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Chopart Joint Injuries - Comprehensive Overview

1. Anatomy and Named Structure

Constituent Joints

Key Ligamentous Supports

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2. Epidemiology and Etiology

• Midfoot fractures occur at an estimated 3.6/100,000/year (Court-Brown et al.)
• Chopart injuries occur 4x less frequently than Lisfranc injuries
• In a review of 155 midfoot fractures/dislocations, pure Chopart fracture-dislocations accounted for 16%, Chopart-Lisfranc combined for 16.8%
• Misdiagnosis rate is 20-41% - symptoms are frequently attributed to ankle sprain
• The incidence has risen with motor vehicle airbag use (patients who previously would not have survived now sustain severe blunt foot trauma)

Causes / Etiological Factors

1. Falls (stairs, height) - most common low-energy cause
2. Sports injuries - particularly football, equestrian, skiing
3. Motor vehicle accidents (MVA) - high-energy; associated with severe fracture-dislocations
4. Pedestrian vs. vehicle accidents - high energy
5. Axial loading injuries (e.g., fall from height, landing on plantar-flexed foot)
6. Twisting injuries with or without inversion/eversion component

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3. Mechanism of Injury

Main and Jowett Classification (1975)

Inversion Injuries (Most Common ~75%)

• Lateral distraction - avulsion of bifurcate ligament, dorsal calcaneocuboid ligament, extensor digitorum brevis origin; may produce anterior calcaneal process fracture
• Medial compression - impaction of talar head and navicular body
• When accompanied by plantar flexion: distraction propagates dorsally through the talonavicular joint → dorsal talonavicular ligament tear or dorsal navicular avulsion

Eversion/Abduction Injuries (Less Common)

• "Nutcracker" mechanism at the calcaneocuboid joint
• Compressive impaction on lateral side → comminuted anterior calcaneus and posterolateral cuboid fractures (often depressed)
• Medial distraction → navicular tuberosity avulsion (tibialis posterior traction), spring ligament injury

High-Energy Injuries

• MVA / crush: Complete fracture-dislocation of both TNJ and CCJ (complete Chopart dislocation)
• Swivel dislocations: Medial or lateral deforming forces causing TNJ and/or CCJ dislocation while the calcaneus rotates around the talus

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4. Classification of Chopart Injuries

Spectrum of Injury

GRADE 1 - Sprain/Ligament injury (no dislocation)
GRADE 2 - Ligament injury WITH dislocation (pure dislocation)
GRADE 3 - Fracture WITHOUT dislocation
GRADE 4 - Fracture WITH dislocation (fracture-dislocation)

By Direction (Clinical Classification)

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5. Associated Injuries

Local Associated Injuries

• Lisfranc joint injuries (most common co-injury; combined Chopart-Lisfranc has worst prognosis)
• Navicular fractures (body, tuberosity, stress fractures)
• Cuboid fractures (avulsion or nutcracker compression type)
• Anterior calcaneal process fractures (bifurcate ligament avulsion)
• Talar head fractures (impaction from navicular in medial stress)
• Cuneiform fractures (rare in isolation)
• Subtalar joint injuries (in high-energy mechanisms)
• Compartment syndrome of the foot (must be ruled out in all significant injuries)

Systemic/Regional Associated Injuries (High-Energy)

• Calcaneal fractures
• Tibial/fibular fractures (pilon fracture)
• Knee injuries (dashboard mechanism)
• Pelvic fractures
• Neurovascular injury (peroneal nerve, dorsalis pedis artery)
• Open wounds and soft tissue degloving

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6. Signs and Symptoms

History

• Mechanism: twisting of foot, fall, MVA
• Inability or difficulty weight-bearing
• Onset of midfoot/dorsal foot pain

Clinical Examination

Red Flags Requiring Urgent Assessment

• Tense compartments (pain out of proportion, pain with passive stretch of toes)
• Neurovascular compromise (pallor, absent pulses, paraesthesia)
• Open fracture

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7. Investigations

Plain Radiography (First-Line)

• Dorsoplantar (AP) view
• Lateral view
• Oblique view

Radiographs are often normal or show only subtle findings - the diagnosis is frequently missed.

• Loss of parallelism at the talonavicular or calcaneocuboid joint
• Fleck avulsion fractures at ligament attachment sites
• Anterior calcaneal process fracture
• Navicular tuberosity avulsion
• Cuboid compression/avulsion
• Joint space widening

Computed Tomography (CT) - Gold Standard for Bony Injury

• Any clinically suspected Chopart injury even with normal X-rays
• All confirmed injuries for surgical planning
• Assessment of comminution, articular involvement, and column length

• Subtle articular fractures invisible on plain X-ray
• Degree of comminution and displacement
• Associated injuries to adjacent bones
• 3D reconstruction for surgical planning

MRI - Gold Standard for Ligamentous Injury

• Suspected purely ligamentous injury (normal CT)
• Assessment of spring ligament, bifurcate ligament, plantar fascia
• Chronic instability evaluation
• Differentiating sprain from occult fracture

1. Lateral distraction / medial compression (inversion)
2. Dorsal distraction (plantar flexion + inversion)
3. Medial distraction / lateral compression (eversion/"nutcracker")

Bone Scan / SPECT

• Useful for detecting occult fractures (navicular stress fractures)
• Less commonly used with widespread CT/MRI availability

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8. Treatment

General Principles

1. Anatomic reduction of the Chopart joint
2. Restoration and maintenance of column length (medial and lateral)
3. Stable fixation until healing
4. Prevention of post-traumatic arthritis and flatfoot deformity

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Non-Operative Treatment

• Isolated ligamentous sprain (Grade 1-2) without instability or dislocation
• Nondisplaced avulsion fractures
• Nondisplaced navicular/cuboid fractures

• RICE (rest, ice, compression, elevation) initially
• Non-weight-bearing in a below-knee (BK) cast for 6-8 weeks
• Controlled motion walking boot or aircast splint
• Progressive weight-bearing with soft brace for 6 further weeks
• Outpatient orthopedic follow-up within 48 hours for non-operative injuries

Note: More aggressive immobilization (6-8 weeks SLC rather than walking boot) is recommended compared to ankle sprains, as Chopart sprains can lead to significant chronic instability.

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Operative Treatment

• Displaced fractures
• Any dislocation (pure or fracture-dislocation)
• Instability after reduction
• Failed closed reduction
• Open fractures

Step 1: Closed Reduction (Attempt First)

• Apply manual traction in the axial vector
• Reverse the mechanism of injury (e.g., eversion for an inversion dislocation)
• Assess under fluoroscopy

Step 2: Patient Positioning

• Supine, knee flexed 90°
• Tourniquet applied to thigh

Step 3: Surgical Approaches

Step 4: Fracture Fixation

Critical principle: Loss of lateral column length leads to flatfoot deformity and peritalar subluxation. External fixation or distraction may be required before definitive fixation.

Step 5: Stabilization of Residual Instability

• Minimum 2 x 1.8 mm K-wires per unstable column
• Wires placed perpendicular to the joint surface

Aftercare Protocol

Gastrocnemius release may be required for postoperative equinus contracture, more common in mid- and hind-foot injuries.

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9. Complications

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10. Prognosis

• Purely ligamentous sprains treated conservatively: generally good if properly immobilized
• Displaced fracture-dislocations: most patients cannot return to pre-injury activity level by 2 years (Campbell's, 2026)
• Early anatomical reduction and operative fixation gives significantly better AOFAS and VAS scores than late or inadequate treatment
• Combined Chopart + Lisfranc injuries have the lowest functional scores
• A 2026 study (van Meelen et al., PMID 41578167) specifically examined outcomes of combined navicular + talar head fractures - a particularly morbid injury pattern

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Summary Diagram

CHOPART INJURY ALGORITHM

Suspected Chopart Injury
(midfoot pain, swelling, mechanism)
           ↓
3-view foot X-ray (not ankle)
           ↓
    ┌──────┴──────┐
  Normal       Abnormal
    ↓               ↓
CT + MRI       CT scan
    ↓               ↓
Confirmed injury   Classify severity
    ↓               
  ┌──────────────────────────────────┐
  │  NON-DISPLACED / SPRAIN ONLY    │
  │  Non-weight-bearing cast 6-8wk  │
  │  Progressive WB with brace      │
  └──────────────────────────────────┘
                ↓
  ┌──────────────────────────────────┐
  │  DISPLACED / DISLOCATION        │
  │  1. Closed reduction attempt    │
  │  2. If failed → Open reduction  │
  │  3. ORIF (lag screws / plates)  │
  │  4. K-wire stabilization        │
  │  5. NWB 6-12 weeks              │
  │  6. K-wire removal + rehab      │
  └──────────────────────────────────┘

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• Campbell's Operative Orthopaedics, 15th Ed (2026) - Midfoot Fractures and Dislocations, pp. 5199-5201
• Rosen's Emergency Medicine, 9th Ed - Midtarsal Joint Injuries, p. 751
• Imaging Anatomy Text and Atlas, Vol. 3 - Transverse Tarsal Joint, p. 855
• AO Surgery Reference - Treatment of Chopart Injuries (surgeryreference.aofoundation.org)
• Metcalfe TSN et al. "Chopart dislocations: a review of diagnosis, treatment and outcomes." Arch Orthop Trauma Surg 2024 Jan [PMID: 37715068]
• Rammelt S, Missbach T. "Chopart joint injuries: assessment, treatment, and 10-year results." J Orthop Trauma 2023;37:e14
• Abs B et al. "The missed chapter on midfoot: Chopart injuries." Radiol Med 129:1840-1848 (2024)
• van Meelen TS et al. "Functional Outcome of Chopart Injuries Involving Combined Fractures of the Navicular and Talar Head." Foot Ankle Spec 2026 [PMID: 41578167]