Total Ankle Replacement (Tibiotalar Arthroplasty)

Indications for Total Ankle Replacement

Primary Indications

• End-stage primary or post-traumatic tibiotalar osteoarthritis with preserved motion and low-to-moderate physical demand
• Adjacent-joint arthritis (subtalar or talonavicular) where arthrodesis would accelerate degeneration of those joints
• Patients who prioritise motion preservation over fusion for functional activities such as stair climbing or uneven ground walking

Contraindications

Absolute:

• Active or recent deep infection
• Avascular necrosis of the talus with collapse
• Severe fixed coronal deformity greater than 15-20 degrees not correctable by osteotomy
• Peripheral neuropathy (Charcot neuroarthropathy)
• Insufficient bone stock for component support

Relative:

• High physical demand (manual labour, high-impact sports)
• Obesity (BMI greater than 35)
• Poor soft-tissue envelope or prior anterior incisions with compromised vascularity
• Young age (less than 50 years) with long life expectancy

Evidence Comparing TAR versus Arthrodesis

Functional Outcomes

• Modern three-component mobile-bearing implants achieve 20-30 degrees of sagittal motion and improve AOFAS scores by 30-40 points at 5 years
• Gait analysis demonstrates more physiologic ankle kinematics and reduced compensatory knee and hip motion compared with arthrodesis
• Patient-reported outcomes favour TAR for activities requiring ankle dorsiflexion; fusion patients report higher rates of adjacent-joint pain at 10 years

Survivorship and Revision

• Registry data (NJR, AJRR, AOANJRR) show 5-year survivorship of 85-92 percent and 10-year survivorship of 70-85 percent for contemporary implants
• Revision rate at 10 years is approximately 15-25 percent — most commonly for aseptic loosening, subsidence, or infection
• Arthrodesis has lower re-operation rate for the index joint but higher rates of symptomatic adjacent-joint arthritis requiring later fusion

Complications

• Wound complications and infection are higher after TAR (5-15 percent wound issues, 1-3 percent deep infection) than after arthrodesis
• Non-union after arthrodesis occurs in 5-10 percent of cases and may require revision surgery
• Both procedures carry risk of deep-vein thrombosis, but TAR patients mobilise earlier

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Anterior Ankle Approach for Total Ankle Replacement

Surface Landmarks and Incision

• The incision is centred over the ankle joint, slightly lateral to the midline, from 6-8 cm proximal to the joint line to the navicular tuberosity distally
• The interval lies between the tibialis anterior tendon (medial) and the extensor hallucis longus tendon (lateral)
• The deep peroneal nerve and anterior tibial artery lie within this interval immediately deep to the superior extensor retinaculum

Deep Dissection and Neurovascular Protection

• Incise the retinaculum in line with the skin incision and identify the neurovascular bundle
• Develop the interval lateral to the tibialis anterior tendon to keep the neurovascular structures within the lateral flap
• Protect the bundle with a vessel loop throughout the procedure
• Perform a full-thickness capsulotomy and elevate the capsule medially and laterally as full-thickness flaps

Critical Bony Anatomy

• The tibial plafond is trapezoidal — wider anteriorly than posteriorly
• The talar dome is biconcave with a central ridge; medial and lateral gutters contain osteophytes that must be resected
• The fibular gutter is often narrowed by osteophytes and requires thorough debridement to allow component rotation

Ligamentous Restraints

• The deltoid ligament provides medial stability; the anterior talofibular and calcaneofibular ligaments provide lateral stability
• In severe varus deformity the deltoid may be contracted and require release; in valgus the lateral ligaments may be attenuated
• Assess stability after bone resection and before final implantation

Positioning and Preparation

Patient position: Supine with a bump under the ipsilateral hip to internally rotate the limb. The foot is placed at the end of the table to allow full dorsiflexion and plantarflexion. A thigh tourniquet is applied and inflated to 300 mmHg after exsanguination.

Anaesthesia: Spinal or general anaesthesia with regional block for postoperative analgesia. Antibiotic prophylaxis (cefazolin or vancomycin if MRSA risk) is given within 60 minutes of incision.

Equipment: Radiolucent table, large C-arm, ankle arthroplasty instrumentation set, oscillating saw with narrow blades, laminar spreaders, Hintermann distractor, fluoroscopy.

Step-by-Step Surgical Technique

Step 1: Exposure and Osteophyte Removal

Make the anterior incision and develop the interval as described. Identify and protect the deep peroneal nerve and anterior tibial artery. Perform a full-thickness capsulotomy. Remove all anterior, medial, and lateral osteophytes using osteotomes and rongeurs. Debride the medial and lateral gutters completely to prevent impingement and allow accurate component rotation.

Step 2: Tibial Resection

Place the extramedullary tibial alignment guide parallel to the tibial crest and set the coronal alignment to 0-2 degrees valgus. Set the posterior slope to 3-5 degrees for mobile-bearing designs. Protect the medial and lateral malleoli with retractors. Perform the tibial cut with an oscillating saw, ensuring the blade exits safely without fracturing the malleoli. Remove the resected bone and confirm the cut surface is perpendicular to the mechanical axis.

Step 3: Talar Resection and Gutter Preparation

Use the talar resection guide referenced from the tibial cut. Perform the talar dome resection, protecting the posterior neurovascular structures. Resect any remaining osteophytes from the talar neck and posterior aspect. Prepare the medial and lateral talar gutters to accept the component flanges. Verify that the talar cut is parallel to the tibial cut in the coronal plane.

Step 4: Trial Reduction and Ligament Balancing

Insert trial tibial and talar components. Assess coronal and sagittal stability. Perform any necessary ligament releases or additional bone resection to achieve balanced gaps. Verify full dorsiflexion and plantarflexion without impingement. Use fluoroscopy to confirm neutral mechanical axis and appropriate component sizing.

Step 5: Final Implantation

Remove trials. Irrigate the bone surfaces. For cemented components, apply cement to the tibial and talar surfaces and impact the final components. For press-fit designs, impact the components directly. Ensure no cement extrusion into the gutters or posterior capsule. Confirm final alignment and stability with fluoroscopy.

Step 6: Wound Closure

Close the capsule with absorbable suture. Approximate the retinaculum. Close the subcutaneous layer and skin with interrupted nylon or absorbable suture without tension. Apply a sterile dressing and posterior splint or boot. Consider a drain and negative-pressure dressing in high-risk patients.

Implant Designs

Mobile-Bearing (Three-Component) Designs

• Consist of a tibial tray, mobile polyethylene insert, and talar component
• Allow greater sagittal and coronal motion (up to 30-40 degrees total arc)
• Require precise alignment to avoid edge loading and insert dislocation
• Examples: STAR, Mobility, Salto Talaris, INBONE

Fixed-Bearing Designs

• Tibial and talar components with a fixed polyethylene insert
• More constrained; tolerate mild malalignment better than mobile-bearing
• Lower dislocation risk but less physiologic motion
• Preferred in severe deformity or ligament insufficiency

Complications — Recognition, Prevention, Management

Registry Survivorship

• Swedish Ankle Registry (Henricson 2011): 10-year survivorship 72 percent for early designs; modern implants exceed 80 percent
• National Joint Registry (UK): 5-year revision rate approximately 8-12 percent for contemporary prostheses
• Australian Orthopaedic Association National Joint Replacement Registry: 10-year revision rate 15-20 percent; mobile-bearing designs outperform fixed-bearing in some cohorts
• American Joint Replacement Registry: early data show 5-year survivorship greater than 85 percent with newer designs

Postoperative Protocol

Phase 1: Weeks 0-2 (Protected)

• Posterior splint or boot with ankle in neutral
• Non-weight-bearing or heel-touch weight-bearing with crutches
• Elevation and ice to control swelling
• Suture removal at 14-21 days
• Begin gentle active dorsiflexion and plantarflexion once wound stable (week 2)

Phase 2: Weeks 3-6 (Progressive Loading)

• Transition to walking boot with progressive weight-bearing as tolerated
• Active and active-assisted range-of-motion exercises
• Oedema control and scar massage
• Proprioception and strengthening begin at week 4

Phase 3: Weeks 7-12 (Functional Recovery)

• Wean from boot to supportive shoe
• Full weight-bearing
• Formal physiotherapy for gait training, strengthening, and balance
• Return to low-impact activities (swimming, cycling) at 8-10 weeks

Phase 4: Months 3-6 (Return to Activity)

• Progressive strengthening and proprioception
• Return to work (sedentary 6-8 weeks, manual 12-16 weeks)
• Low-impact sports at 4-6 months; high-impact activities discouraged

Special Case: Severe Coronal Deformity

Patients with fixed varus or valgus greater than 15 degrees are relative contraindications for TAR. Options include:

• Supramalleolar osteotomy to correct alignment before or at the time of TAR
• Staged corrective osteotomy followed by TAR once alignment is neutral
• Primary arthrodesis if deformity is not correctable or bone stock is poor

Special Case: Prior Ankle Surgery or Infection

• Previous incision location must be considered; medial or lateral approaches may be preferable in some cases
• History of infection requires thorough work-up (CRP, ESR, aspiration, nuclear imaging) before proceeding
• Staged revision with antibiotic spacer is mandatory for active or recent deep infection