Ankle Arthrodesis

 

oafusionfusion

 

Disadvantages of Arthrodesis 

 

Non union rates

ROM loss / decreased gait speed / poor mobility over uneven surfaces

Arthritic degeneration in subtalar joint

 

Types of Tibiotalar Arthrodesis

 

1.  Intra-articular

 

A. Open - indicated with significant deformity / malalignment

B. Arthroscopic - indicated with minimal deformity

 

2.  Extra-articular / External fixation

 

Sepsis

 

Ankle fusion position

 

1.  Neutral Dorsiflexion - if fused in plantar flexion develop genu recurvatum to put foot on floor

2.  Valgus 5° - excess varus causes cavovarus locking subtalar joint during gait

3.  External rotation 5-10°  - normal foot progression angle

4.  Talus posterior on tibia - preserves heel and decreases lever arm = less energy required for toe-off

 

Surgical Techniques 

 

Options

 

Open - anterior / transfibular

Arthroscopic

 

Issues

 

Open versus arthroscopic ankle arthrodesis

 

Bai et al Medicine 2021

- systematic review of 18 studies and 1100 patients

- arthroscopic associated with increased union rates / faster union / lower pain scores

- arthroscopic with fewer complication / blood loss / hospital stay

 

Number of screws in crossed screw fixation

 

Izzo et al Foot Ankle Spec 2023

- systematic review of 15 studies and 670 patients

- 2 vs 3 screws

- non-significant difference in non-union and complication rates

 

Anterior plate augmentation

 

Ankle Fusion APfusion

 

Mitchell et al Foot Ankle Int 2017

- comparison of 26 compression screws versus 39 with anterior plate + crossed screws

- nonunion screws v plate augmentation: 15% v 8%

- revision rate screws v plate augmentation: 8% v 3%

 

Bone grafting

 

Heifner et al J Foot Ankle Surg 2021

- systematic review of role of bone grafting in open ankle fusion fixed with screws

- no bone graft v fibular onlay graft  v bone grafting

- 95% union rate for all three groups

 

Open Intra-articular Technique

 

Indication

 

Malalignment > 15 degrees

 

Ankle OAruwion

 

Approaches

 

Transfibular

Anterior

 

Transfibular

 

Fibula Osteotomy Ankle FusionFibular osteotomy

 

Ankle Fusion APAnkle Fusion Lateral

 

Technique

 

Surgical technique PDF

 

Incision over distal fibula, curved forward over subtalar joint

- subperiosteally expose distal fibula

- protect peroneal tendons posteriorly

- oblique osteotomy 6 cm above joint

- can externally rotate fibula +/- remove medial half +/- resect distal fibula

- insert lamina spreader / distractor into joint

- use oscillating saw / burr to prepare joint surfaces

- protect medial malleolus

 

+/- Anteromedial incision to prepare medial gutter

- medial to tibialis anterior, protect saphenous nerve and vein

- protect deltoid ligament (provides blood supply to talus)

 

Fixation

- position foot, check with image intensifier

- +/- bone graft

- two cannulated screws from medial tibia to talus dome / neck

- +/- screw medial malleolus to talus

- +/- screw fixation fibular / onlay graft

 

Anterior approach

 

fusionfusion

 

fusionfusionfusion

 

Technique

 

Acumed anterior ankle fusion video

 

Arthrex surgical technique PDF

 

Anterior midline approach

- between tibialis anterior and EHL

- tibia and talar pins and ankle distractor

- debride joint surfaces

- fix with anatomically contoured anterior plate + screws

 

Arthroscopic ankle fusion

 

Contra-indications

 

Varus / valgus malalignment > 15 degrees

 

Technique

 

Arthroscopic techniques PDF

 

Arthrex arthroscopic fusion video

 

Ankle distractor

- anteromedial and anterolateral portals

- +/- posterolateral portal for flow

- debride cartilage surfaces with burr

- +/- bone graft

- neutral dorsiflexion, slight eversion / slight external rotation

- fix with 3 x 6.5 mm cannulated screws

- 2 medial and one lateral

 

Complications

 

Infection

Wound breakdown

Nerve damage

 

Nonunion

 

Incidence

 

Heifner et al J Foot Ankle Surg 2021

- systematic review of ankle fusion

- 95% union rate

 

Leslie et al Foot Ankle Int 2023

- systematic review of CT confirmed union rate after ankle fusion in 237 ankles

- union rate 86%

 

fusion union

 

Risk factors

 

Patel et al Foot Ankle Spec 2023

- systematic review of risk factors for nonunion

- male / smoking / previous operative infection / AVN

 

FusionArthrodesis nonunion lateral

 

Adjacent joint arthritis / Subtalar arthritis

 

SooHoo et al JBJS Am 2007

- database of 4700 ankle fusions

- subtalar arthrodesis rate of 3% at 5 years