High-yield overview

Supine with a bump | Two incisions | Dorsal neurovascular bundle at risk

SupinePosition with ipsilateral buttock bump

2Incisions for full Chopart access

Deep peronealNerve at risk medially with the dorsalis pedis artery

ChopartTransverse tarsal joint (talonavicular plus calcaneocuboid)

Critical Must-Knows

Supine with an ipsilateral buttock bump internally rotates the foot and gives access to both the dorsal talonavicular and the lateral calcaneocuboid incisions
Dorsal neurovascular bundle - the deep peroneal nerve and dorsalis pedis artery lie medial to the dorsal incision between EHL and EDL and must be protected
Two incisions are usually required to expose both Chopart joints cleanly through a healthy skin bridge
Calcaneocuboid internervous plane lies between peroneus tertius (deep peroneal nerve) and peroneus brevis (superficial peroneal nerve)
Sural nerve is the key at-risk structure in the lateral calcaneocuboid incision
Workhorse for triple arthrodesis, double (Chopart) arthrodesis and calcaneonavicular coalition resection

When & Why

What it exposes. The dorsolateral approach exposes the two components of the Chopart (transverse tarsal) joint - the talonavicular joint dorsomedially and the calcaneocuboid joint laterally. A single incision cannot expose both joints safely, so the strategy uses one dorsal incision (lateral to the tibialis anterior and extensor hallucis longus tendons) to reach the talonavicular joint and a second lateral incision over the calcaneocuboid joint, avoiding a large degloving flap while protecting the named dorsal and lateral neurovascular structures. Why this approach is chosen. The transverse tarsal joint is the functional unit that links the hindfoot to the midfoot and is essential for shock absorption and adaptation to uneven ground. The talonavicular joint lies dorsomedially and the calcaneocuboid joint lies laterally, so two well-spaced incisions expose both joints through healthy skin.

The two axes of the Chopart joint

The transverse tarsal joint moves around two axes that share the talonavicular and calcaneocuboid joints: a longitudinal axis (roughly aligned with the long axis of the foot, governing inversion and eversion) and an oblique axis. When the hindfoot inverts the two joints lock, making the foot a rigid lever for push-off, and when it everts they unlock, making the foot a mobile adaptor. This is why fusing the Chopart joints stiffens the hindfoot and shifts load to the adjacent ankle and tarsometatarsal joints.

Mnemonic

CHOPARTCHOPART - The two joints and how to reach them

Calcaneocuboid joint

Reached by the lateral incision over the sinus tarsi

Hindfoot deformity

The classic indication for triple or double fusion

One dorsal incision lateral to EHL

Exposes the talonavicular joint

Protect the dorsalis pedis bundle

Deep peroneal nerve and artery run medial to the incision

Arthrodesis of TN and CC

The goal of double and triple fusion

Retract extensors medially

Together with the neurovascular bundle

Talonavicular joint

The dorsal member of the Chopart joint

Hook:Chopart is two joints, the talonavicular and the calcaneocuboid, reached by two incisions.

### Indications and approach selection Primary indications:

Triple arthrodesis (subtalar plus talonavicular plus calcaneocuboid fusion) for fixed hindfoot deformity - severe pes planovalgus, cavovarus foot (for example Charcot-Marie-Tooth disease), neglected clubfoot, or post-traumatic hindfoot arthritis
Double (Chopart) arthrodesis - isolated talonavicular and calcaneocuboid arthritis with a preserved, reducible subtalar joint
Isolated talonavicular arthrodesis for primary inflammatory or post-traumatic arthritis of the talonavicular joint
Isolated calcaneocuboid arthrodesis for calcaneocuboid arthritis
Calcaneonavicular coalition resection in the symptomatic adolescent or young adult (the dorsolateral or sinus tarsi approach is the classic exposure for the coalition bar)
Open reduction and internal fixation of Chopart (midfoot) fracture-dislocation injuries
Revision midfoot surgery including non-union exploration and grafting of the Chopart joints

Matching the indication to the procedure
Clinical problem	Typical procedure	Exposure used
Fixed hindfoot deformity or arthritic subtalar joint	Triple arthrodesis	Dorsal TN plus lateral CC plus sinus tarsi
Isolated Chopart arthritis with a good subtalar joint	Double (Chopart) arthrodesis	Dorsal TN plus lateral CC
Isolated talonavicular arthritis	TN arthrodesis	Dorsal TN incision (or medial approach)
Symptomatic calcaneonavicular coalition	Coalition resection with interposition	Lateral sinus tarsi incision
Chopart fracture-dislocation	ORIF of TN and/or CC	Dorsal and lateral incisions as needed

Contraindications:

Poor soft-tissue envelope over the dorsum or lateral midfoot (blistering, severe contusion, previous incisional compromise)
Active infection of the surgical field
Severe peripheral vascular disease, because the dorsalis pedis artery and its tarsal branches are directly at risk and the foot relies on an intact dorsalis pedis contribution in many patients
Relative - heavy smoking and poorly controlled diabetes increase non-union and wound risk and should be optimised before elective fusion Pre-operative work-up:
Weight-bearing anteroposterior, lateral and oblique radiographs of the foot and ankle to assess alignment, joint space and deformity
A computed tomography scan to characterise tarsal coalition, assess bony detail and plan fixation, particularly for complex Chopart injuries
Magnetic resonance imaging when inflammatory arthritis, osteonecrosis or occult coalition is suspected
Vascular assessment with palpation of the dorsalis pedis and posterior tibial pulses and, where reduced, Doppler or angiographic evaluation before any fusion that endangers the dorsalis pedis Alternative and complementary approaches:
Medial approach to the talonavicular joint - an incision over the navicular tuberosity between tibialis anterior and tibialis posterior, used for isolated talonavicular fusion or accessory navicular excision (the Kidner procedure)
Sinus tarsi (Ollier) approach - the lateral incision extended proximally exposes the subtalar joint and is combined with the dorsal incision for triple arthrodesis
Anterior approach to the ankle - the dorsal incision extended proximally for combined ankle and Chopart pathology
Dorsal tarsometatarsal approach - the dorsal incision extended distally when midfoot (Lisfranc) involvement also requires fixation or fusion

The Exposure

Work down through the layers with the patient supine and bumped, opening the talonavicular joint dorsally (lateral to the extensors) and the calcaneocuboid joint laterally (in the peroneal interval), protecting the dorsal neurovascular bundle at every step.

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Image Needed: Clinical PhotoHigh Priority

Intra-operative photograph of the dorsolateral Chopart approach: two well-spaced incisions on the dorsum and lateral border of the foot, the dorsal neurovascular bundle retracted medially with the extensor tendons, and the talonavicular and calcaneocuboid joints exposed for arthrodesis.

Context: A verified image is being sourced for this exposure.

Pending image generation or sourcing

Exposure sequence

Step 1Position, landmarks and incision planning

Place the patient supine on a radiolucent table with a bump under the ipsilateral buttock to internally rotate the leg and bring the lateral foot toward the surgeon, giving simultaneous access to the dorsal and lateral incisions
Apply a thigh tourniquet and exsanguinate with an Esmarch bandage, and confirm C-arm access from the opposite side before draping
Palpate the landmarks: tibialis anterior tendon (to the medial cuneiform and first metatarsal base), EHL (the medial border of the safe corridor), the navicular tuberosity, the sinus tarsi (soft depression just distal to the lateral malleolus), and the lateral malleolus with the base of the fifth metatarsal bracketing the lateral incision
Plan a dorsal talonavicular incision - longitudinal, about four to six centimetres, centred over the talonavicular joint and placed lateral to the tibialis anterior and EHL tendons (confirm the joint with a needle and fluoroscopy)
Plan a lateral calcaneocuboid incision - longitudinal or slightly oblique, about four to five centimetres, over the dorsolateral calcaneocuboid joint in line with the fourth ray and just distal to the sinus tarsi
Maintain a generous skin bridge of at least four to five centimetres between the two incisions to protect the dorsal skin flap

Step 2Dorsal TN incision and the superficial peroneal nerve

Incise the skin sharply along the planned dorsal line and deepen through subcutaneous fat
Identify and protect the superficial peroneal nerve branches (the intermediate dorsal cutaneous nerve) in the subcutaneous fat with a vessel loop, avoiding traction

Step 3Open the extensor interval lateral to EHL

Divide the inferior extensor retinaculum in the line of the incision (it will need careful repair at closure to prevent extensor bowstringing)
Develop the interval lateral to extensor hallucis longus, working down to bone on the dorsolateral talar neck and navicular

Step 4Mobilise the dorsal neurovascular bundle and open the TN joint

Identify the dorsal neurovascular bundle - the deep peroneal nerve and dorsalis pedis artery running together between EHL and EDL immediately medial to the incision
Mobilise the bundle gently and retract it medially together with the extensor mass (tibialis anterior, EHL and EDL), staying lateral to it so it is carried medially and protected
Incise the talonavicular joint capsule dorsally to expose the talar head and the proximal navicular, then subperiosteally elevate the capsule to expose the joint surfaces for denudation, taking care to stay on bone

Step 5Lateral CC incision and the sural nerve

Through the separate lateral incision, incise the skin and protect the sural nerve (its lateral dorsal cutaneous branch) in the subcutaneous fat, supplying the lateral hindfoot and lateral border of the foot

Step 6Develop the peroneal internervous plane to the CC joint

Develop the genuine internervous plane between peroneus tertius (deep peroneal nerve) dorsally and peroneus brevis (superficial peroneal nerve) plantarward, retracting peroneus brevis plantarward directly down to the calcaneocuboid joint capsule

Step 7Elevate EDB and expose the CC joint and sinus tarsi

Elevate the extensor digitorum brevis from its calcaneal origin and retract it distally to expose the calcaneocuboid joint and the floor of the sinus tarsi
Ligate branches of the lateral tarsal artery with careful diathermy, then incise the calcaneocuboid capsule to expose the anterior calcaneus and cuboid articular surfaces

Step 8Decorticate, fuse in valgus and close

For arthrodesis, decorticate both joint surfaces down to bleeding cancellous bone, position the hindfoot in about 5 degrees of valgus with a plantigrade forefoot, and fix with screws or staples
Confirm reduction and hardware position with intra-operative fluoroscopy in AP, lateral and oblique views
Repair the inferior extensor retinaculum if it was divided, close the capsule over each joint where possible, and close in layers over a well-padded posterior splint with the foot in the corrected plantigrade position

Why there is no true internervous plane dorsally

On the dorsum of the foot the extensor compartment (tibialis anterior, EHL, EDL, peroneus tertius and extensor digitorum brevis) is supplied throughout by the deep peroneal nerve, so the dorsal talonavicular exposure is an inter-tendinous interval rather than a true internervous plane. The safety of the approach comes from staying lateral to the deep peroneal nerve and dorsalis pedis bundle and retracting them medially with the extensor tendons. The lateral calcaneocuboid incision, by contrast, exploits a genuine internervous plane between peroneus tertius (deep peroneal) and peroneus brevis (superficial peroneal).

Comparing the two Chopart incisions
Feature	Dorsal TN incision	Lateral CC incision
Joint exposed	Talonavicular joint	Calcaneocuboid joint and sinus tarsi
Incision	Longitudinal, lateral to TA and EHL	Over the CC joint, just distal to the lateral malleolus
Plane	Inter-tendinous interval, not a true internervous plane	True internervous plane: peroneus tertius and peroneus brevis
Key nerve at risk	Deep peroneal nerve (medial, with dorsalis pedis)	Sural nerve (subcutaneous, lateral)
Tendons	TA, EHL and EDL retracted medially	Peroneus brevis and longus protected laterally

Examiner favourite - the dorsalis pedis and first web space

The dorsalis pedis artery is the continuation of the anterior tibial artery and runs with the deep peroneal nerve on the dorsum of the foot between extensor hallucis longus and extensor digitorum longus. The deep peroneal nerve supplies the first dorsal interosseous and extensor digitorum brevis and carries sensation from the first web space. Knowing this allows you to explain to the examiner exactly why a dorsal talonavicular incision placed lateral to EHL puts this bundle at risk and must be retracted medially.

Mnemonic

STEPSSTEPS - Operative sequence

Supine with an ipsilateral bump

Internally rotate the foot for lateral access

Two incisions planned

Dorsal for TN, lateral for CC

Extensors retracted medially

Develop the plane lateral to EHL, protect the NV bundle

Peroneus tertius and brevis interval

The internervous plane for the calcaneocuboid joint

Subperiosteal decancellation and fusion

Denude cartilage to bleeding bone, fix and close in layers

Hook:Supine, Two incisions, Extensors retracted, Peroneal interval, Subperiosteal fusion.

Protect the dorsal neurovascular bundle at every step

The deep peroneal nerve and dorsalis pedis artery run together between EHL and EDL immediately medial to the dorsal talonavicular incision. They must be identified, gently mobilised and retracted medially with the extensor mass. Injury causes a numb first web space, loss of extensor digitorum brevis function, and ischaemia of the toes if the artery is divided in a dysvascular foot. Never place retractors under tension against the bundle, and confirm the dorsalis pedis pulse before and after tourniquet deflation.

Dangers & Extensions

Structures at risk, by layer

Danger structures and how to protect them
Layer	Structure at risk	How to protect it
Subcutaneous (dorsal)	Superficial peroneal nerve branches (intermediate dorsal cutaneous)	Identify in the fat, vessel loop, gentle retraction, no traction
Subcutaneous (lateral)	Sural nerve (lateral dorsal cutaneous branch)	Identify and protect throughout the lateral incision to avoid neuroma
Deep dorsal	Deep peroneal nerve and dorsalis pedis artery	Mobilise gently and retract medially with the extensor mass
Deep dorsal	Extensor tendons (TA, EHL, EDL)	Retract medially, avoiding sheath abrasion and retractor tension
Deep lateral	Peroneus brevis and longus tendons	Retract plantarward in the peroneal internervous interval
Deep lateral	Lateral tarsal artery branches	Careful diathermy and meticulous haemostasis deep to EDB
Medial (if incision drifts)	Saphenous nerve and great saphenous vein	Keep the dorsal incision lateral to EHL

Mnemonic

DANGERDANGER - Nerves, vessels and tendons to protect

Deep peroneal nerve

Medial, in the dorsal NV bundle

Artery - the dorsalis pedis

Travels with the deep peroneal nerve

Nerve - the sural

Lateral in the CC incision

Guard the extensor tendons

TA, EHL and EDL retracted medially

Elevate EDB and protect superficial peroneal branches

Subcutaneous sensory nerves on the dorsum

Retract the peroneal tendons

Peroneus brevis and longus protected laterally

Hook:Name the danger structures per layer - subcutaneous sensory nerves, then the deep dorsal bundle and tendons.

Extending the approach:

Proximally - the dorsal talonavicular incision can be extended proximally along the axis of the long extensors to become the anterior approach to the ankle, useful for combined ankle and Chopart fusion
Distally - the dorsal incision extends distally onto the dorsum of the midfoot to reach the tarsometatarsal (Lisfranc) joints for extended midfoot fusion or fixation
Sinus tarsi extension - the lateral calcaneocuboid incision is extended proximally into the sinus tarsi to expose the subtalar joint, which is the key to completing a triple arthrodesis
Lateral column extension - the lateral incision can be carried distally along the lateral column for lateral tarsometatarsal work Closure and post-operative care:
Achieve meticulous haemostasis after tourniquet deflation, paying attention to the lateral tarsal and dorsalis pedis branches
Close the joint capsule over each prepared joint where possible using absorbable suture, and repair the inferior extensor retinaculum carefully to prevent extensor tendon bowstringing
Close in layers and apply a well-padded posterior splint with the foot in the corrected, plantigrade position
0 to 2 weeks - strict non-weight-bearing in a posterior splint, elevation, wound observation, DVT prophylaxis
2 weeks - wound check and suture removal, transfer into a non-weight-bearing short leg cast or controlled ankle motion boot
6 weeks - weight-bearing radiographs, progress to weight-bearing in a boot if the fusion is consolidating
10 to 12 weeks - transition to a normal shoe with a rocker sole if radiographic union is confirmed
3 to 6 months - full recovery, footwear modification and orthotic as needed

Why hindfoot valgus matters

A fused hindfoot is locked in whatever position it is set. Aiming for about 5 degrees of hindfoot valgus with a plantigrade, neutral forefoot restores the shock-absorbing alignment of the Chopart joint and avoids locking the patient into varus (which causes lateral ankle overload) or planovalgus (which loads the medial ankle and the plantar fascia). Always confirm the corrected position on fluoroscopy before final fixation.

Procedures Through This Approach

Procedures through the dorsolateral Chopart approach
Procedure	Joint(s)	Key technical point
Triple arthrodesis	Subtalar, TN, CC	Add the sinus tarsi extension for the subtalar joint and prepare all three joints before fixing
Double (Chopart) arthrodesis	TN and CC	Fuse the two Chopart joints with the subtalar joint preserved
Isolated TN arthrodesis	Talonavicular	Dorsal incision alone, denude talar head and navicular
Isolated CC arthrodesis	Calcaneocuboid	Lateral incision alone, decorticate anterior calcaneus and cuboid
Calcaneonavicular coalition resection	Calcaneus-navicular bar	Elevate EDB, excise the bar in the sinus tarsi, interpose fat or EDB muscle
Chopart injury ORIF	TN and/or CC	Restore joint congruity and column length, repair capsule

Complementary and alternative exposures
Exposure	Reached by	Used for
Sinus tarsi (Ollier)	Lateral CC incision extended proximally	Subtalar joint and triple arthrodesis
Anterior ankle	Dorsal TN incision extended proximally	Ankle plus Chopart fusion
Tarsometatarsal (Lisfranc)	Dorsal incision extended distally	Midfoot fusion or fixation
Medial TN approach	Incision over the navicular tuberosity	Isolated TN fusion and accessory navicular (Kidner)

Accessory navicular - a medial exception

The accessory navicular sits on the medial aspect of the navicular tuberosity at the insertion of the tibialis posterior tendon and is classically approached through a medial incision over the navicular for the Kidner procedure, not through the dorsolateral approach. The dorsolateral exposure gives access to the navicular body for talonavicular fusion and to the lateral Chopart joints. When an accessory navicular coexists with symptomatic Chopart arthritis, plan the medial and dorsolateral incisions as separate, well-spaced exposures.

Viva & Exam Focus

Exam viva scenarios

Practise clinical reasoning and management decisions out loud

Viva scenarioStandard

Clinical prompt

“A 58-year-old with severe symptomatic arthritis of the talonavicular and calcaneocuboid joints is scheduled for a double (Chopart) arthrodesis. Describe your surgical approach to these joints.”

Practical approach

I would position the patient supine on a radiolucent table with a bump under the ipsilateral buttock to internally rotate the foot, giving simultaneous access to the dorsum and lateral side, and apply a thigh tourniquet after exsanguination. I expose the talonavicular joint through a dorsal longitudinal incision of about four to six centimetres centred over the joint and placed lateral to the tibialis anterior and extensor hallucis longus tendons. I deepen through subcutaneous fat, identifying and protecting the superficial peroneal nerve branches, then divide the inferior extensor retinaculum in the line of the incision. I develop the interval lateral to extensor hallucis longus, identify the deep peroneal nerve and dorsalis pedis artery running between EHL and EDL, and mobilise and retract them medially together with the extensor tendons. I then open the talonavicular capsule dorsally to expose the talar head and navicular. For the calcaneocuboid joint I make a separate lateral incision over the joint just distal to the sinus tarsi, protect the sural nerve in the subcutaneous tissue, and develop the true internervous plane between peroneus tertius and peroneus brevis, retracting the peroneus brevis plantarward and elevating extensor digitorum brevis distally to expose the joint. I decorticate both joints to bleeding cancellous bone, position the hindfoot in about 5 degrees of valgus, fix with screws or staples, confirm reduction on fluoroscopy, repair the retinaculum and close in layers over a posterior splint.

Key clinical points

Supine with an ipsilateral bump for dorsal and lateral access

Two incisions: dorsal for TN lateral to EHL, lateral for CC over the sinus tarsi

Protect superficial peroneal branches dorsally and the sural nerve laterally

Identify and retract the deep peroneal nerve and dorsalis pedis medially with the extensors

CC internervous plane: peroneus tertius (deep peroneal) and peroneus brevis (superficial peroneal)

Decorticate both joints to bleeding bone and fuse the hindfoot in slight valgus

Repair the inferior extensor retinaculum and close in layers

Immobilise non-weight-bearing in a posterior splint

Common pitfalls

Not mentioning the deep peroneal nerve and dorsalis pedis as the key danger medially

Failing to protect the sural nerve in the lateral incision

Describing a single incision for both joints instead of two well-spaced incisions

Forgetting the internervous plane for the calcaneocuboid joint

Further questions

“How would you extend this approach to perform a triple rather than a double arthrodesis?”

“What is the deep peroneal nerve and dorsalis pedis at risk of during the dorsal dissection?”

“How would you manage a talonavicular non-union?”

Viva scenarioChallenging

Clinical prompt

“Two days after a talonavicular fusion performed through a dorsal approach, the patient reports numbness in the first web space and the toes are cool. The dorsalis pedis pulse is weaker than pre-operatively. How do you assess and manage this?”

Practical approach

This presentation points to compromise of the dorsal neurovascular bundle, namely the deep peroneal nerve (which carries first web space sensation) and the dorsalis pedis artery, both of which lie between EHL and EDL immediately medial to the dorsal talonavicular incision. I would first exclude a correctable extrinsic cause by loosening or splitting any tight dressings or cast and elevating the limb, then perform a focused examination comparing the dorsalis pedis and posterior tibial pulses and the capillary refill with the contralateral limb, and document the precise sensory and motor deficit of the deep peroneal and superficial peroneal nerves. I would arrange urgent Doppler studies and, if there is any concern for acute arterial insufficiency, a vascular surgery review with consideration of CT angiography, because an expanding haematoma compressing the artery or an iatrogenic dorsalis pedis injury may need urgent exploration. If the perfusion is intact and the deficit is purely sensory, the most likely diagnosis is a neuropraxia of the deep peroneal nerve from traction or retraction, which I would manage expectantly with careful monitoring, protection of the insensate skin, and nerve conduction studies at around three weeks if there is no recovery. I would counsel the patient honestly that most traction injuries recover but that some sensory deficit can persist, and I would document the findings and the discussion.

Key clinical points

Loosen the dressing first and exclude extrinsic compression

Examine dorsalis pedis and posterior tibial pulses and capillary refill against the other side

Deep peroneal nerve carries first web space sensation - its injury is the likely cause of the numbness

Dorsalis pedis compromise with a cool foot is a vascular emergency requiring urgent Doppler and vascular review

Distinguish neuropraxia (observe) from acute arterial insufficiency (explore)

Document the deficit and counsel the patient honestly about prognosis

Nerve conduction studies at around three weeks if no sensory recovery

Aim to prevent the complication by gentle mobilisation of the bundle at the index operation

Common pitfalls

Reassuring the patient without examining the pulses and excluding a tight dressing

Missing acute arterial insufficiency that needs urgent exploration

Promising full nerve recovery when the deficit may be permanent

Not documenting the deficit and the discussion with the patient

Further questions

“How would you protect the deep peroneal nerve and dorsalis pedis during the index operation?”

“When would you request formal nerve conduction studies?”

“What is the role of the dorsalis pedis in foot perfusion in a patient with peripheral vascular disease?”

Viva scenarioChallenging

Clinical prompt

“A 13-year-old gymnast has refractory lateral midfoot pain and recurrent ankle sprains. Imaging shows a calcaneonavicular coalition. Describe the surgical approach and the technique for resection.”

Practical approach

Calcaneonavicular coalition is a fibrous, cartilaginous or bony bar between the anterior process of the calcaneus and the lateral aspect of the navicular, and it is classically approached through a dorsolateral or sinus tarsi approach, which is exactly the lateral component of the Chopart exposure. I would position the patient supine with a bump under the ipsilateral buttock and use a thigh tourniquet. I make a dorsolateral incision centred over the sinus tarsi, identify and protect the sural nerve in the subcutaneous fat, and develop the internervous plane between peroneus tertius and peroneus brevis. I elevate the extensor digitorum brevis from its origin on the calcaneus and retract it distally to expose the floor of the sinus tarsi, where the coalition bar is palpated and confirmed with imaging. I place a blunt retractor around the medial aspect of the bar to protect the deep medial neurovascular and tendinous structures, then excise the coalition with osteotomes and rongeurs, removing a generous block of bone so that the gap is wide enough to prevent recurrence. I confirm complete resection by direct visualisation and by interposing local tissue - the extensor digitorum brevis muscle belly or, as Mubarak described, a free fat graft - into the defect to prevent bony regrowth. I do not fuse the joint at this age, as the goal is to restore motion and relieve symptoms while preserving the native joints. I close in layers over a splint and mobilise the patient early once the wound has healed.

Key clinical points

Calcaneonavicular coalition lies in the floor of the sinus tarsi between the anterior calcaneus and lateral navicular

Approach through the dorsolateral or sinus tarsi component of the Chopart exposure

Develop the peroneus tertius and peroneus brevis internervous plane

Elevate extensor digitorum brevis distally to expose the bar

Protect the deep medial structures with a blunt retractor around the bar

Resect a generous block and confirm complete removal

Interpose EDB muscle or a fat graft (Mubarak) to prevent recurrence

Preserve the native joints in the skeletally immature patient

Common pitfalls

Recommending primary fusion in a young patient with a resectable coalition

Removing too little bone, which leads to recurrence

Failing to interpose tissue into the defect

Injuring the sural nerve or the deep medial structures during resection

Further questions

“What are the radiographic signs of a calcaneonavicular coalition on the oblique view?”

“When would you offer subtalar or triple fusion instead of resection?”

“What is the role of interposition material and which gives the lowest recurrence?”

Exam day cheat sheet

DORSOLATERAL APPROACH TO THE CHOPART JOINTS

Position and incisions

Supine with an ipsilateral buttock bump to internally rotate the foot
Two incisions: dorsal for the talonavicular joint, lateral for the calcaneocuboid joint
Dorsal TN incision is longitudinal, lateral to tibialis anterior and EHL
Lateral CC incision is over the joint, just distal to the sinus tarsi
Maintain a skin bridge of at least four to five centimetres between incisions

Internervous planes

Dorsal TN exposure is an inter-tendinous interval, not a true internervous plane (all extensors are deep peroneal nerve)
Stay lateral to EHL and retract the extensors and the NV bundle medially
Lateral CC plane is a TRUE internervous plane: peroneus tertius (deep peroneal) and peroneus brevis (superficial peroneal)
Elevate extensor digitorum brevis distally to reach the CC joint and sinus tarsi

Structures at risk

Deep peroneal nerve and dorsalis pedis artery - the dorsal neurovascular bundle, medial to the TN incision
Superficial peroneal nerve branches - subcutaneous on the dorsum
Sural nerve - subcutaneous in the lateral CC incision
Saphenous nerve and great saphenous vein - medially if the incision drifts
Extensor tendons retracted medially, peroneal tendons protected laterally

Dissection principles

Identify and protect sensory nerves in subcutaneous fat first
Mobilise the deep peroneal nerve and dorsalis pedis and retract them medially with the extensors
Incise each joint capsule to expose the articular surfaces
Decorticate to bleeding cancellous bone for arthrodesis
Subperiosteal elevation keeps the dissection on bone and protects deep structures

Extension and procedures

Extend the dorsal incision proximally for the anterior approach to the ankle
Extend the dorsal incision distally for the tarsometatarsal joints
Extend the lateral incision into the sinus tarsi for the subtalar joint and triple arthrodesis
Triple, double (Chopart) and isolated TN or CC arthrodesis are the main procedures
Calcaneonavicular coalition is resected through the sinus tarsi component with tissue interposition

Closure and post-operative care

Meticulous haemostasis of tarsal arterial branches after tourniquet deflation
Repair the inferior extensor retinaculum if divided
Layered closure and a well-padded posterior splint in the plantigrade position
Non-weight-bearing for about six weeks, then progressive weight-bearing in a boot
Counsel on non-union risk, especially of the talonavicular joint, in smokers

How to present this approach in the Operative Surgery station

For the Operative Surgery station, describe the dorsolateral approach to the Chopart joints systematically: supine positioning with a bump, two incisions (dorsal for the talonavicular joint lateral to EHL, lateral for the calcaneocuboid joint), the internervous plane (peroneus tertius and peroneus brevis for the CC joint, an inter-tendinous interval dorsally), the deep peroneal nerve and dorsalis pedis as the key danger, and the procedures performed through it.

References

Guidelines, registries and global practice Triple and double arthrodesis of the hindfoot and midfoot is performed worldwide, and the surgical principles converge across examination systems (advanced orthopaedic practice and advanced orthopaedic practice, DNB and MS, MRCS, SICOT). The dorsolateral approach to the Chopart joints is the standard workhorse exposure taught across all of these systems. Weight-bearing radiographs and a CT or MRI for coalition and subtle arthritis are near-universal, and the emphasis on protecting the deep peroneal nerve and dorsalis pedis bundle, on using two well-spaced incisions, and on fusing the hindfoot in slight valgus is shared.

Where international guidance converges on Chopart and hindfoot fusion
Body	Position on Chopart and hindfoot fusion
AO Foundation	Anatomic restoration of the foot columns and rigid fixation of prepared, decorticated joints. Weight-bearing radiographs and cross-sectional imaging are used to plan fusion
BOA and BOAST (foot and ankle)	Multidisciplinary care for the diabetic or high-risk foot, off-loading and optimal glycaemic control before elective fusion, and patient-centred consent on non-union and wound risk
AAOS and international foot and ankle societies	Triple arthrodesis reserved for fixed, rigid deformity and arthritic hindfeet. Isolated or double fusion is preferred when the subtalar joint is preserved to limit adjacent-joint degeneration

Population and outcome evidence:

Triple arthrodesis reliably relieves pain and corrects deformity, but long follow-up shows radiographic degenerative change in adjacent joints (the ankle and the naviculocuneiform joints) in a substantial proportion of patients, even when they remain functionally satisfied.
Calcaneonavicular coalition resection with fat or muscle interposition gives good pain relief and a low recurrence rate compared with resection alone. Global practice variation: In high-resource settings, headless screws, low-profile plates and intra-operative CT are routine and allow early protected weight-bearing. In resource-limited settings the same joints are exposed through the identical dorsolateral incisions and stabilised with large-fragment cancellous or small-fragment screws and staples, with a longer period of cast immobilisation. Consent (globally applicable): discuss wound problems and infection, injury to the deep peroneal nerve and dorsalis pedis with numbness of the first web space, non-union (particularly of the talonavicular joint and especially in smokers), residual or recurrent deformity, and progressive arthritis of adjacent joints over the long term.

Evidence

Triple Arthrodesis: 25- and 44-Year Average Follow-up of the Same Patients

Saltzman CL, Fehrle MJ, Cooper RR, Spencer EC, Ponseti IV • Journal of Bone and Joint Surgery (Am) (1999)

Key Findings:

Landmark very-long-term follow-up of patients who underwent triple arthrodesis by Ponseti, reviewed at an average of 25 and again at 44 years
Patients remained functionally satisfied with their outcome despite frequent radiographic degenerative change in adjacent joints
Underlines the durability of pain relief after triple arthrodesis but also the predictable late arthritis of the ankle and midfoot

Evidence

Clinical Outcome After Primary Triple Arthrodesis

Pell RF IV, Myerson MS, Schon LC • Journal of Bone and Joint Surgery (Am) (2000)

Key Findings:

Modern series reporting the outcome of primary triple arthrodesis for hindfoot deformity and arthritis
High union and patient satisfaction rates, with satisfaction driven mainly by correction of residual deformity and pain relief
Supports triple arthrodesis through extensile lateral and dorsal Chopart exposures as a reliable salvage procedure

Evidence

Triple Arthrodesis: A Critical Long-term Review

Angus PD, Cowell HR • Journal of Bone and Joint Surgery (Br) (1986)

Key Findings:

Critical long-term review of triple arthrodesis documenting good subjective results in the majority of patients
Residual deformity and adjacent-joint degenerative change were found in a substantial proportion at long follow-up
Emphasises that the goal of surgery is a plantigrade, pain-free foot rather than a radiographically normal hindfoot

Evidence

Calcaneonavicular Coalition: Treatment by Excision and Fat Interposition

Mubarak SJ, Patel PN, Upasani VV, Moor MA, Wenger DR • Journal of Pediatric Orthopaedics (2009)

Key Findings:

Describes excision of the calcaneonavicular coalition through the dorsolateral sinus tarsi approach with interposition of a free fat graft
Fat interposition gave a lower rate of bony recurrence than the extensor digitorum brevis muscle interposition previously favoured
Establishes the modern technique for coalition resection accessed through the same lateral Chopart exposure

Evidence

Triple Arthrodesis in Rheumatoid Arthritis

Figgie MP, O'Malley MJ, Ranawat C, Inglis AE, Sculco TP • Clinical Orthopaedics and Related Research (1993)

Key Findings:

Reports reliable correction of severe rheumatoid hindfoot deformity using triple arthrodesis
Pain relief and improved ambulation were achieved despite the challenging soft tissues of the rheumatoid foot
Supports the dorsolateral Chopart approach as part of hindfoot reconstruction in inflammatory arthritis