Post-traumatic Predominance | Arthrodesis vs TAR | Functional Outcomes | Adjacent Joint Disease
TREATMENT OPTIONS
Critical Must-Knows
- Post-traumatic is the commonest cause (78% in Valderrabano series) - unlike hip/knee (primary OA)
- Ankle arthrodesis remains the durable reference standard - bone non-union about 12% on radiographs but only ~7% symptomatic in TARVA
- TAR for lower demand, good alignment, adequate bone stock, intact deltoid
- Accelerated adjacent (ipsilateral foot) OA is consistent at 22 years post-fusion (Coester)
- Neutral alignment critical for both fusion and replacement
Clinical Pearls
- "Most ankle OA is post-traumatic (fractures, instability, osteochondral lesions)
- "Ankle tolerates less cartilage loss than hip/knee before symptoms
- "TAR contraindicated with significant varus/valgus deformity, neuropathy, AVN
- "Fusion position: neutral DF, 5 degrees valgus, 5-10 degrees ER, slight posterior translation
- "TARVA RCT (2023): no significant difference in walking/standing score at 1 year; both improve quality of life
Clinical Imaging
Imaging Gallery
Critical Ankle Arthritis Exam Points
Post-traumatic Predominance
Ankle OA is predominantly post-traumatic (78% in Valderrabano's series of 406 ankles, vs only 9% primary) - this differs from hip and knee where primary OA predominates. Causes include malunited fractures, recurrent instability, and osteochondral lesions. The latency from injury to end-stage OA averages around 20 years. Always take a detailed trauma history.
Fusion vs Replacement
Arthrodesis is the gold standard with reliable outcomes. TAR for lower-demand patients with good alignment, adequate bone stock, and intact deltoid. Contraindications to TAR: severe deformity, AVN, neuropathy, young high-demand patients.
Fusion Position
Optimal fusion position: neutral dorsiflexion, 5 degrees hindfoot valgus, 5-10 degrees external rotation, slight posterior translation of talus. Malposition causes significant functional impairment.
Adjacent Joint Disease
Accelerated ipsilateral foot OA is consistent at a mean 22 years post-fusion (Coester, JBJS 2001) - the subtalar, talonavicular and calcaneocuboid joints are significantly more arthritic than the contralateral side, whereas the knee is not. This drives interest in motion-preserving TAR but patient selection is critical.
Ankle Arthritis Management At a Glance
| Treatment | Indications | Advantages | Disadvantages |
|---|---|---|---|
| Conservative | Early disease, low demand, comorbidities | Non-invasive, reversible | Limited long-term efficacy |
| Arthrodesis | Durable reference standard, most patients | Reliable pain relief, ~12% radiographic non-union (~7% symptomatic) | Loss of motion, adjacent joint disease |
| TAR | Lower demand, good alignment, adequate bone | Motion preservation, gait improvement | Higher revision rate, strict selection |
| Supramalleolar osteotomy | Malalignment with early arthritis | Joint preservation, corrects deformity | Limited to appropriate deformity patterns |
| Distraction arthroplasty | Young patients, limited disease | Joint preservation | Limited evidence, prolonged treatment |
ANKLE - CANKLE - Causes of Ankle Arthritis
| A | After fracture Post-traumatic is most common (70%) |
| N | Neurological conditions Charcot, hemophilia, neuropathy |
| K | Kinematic instability Recurrent sprains, chronic instability |
| L | Lesions osteochondral OCD, osteonecrosis |
| E | Erosive arthropathies RA, psoriatic, gout |
| A | After fracture Post-traumatic is most common (70%) | L | Lesions osteochondral OCD, osteonecrosis |
| N | Neurological conditions Charcot, hemophilia, neuropathy | E | Erosive arthropathies RA, psoriatic, gout |
| K | Kinematic instability Recurrent sprains, chronic instability |
Hook:ANKLE arthritis is mostly post-traumatic unlike hip/knee
FUSION - OFUSION - Optimal Position
| F | Foot plantigrade Neutral dorsiflexion (not equinus) |
| U | Upright hindfoot 5 degrees valgus (not varus) |
| S | Slight external rotation 5-10 degrees matching opposite side |
| I | In slight translation Talus posterior on tibia |
| O | On neutral ankle Match contralateral alignment |
| N | No equinus Plantigrade foot essential |
| F | Foot plantigrade Neutral dorsiflexion (not equinus) | S | Slight external rotation 5-10 degrees matching opposite side | O | On neutral ankle Match contralateral alignment |
| U | Upright hindfoot 5 degrees valgus (not varus) | I | In slight translation Talus posterior on tibia | N | No equinus Plantigrade foot essential |
Hook:FUSION position must be perfect for good outcomes - neutral DF, slight valgus, ER
TAR - CTAR - Contraindications
| T | Talar AVN Poor bone stock for fixation |
| A | Alignment severe deformity Greater than 15 degrees varus/valgus |
| R | Rheumatoid severe With poor bone quality |
| T | Talar AVN Poor bone stock for fixation |
| A | Alignment severe deformity Greater than 15 degrees varus/valgus |
| R | Rheumatoid severe With poor bone quality |
Hook:TAR has strict contraindications - AVN, severe deformity, neuropathy are absolute
INFECTION AINFECTION After Ankle Surgery
| I | Immediate presentation Less than 3 weeks = acute |
| N | Not healing wounds Persistent drainage |
| F | Fever, pain, warmth Classic signs |
| E | ESR, CRP elevated Inflammatory markers |
| C | Culture samples Multiple intraoperative samples |
| T | Treatment staged Debridement, spacer, revision |
| I | Irrigation thorough High-volume lavage |
| O | Organism identification Guide antibiotic therapy |
| N | Notify ID team Multidisciplinary approach |
| I | Immediate presentation Less than 3 weeks = acute | E | ESR, CRP elevated Inflammatory markers | I | Irrigation thorough High-volume lavage |
| N | Not healing wounds Persistent drainage | C | Culture samples Multiple intraoperative samples | O | Organism identification Guide antibiotic therapy |
| F | Fever, pain, warmth Classic signs | T | Treatment staged Debridement, spacer, revision | N | Notify ID team Multidisciplinary approach |
Hook:INFECTION management is systematic - identify organism and treat appropriately
Overview and Epidemiology
Ankle arthritis is less common than hip or knee arthritis but causes significant disability. Importantly, the etiology differs fundamentally from other large joints.
Aetiology distribution (Valderrabano et al., CORR 2009, 406 ankles):
- Post-traumatic: 78% (malleolar fractures most common, then instability and osteochondral lesions)
- Secondary (inflammatory, haemophilic, clubfoot, AVN, etc.): 13%
- Primary osteoarthritis: 9% (rare, unlike hip/knee)
These figures differ from the older "70%" estimate widely quoted; the contemporary single-centre series of end-stage patients reports closer to 78% post-traumatic. Either way, trauma dominates and primary OA is uncommon.
Key epidemiological features:
- Symptomatic ankle OA is roughly 9 times less common than knee OA; primary ankle OA is rare
- Post-traumatic OA develops after a long latency - mean about 20.9 years (range 1-52) after ankle fracture (Horisberger et al.)
- Shorter latency with pilon/plafond fractures, healing complications, and older age at injury
- The mean tibiotalar alignment in end-stage ankle OA is varus regardless of aetiology
- End-stage ankle OA causes mental and physical disability at least as severe as end-stage hip OA (Glazebrook et al., SF-36 study)
Why Post-traumatic Predominates
The ankle joint has the thinnest articular cartilage of major weight-bearing joints (1-1.5mm vs 3-4mm in knee). This makes it vulnerable to damage from fracture incongruity but also means it normally distributes load efficiently. Post-traumatic changes from malunion or instability rapidly lead to OA.
Natural history without treatment:
- Progressive joint space narrowing
- Osteophyte formation limiting motion
- Increasing pain and functional limitation
- Deformity development (usually varus)
- Gait abnormalities and proximal compensation
Anatomy and Biomechanics
The ankle (tibiotalar) joint is a highly constrained mortise joint with minimal inherent stability from soft tissues alone.
Bony anatomy:
- Tibial plafond: Concave articular surface
- Medial malleolus: Medial buttress
- Fibula/lateral malleolus: Lateral buttress, 1cm more distal than medial
- Talus: Wider anteriorly (trapezoidal), provides stability in dorsiflexion
Ligamentous stability:
- Deltoid (medial): Primary restraint to valgus; deep and superficial components
- Lateral complex: ATFL, CFL, PTFL - resist varus
- Syndesmosis: AITFL, PITFL, interosseous ligament - maintain mortise width
Deltoid Integrity for TAR
An intact deltoid ligament is essential for TAR success. Preoperative valgus deformity with deltoid insufficiency is a relative contraindication to TAR as the implant will fail to balance properly.
Biomechanics:
- Range of motion: Primarily dorsiflexion (20 degrees) and plantarflexion (50 degrees)
- Force transmission: 5x body weight during running
- Contact area: Small (approximately 350mm²) but high congruency
- Axis of rotation: Oblique through tips of malleoli
Adjacent joint relationship:
- Subtalar joint: 25-30 degrees of motion, compensates for ankle fusion
- Talonavicular joint: Allows additional accommodation
- Hindfoot complex function interdependent
Why ankle tolerates fusion:
- Subtalar joint provides significant compensatory motion
- Talonavicular accommodates rotation
- Gait adaptations possible with proper fusion position
Classification Systems
Radiographic Grading
| Grade | Radiographic Features | Clinical Correlation |
|---|---|---|
| Grade 0 | No features of OA | Asymptomatic |
| Grade 1 | Doubtful narrowing, possible osteophytes | Minimal symptoms |
| Grade 2 | Definite osteophytes, possible narrowing | Moderate symptoms |
| Grade 3 | Moderate osteophytes, definite narrowing, some sclerosis | Significant symptoms |
| Grade 4 | Large osteophytes, marked narrowing, severe sclerosis, deformity | End-stage disease |
Originally designed for knee OA but commonly applied to ankle.
Clinical Assessment
History:
- Pain location (anterior, medial, lateral)
- Relationship to activity and weight bearing
- Morning stiffness duration
- Previous trauma (fractures, sprains, instability)
- Previous surgery
- Functional limitations (walking distance, stairs, uneven ground)
- Night pain (suggests more advanced disease)
- Response to conservative treatment
Examination:
Clinical Examination Findings
| Finding | Significance | Implications |
|---|---|---|
| Range of motion | Reduced DF/PF, crepitus | Severity indicator |
| Alignment | Varus/valgus tilt | Affects surgical planning |
| Instability | Anterior drawer, talar tilt | May need ligament reconstruction |
| Tenderness | Location guides differential | Anterior = impingement, medial/lateral = gutter OA |
| Gait | Antalgic, compensatory patterns | Functional assessment |
| Adjacent joints | Subtalar, talonavicular motion | Fusion compensates, TAR requires |
Adjacent Joint Assessment
Adequate subtalar and talonavicular motion is essential for good outcomes after ankle fusion. If these joints are already arthritic or fused, ankle fusion will cause significant stiffness. This may favor TAR if other factors permit.
Provocative tests:
- Anterior impingement test (pain with forced dorsiflexion)
- Compression/rotation test (pain with axial load and rotation)
- Silfverskiold test (gastrocnemius contracture assessment)
Vascular assessment:
- Dorsalis pedis and posterior tibial pulses
- Capillary refill
- Consider ABI if concerns (diabetics, smokers)
Differential diagnosis of the painful, stiff ankle:
Ankle OA - Differential Diagnosis
| Condition | Discriminating features | Key investigation |
|---|---|---|
| Tibiotalar OA | Anterior/diffuse ankle-line pain, dorsiflexion loss, varus tilt | Weight-bearing AP/lateral/mortise radiographs |
| Subtalar arthritis | Hindfoot pain below the malleoli, pain on inversion/eversion, normal tibiotalar line | Broden/hindfoot views; selective subtalar local-anaesthetic injection |
| Chronic lateral ankle instability | Giving-way, positive anterior drawer and talar tilt, often younger | Stress radiographs; MRI of ATFL/CFL |
| Osteochondral lesion of talus | Focal, deep, activity-related pain, may catch/lock, often near-normal joint space | MRI (or CT) of talar dome |
| Anterior ankle (footballer's) impingement | Anterior pain at terminal dorsiflexion, anterior osteophytes, preserved joint space | Lateral radiograph; impingement test |
| Inflammatory arthropathy (RA/seronegative) | Bilateral/symmetrical, multi-joint, morning stiffness, systemic features | RF/anti-CCP, CRP/ESR, HLA-B27 if indicated |
| Charcot neuroarthropathy | Warm, swollen, often painless deformity in neuropathic (diabetic) foot | Radiographs (fragmentation/dislocation), HbA1c, sensory testing |
| Crystal arthropathy (gout/CPPD) | Acute hot swollen joint, rapid onset, hyperuricaemia or chondrocalcinosis | Joint aspirate for crystals; serum urate |
Investigations
Weight-bearing views essential
Standard views:
- Weight-bearing AP ankle
- Weight-bearing lateral ankle
- Mortise view
- Hindfoot alignment view if deformity
Key features to assess:
- Joint space narrowing pattern
- Osteophyte location and size
- Subchondral sclerosis and cysts
- Deformity (varus/valgus tilt)
- Adjacent joint involvement
Stress views:
- Anterior drawer (ATFL integrity)
- Talar tilt (CFL integrity)
- Consider if instability suspected
Weight-bearing views are critical as they reveal functional joint space and alignment.
Management Algorithm
First-line management
Activity modification:
- Low-impact activities
- Weight loss if overweight
- Avoid aggravating activities
Medications:
- NSAIDs (oral or topical)
- Acetaminophen
- Consider PPI protection long-term
Bracing:
- Ankle-foot orthosis (AFO)
- Rocker-bottom shoes
- Custom orthotics
Injections:
- Corticosteroid (2-3 per year maximum)
- Hyaluronic acid (limited evidence)
- PRP (experimental)
Physical therapy:
- Strengthening periarticular muscles
- Range of motion maintenance
- Gait training
Conservative measures may delay surgery but rarely prevent eventual progression in symptomatic patients.
Surgical Technique
Anterior or lateral approach
Positioning:
- Supine with bump under ipsilateral hip
- Tourniquet at thigh
Ankle Fusion Steps
Anterior approach between tibialis anterior and EHL, or lateral transfibular approach. Protect superficial peroneal nerve.
Remove all articular cartilage from tibial plafond and talar dome. Use curettes, osteotomes, or burr. Fenestrate subchondral bone. Preserve overall contour for stability.
Position foot: neutral DF, 5 degrees valgus, 5-10 degrees ER, slight posterior translation. Compare to opposite side. Check alignment with fluoroscopy.
Multiple options: crossed screws (2-3 large fragment), anterior plate, IM nail. Compress fusion site. Confirm alignment on final fluoroscopy.
Layered closure. Posterior splint in neutral position. Non-weight bearing initially.
Crossed screws technique: 6.5-7.3mm cannulated screws, typically 2 from anterior tibia into talus and 1 from medial malleolus into talus.
Complications
Ankle arthrodesis
Early:
- Wound complications (5-10%)
- Infection (2-5%)
- DVT/PE
- Nerve injury (superficial peroneal)
Delayed:
- Nonunion (5-10%)
- Malunion (position errors)
- Hardware prominence/irritation
Late:
- Accelerated ipsilateral foot OA (subtalar, talonavicular, calcaneocuboid) - significantly worse than contralateral side at 22 years (Coester)
- Persistent pain
- Stress fractures
Risk factors for nonunion:
- Smoking (most significant)
- Diabetes
- AVN of talus
- Previous infection
- Technical errors
Smoking cessation is mandatory before fusion surgery.
Postoperative Care
Rehabilitation Phases
Non-weight bearing, posterior splint. Elevation. Wound check at 2 weeks.
Non-weight bearing, short leg cast. Continue elevation. Serial X-rays.
Protective weight bearing in CAM boot if union progressing. PT for adjacent joint ROM.
Wean boot. Rocker-bottom shoes. Gait training.
Union assessment with CT if radiographic healing uncertain. May require bone stimulation if delayed.
Outcomes and Prognosis
Treatment Outcomes Comparison
| Treatment | Pain/Function | Reoperation/Revision | Survivorship/Union |
|---|---|---|---|
| Ankle Arthrodesis | Reliable pain relief; stiff but functional | Revision 5% (1yr) / 11% (5yr) - SooHoo | Radiographic non-union ~12%, symptomatic ~7% (TARVA) |
| Total Ankle Replacement | Better ROM and gait; equivalent QoL gain to fusion | Revision 9% (1yr) / 23% (5yr) - SooHoo; 17% (COFAS) | Registry survival 80-91% at 5yr, 66-84% at 10yr (Perry) |
| Supramalleolar Osteotomy | Joint-preserving; correction of mechanical axis | Conversion to fusion/TAR over time | May delay arthroplasty/fusion in malaligned early OA |
Arthrodesis outcomes:
- Reliable, durable pain relief and return to demanding activity
- Some difficulty on uneven ground; shoe-wear modifications may help
- Radiographic non-union about 12% but only ~7% symptomatic in the TARVA cohort
- Accelerated ipsilateral foot OA at long-term follow-up (Coester)
TAR outcomes:
- Better gait kinematics and preserved ankle ROM than fusion
- Equivalent quality-of-life improvement to fusion at 1 year (TARVA)
- Higher reoperation/revision rate than fusion; careful patient selection critical
Head-to-head evidence:
- TARVA RCT (2023, 303 patients): no statistically significant difference in the primary walking/standing score at 52 weeks; both arms improved quality of life. A post-hoc analysis favoured fixed-bearing TAR over fusion.
- COFAS prospective multicentre cohort (Daniels, 2014): comparable intermediate-term clinical scores, but higher reoperation and major-complication rates after TAR.
- STAR pivotal trial (Saltzman, 2009): TAR non-inferior to fusion for overall success, with equivalent pain relief and better function but more secondary procedures.
The choice between fusion and TAR depends on patient factors (age, demand, deformity, bone stock, deltoid competence) and surgeon experience.
Evidence Base
TARVA: TAR vs Arthrodesis RCT
- No significant difference in primary walking/standing outcome at 1 year
- Wound-healing (13.4% vs 5.7%) and nerve injury (4.2% vs under 1%) higher after TAR
- Radiographic fusion non-union 12.1% but only 7.1% symptomatic
- Post-hoc: fixed-bearing TAR favoured over fusion
Global Registry TAR Survival
- 5-year survival 80-91%
- 10-year survival 66-84%
- Between-country variation widens with time
- Even at 5 years over 80% revision-free survival
COFAS: Intermediate-term TAR vs Fusion
- Comparable patient-reported outcome scores
- Higher reoperation rate after TAR (17% vs 7%)
- Higher major complication rate after TAR (19% vs 7%)
- Treatment tailored to patient presentation
Reoperation: Population-level Data
- TAR higher major revision (HR 1.93)
- Fusion higher subsequent subtalar fusion (HR for TAR 0.28)
- TAR higher device-related infection
- Trade-off: revision risk vs adjacent-joint salvage
Adjacent Joint OA After Fusion
- Accelerated ipsilateral foot OA at 22 years
- Subtalar and talonavicular most affected
- Knee not significantly affected
- Longest follow-up series of ankle fusion
Post-traumatic Aetiology Predominance
- 78% post-traumatic
- Only 9% primary OA
- 13% secondary
- Varus alignment predominates
Optimal Fusion Position (Gait Study)
- Neutral dorsiflexion essential
- 0-5 degrees valgus (not varus)
- 5-10 degrees external rotation
- Posterior talar translation reduces knee stress
Disability Equivalent to Hip OA
- Ankle OA as disabling as hip OA
- All SF-36 subscales ~2 SD below normal
- Worse mental component than hip OA
- Justifies aggressive treatment of end-stage disease
Exam Viva Scenarios
Use these scenarios to practise clinical reasoning and management decisions
Scenario 1: Treatment Choice
"A 58-year-old woman presents with end-stage ankle arthritis following an ankle fracture 20 years ago. She has 15 degrees of varus deformity. She works as a receptionist and wants to return to walking for exercise. What are her surgical options?"
Scenario 2: TAR Candidate
"A 65-year-old retired man presents with ankle arthritis and neutral alignment. His subtalar joint has good motion. He is a non-smoker with well-controlled diabetes. He wants to maintain ankle motion for recreational golf. Would you consider TAR?"
Scenario 3: Fusion Nonunion
"A patient returns 4 months after ankle fusion with persistent pain. X-rays show incomplete union at the fusion site. He is a smoker. How would you manage this?"
MCQ Practice Points
Key facts for MCQs:
- Post-traumatic aetiology: 78% most common (Valderrabano); primary OA only 9%
- Latency from fracture to end-stage OA: mean ~21 years
- Fusion: radiographic non-union ~12%, symptomatic ~7% (TARVA)
- TAR registry survival: ~80-91% at 5 years, 66-84% at 10 years (Perry)
- Accelerated ipsilateral foot OA after fusion at 22 years (Coester)
- Fusion position: neutral DF, 5 degrees valgus, 5-10 degrees ER, posterior translation
Common MCQ topics:
- Etiology of ankle OA (post-traumatic predominance)
- Fusion vs TAR indications
- Optimal fusion position
- TAR contraindications
- Complications (nonunion risk factors)
- Adjacent joint arthritis incidence
- Post-traumatic OA pathophysiology
Differential diagnosis points:
- Subtalar arthritis (hindfoot pain, different motion loss)
- Ankle instability (positive drawer, talar tilt)
- Osteochondral lesion (may be early cause)
- Inflammatory arthritis (symmetrical, systemic features)
Ankle OA Aetiology
Q: What is the most common aetiology of ankle osteoarthritis? A: Post-traumatic - 78% in Valderrabano's series, unlike the hip and knee where primary OA predominates. Only about 9% of end-stage ankle OA is primary/idiopathic.
Fusion Position
Q: What is the optimal fusion position for ankle arthrodesis? A: Neutral dorsiflexion, 5 degrees valgus, 5-10 degrees external rotation, and slight posterior translation of the talus.
TAR Survivorship
Q: What is the implant survivorship for modern total ankle replacement? A: Global registries (Perry, 2022) report about 80-91% at 5 years and 66-84% at 10 years, varying by country - quote registry figures, not single-centre best cases.
TAR Contraindications
Q: What deformity threshold is a relative contraindication for TAR? A: Greater than 15-20 degrees varus or valgus deformity, as it affects implant longevity and function.
Adjacent Joint Arthritis
Q: What happens to adjacent joints after ankle fusion? A: Coester (JBJS 2001) showed accelerated ipsilateral foot OA at a mean 22 years - subtalar, talonavicular and calcaneocuboid joints significantly more arthritic than the contralateral side, while the knee is spared.
Guidelines, Registries & Global Practice
Global epidemiology. Symptomatic ankle OA is far less common than knee or hip OA, and unlike those joints it is predominantly post-traumatic. In Valderrabano's series of 406 end-stage ankles, 78% were post-traumatic, 13% secondary and only 9% primary. The latency from ankle fracture to end-stage OA is long (mean ~21 years), so the disease burden falls on a relatively young, working-age population - and its disability is at least as severe as end-stage hip OA (Glazebrook).
Guidance compared, side by side:
Guidelines & Consensus on End-Stage Ankle OA
| Body / region | Position | Evidence base |
|---|---|---|
| NICE / BOFAS (UK) | Both ankle fusion and TAR are recognised options for end-stage ankle OA; shared decision-making, with TAR favoured for older, lower-demand patients and fusion for high-demand or major-deformity cases | Informed by the TARVA RCT and UK practice |
| AAOS / US foot & ankle societies | No single mandated procedure; emphasise patient selection (alignment, bone stock, deltoid, demand). Arthrodesis remains the durable reference standard, TAR an accepted motion-preserving alternative | Level II-III comparative and registry data |
| AO Foundation | Technique-focused: anatomical fracture reduction to prevent post-traumatic OA; for end-stage disease, rigid compression arthrodesis (screw/plate/nail) or arthroscopic fusion in suitable joints | Expert consensus + biomechanical data |
| EFORT / European foot & ankle | TAR uptake higher in parts of Europe; supramalleolar osteotomy promoted for malaligned early/intermediate OA as a joint-preserving option | Cohort and registry evidence |
Registry evidence. Pooled national arthroplasty registries (AOANJRR Australia, NZ Joint Registry, Norwegian and Swedish registries) show primary TAR survival of about 80-91% at 5 years and 66-84% at 10 years, with consistently higher survival in Australia and New Zealand than in Norway and Sweden (Perry et al., 2022). Population-level discharge data (SooHoo) and the COFAS prospective cohort (Daniels) both confirm higher reoperation rates after TAR than after fusion, balanced against a lower rate of subsequent subtalar fusion after TAR.
Practice variation. TAR uptake is highly variable internationally - higher in parts of Europe, Australia and North America, and lower in limited-resource settings where arthrodesis (often without expensive implants) remains the default for cost, durability and lower revision-infrastructure requirements. In high-demand manual labourers and in any setting where revision capability is limited, fusion is generally preferred worldwide. Smoking cessation is a universal, evidence-based prerequisite for fusion regardless of health system, given its strong effect on non-union risk.
Exam Cheat Sheet
Ankle Arthritis
Clinical summary
Key Numbers
- •Post-traumatic: 78% (primary OA only 9%)
- •Fusion non-union: ~12% radiographic, ~7% symptomatic
- •TAR registry survival: 80-91% at 5yr, 66-84% at 10yr
- •Accelerated ipsilateral foot OA at 22 years post-fusion
Fusion Position (Critical)
- •Neutral dorsiflexion
- •5 degrees hindfoot valgus
- •5-10 degrees external rotation
- •Slight posterior translation
TAR Contraindications
- •Severe deformity greater than 15-20 degrees
- •Talar AVN
- •Peripheral neuropathy
- •Young, high-demand patients
TAR Ideal Candidate
- •Age greater than 55 years
- •Lower demand activity
- •Neutral alignment
- •Intact deltoid ligament
Exam Traps
- •Recommending TAR for severe varus
- •Wrong fusion position
- •Not knowing post-traumatic predominance
- •Operating on active smoker
References
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- Saltzman CL, Mann RA, Ahrens JE, et al. Prospective controlled trial of STAR total ankle replacement versus ankle fusion: initial results. Foot Ankle Int. 2009;30(7):579-596. PMID: 19589303. doi:10.3113/FAI.2009.0579
- Coester LM, Saltzman CL, Leupold J, Pontarelli W. Long-term results following ankle arthrodesis for post-traumatic arthritis. J Bone Joint Surg Am. 2001;83(2):219-228. PMID: 11216683. doi:10.2106/00004623-200102000-00009
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- Goldberg AJ, Bordea E, Chowdhury K, et al. Cost-utility analysis of total ankle replacement compared with ankle arthrodesis: the TARVA study. Pharmacoecon Open. 2024;8(2):235-249. PMID: 38189868. doi:10.1007/s41669-023-00449-4
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