Causes
Unlike hip and knee osteoarthritis, ankle arthritis is commonly secondary to:
- previous fracture
- chronic instability
- malalignment
- inflammatory arthropathy
- osteonecrosis
- infection
Assessment
History should establish:
- location and mechanical pattern of pain
- walking distance and activity restriction
- instability
- previous injury or surgery
- footwear and orthotic use
Examination assesses:
- coronal alignment
- ankle and subtalar movement
- adjacent-joint symptoms
- Achilles/gastrocnemius tightness
- neurovascular status
- whether deformity is correctable
Imaging
Weight-bearing ankle radiographs are fundamental. Include full-length or hindfoot-alignment imaging when deformity is important. CT helps define bone loss and adjacent-joint disease; weight-bearing CT can be useful where available.
Weight-bearing AP, mortise and lateral radiographs are central. Look for:
- joint-space loss
- talar tilt or translation
- coronal deformity
- anterior or posterior subluxation
- osteophytes
- cysts
- bone loss
- adjacent-joint degeneration
Long-leg alignment imaging may be required when proximal deformity contributes. CT is useful for complex bone loss, malunion or surgical planning.
Non-operative treatment
- activity modification
- analgesia
- footwear modification
- brace or ankle-foot orthosis
- rocker sole
- weight management where relevant
- image-guided injection for selected patients
Options include:
- activity modification
- weight optimisation where relevant
- analgesia
- physiotherapy
- bracing or rocker-bottom footwear
- injections for temporary symptom control
Treatment should address the mechanical problem as well as pain.
Joint-preserving surgery
Selected patients with asymmetric disease and correctable malalignment may benefit from:
- osteotomy to redistribute load
- debridement for focal impingement rather than diffuse end-stage disease
In selected patients with asymmetric early disease and correctable malalignment, supramalleolar or other realignment osteotomy can redistribute load. This is inappropriate when there is diffuse end-stage cartilage loss or uncorrectable deformity.
Arthroscopic debridement has a limited role for focal impingement or loose bodies and is not a definitive treatment for established end-stage OA.
Arthrodesis
Advantages:
- reliable pain relief in appropriate patients
- durable solution for severe deformity or poor bone conditions
Limitations:
- loss of ankle motion
- altered gait
- increased load on adjacent joints over time
Fusion can be open or arthroscopic depending on deformity, bone loss and previous surgery.
Ankle fusion remains reliable for pain relief when union is achieved. Important principles:
- correct alignment
- stable fixation
- broad viable bone contact
- correction of deformity
- appropriate soft-tissue management
Aim for a plantigrade foot with neutral or slight valgus hindfoot and appropriate sagittal position. Malposition can be more disabling than loss of ankle motion itself.
Disadvantages include loss of ankle movement and increased load through adjacent joints over time.
Total ankle replacement
Potential advantages:
- preserves ankle motion
- may reduce compensatory demand on adjacent joints
Limitations:
- implant-related failure and revision risk
- technically sensitive alignment and balancing
- not suitable for every deformity, infection history, neuropathic joint or bone-loss pattern
Replacement preserves tibiotalar motion and may reduce compensatory demand on adjacent joints, but requires careful patient selection.
Factors influencing suitability include:
- age and activity
- deformity
- ligament balance
- bone stock
- neuropathy
- vascular status
- infection history
- adjacent-joint disease
Complications include wound problems, infection, malleolar fracture, subsidence, loosening, polyethylene failure and need for revision.
Choosing fusion versus replacement
Consider age, activity, deformity, subtalar and midfoot arthritis, bone quality, neuropathy, previous infection and patient priorities. There is no single operation that is best for every arthritic ankle.
Pattern and cause
Primary ankle osteoarthritis is less common than primary hip or knee osteoarthritis. Many patients have a history of:
- previous fracture
- chronic instability
- malalignment
- inflammatory disease
- infection
- osteochondral injury
This makes deformity analysis and the condition of adjacent joints especially important.
Clinical assessment
Establish:
- pain location
- stiffness
- walking tolerance
- instability
- previous surgery
- infection history
- smoking and vascular status
- activity expectations
Examine alignment from the knee to the foot. Varus or valgus at the tibia, ankle or hindfoot may be a driver of asymmetric loading.
Assess subtalar and midfoot motion because these joints will compensate differently after ankle fusion and influence suitability for ankle replacement.
FRCS synthesis
Do not frame fusion versus replacement as a simple age cut-off. Present the decision as a balance of deformity, bone/soft tissue, adjacent joints, activity, comorbidity and reconstructive goals.