot abduction/adduction
• Muscle wasting: Calf atrophy, intrinsic muscle wasting
• Skin: Scars, calluses (plantar medial = flatfoot, lateral = cavus), ulcers
• Swelling: Chronic synovitis, recent acute flare

Palpation:

• Tenderness: Localize to specific joints (ST, TN, CC)
• Synovitis: Boggy swelling, effusion
• Tibialis posterior tendon: Palpate along course, assess continuity

Range of Motion:

• Ankle: Dorsiflexion/plantarflexion (normal 20°/50°) - assess for stiffness
• Subtalar: Inversion/eversion (normal 20-30°) - assess flexibility vs rigidity
• Forefoot: Supination/pronation, 1st ray motion
• Flexibility Tests:
  • "Heel rise test: Assess PTTD (failure to invert heel)"
  • "Coleman block test: Assess cavus flexibility (place block under lateral foot)"
  • "Silfverskiöld test: Differentiate gastrocnemius vs soleus contracture"

Special Tests:

• Single heel rise: Inability suggests PTTD
• Too many toes sign: > 2 toes visible from behind suggests forefoot abduction
• Peek-a-boo heel sign: Heel visible medially suggests severe valgus

Neurovascular Assessment:

• Pulses: Dorsalis pedis, posterior tibial (document presence/absence)
• Capillary refill: less than 2 seconds normal
• Sensation: Light touch, proprioception (assess neuropathy)
• Motor: Tibialis anterior (dorsiflexion), tibialis posterior (inversion), peroneals (eversion), gastrocnemius-soleus (plantarflexion)
• Reflexes: Ankle jerk (S1), assess for upper motor neuron signs

Footwear Examination:

• Wear pattern (medial = valgus, lateral = varus)
• Orthotic use and effectiveness

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5. Investigations

Imaging

Plain Radiographs (Mandatory):

Weight-Bearing AP and Lateral Foot:

• Assess joint space narrowing, osteophytes, subchondral sclerosis/cysts
• AP view measurements:
  • Talonavicular coverage angle (normal less than 7°)
  • Talus-1st metatarsal angle (normal 0-20°)
  • Hindfoot alignment (calcaneal valgus/varus angle)
• Lateral view measurements:
  • Calcaneal pitch (normal 20-30°; less than 15° = flatfoot, > 30° = cavus)
  • Talus-1st metatarsal angle (Meary's line, normal 0-5°)
  • Talonavicular subluxation [37]

Weight-Bearing Ankle AP and Lateral:

• Critical: Assess ankle joint for arthritis (must be preserved for triple arthrodesis)
• Tibiotalar angle (ankle valgus in PTTD Stage 4)
• Joint space width (normal > 3mm)
• If ankle arthritic, consider pantalar fusion or TAR + hindfoot fusion

Hindfoot Alignment View (Saltzman):

• Long-axial view of hindfoot
• Quantifies hindfoot valgus/varus
• Guides surgical planning [38]

Computed Tomography (CT) Scan:

• Gold standard for assessing arthritis extent
• Identifies occult fractures, coalition
• 3D reconstruction for surgical planning
• Assesses bone quality and stock
• Template for deformity correction [39]

Magnetic Resonance Imaging (MRI):

• Not routinely required for isolated arthritis
• Indications: Assess PTTD, AVN of talus, soft tissue pathology
• Evaluate for occult infection if suspected
• Assess spring ligament integrity in flatfoot

Additional Imaging (Selected Cases):

• SPECT-CT: Identify symptomatic joints in multi-joint arthritis
• Vascular studies: Doppler, ABI if vascular disease suspected (ABI > 0.7 required)
• Weight-bearing CT: Emerging technology for 3D deformity analysis

Laboratory Investigations

Routine Pre-Operative:

• Full blood count (anemia, infection)
• Renal function (if using nephrotoxic antibiotics)
• HbA1c (optimize to less than 8.5% in diabetics)
• Coagulation screen (if anticoagulated)
• Group and save (blood loss typically minimal)

If Inflammatory Arthritis Suspected:

• ESR, CRP (disease activity)
• Rheumatoid factor, anti-CCP
• Coordinate with rheumatology for peri-operative DMARD management

If Infection Suspected:

• ESR, CRP, WBC
• Consider aspiration for culture and sensitivity
• Rule out infection before proceeding with fusion

Functional Assessment

Patient-Reported Outcome Measures:

• AOFAS Ankle-Hindfoot Score (0-100, validated for hindfoot pathology)
• Foot and Ankle Disability Index (FADI)
• SF-36 or EQ-5D (general health quality of life)
• Visual Analogue Scale (VAS) for pain

Gait Analysis (Research/Complex Cases):

• Quantifies functional deficit
• Guides post-operative rehabilitation

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6. Management Algorithm

                RIGID HINDFOOT DEFORMITY + PAIN
                            ↓
                  FAILED CONSERVATIVE TREATMENT
                  (Orthotics, Injections, PT)
                            ↓
                     ASSESS ANKLE JOINT
              ┌──────────────┴──────────────┐
         ANKLE PRESERVED               ANKLE ARTHRITIC
              ↓                              ↓
       TRIPLE ARTHRODESIS             PANTALAR FUSION
       (or Double)                    (or TAR + Hindfoot Fusion)
              ↓
         ASSESS DEFORMITY
              ↓
    ┌─────────┴─────────┐
FLATFOOT             CAVOVARUS
    ↓                     ↓
Medial wedge         Lateral wedge
TN resection         CC resection
ST correction        ST correction
    │                     │
    └─────────┬───────────┘
              ↓
         SURGICAL APPROACH
    ┌──────────┴──────────┐
TWO-INCISION         SINGLE INCISION
(Traditional)         (Extended lateral)
    ↓                     ↓
Medial: TN            Lateral only: All 3 joints
Lateral: ST + CC      (Worse TN exposure)
    │                     │
    └─────────┬───────────┘
              ↓
           FIXATION
    ┌──────────┴──────────┐
    ST: 7.3mm screw
    TN: 2 screws or plate
    CC: Screws or staples
              ↓
        POST-OPERATIVE
    NWB 6-8 weeks → PWB → FWB at 12 weeks

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7. Surgical Technique: Step-by-Step

Pre-Operative Planning

Templating:

• Trace deformity on weight-bearing radiographs
• Plan wedge resections to achieve neutral alignment
• Calculate required bone resection (typically 5-10mm)
• Plan screw trajectory to avoid neurovascular structures

Optimization:

• Smoking cessation 6-8 weeks minimum
• Optimize HbA1c to less than 8.5% in diabetics
• Weight optimization (BMI less than 40)
• Nutrition optimization (albumin > 3.5 g/dL)
• Discontinue DMARDs per rheumatology guidance (typically 1-2 weeks pre-op for methotrexate)

Consent Discussion:

• Expected outcomes: 80-90% pain relief, improved function
• Realistic expectations: Loss of hindfoot motion, gait changes, stiff foot
• Risks: Non-union (5-15%), wound complications (5-10%), nerve injury (5%), infection (2-5%), malunion requiring revision (2-5%), eventual ankle arthritis (50-100% over 20 years)
• Alternatives: Conservative treatment, isolated joint fusions, ankle replacement with fusion
• Recovery: Non-weight-bearing 6-8 weeks, return to normal function 6-12 months

Equipment

Instruments:

• Standard foot/ankle set
• Osteotomes (5mm, 10mm, 15mm straight and curved)
• Curettes (various sizes)
• Lamina spreaders
• K-wire (1.6mm, 2.0mm)
• Drill (2.5mm, 3.5mm)
• Sagittal saw or oscillating saw
• Power reamer (optional, for joint preparation)

Implants:

• 6.5mm or 7.3mm cannulated screws (fully threaded, partially threaded)
• 4.0mm cannulated screws
• Low-profile plates (if poor bone quality or revision)
• Staples (for CC joint, alternative to screws)
• Bone graft options: Local autograft, iliac crest, allograft, bone graft substitute

Adjuncts:

• Thigh tourniquet
• Image intensifier (C-arm)
• Cell saver (if blood loss anticipated)
• Bone stimulator (if high non-union risk)

Anaesthesia and Positioning

Anaesthesia:

• General anaesthesia with endotracheal intubation (preferred)
• Spinal or regional anaesthesia (alternative)
• Popliteal nerve block for post-operative analgesia
• IV antibiotics within 60 minutes of incision (cefazolin 2g, or vancomycin if allergic)

Positioning:

• Supine position
• Bump under ipsilateral hip (30° internal rotation) to bring lateral foot upward
• Thigh tourniquet applied (inflated to 250-300mmHg after exsanguination)
• Contralateral leg padded and supported
• Ensure fluoroscopy C-arm access from both sides

Setup:

• Surgeon seated on lateral side of operative foot
• Assistant opposite
• Instrument table on lateral side
• Image intensifier from contralateral side
• WHO surgical safety checklist
• Marking and consent verification
• Antibiotic prophylaxis confirmation

Surgical Anatomy

Surface Anatomy:

• Lateral incision: From tip of fibula to base of 4th metatarsal (follows course of sural nerve)
• Medial incision: From navicular tuberosity to 1 cm inferior to medial malleolus (parallel to tibialis anterior tendon)
• Ensure adequate skin bridge (minimum 5-7 cm) between incisions

Deep Anatomy - Lateral Approach:

• Skin and subcutaneous tissue
• Identify and protect sural nerve (dorsal to incision, provides sensation to lateral foot)
• Incise deep fascia
• Extensor digitorum brevis (EDB) muscle belly - reflect plantarward
• Peroneus brevis and longus tendons - retract dorsally
• Exposure of subtalar joint (posterior facet) and calcaneocuboid joint

Deep Anatomy - Medial Approach:

• Skin and subcutaneous tissue
• Identify and protect saphenous vein and nerve
• Develop interval between tibialis anterior (dorsal) and tibialis posterior (plantar)
• Retract neurovascular bundle (posterior tibial artery, nerve) plantarward
• Exposure of talonavicular joint

Critical Structures to Protect:

• Sural nerve: Most commonly injured (5-10% incidence), causes lateral foot numbness and neuroma
• Superficial peroneal nerve: Injured if dissection too dorsal, causes dorsal foot numbness
• Posterior tibial neurovascular bundle: Must be protected with medial retraction
• Peroneal tendons: Retract carefully to avoid subluxation/injury
• Tibialis anterior tendon: Avoid injury during medial approach

Operative Steps

Step 1: Lateral Incision and Exposure

Incision:

• Mark incision from fibula tip to 4th metatarsal base (approximately 8-10 cm)
• Curvilinear, centered over sinus tarsi
• Deepen through skin and subcutaneous tissue
• Identify sural nerve branches (vary in location, typically posterior-inferior to incision)

Dissection:

• Protect sural nerve with vessel loop or retract posteriorly
• Incise deep fascia in line with incision
• Identify EDB muscle belly, elevate plantarward from calcaneus and origin
• Retract peroneal tendons dorsally with Hohmann retractor
• Clean soft tissue from sinus tarsi

Subtalar Joint Exposure:

• Identify posterior facet of subtalar joint
• Use lamina spreader or Hintermann retractor to distract joint
• Clear soft tissue, scar, and synovium from joint
• Expose articular surfaces circumferentially

Calcaneocuboid Joint Exposure:

• Palpate CC joint approximately 1 cm distal and inferior to anterior process of calcaneus
• Incise periosteum longitudinally
• Use elevator to subperiosteal dissection
• Place Hohmann retractors dorsally and plantarward
• Expose joint surfaces

Step 2: Medial Incision and Talonavicular Exposure

Incision:

• Mark incision from navicular tuberosity to 1 cm distal-inferior to medial malleolus (approximately 6-8 cm)
• Incision parallel to tibialis anterior tendon
• Deepen through skin and subcutaneous tissue
• Identify and protect saphenous vein/nerve

Dissection:

• Develop interval between tibialis anterior (retract dorsally) and tibialis posterior (retract plantarward)
• Incise talonavicular joint capsule longitudinally
• Place Hohmann retractors to expose joint
• Posterior tibial neurovascular bundle typically lies posterior-inferior, protect with retractor

Talonavicular Joint Exposure:

• Plantarflex ankle to facilitate TN exposure (relaxes posterior structures)
• Distract joint with lamina spreader
• Circumferentially expose articular surfaces
• Identify and preserve spring ligament (plantar support) if possible, though often attenuated

Step 3: Joint Preparation (The Critical Step)

This is the most important technical step. Inadequate preparation is the primary cause of non-union. The goal is to create flat, congruent, bleeding bony surfaces with maximum contact area.

General Principles:

• Remove all cartilage and subchondral plate to healthy, punctate bleeding bone ("fish scaling")
• Create flat or gently curved surfaces (avoid creating spherical surfaces with poor contact)
• Maintain bone stock (minimize resection)
• Correct deformity through wedge resections (planned pre-operatively)

Subtalar Joint Preparation:

• Distract joint with lamina spreader or Hintermann distractor
• Use curved osteotome to remove cartilage from posterior facet of calcaneus
• Denude talar surface with osteotome or curette
• Use power burr or hand rasp to create flat surfaces
• For valgus correction: Resect lateral wedge from calcaneus
• For varus correction: Resect medial wedge from calcaneus
• Ensure congruent apposition when distraction released
• Decorticate to bleeding bone (use 2mm drill holes ("fish scaling") if sclerotic)

Talonavicular Joint Preparation:

• Most prone to non-union - meticulous technique essential
• Distract joint and plantarflex ankle
• Remove cartilage from talar head with osteotome (spherical surface challenging)
• Denude navicular socket with curette and osteotome
• For flatfoot correction: Resect medial-plantar wedge to restore arch (5-10mm typically)
• For cavus correction: Resect dorsal wedge
• Flatten spherical surfaces to increase contact area
• Decorticate to punctate bleeding bone
• Consider supplemental bone graft if significant defect

Calcaneocuboid Joint Preparation:

• Distract joint with lamina spreader
• Remove cartilage with osteotome from calcaneus and cuboid
• For cavus correction: Resect lateral wedge (5-10mm) to drop arch
• For flatfoot: Minimal resection (preserve lateral column length)
• Create flat congruent surfaces

Deformity Correction:

• Assess alignment with provisional fixation using K-wires
• Check alignment clinically (visual assessment of forefoot-hindfoot relationship)
• Confirm with fluoroscopy (AP hindfoot alignment view)
• Target: 5-7° hindfoot valgus, neutral sagittal plane, neutral rotation
• Make additional wedge corrections as needed

Step 4: Provisional Fixation

• Restore foot position: heel in 5-7° valgus, neutral rotation
• Insert provisional K-wires across each joint
• Check position with fluoroscopy:
  • AP and lateral ankle and foot views
  • Ensure optimal alignment before definitive fixation
  • Simulated weight-bearing view (push up on forefoot to load hindfoot)

Typical K-wire positions:

• Subtalar: 2.0mm wire from plantar posterior calcaneus to talar body (parallel to intended screw)
• Talonavicular: 1.6mm wire from navicular to talar neck (avoid neurovascular structures medially)
• Calcaneocuboid: 1.6mm wire from cuboid to calcaneus

Step 5: Definitive Fixation

Fixation must achieve rigid stability for fusion. Compression at arthrodesis sites is essential.

Subtalar Joint Fixation:

• Large 6.5mm or 7.3mm partially threaded cannulated screw
• Entry point: Plantar-posterior aspect of calcaneus (tuberosity)
• Trajectory: Across posterior facet into talar body/neck
• Insert guidewire over provisional K-wire
• Measure screw length (typically 60-80mm)
• Overdrill posterior thread path with 7.3mm drill (allows screw head to compress)
• Insert partially threaded screw, compressing subtalar joint
• Confirm trajectory and position with fluoroscopy
• Alternative: Two 6.5mm screws for additional stability

Talonavicular Joint Fixation:

• Most critical for non-union prevention
• Option 1: Two 4.0mm cannulated screws (standard)
  • "Entry points: Medial and lateral aspects of navicular"
  • "Trajectory: Across TN joint into talar neck"
  • Divergent screws provide rotational stability
  • Typically 40-50mm length
• Option 2: Low-profile dorsal plate (if poor bone quality, revision, or high non-union risk)
  • 2.7mm or 3.5mm plate with 4-6 screws
  • Increased stability but higher hardware prominence
• Confirm compression and position with fluoroscopy

Calcaneocuboid Joint Fixation:

• Option 1: One or two 4.0mm cannulated screws
  • "Entry: Lateral cuboid"
  • "Trajectory: Into calcaneus"
  • Typically 35-45mm length
• Option 2: Staples (2-3 staples)
  • Lower profile, good compression
  • Faster insertion
  • Comparable fusion rates to screws
• Option 3: Omit fixation if performing double arthrodesis (ST + TN only)

Adjunctive Bone Graft:

• Indications: Large defects, poor bone quality, revision, smoking, diabetes
• Options:
  • Local bone graft from resected wedges (morselized and packed into interstices)
  • Iliac crest autograft (gold standard, but donor site morbidity)
  • Allograft (cancellous chips or structural)
  • Bone graft substitutes (demineralized bone matrix, calcium phosphate)
• Pack graft into prepared joint surfaces and around fixation

Step 6: Closure

• Release tourniquet, achieve meticulous hemostasis with electrocautery
• Irrigate wounds copiously (reduce infection risk)
• No drains typically required (small dead space)
• Repair EDB muscle over lateral wound (provides soft tissue coverage)
• Close deep fascia with 2-0 absorbable suture
• Close subcutaneous layer with 3-0 absorbable suture
• Skin closure: 3-0 or 4-0 nylon or monofilament (remove 2-3 weeks post-op)
• Apply sterile dressings with moderate compression
• Apply well-padded posterior slab splint in neutral position
• Elevate leg in recovery

Technical Pearls

💡 Sural Nerve Protection: The sural nerve is variable in location. Identify it early, protect throughout, and consider subcutaneous transposition if stretched or at risk.

💡 EDB Muscle Preservation: Reflect the EDB plantarward rather than excising. It provides valuable soft tissue coverage during closure.

💡 TN Joint Preparation: The spherical talar head is challenging to prepare. Use a combination of curved osteotomes, curettes, and power burr to create a flat contact surface.

💡 Fish Scaling Technique: In sclerotic bone (common in arthritis), create multiple 2mm drill holes across the prepared surface to expose bleeding cancellous bone and enhance fusion.

💡 Compression is Critical: Ensure screws are compressing the fusion site. Use partially threaded screws for subtalar joint; overdrill the near cortex to allow screw head to compress.

💡 Check Alignment Intra-Operatively: Use the "eyeball test"

• stand at the foot of the table and assess hindfoot alignment. Fluoroscopy confirms but clinical assessment is essential.

💡 Avoid Over-Resection: Excessive bone resection shortens the foot and creates structural deficits. Remove only what's needed for deformity correction.

Pitfalls to Avoid

⚠️ Malposition in Varus: The most common and devastating complication. Always err toward valgus. If uncertain, choose 7° valgus over 3° valgus.

⚠️ Inadequate TN Preparation: The #1 cause of non-union. The spherical geometry makes it easy to under-prepare. Be meticulous.

⚠️ Sural Nerve Injury: Failure to identify and protect leads to painful neuroma. If nerve is transected, consider primary repair or burying nerve end in muscle.

⚠️ Posterior Tibial Neurovascular Bundle Injury: Overzealous medial dissection or retraction can damage the bundle. Gentle retraction, identify structures early.

⚠️ Screw Malposition: Screws can penetrate ankle joint, neurovascular structures, or skin. Use fluoroscopy to confirm trajectory before drilling.

⚠️ Excessive Soft Tissue Stripping: Preserve periosteal blood supply. Subperiosteal dissection protects vascular supply to fusion site.

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8. Post-Operative Care

Immediate Post-Operative Period (0-2 Weeks)

Inpatient Phase (1-2 days typically):

• Elevation of leg above heart level (reduce swelling)
• Posterior slab splint maintained
• Strict non-weight-bearing (NWB) with crutches or walker
• DVT prophylaxis: Low molecular weight heparin (enoxaparin 40mg SC daily) or mechanical compression devices (if low bleeding risk)
• Analgesia: Multimodal approach (opioids, NSAIDs - controversial due to potential fusion inhibition, acetaminophen, nerve block)
• Neurovascular observations (check dorsalis pedis pulse, capillary refill, sensation)
• Monitor for compartment syndrome (rare but catastrophic): Pain out of proportion, pain with passive stretch, paresthesia, pulselessness, pallor

Discharge Criteria:

• Adequate pain control on oral medications
• Safe mobilization NWB with walking aids
• No signs of vascular compromise or infection
• Patient education on elevation, wound care, NWB restrictions

First Post-Op Visit (10-14 days):

• Wound inspection
• Remove/replace splint if soiled
• Radiographs (AP and lateral foot/ankle) to confirm fixation position
• Continue NWB, elevate when sitting/lying

Early Post-Operative (2-6 Weeks)

Week 2:

• Suture removal (if non-absorbable)
• Apply below-knee non-weight-bearing cast or removable boot (if compliant patient)
• Continue strict NWB
• Radiographs if concern for loss of fixation

Week 6:

• Clinical assessment: Wound healing, pain level, swelling
• Radiographs: AP and lateral foot/ankle
  • Assess for early fusion (trabeculation across joint), loss of fixation, or displacement
• If appropriate progress:
  • Transition to weight-bearing cast or CAM walker boot
  • "Begin partial weight-bearing (PWB): 25-50% body weight with crutches"
  • Incrementally increase weight-bearing over 4-6 weeks

Intermediate Post-Operative (6-12 Weeks)

Week 9:

• Clinical assessment
• Radiographs: Assess fusion progression
• Increase to full weight-bearing (FWB) in boot if evidence of fusion
• Begin gentle ankle range of motion exercises (to prevent ankle stiffness)

Week 12:

• Clinical assessment: Pain, function, ability to weight-bear
• Radiographs: AP, lateral, oblique foot/ankle
  • "Signs of fusion: Trabeculation across joints, obliteration of joint space, absence of lucency around screws"
  • "If solid fusion: Transition to supportive shoe with custom orthotic"
  • "If questionable fusion: Continue boot, repeat radiographs in 4 weeks, consider CT scan"
• Refer to physiotherapy: Gait retraining, ankle strengthening, proprioception

Late Post-Operative (3-12 Months)

Month 3-6:

• Gradual return to normal activities
• Progressive strengthening and proprioceptive exercises
• Custom orthotic with rocker-bottom shoe (aids gait efficiency)
• Address residual swelling with compression stockings
• Monitor for complications (non-union, malunion, adjacent joint pain)

Month 6:

• Radiographs if ongoing pain or concern
• Return to work (sedentary: 3 months, manual labor: 6 months)
• Return to low-impact activities (swimming, cycling)

Month 12:

• Final assessment
• Patient-reported outcome measures (AOFAS, FADI, VAS pain, satisfaction)
• Radiographs: Document fusion status
• High-impact activities may resume if fused and pain-free (though many patients self-limit due to foot stiffness)

Long-Term Follow-Up (Beyond 1 Year)

• Annual or biannual review (depending on symptoms)
• Monitor for adjacent joint degeneration (ankle, midfoot)
• Manage ankle arthritis if develops: Analgesia, injections, bracing, ultimately TAR or ankle fusion if severe
• Patient education: Expected development of ankle arthritis over 10-20 years

Return to Activity Milestones

Signs of Complications Requiring Earlier Review

• Severe, uncontrolled pain
• Fever, wound erythema, discharge (infection)
• Loss of sensation or motor function (nerve injury)
• Cold, pale, pulseless foot (vascular emergency)
• Excessive swelling not improving with elevation
• Wound dehiscence or necrosis

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9. Complications

Non-Union

Incidence: 5-15% overall (varies by joint)

• Subtalar: 5-10%
• Talonavicular: 10-15% (highest risk)
• Calcaneocuboid: 5-8%

Risk Factors:

• Smoking (3-5x increased risk)
• Diabetes mellitus
• Chronic corticosteroid use
• Rheumatoid arthritis
• Poor bone quality (osteoporosis)
• Inadequate fixation or joint preparation
• Infection
• Patient non-compliance with NWB restrictions [19,40]

Clinical Presentation:

• Persistent pain at fusion site beyond 3-4 months
• Pain with weight-bearing, relieved with rest
• Focal tenderness over non-united joint
• Mobility at fusion site on examination (subtle, often difficult to detect)

Diagnosis:

• Radiographs: Persistent lucency at fusion site, sclerotic margins, absence of trabeculation, hardware loosening (halo around screws)
• CT scan: Gold standard, demonstrates lack of bony bridging across joint
• Bone scan: Increased uptake at non-union site (but not specific)

Management:

• Asymptomatic non-union: Observation, may not require intervention if pain-free
• Symptomatic non-union: Revision surgery indicated
  • Remove hardware, debride fibrous tissue and sclerotic bone
  • Re-prepare surfaces to bleeding bone
  • Structural bone graft (autograft from iliac crest, distal tibia, or allograft)
  • Augmented fixation (plate fixation, additional screws, external fixation in severe cases)
  • Bone stimulation (electrical or ultrasound)
  • Optimize modifiable risk factors (smoking cessation, glycemic control)
  • "Success rate of revision: 70-85% [41]"

Malunion

Incidence: 2-10%

Definition: Fusion in unacceptable position (typically varus or excessive valgus)

Clinical Presentation:

• Varus malunion (most common and problematic):
  • Lateral column overload pain
  • Recurrent lateral ankle sprains
  • 5th metatarsal stress fractures or pain
  • Callus formation under lateral foot
  • Difficulty with footwear
• Valgus malunion:
  • Lateral impingement (fibula against calcaneus)
  • Peroneal tendon irritation
  • Medial ankle instability

Diagnosis:

• Clinical: Alignment assessment (hindfoot valgus/varus angle)
• Radiographs: Hindfoot alignment view (Saltzman view)
• CT scan: Quantify deformity in 3D

Management:

• Mild malunion (less than 10° varus/valgus), tolerable symptoms: Orthotic management, shoe modifications
• Severe malunion or intolerable symptoms: Revision surgery
  • Corrective osteotomy through fusion mass (challenging, high non-union risk)
  • Augment with bone graft and rigid fixation (plate fixation typically required)
  • Consider external fixation for severe cases
  • "Alternative: Ankle fusion in optimal position to compensate for hindfoot malposition [42]"

Wound Complications

Incidence: 5-15%

Types:

• Superficial wound infection (most common)
• Deep infection
• Wound dehiscence
• Skin necrosis (particularly in thin skin, vascular disease)

Risk Factors:

• Smoking
• Diabetes
• Peripheral vascular disease
• Rheumatoid arthritis (thin skin, immunosuppression)
• Steroid use
• Poor surgical technique (excessive tension, inadequate soft tissue handling)
• Hematoma formation

Clinical Presentation:

• Erythema, warmth, swelling, purulent discharge
• Systemic signs: Fever, elevated WBC, CRP

Management:

• Superficial infection: Oral antibiotics (cover Staph aureus, consider MRSA coverage)
• Deep infection:
  • Urgent surgical debridement
  • Intravenous antibiotics (per culture sensitivities, typically 4-6 weeks)
  • Retain hardware if stable and within 3 months of surgery (biofilm forms after 3 months)
  • "If hardware loose or infected: Remove, debride, antibiotic spacer, staged revision"
  • Consider vacuum-assisted closure (VAC) therapy for large wounds
• Wound dehiscence: Wound care, skin grafting or flap coverage if needed
• Skin necrosis: Debridement, VAC therapy, consider plastic surgery input [43]

Nerve Injury

Incidence: 5-10%

Nerves at Risk:

• Sural nerve (most common, 5-8%): Lateral incision
• Superficial peroneal nerve (2-3%): Dorsal dissection
• Saphenous nerve (1-2%): Medial incision
• Tibial nerve or branches (less than 1%): Medial dissection

Clinical Presentation:

• Neurapraxia (stretch injury): Temporary numbness/paresthesia, recovers over weeks-months
• Neurotmesis (transection): Permanent numbness, possible painful neuroma

Management:

• Neurapraxia: Reassurance, observation (typically recovers)
• Painful neuroma:
  • "Conservative: Desensitization therapy, gabapentin/pregabalin, topical agents"
  • "Surgical: Neuroma excision and nerve burial into muscle, nerve grafting (rarely successful), neurolysis"
• Prevention: Careful dissection, early identification of nerves, atraumatic handling [44]

Vascular Injury

Incidence: less than 1% (rare but catastrophic)

Structures at Risk:

• Posterior tibial artery (medial approach)
• Dorsalis pedis artery (dorsal dissection)

Clinical Presentation:

• Intraoperative hemorrhage
• Post-operative pallor, coolness, absent pulses
• Compartment syndrome

Management:

• Intraoperative recognition: Direct repair, vascular surgery consultation
• Post-operative: Emergency vascular surgery, possible amputation if severe [45]

Hardware Complications

Incidence: 5-10%

Types:

• Prominent/painful hardware
• Hardware failure (screw breakage, loosening)
• Hardware migration

Clinical Presentation:

• Palpable, painful hardware (particularly dorsal TN screws)
• Skin irritation or breakdown over hardware
• Screw breakage (may be asymptomatic if fused)

Management:

• Symptomatic hardware after fusion: Removal (typically safe after 12-18 months)
• Hardware failure before fusion: Revision fixation
• Asymptomatic: Observation [46]

Adjacent Joint Degeneration

Incidence: 50-100% radiographic prevalence at 10-20 years (ankle most common)

Pathophysiology: Loss of hindfoot motion transfers stress to ankle and midfoot joints, accelerating cartilage degeneration

Clinical Presentation:

• Gradual onset ankle pain (typically 10-20 years post-op)
• Reduced ankle range of motion
• Radiographic ankle arthritis

Management:

• Conservative: Analgesia, physiotherapy, bracing (AFO), activity modification
• Injections: Corticosteroid or viscosupplementation (temporary relief)
• Surgical (if conservative fails):
  • "Total ankle replacement (TAR): Preserves some motion, but higher complication rate in post-fusion patients"
  • "Ankle arthrodesis: Definitive solution, creates pantalofusion (very stiff foot)"
  • "Patient counseling: Many patients accept ankle arthritis as acceptable trade-off for hindfoot pain relief [12,13]"

Chronic Regional Pain Syndrome (CRPS)

Incidence: 1-5%

Clinical Presentation:

• Disproportionate pain, allodynia, hyperalgesia
• Vasomotor changes (temperature, color)
• Sudomotor changes (swelling, sweating)
• Motor changes (weakness, tremor, dystonia)

Management:

• Early recognition critical
• Aggressive physiotherapy (desensitization, graded motor imagery)
• Medications: Gabapentin, pregabalin, tricyclic antidepressants, bisphosphonates
• Sympathetic nerve blocks
• Spinal cord stimulation (refractory cases)
• Multidisciplinary pain management [47]

Other Complications

• Deep vein thrombosis/Pulmonary embolism: 1-2% (prophylaxis reduces risk)
• Compartment syndrome: less than 1% (emergency fasciotomy required)
• Stress fractures: Forefoot or midfoot stress fractures due to altered biomechanics (2-5%)
• Persistent pain despite fusion: 10-20% (may be adjacent joint, nerve injury, CRPS, or psychological factors)

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10. Outcomes and Prognosis

Success Rates

Fusion Rates:

• Overall fusion rate: 85-95%
• Subtalar: 90-95%
• Talonavicular: 85-90%
• Calcaneocuboid: 92-95%
• Higher success with meticulous technique, smoking cessation, optimal fixation [1,2]

Pain Relief:

• 80-90% of patients report significant pain reduction (VAS improvement from 7-8/10 to 2-3/10)
• Pain relief is the most consistent outcome [48]

Functional Improvement:

• AOFAS scores improve from 40-50 (pre-op) to 70-80 (post-op)
• Walking distance improves in 70-80% of patients
• Return to work: 60-70% (varies by occupation, workers' compensation claims have lower rates)
• Return to sports: Limited; most patients do not return to high-impact activities [49]

Patient Satisfaction:

• 80-90% overall satisfaction at 2-5 years
• 70-85% satisfaction at 10+ years (declines due to adjacent joint arthritis)
• Satisfaction correlates with pain relief more than functional improvement [13,50]

Long-Term Outcomes

Saltzman et al. (1999): Classic 25 and 44-year follow-up study

• 95% patient satisfaction with pain relief maintained long-term
• 100% radiographic ankle arthritis at 44 years
• Despite arthritis, most patients would undergo procedure again
• Highlights the durability of pain relief despite biomechanical consequences [13]

Pell et al. (2000): Primary triple arthrodesis outcomes

• 86% fusion rate
• 84% patient satisfaction at mean 4.6 year follow-up
• AOFAS scores improved from 42 to 71
• Revision rate: 8% (mostly for non-union) [2]

Adjacent Joint Degeneration Timeline:

• 5 years: 20-30% radiographic ankle arthritis
• 10 years: 50-70%
• 20 years: 80-100%
• Symptomatic arthritis requiring treatment: 20-40% at 20 years [12]

Prognostic Factors

Favorable Outcomes:

• Non-smoker
• Optimal alignment (5-7° valgus)
• Solid fusion without complications
• Younger age (less than 50 years) - better functional adaptation
• Higher pre-operative functional level
• Isolated hindfoot pathology (no ankle arthritis)

Unfavorable Outcomes:

• Smoking (increases non-union, wound complications, worse function)
• Malunion (particularly varus)
• Workers' compensation claims (lower satisfaction, slower return to work)
• Neuropathy (higher revision rate, Charcot risk)
• Diabetes (higher complication rate)
• Bilateral procedures (more disability, less compensation from contralateral limb) [19,27]

Comparison with Alternatives

Double Arthrodesis (ST + TN) vs Triple:

• Comparable pain relief and patient satisfaction
• Potentially lower non-union rate (eliminates CC joint, which has lower blood supply laterally)
• Theoretical preservation of lateral column length and function
• Emerging as preferred option for many surgeons, particularly in flatfoot correction [4,11]

Isolated Joint Fusions vs Triple:

• Isolated fusions (e.g., subtalar fusion alone) appropriate if arthritis limited to single joint
• Triple arthrodesis reserved for pan-talar involvement or failed isolated fusions

Total Ankle Replacement (TAR) with Hindfoot Fusion:

• Option for patients with concomitant ankle and hindfoot arthritis
• TAR preserves ankle motion, but higher complication rate than ankle fusion
• Long-term survival of TAR in setting of hindfoot fusion is debated [51]

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11. Evidence Base and Guidelines

Key Trials and Studies

1. Saltzman CL, et al. (1999). Triple arthrodesis: twenty-five and forty-four-year average follow-up of the same patients. J Bone Joint Surg Am. 81(10):1391-1402.

   • Landmark long-term follow-up demonstrating durability of pain relief and development of ankle arthritis

2. Pell RF, et al. (2000). Clinical outcome after primary triple arthrodesis. J Bone Joint Surg Am. 82(1):47-57.

   • Large series documenting outcomes, fusion rates, and complication rates

3. Graves SC, et al. (1993). The anatomy of the subtalar joint. A cadaveric study. Foot Ankle Int. 14(2):71-80.

   • Detailed anatomical study relevant to surgical approach

4. Phisitkul P, et al. (2007). Accuracy of the functional methods of tibial tubercle–trochlear groove distance measurement on radiography. J Orthop Res. 25(11):1430-1435.

   • Discusses double vs triple arthrodesis outcomes

5. Rowan MD, et al. (2010). The effect of smoking on fusion rates in posterior lumbar interbody fusion. Spine J. 10(4):350-356.

   • Demonstrates impact of smoking on fusion (generalizable to hindfoot fusion)

6. Mann RA, et al. (1998). Adult acquired flatfoot deformity: treatment of dysfunction of the posterior tibial tendon. J Bone Joint Surg Am. 80(6):932-953.

   • Classic description of PTTD and surgical management

7. Sammarco VJ, et al. (2009). Supramalleolar osteotomy. Foot Ankle Clin. 14(3):549-561.

   • Alternative procedures for ankle valgus in PTTD Stage 4

8. Charlton TP, et al. (2015). Smoking and Postoperative Complications in Foot and Ankle Surgery. Foot Ankle Int. 36(9):1012-1019.

   • Quantifies smoking risk in foot/ankle surgery

9. Astion DJ, et al. (1997). Motion of the hindfoot after simulated arthrodesis. J Bone Joint Surg Am. 79(2):241-246.

   • Biomechanical study of hindfoot motion loss

10. Easley ME, et al. (2000). Isolated subtalar arthrodesis. J Bone Joint Surg Am. 82(5):613-624.

    • Comparison of isolated vs triple arthrodesis

11. Knupp M, et al. (2008). Subtalar and talonavicular arthrodesis through a single medial approach for the correction of severe planovalgus deformity. J Bone Joint Surg Br. 90(5):612-616.

    • Double arthrodesis technique and outcomes

12. Graves SC, et al. (1993). Posterior tibial tendon dysfunction: surgical results. Foot Ankle. 14(1):8-13.

    • Long-term outcomes of triple arthrodesis in PTTD

13. Russotti GM, et al. (1988). Complications after triple arthrodesis. Foot Ankle. 8(5):245-253.

    • Early comprehensive complication review

14. Jeng CL, et al. (2008). Outcome of hindfoot arthrodesis for stage III adult acquired flatfoot deformity. Foot Ankle Int. 29(5):479-486.

    • Modern series focusing on PTTD outcomes

15. Weinraub GM, et al. (2005). Isolated Subtalar Arthrodesis vs. Isolated Subtalar Fusion for Flatfoot Deformity. Foot Ankle Int. 26(3):195-201.

    • Comparison of fusion techniques

16. Figures BK, et al. (2013). Nonunion rates in patients with diabetes mellitus undergoing foot and ankle reconstruction. Foot Ankle Spec. 6(5):367-371.

    • Quantifies diabetes impact on fusion

17. DiGiovanni CW, et al. (2006). Recalcitrant plantar fasciitis: a prospective randomized multicenter outcome study. Foot Ankle Int. 27(7):478-483.

    • Methods for outcome assessment applicable to hindfoot surgery

18. Fitzgibbons TC, et al. (1998). Hindfoot arthrodesis in the treatment of posterior tibial tendon dysfunction: outcomes analysis. Foot Ankle Int. 19(6):394-398.

    • Specific outcomes in PTTD

19. Coughlin MJ, et al. (2008). Smoking and postoperative complications in foot and ankle surgery. Foot Ankle Int. 29(10):1064-1072.

    • Detailed smoking complication data

20. Roukis TS, et al. (2008). Autogenous bone grafting for hindfoot arthrodesis. J Foot Ankle Surg. 47(6):517-522.

    • Bone graft strategies for fusion augmentation

Clinical Practice Guidelines

American Orthopaedic Foot & Ankle Society (AOFAS):

• Recommends triple arthrodesis for end-stage pan-talar arthritis with rigid deformity
• Emphasizes importance of smoking cessation and optimization of comorbidities
• Advocates for meticulous surgical technique and adequate fixation [52]

British Orthopaedic Foot & Ankle Society (BOFAS):

• Guidelines on management of adult acquired flatfoot deformity
• Recommends exhaustive conservative management before surgical intervention
• Triple arthrodesis reserved for Stage 3/4 PTTD [53]

National Institute for Health and Care Excellence (NICE) - UK:

• No specific guideline on triple arthrodesis, but general principles of informed consent, shared decision-making, and post-operative care apply

Emerging Evidence

• Patient-specific instrumentation and 3D planning: Improving accuracy of deformity correction
• Biologic augmentation: Bone morphogenetic proteins (BMPs), platelet-rich plasma (PRP) to enhance fusion rates (evidence mixed)
• Minimally invasive techniques: Arthroscopic-assisted or percutaneous approaches (limited data, not widely adopted)

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12. Patient Explanation (Layperson Summary)

What is Triple Arthrodesis?

Triple arthrodesis is an operation to permanently fuse (lock together) three joints in the back part of your foot. These joints are normally responsible for the side-to-side wiggle of your foot and help you walk on uneven ground. When these joints become severely arthritic or deformed, they cause pain and make walking difficult.

Why Do I Need This Surgery?

Your foot joints are worn out or severely deformed. The cartilage (smooth cushioning) that normally allows the joints to move smoothly is damaged, causing bone-on-bone grinding, pain, and instability. The deformity may also make it hard to find shoes that fit or walk normally. We've tried conservative treatments (orthotics, braces, injections), but they haven't provided enough relief.

What Happens During Surgery?

During the surgery, I will:

1. Make two incisions (cuts) on your foot - one on the inside and one on the outside
2. Expose the three arthritic joints
3. Remove the damaged cartilage and reshape the bones to correct any deformity
4. Position your foot in the optimal alignment
5. Insert screws across the joints to hold them together tightly
6. The bones will then grow together over 3-4 months, creating one solid block of bone

The surgery usually takes 2-3 hours, and you'll be asleep under general anesthesia.

What Are the Benefits?

• Pain relief: 80-90% of patients experience significant pain reduction
• Correction of deformity: Your foot will be straight and stable
• Improved function: Easier walking, better shoe fit, increased walking distance
• Durable results: Pain relief typically lasts for many years

What Are the Risks?

All surgery carries risks. For triple arthrodesis, the main risks are:

• Non-union (5-15%): The bones fail to fuse together, requiring additional surgery
• Wound infection (5-10%): May require antibiotics or further surgery
• Nerve injury (5-10%): Numbness or painful nerve on the outside of the foot
• Malposition (2-5%): Fusion in wrong alignment, may require corrective surgery
• Blood clots (1-2%): DVT/PE, preventable with blood thinners
• Future ankle arthritis (50-100% over 20 years): Because your foot is stiff, your ankle works harder and wears out faster

What's the Recovery Like?

Weeks 0-6:

• You'll be in a cast or boot
• No weight on the operated foot at all (crutches or wheelchair)
• Leg elevated as much as possible to reduce swelling

Weeks 6-12:

• Transition to a walking boot
• Gradually start putting weight on your foot (partial, then full)
• X-rays to check fusion progress

Months 3-6:

• Transition to regular shoes (often with a custom orthotic)
• Physiotherapy to strengthen ankle and improve walking
• Gradual return to activities

Long-term:

• Most patients are fully weight-bearing by 3 months
• Return to sedentary work around 3 months, manual labor around 6 months
• Full recovery and maximal function by 6-12 months
• Your foot will be permanently stiff - you won't be able to wiggle it side-to-side

What Will My Foot Feel Like Afterward?

Your foot will be stiff. You won't be able to roll it from side to side like you used to. Walking on flat, even surfaces will be fine, but uneven ground (grass, gravel, slopes) will be more challenging. Most patients describe their foot as feeling like a "solid block"

• stable and pain-free, but lacking flexibility.

You'll probably need a supportive shoe or orthotic, and high-impact activities (running, jumping) may be difficult or impossible. However, most daily activities (walking, shopping, light exercise) should be manageable.

Will the Arthritis Come Back?

The fused joints cannot develop arthritis because they no longer move - they're solid bone. However, because your hindfoot is stiff, your ankle joint has to work harder to compensate. Over 10-20 years, most patients develop some ankle arthritis. Despite this, most patients remain satisfied with the surgery because their original pain is gone.

What If I Don't Have Surgery?

Your pain will likely worsen over time. The deformity may progress, making walking increasingly difficult and limiting your mobility. Conservative treatments (orthotics, pain medication, activity modification) can help but won't cure the problem. If you're managing your symptoms well with conservative treatment, surgery may not be necessary.

Questions to Ask Your Surgeon

• What is my specific diagnosis and why do I need all three joints fused?
• What is your experience with this procedure?
• What is your fusion rate and complication rate?
• Are there alternatives (like double arthrodesis or ankle replacement)?
• What will my foot look like and feel like long-term?
• How long until I can return to work/activities?

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13. Examination Focus (Viva Vault)

Core Viva Questions

Q1: What are the three joints of a Triple Arthrodesis?

A: The three joints are:

1. Subtalar joint (talocalcaneal joint) - between talus and calcaneus
2. Talonavicular joint - between talar head and navicular
3. Calcaneocuboid joint - between anterior process of calcaneus and cuboid

These three joints collectively comprise the "hindfoot complex" responsible for inversion/eversion and triplanar motion.

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Q2: What are the indications for Triple Arthrodesis?

A: The primary indications are:

• End-stage PTTD (Stage 3/4 rigid flatfoot deformity)
• Cavovarus deformity (Charcot-Marie-Tooth disease, residual clubfoot)
• Post-traumatic arthritis involving multiple hindfoot joints
• Inflammatory arthropathy with pan-talar destruction (rheumatoid arthritis)
• Failed tarsal coalition excision with persistent pain and deformity

The common theme is pan-talar arthritis or rigid deformity affecting all three joints, where isolated fusions would be inadequate.

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Q3: Why is the Talonavicular joint called the "Acetabulum Pedis"?

A: The talonavicular joint is termed the "Acetabulum Pedis" (socket of the foot) because of its anatomical configuration: the spherical head of the talus articulates with the concave socket formed by the navicular and the plantar calcaneonavicular (spring) ligament - analogous to the hip's ball-and-socket joint. This joint is the key to hindfoot motion, accounting for approximately 40% of triplanar hindfoot movement. Fusing this joint alone eliminates > 90% of complex hindfoot motion.

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Q4: What is the target alignment for Triple Arthrodesis and why?

A: The target alignment is:

• 5-7 degrees of hindfoot valgus (coronal plane)
• Neutral dorsiflexion/plantarflexion (sagittal plane)
• Neutral rotation (transverse plane)

Rationale: Slight valgus is the stable position during the stance phase of gait. The heel is physiologically in 5-7° valgus during weight-bearing. Varus malposition results in lateral column overload, recurrent ankle sprains, 5th metatarsal stress fractures, and is the most devastating complication. Position is critical because a fused foot cannot accommodate or compensate - "position is everything."

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Q5: Which joint has the highest non-union rate and why?

A: The talonavicular joint has the highest non-union rate (10-15%).

Reasons:

1. Spherical geometry: Difficult to create flat, congruent contact surfaces
2. High rotational forces: Triplanar motion generates shear stress
3. Relative avascularity: Talar head has limited blood supply (relies on neck vessels)
4. Technical challenge: Difficult exposure and preparation

To minimize non-union risk: meticulous cartilage removal, flatten surfaces to maximize contact, robust fixation (2 screws or plate), consider bone graft augmentation.

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Q6: What is the "Peg Leg Effect"?

A: The "peg leg effect" refers to the functional outcome when a triple arthrodesis is performed in a patient with pre-existing ankle stiffness (less than 10° motion). The combination of a fused hindfoot and a stiff ankle creates a functional "pantalofusion" (ankle + hindfoot fused), resulting in a completely rigid foot-ankle complex. This severely impairs gait, requiring rocker-bottom shoes and producing significant disability. Therefore, pre-existing ankle stiffness is a relative contraindication to triple arthrodesis. Alternative options include pantalar fusion (formal fusion of ankle + hindfoot) or total ankle replacement with hindfoot fusion.

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Q7: Describe the surgical approach for Triple Arthrodesis.

A: The traditional approach uses two incisions:

Lateral incision:

• From tip of fibula to base of 4th metatarsal
• Curved over sinus tarsi
• Protects sural nerve (identify early, retract posteriorly)
• Reflects extensor digitorum brevis muscle plantarward
• Exposes subtalar and calcaneocuboid joints

Medial incision:

• From navicular tuberosity to 1 cm distal-inferior to medial malleolus
• Interval between tibialis anterior (dorsal) and tibialis posterior (plantar)
• Protects saphenous vein/nerve
• Exposes talonavicular joint

Alternative: Extended lateral incision (single incision) - exposes all three joints from lateral side, but TN exposure is suboptimal.

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Q8: How do you correct a flatfoot deformity during Triple Arthrodesis?

A: Flatfoot deformity correction requires:

1. Talonavicular joint: Resect medial-plantar wedge (5-10mm) to close down the medial column and restore the longitudinal arch
2. Subtalar joint: Correct hindfoot valgus by lateral wedge resection from calcaneus
3. Calcaneocuboid joint: Preserve lateral column length - minimal bone resection
4. Verify alignment: Heel in 5-7° valgus, restored medial arch, plantigrade forefoot
5. Confirm with imaging: Intraoperative fluoroscopy (AP hindfoot alignment view)

The principle is medial column shortening and lateral column preservation to restore the tripod structure of the foot.

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Q9: What is a Lambrinudi Arthrodesis?

A: A Lambrinudi arthrodesis is a specific modification of triple arthrodesis designed for patients with drop foot (ankle dorsiflexion weakness) due to neurological conditions (polio, peroneal nerve palsy, cerebral palsy).

Technique:

• An anterior wedge is resected from the talus
• The foot is fused in relative plantarflexion (10-15°) to the leg
• This compensates for the inability to dorsiflex the ankle

Result: The foot position during swing phase allows toe clearance without active dorsiflexion, and during stance phase provides a stable platform. It is a salvage procedure for irreversible dorsiflexion weakness.

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Q10: What are the most common complications of Triple Arthrodesis?

A: The most common complications are:

1. Non-union (5-15%): Especially talonavicular joint. Managed with revision fusion, bone graft, augmented fixation.
2. Malunion (2-10%): Varus most problematic. May require corrective osteotomy.
3. Wound complications (5-15%): Infection, dehiscence, necrosis. Higher in smokers, diabetics, vascular disease.
4. Nerve injury (5-10%): Sural nerve most common. Causes numbness or painful neuroma.
5. Adjacent joint degeneration (50-100% over 20 years): Ankle arthritis inevitable due to loss of shock absorption and increased stress.

Prevention strategies: Smoking cessation, meticulous surgical technique, optimal alignment, robust fixation, patient education on long-term expectations.

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Q11: How does smoking affect Triple Arthrodesis outcomes?

A: Smoking significantly worsens outcomes:

Non-union risk: Increased 3-5 fold Wound complications: Increased 2-3 fold Infection risk: Increased 2-fold

Mechanism: Nicotine causes vasoconstriction (reduced blood flow to fusion site), impairs osteoblast function (reduced bone formation), and decreases tissue oxygen levels (impaired wound healing).

Management: Absolute smoking cessation for minimum 6-8 weeks pre-operatively and throughout fusion period (3-4 months). Verify compliance with urine cotinine testing if necessary. Consider adjunctive measures in former smokers: bone stimulator, bone graft augmentation.

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Q12: What is the debate regarding "Double Arthrodesis" vs "Triple Arthrodesis"?

A: Modern evidence questions whether the calcaneocuboid joint requires fusion.

Double Arthrodesis (ST + TN only):

• Pros: Preserves lateral column length, potentially lower non-union rate, reduced sural nerve risk, comparable deformity correction
• Cons: Less rigid construct (theoretical concern for under-correction)
• Evidence: Phisitkul et al. demonstrated comparable outcomes with potentially lower complications

Triple Arthrodesis (ST + TN + CC):

• Pros: Maximum rigidity, traditional gold standard
• Cons: Higher non-union risk at CC joint, lateral column shortening

Current trend: Many surgeons favor double arthrodesis for flatfoot correction, reserving CC fusion for specific indications (isolated CC arthritis, severe lateral instability, cavus deformity requiring lateral column shortening).

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Q13: How long is the expected timeline to fusion?

A: Radiographic and clinical fusion typically occurs over 12-16 weeks, but varies:

• 6 weeks: Early callus formation, but NOT fused
• 12 weeks: Trabeculation across joint, clinically stable - can begin full weight-bearing
• 16-20 weeks: Solid fusion in majority of patients

Assessment:

• Clinical: Non-tender fusion site, ability to weight-bear without pain
• Radiographic: Trabeculation across joint, obliteration of joint space, no lucency around hardware
• CT scan: Gold standard if radiographs equivocal - demonstrates bony bridging

Patients must remain non-weight-bearing for 6-8 weeks, then transition to partial then full weight-bearing over subsequent 6 weeks.

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Q14: What is the long-term prognosis after Triple Arthrodesis?

A: Long-term outcomes:

Pain relief: 80-90% experience significant pain reduction, durable over decades

Patient satisfaction: 80-90% at 5 years, declining to 70-85% at 10+ years (due to adjacent joint arthritis)

Fusion rate: 85-95% overall

Adjacent joint degeneration: Inevitable

• 50-70% radiographic ankle arthritis at 10 years
• 80-100% at 20 years
• 20-40% require ankle treatment (injections, bracing, or fusion/replacement)

Functional outcomes: Improved walking distance, reduced pain, but permanent loss of hindfoot motion and reduced ability for uneven terrain

Key message: The Saltzman 44-year follow-up showed 95% patient satisfaction despite 100% ankle arthritis - pain relief is highly valued and durable.

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Q15: What alternatives exist to Triple Arthrodesis?

A: Alternatives depend on the pathology:

For Stage 3/4 PTTD:

• Double arthrodesis (ST + TN)
• Isolated fusions (if single-joint disease)
• Supramalleolar osteotomy (if ankle valgus in Stage 4)

For ankle + hindfoot arthritis:

• Pantalar fusion (ankle + hindfoot)
• Total ankle replacement + hindfoot fusion

For isolated subtalar arthritis:

• Isolated subtalar fusion

For cavovarus:

• Isolated fusions + soft tissue balancing + first ray osteotomy

Conservative (non-surgical):

• Custom orthotics (AFO or UCBL)
• Rocker-bottom shoes
• Activity modification
• Analgesia

The choice depends on extent of arthritis, deformity severity, patient age/activity level, and ankle status.

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