Chopart Injury

1. Clinical Overview

Summary

The Chopart Joint (Midtarsal Joint, Transverse Tarsal Joint) is a complex articulation consisting of the Talonavicular (TN) and Calcaneocuboid (CC) joints. This S-shaped joint complex is critical for the foot's ability to transition from a flexible shock absorber during heel strike to a rigid lever for push-off during gait. [1]

Chopart injuries encompass a spectrum from occult ligamentous sprains ("Midfoot Sprain") to devastating fracture-dislocations that can permanently disable the foot. The classic "Nutcracker Fracture" occurs when an abduction force crushes the cuboid between the calcaneus and the metatarsal bases. [2]

These injuries are frequently missed on initial evaluation, with studies reporting diagnostic delays in 38-41% of cases, particularly in polytrauma patients. [3,4] If left untreated or inadequately managed, Chopart injuries lead to chronic pain, post-traumatic arthritis, progressive deformity, and loss of normal gait mechanics. [5]

The Chopart joint is named after François Chopart (1743-1795), a French surgeon who described disarticulation at this level for foot amputations. Understanding the biomechanical importance of this joint complex is essential for orthopedic surgeons, emergency physicians, and trauma specialists.

Key Facts

The Locking Mechanism: The Chopart joint functions through a sophisticated biomechanical coupling with the subtalar joint. When the subtalar joint inverts, the axes of the TN and CC joints diverge, creating a "locked" rigid foot ideal for push-off (lever arm function). When the subtalar joint everts, these axes become parallel, "unlocking" the midfoot to allow flexibility for shock absorption on heel strike. [6] Disruption of this mechanism results in loss of the windlass effect and push-off power.

The Nutcracker Mechanism: An abduction force applied to the forefoot compresses the lateral column, specifically the cuboid, between the calcaneus proximally and the 4th/5th metatarsal bases distally. The cuboid literally gets crushed like a nut between two hard surfaces, resulting in comminution and impaction. [7]

The "Piano Key" Sign: Instability of the TN or CC joints allows independent vertical translation of the metatarsal heads when manually stressed, resembling piano keys being depressed. This clinical sign indicates significant ligamentous disruption. [8]

The Fleck Sign: A small avulsion bone fragment dorsal to the TN or CC joint on lateral radiograph represents avulsion of the bifurcate ligament or dorsal capsular structures. This "fleck" is pathognomonic for significant ligamentous injury and indicates the need for advanced imaging. [9]

Lateral Column Length: Restoration of lateral column length is the primary surgical goal. Shortening of the lateral column (cuboid compression) results in forefoot abduction, pes planovalgus deformity, and altered gait mechanics. [10]

Clinical Pearls

"The Missed Midfoot": In polytrauma patients with distracting injuries, Chopart injuries are missed in up to 41% of cases on initial evaluation. Maintain a high index of suspicion for midfoot injury in any patient with foot pain following high-energy trauma, even if initial radiographs appear normal. [4]

"CT is Mandatory": If a patient with midfoot trauma cannot weight bear comfortably AND plain radiographs show no obvious fracture, CT imaging is mandatory. CT will reveal occult impaction fractures, subtle malalignment, and the true extent of comminution. [11]

"Bridge Plating Principle": You cannot place screws into a comminuted, impacted cuboid ("mush"). The surgical strategy requires a bridge plate spanning from the calcaneus to the 4th/5th metatarsals, maintaining lateral column length while the cuboid consolidates. Bone graft or substitute fills the void. The plate is typically removed at 3-4 months. [12]

"Primary Fusion for Talonavicular": Highly displaced or comminuted TN fracture-dislocations have an extremely high rate of post-traumatic arthritis (> 80%). Some surgeons advocate primary arthrodesis of the TN joint to avoid 1-2 years of progressive pain before inevitable fusion. [13]

"The Bifurcate Ligament": This Y-shaped ligament originates on the anterior process of the calcaneus and inserts into both the cuboid (calcaneocuboid limb) and navicular (calcaneonavicular limb). It is the primary static stabilizer of the Chopart joint. Avulsion indicates severe instability. [14]

2. Epidemiology

Demographics

Incidence: Chopart injuries are genuinely rare, accounting for approximately 0.3-0.4% of all fractures and approximately 7% of midfoot injuries. [15] However, the true incidence may be underestimated due to frequent misdiagnosis or underdiagnosis.

Age Distribution:

Bimodal distribution
Young adults (20-40 years): High-energy mechanisms (MVA, motorcycle accidents, industrial injuries)
Older adults (> 60 years): Low-energy mechanisms (simple falls, twisting injuries) in osteoporotic bone

Gender: Male predominance (approximately 3:1) due to higher exposure to high-energy trauma and occupational hazards. [16]

Associated Injuries:

Polytrauma: Up to 60% of Chopart injuries occur in polytrauma patients
Ipsilateral limb injuries: Calcaneal fractures (20%), ankle fractures (15%), Lisfranc injuries (10%)
Spine injuries: Thoracolumbar fractures in high-energy axial loading mechanisms

Mechanism of Injury

High-Energy Mechanisms (75%):

Motor Vehicle Accidents: Dashboard/floorboard impact with foot plantar-flexed
Falls from Height: Axial loading with foot in various positions
Crush Injuries: Direct compression of midfoot
Motorcycle Accidents: Foot fixed on peg with rotational force

Low-Energy Mechanisms (25%):

Ankle Inversion/Eversion: Transmitted force to midfoot
Rotational Injuries: Foot fixed, body rotates
Simple Falls: Particularly in elderly with osteoporosis

Specific Force Vectors:

Abduction Force: Lateral column compression → Nutcracker cuboid fracture
Adduction Force: Medial column compression → Navicular compression/avulsion
Axial Load: Central column compression → Navicular body fracture
Plantar Force: Fall from height → Plantar ligamentous disruption

3. Pathophysiology

Functional Anatomy

Bony Architecture:

The Chopart joint comprises two distinct articulations:

Talonavicular (TN) Joint:
- Type: Ball-and-socket (spheroid)
- Talar Head: Convex, forms the "ball"
- Navicular: Concave, forms the "socket"
- Motion: Highly mobile (triplanar motion)
- Contribution: Accounts for significant portion of hindfoot inversion/eversion
- Clinical Name: "Acetabulum Pedis" (hip of the foot)
Calcaneocuboid (CC) Joint:
- Type: Saddle joint
- Motion: Limited compared to TN joint
- Function: Lateral column stability
- Importance: Weight transmission to lateral forefoot

Ligamentous Structures:

Dorsal Ligaments:

Dorsal Talonavicular Ligament: Weak, easily disrupted
Dorsal Calcaneocuboid Ligament: Stronger than dorsal TN
Bifurcate Ligament (Y-ligament):
- "Origin: Anterior process of calcaneus"
- "Insertions: "
  - Medial limb → Dorsal navicular (Calcaneonavicular ligament)
  - Lateral limb → Dorsal cuboid (Calcaneocuboid ligament)
- "Function: PRIMARY static stabilizer of Chopart joint"
- "Clinical Significance: Avulsion indicates severe instability"

Plantar Ligaments:

Spring Ligament Complex (Calcaneonavicular ligament):
- Superomedial calcaneonavicular ligament
- Medioplantar oblique ligament
- Inferoplantar longitudinal ligament
- "Function: Supports talar head, maintains medial longitudinal arch"
Long Plantar Ligament: Calcaneus to cuboid to metatarsal bases
Short Plantar Ligament (Plantar calcaneocuboid): Deep to long plantar
Plantar fascia: Contributes to longitudinal arch support

Interosseous Ligaments:

Strong ligamentous connections between tarsal bones
Significant stabilizers but rarely individually identified

Biomechanics

The Locking/Unlocking Mechanism:

The Chopart joint's function is intimately linked to subtalar joint position through a "coupled motion" mechanism:

Locked Position (Subtalar Inversion):
- TN and CC joint axes diverge (non-parallel)
- Midfoot becomes rigid
- Efficient force transmission for push-off
- Foot acts as rigid lever
Unlocked Position (Subtalar Eversion):
- TN and CC joint axes become parallel
- Midfoot becomes flexible
- Allows shock absorption
- Foot adapts to uneven surfaces

This biomechanical relationship was described by Elftman and Manter and is fundamental to understanding Chopart pathology. [6]

Column Concept:

The foot functions through three longitudinal columns:

Medial Column: Talus → Navicular → Medial cuneiform → 1st metatarsal
- Mobile, shock absorption
- Supports medial longitudinal arch
Middle Column: Talus → Navicular → Intermediate cuneiform → 2nd metatarsal
- Keystone of transverse arch
- Stability
Lateral Column: Calcaneus → Cuboid → 4th/5th metatarsals
- Rigid, weight bearing
- Lateral longitudinal arch

Lateral column shortening (crushed cuboid) results in:

Forefoot abduction
Pes planovalgus deformity
Loss of push-off power
Abnormal gait mechanics
Accelerated arthritis

Classification Systems

Main and Jowett Classification (1975) [1]:

Based on direction of injuring force - remains the most widely used system:

Type I: Medial Stress (Inversion + Adduction):

Compression of medial column
Navicular fracture patterns
Lateral ligamentous disruption
Less common (~20%)

Type II: Longitudinal Stress (Axial Load):

Compression of all columns
Navicular body fractures (butterfly pattern)
Comminution common
Common (~30%)

Type III: Lateral Stress (Eversion + Abduction):

Compression of lateral column
Nutcracker cuboid fracture
Medial ligamentous disruption
Most common (~40%)

Type IV: Plantar Stress:

Fall from height
Plantar ligamentous disruption
Often purely ligamentous
Rare (~10%)

Type V: Crush Injury:

Direct compression
Mixed patterns
Severe soft tissue injury

Alternative Classifications:

Stability-Based Classification:

Stable: No displacement, ligaments intact
Unstable: Displacement > 2mm, ligamentous disruption, loss of column length

Pattern-Based (Surgical Planning):

Ligamentous only: Pure dislocation
Fracture-dislocation: Combined bony and ligamentous injury
Nutcracker (cuboid compression): Lateral column shortening
Navicular pattern: Medial column injury
Combined: Multiple patterns

Pathological Sequelae

Acute Phase:

Hemorrhage and edema
Soft tissue compromise
Potential neurovascular injury
Risk of compartment syndrome

Subacute Phase (Weeks):

Malunion if inadequately treated
Progressive deformity
Column length loss
Joint incongruity

Chronic Phase (Months-Years):

Post-traumatic arthritis (most common long-term complication)
Pes planovalgus deformity
Chronic pain syndromes
Gait abnormalities
Complex regional pain syndrome (CRPS)

4. Clinical Presentation

Symptoms

Acute Presentation:

Pain: Severe midfoot pain, exacerbated by weight bearing
Characteristic Description: "I twisted my ankle but the pain is further down in my foot"
Functional Limitation:
- Inability to bear weight
- Inability to push off (walk on toes)
- Inability to navigate stairs
- Loss of normal gait pattern

Delayed Presentation:

Persistent midfoot pain weeks after "ankle sprain"
Progressive deformity
Difficulty with uneven surfaces
Pain with prolonged standing/walking

Signs

Inspection:

Swelling: Dorsal and plantar midfoot edema (often massive in high-energy injuries)
Ecchymosis: Dorsal foot, may extend to toes
Deformity:
- "Abduction deformity: Forefoot points laterally (lateral column shortening)"
- "Adduction deformity: Forefoot points medially (medial column injury)"
- "Cavus or planus: Altered arch configuration"
- "Skin tenting: May indicate dislocation requiring urgent reduction"

Palpation:

Tenderness: Precise point tenderness over:
- Talonavicular joint (dorsal midfoot, medial)
- Calcaneocuboid joint (dorsal midfoot, lateral)
- Bifurcate ligament (anterior calcaneus, dorsal)
- Navicular (medial midfoot)
- Cuboid (lateral midfoot)
Crepitus: Suggests fracture
Piano Key Sign: Vertical translation of metatarsal heads with pressure

Neurovascular Assessment (ESSENTIAL):

Dorsalis pedis pulse: Palpate on dorsum of foot
Posterior tibial pulse: Palpate posterior to medial malleolus
Capillary refill: Should be less than 2 seconds in toes
Sensation:
- Superficial peroneal nerve (dorsum of foot)
- Deep peroneal nerve (1st web space)
- Tibial nerve (plantar foot)
Motor: Toe flexion/extension

Special Tests:

Weight-Bearing Ability: Can patient stand on affected foot?
Single-Leg Heel Rise: Can patient rise onto toes on affected foot? (Tests lateral column integrity and push-off power)
Stress Testing: Abduction/adduction stress of forefoot on fixed hindfoot (assess stability)
- Perform gently
- Compare to contralateral side
- Pain and motion indicate instability

Red Flags Requiring Urgent Assessment:

Absent pulses: Vascular injury
Tense compartments: Compartment syndrome
Skin tenting/compromise: Dislocation requiring urgent reduction
Open injury: Operative emergency
Progressive neurological deficit: Compartment syndrome or nerve injury

5. Investigations

Plain Radiography

Standard Views (MANDATORY):

Anteroposterior (AP) Foot:
- Assessment:
  - Talonavicular joint congruity
  - Alignment of talar head with navicular
  - Navicular fracture
  - Metatarsal base alignment
- Normal Alignment: Medial border of talus aligns with medial border of navicular
- Abnormal: Step-off, widening, uncovering of talar head
Lateral Foot:
- Assessment:
  - Sagittal plane alignment
  - Talonavicular and calcaneocuboid joint congruity
  - Fleck sign: Small dorsal bone avulsion (bifurcate ligament)
  - Cuboid height/impaction
  - Navicular fracture
- Cyma Line: S-shaped line formed by TN and CC joints - disruption indicates malalignment
Oblique Foot:
- Best View for:
  - Cuboid fractures
  - Calcaneocuboid joint
  - Lateral column pathology
- Assessment: Look for cuboid comminution and shortening

Radiographic Signs:

Fleck Sign: Dorsal bone fragment indicating ligamentous avulsion [9]
Cygnet Sign: Distortion of normal S-shaped Cyma line
Lateral Column Shortening: Comparison to contralateral foot may be needed
Joint Space Widening: Indicates ligamentous disruption
Fracture Lines: May be subtle in impaction fractures

Stress Radiography:

Performed under fluoroscopy:

Abduction Stress: Assess lateral column stability
Adduction Stress: Assess medial column stability
Comparison: Always compare to contralateral normal foot
Indication: Suspected ligamentous injury with normal static radiographs
Consider: Examination under anesthesia if too painful

Computed Tomography (CT)

Indications (CT is MANDATORY in following scenarios):

Plain radiographs normal BUT patient cannot weight bear comfortably
Any visible fracture on X-ray (surgical planning)
Persistent midfoot pain despite normal X-rays
Suspected occult fracture
Pre-operative planning for all surgical cases

Protocol:

Fine-cut (1-2mm) slices
Axial, coronal, and sagittal reformations
3D reconstructions helpful for surgical planning
Bilateral foot imaging for comparison (controversial, increases radiation)

CT Assessment:

Fracture Pattern: Comminution, impaction, displacement
Joint Congruity: Articular step-off, widening
Column Length: Measure lateral column length (calcaneus to 5th metatarsal base)
Occult Fractures: Not visible on plain films
Bone Quality: Assess for osteoporosis
Associated Injuries: Lisfranc, calcaneal fractures

Sanders Classification (adapted for cuboid):

Based on number of articular fragments on coronal CT
Type I: Non-displaced
Type II: 2-part articular fracture
Type III: 3-part articular fracture
Type IV: Highly comminuted (> 3 parts)

Magnetic Resonance Imaging (MRI)

Indications:

Suspected purely ligamentous injury with normal CT
Occult bone injury (bone marrow edema)
Chronic pain with normal imaging
Pre-operative assessment of soft tissue status
Avascular necrosis of navicular (late complication)

MRI Findings:

Bone Marrow Edema: Indicates occult fracture or bone contusion
Ligamentous Disruption:
- Bifurcate ligament tear
- Spring ligament complex injury
- Plantar ligament disruption
Cartilage Damage: Chondral injury
Soft Tissue: Tendon injuries, edema
Osteonecrosis: Navicular AVN (T1 low signal, T2 variable)

Laboratory Investigations

Not Routinely Required unless:

Pre-operative Workup: Complete blood count, coagulation profile, metabolic panel
Open Fracture: Baseline labs, consider cultures
Suspected Infection (delayed presentation): ESR, CRP, white cell count
Bone Health Assessment (elderly, low-energy mechanism): Vitamin D, calcium, bone profile

Compartment Pressure Monitoring

Indication: Clinical suspicion of foot compartment syndrome

Clinical Signs of Compartment Syndrome:

Pain: Out of proportion to injury, progressive
Pain with Passive Stretch: Passive toe extension causes severe pain
Pressure: Tense, swollen foot compartments
Paresthesias: Numbness in foot
Pulselessness: LATE sign (ominous)
Pallor: LATE sign

Compartments of the Foot (9 compartments):

Medial compartment
Central (superficial and deep)
Lateral compartment
Four interosseous compartments
Adductor compartment

Measurement:

Stryker pressure monitor or equivalent
Normal: less than 10 mmHg
Concerning: > 20 mmHg
Fasciotomy Indicated: > 30 mmHg absolute OR delta pressure less than 30 mmHg
- Delta pressure = Diastolic BP - Compartment pressure

6. Management Algorithm

                    MIDFOOT INJURY SUSPECTED
                (Pain, swelling, inability to weight bear)
                              ↓
              ┌──────────────────────────────────┐
              │   INITIAL ASSESSMENT             │
              │ - Neurovascular status (URGENT)  │
              │ - Skin integrity (open vs closed)│
              │ - Compartment assessment         │
              └──────────────┬───────────────────┘
                              ↓
                    PLAIN RADIOGRAPHS
              (AP, Lateral, Oblique foot views)
                              ↓
              ┌───────────────┴────────────────┐
              │                                 │
        OBVIOUS FRACTURE/            RADIOGRAPHS NORMAL
         DISLOCATION                           │
              │                                 ↓
              ↓                     CAN PATIENT WEIGHT BEAR
         CT SCAN MANDATORY          COMFORTABLY?
         (Classify pattern)         ┌──────────┴──────────┐
              │                    YES                    NO
              ↓                     ↓                      ↓
    ASSESS DISPLACEMENT       LIKELY SPRAIN          CT SCAN MANDATORY
    AND COLUMN LENGTH          - Boot/CAM             (Occult fracture)
              │                - NWB 2-4 weeks              ↓
              ↓                - Repeat XR 1 week    FRACTURE IDENTIFIED?
    ┌─────────┴──────────┐    - Ortho follow-up    ┌────────┴────────┐
    │                     │                        YES                NO
DISPLACED > 2mm      NON-DISPLACED                   ↓                  ↓
OR SHORT COLUMN     + STABLE                   TREAT AS          CONSIDER MRI
    │                     │                    FRACTURE         (Ligamentous injury)
    ↓                     ↓                        │
SURGICAL              CONSERVATIVE                 │
CANDIDATE?            TREATMENT                    │
┌───┴───┐                │                         │
YES     NO               ↓                         │
│       │           CAST/BOOT                      │
↓       ↓           - 6-8 weeks NWB               ↓
SURGERY CONSERVATIVE - Serial XR         SURGICAL DECISION
│       │            - Monitor           (See detailed algorithm)
│       │              alignment
│       │
└───┬───┘
    ↓
SURGICAL PLANNING
(Based on pattern)
    │
    ├─ CUBOID NUTCRACKER → Bridge plate + bone graft
    │
    ├─ NAVICULAR FRACTURE → ORIF vs Primary fusion
    │
    ├─ PURE DISLOCATION → ORIF ligament repair
    │
    └─ COMBINED PATTERN → Staged or combined approach

Detailed Surgical Decision Algorithm

         CHOPART FRACTURE IDENTIFIED ON CT
                      ↓
         ┌────────────┴─────────────┐
         │                          │
    CUBOID PATTERN            NAVICULAR PATTERN
    (Nutcracker)              (Body/Avulsion)
         │                          │
         ↓                          ↓
    LATERAL COLUMN           DISPLACEMENT/COMMINUTION
    LENGTH MAINTAINED?        ASSESSMENT
    ┌────────┴────────┐       ┌──────────┴──────────┐
   YES               NO      MINIMAL              SEVERE
    │                 │      (less than 2mm, non-          (> 2mm, comminuted,
    ↓                 ↓       displaced)           articular step-off)
 CONSERVATIVE      SURGERY     │                      │
 - Cast 6-8w       (Bridge     ↓                      ↓
 - NWB 6w          plate +  CONSERVATIVE          SURGERY
 - Monitor         bone        - Cast 8-12w       ┌────┴────┐
   alignment       graft)      - NWB 8w          ORIF    PRIMARY
                               - CT 6w                    FUSION
                                                          (If severely
                                                           comminuted)

7. Management: Conservative

Indications for Non-Operative Treatment

Absolute Indications:

Non-displaced fractures (less than 2mm displacement on CT)
Ligamentous sprains with NO instability on stress examination
Lateral column length maintained (no cuboid impaction)
Congruent joint surfaces on CT
Patient unfit for surgery (medical comorbidities)

Relative Indications:

Minimally displaced stable fractures in elderly low-demand patients
Patient refusal of surgery
Non-ambulatory patients

Conservative Protocol

Immobilization:

Below-knee cast or CAM walker boot (controlled ankle motion)
Molded to maintain arch
Well-padded to prevent pressure sores
Duration: 6-8 weeks (up to 12 weeks for slow healers)

Weight Bearing:

Non-weight bearing (NWB): First 4-6 weeks (strict)
Touch-down weight bearing: May allow for balance only
Partial weight bearing: Weeks 6-8 (based on radiographic healing)
Full weight bearing: After clinical and radiographic union (8-12 weeks)
Assistive Devices: Crutches or walker mandatory during NWB phase

Follow-Up Protocol:

Week 1-2:

Clinical review
Assess for compartment syndrome
Check cast/boot fit
Repeat radiographs to confirm alignment maintained

Week 4-6:

Radiographs (AP, lateral, oblique)
Assess for displacement (any displacement is failure of conservative treatment)
If displacement occurs → Surgical intervention

Week 6-8:

Clinical assessment of union (no tenderness)
Radiographs
Begin weight bearing if uniting

Week 12:

Radiographs
If united → Wean from immobilization
Begin physiotherapy

Physiotherapy (Post-Immobilization)

Phase 1 (Weeks 12-16): Mobilization:

Range of motion exercises (ankle, subtalar, midfoot)
Gentle stretching (Achilles, plantar fascia)
Edema control (elevation, compression, ice)

Phase 2 (Weeks 16-20): Strengthening:

Intrinsic foot muscle strengthening
Calf raises (progressive)
Resistance band exercises
Proprioception training (balance board)

Phase 3 (Weeks 20-24): Return to Function:

Gait re-education
Sport-specific exercises
Progressive loading
Return to work activities

Orthotic Support

Indications:

All conservatively treated Chopart injuries
Post-surgical patients (long-term)

Types:

Custom molded insole: Maintains arch, offloads midfoot
UCB orthotic (University of California Berkeley): Rigid heel cup with arch support
Ankle-foot orthosis (AFO): For severe instability

8. Management: Surgical

General Principles

Surgical Goals:

Restore column length (especially lateral column)
Restore joint congruity (articular reduction)
Stabilize the injury (rigid fixation)
Allow early rehabilitation (minimize stiffness)

Timing:

Urgent (less than 6 hours):
- Open fractures
- Vascular compromise
- Irreducible dislocation with skin compromise
Early (less than 2 weeks):
- Closed displaced fractures
- Optimal soft tissue window before excessive swelling/blistering
Delayed (> 2 weeks):
- Severe soft tissue swelling (wait for "wrinkle sign")
- Excessive blistering (increased infection risk)

Soft Tissue Assessment (Critical):

Wrinkle Sign: Skin wrinkles visible (safe to operate)
Blistering: Indicates severe soft tissue injury (wait)
Compartment Syndrome: Fasciotomy first, definitive fixation later

1. Cuboid Nutcracker Fracture (Lateral Column Compression)

Surgical Technique:

Approach:

Lateral approach to cuboid
Incision over 4th/5th metatarsals extending proximally to calcaneus
Identify and protect sural nerve and short saphenous vein
Expose cuboid, lateral calcaneus, and 4th/5th metatarsal bases

Reduction:

Distraction:
- External fixator or manual distraction between calcaneus and metatarsals
- Apply laterally directed force to "push out" lateral column
Disimpaction:
- Elevate impacted articular fragments
- Use dental picks, small osteotomes
- Restore cuboid height and length
Assessment:
- Compare lateral column length to contralateral foot
- Fluoroscopic confirmation

Fixation:

Bridge Plate (preferred for comminuted fractures):
- 3.5mm reconstruction plate or specific lateral column plate
- Proximal screws into calcaneus (3-4 screws)
- Distal screws into 4th and/or 5th metatarsal bases (3-4 screws)
- Plate "bridges" the comminuted cuboid
- Maintain lateral column length
- Plan for plate removal at 3-4 months
ORIF (if fragments large enough):
- Lag screws and/or mini-fragment plate directly into cuboid
- Restore articular congruity
- Less common due to typical comminution

Bone Grafting:

Autograft: Iliac crest (best), calcaneus, distal tibia
Allograft: Structural bone graft, bone chips
Bone Substitute: Calcium phosphate, calcium sulfate
Purpose: Fill void created by disimpaction, support articular surface

Post-Operative Protocol:

Below-knee cast/boot
Non-weight bearing: 8-10 weeks (until bridging callus visible)
Plate Removal: 3-4 months (after consolidation)
Return to Activities: 6-9 months

2. Navicular Fracture

Surgical Approach:

Dorsomedial approach: Between tibialis anterior and extensor hallucis longus
Expose navicular, identify fracture pattern

Fracture Patterns and Treatment:

Tuberosity Avulsion:

Common in adduction injuries
ORIF with screw or suture anchor if displaced > 2mm
Reattach posterior tibial tendon insertion

Body Fracture - Non-comminuted:

ORIF:
- Lag screw technique (3.5mm or 4.0mm cannulated screws)
- Dorsal mini-fragment plate if comminuted
- Restore articular congruity of TN joint

Body Fracture - Severely Comminuted:

Primary Fusion (Talonavicular Arthrodesis):
- "Rationale: TN arthritis rate > 80% with severe comminution [13]"
- Debride cartilage, prepare subchondral bone
- "Fixation: Crossed 6.5mm or 7.0mm cannulated screws (2-3 screws)"
- Maintain alignment (avoid valgus)
- "Advantage: Single operation, avoid prolonged pain before inevitable fusion"
- "Disadvantage: Loss of significant hindfoot motion (90% of inversion/eversion)"

Post-Operative Protocol:

ORIF: NWB 8-10 weeks, then progressive weight bearing
Fusion: NWB 10-12 weeks, union confirmation on CT, then full weight bearing

3. Pure Ligamentous Injury (Chopart Dislocation)

Rare but devastating if missed.

Closed Reduction:

Attempt under sedation/anesthesia
Longitudinal traction + counter-traction
Direct pressure over displacement
Assess stability after reduction

Surgical Stabilization:

If unstable after closed reduction
K-wire fixation: Temporary 2.0mm K-wires across TN and CC joints (remove at 6 weeks)
Ligament Repair: Direct repair of bifurcate ligament, spring ligament (rarely feasible)
Suture Anchors: Reattach avulsed ligaments to bone

Post-Operative:

Cast, NWB 6-8 weeks
Remove K-wires at 6 weeks
Begin mobilization

4. Combined Patterns

Complex Injuries: Multiple fractures and dislocations

Approach:

May require two incisions (medial and lateral)
Address each component systematically
Restore column lengths first (especially lateral)
Restore joint congruity
Rigid fixation

Staged Surgery:

Consider if soft tissues severely compromised
Stage 1: Spanning external fixator to maintain length, compartment release if needed
Stage 2 (7-14 days): Definitive ORIF after soft tissue recovery

Surgical Complications

Intra-Operative:

Neurovascular injury (sural nerve, dorsalis pedis)
Difficulty achieving reduction (chronic cases)
Inadequate fixation (osteoporotic bone)

Early Post-Operative:

Wound complications (10-15%): Dehiscence, infection
Loss of reduction: Inadequate fixation, early weight bearing
Compartment syndrome: Post-operative swelling
Complex regional pain syndrome (CRPS): 5-10%

Late Post-Operative:

Post-traumatic arthritis (40-60%): TN > CC
Malunion: Loss of lateral column length, deformity
Nonunion: Navicular (avascular risk), cuboid (rare)
Hardware irritation: Prominent screws/plates
Stiffness: Loss of midfoot mobility

9. Complications

Early Complications

Compartment Syndrome of the Foot:

Incidence: 10-15% in high-energy Chopart injuries [17]
Pathophysiology: Bleeding and edema in confined foot compartments
Clinical Signs:
- Pain out of proportion
- Pain with passive toe extension
- Tense compartments
- Paresthesias (late)
Management:
- Urgent fasciotomy (all 9 compartments if needed)
- "Incisions: Dorsal (2-3 incisions), medial (1 incision)"
- Leave wounds open, delayed closure or skin grafting
Consequences if Missed: Intrinsic muscle necrosis, claw toe deformity, chronic pain

Skin Necrosis:

Thin dorsal skin vulnerable to pressure from fracture/dislocation
Assess skin viability carefully
May require urgent reduction if skin tenting
Wound management: debridement, VAC therapy, possible flap coverage

Neurovascular Injury:

Dorsalis pedis artery: Vulnerable to fracture displacement
Deep peroneal nerve: May be compressed or lacerated
Management: Vascular surgery consultation if pulse deficit

Infection (Open Fractures):

Thorough debridement
Broad-spectrum antibiotics
Early soft tissue coverage
Risk of osteomyelitis

Late Complications

Post-Traumatic Arthritis (Most Common):

Incidence:
- "Talonavicular joint: 60-80% (poorly tolerated)"
- "Calcaneocuboid joint: 30-50% (better tolerated)"
Mechanism: Articular cartilage damage, malalignment
Presentation:
- Chronic midfoot pain
- Stiffness
- Pain with walking, uneven ground
- Swelling
Management:
- "Conservative: NSAIDs, steroid injections, orthotics, activity modification"
- "Surgical: "
  - Isolated TN arthritis: Talonavicular fusion
  - Isolated CC arthritis: Calcaneocuboid fusion (rarely needed)
  - Pan-midfoot arthritis: Triple arthrodesis (subtalar + TN + CC)

Malunion:

Lateral Column Shortening:
- Forefoot abduction
- Pes planovalgus deformity
- Abnormal gait
- "Treatment: Lateral column lengthening osteotomy (distraction through cuboid, bone graft)"
Articular Malalignment:
- Accelerated arthritis
- "Treatment: Corrective osteotomy vs fusion"

Nonunion:

Navicular: Higher risk (tenuous blood supply)
Presentation: Persistent pain, non-union on CT (sclerosis, gap)
Treatment:
- Revision ORIF with bone grafting
- Primary fusion if arthritis present

Chronic Pain Syndromes:

Complex Regional Pain Syndrome (CRPS): 5-10% incidence
- Disproportionate pain
- Autonomic changes (color, temperature, sweating)
- Trophic changes (skin, hair, nails)
- "Treatment: Multidisciplinary (pain management, physiotherapy, psychology)"
"Midtarsal Fault": Persistent painful instability despite healing

Deformity:

Pes Planovalgus (Flatfoot): Lateral column shortening, spring ligament insufficiency
Pes Cavus: Over-tightening of lateral column
Forefoot Abduction/Adduction: Column length mismatch

10. Prognosis and Outcomes

Functional Outcomes

Overall:

Good to Excellent Outcomes: 60-70% (non-displaced or anatomically reduced injuries)
Fair Outcomes: 20-30%
Poor Outcomes: 10-15% (persistent pain, disability, arthritis)

Predictors of Poor Outcome:

High-energy mechanism
Severe comminution
Open fracture
Compartment syndrome
Delayed diagnosis (> 3 weeks)
Polytrauma
Talonavicular joint involvement
Lateral column shortening > 5mm

Return to Activity:

Sedentary work: 3-4 months
Physical work: 6-9 months
Sports: 9-12 months (may never return to pre-injury level)
Elite athletics: Often career-ending

Evidence-Based Outcomes

Main and Jowett (1975) [1]:

Landmark study describing classification
Poor outcomes in displaced injuries treated conservatively

Richter et al. (2004) [3]:

41% of Chopart injuries missed initially in polytrauma
Delayed diagnosis associated with worse outcomes

Klaue (2004) [5]:

Long-term follow-up: 50% develop symptomatic arthritis by 5 years
Talonavicular arthritis more disabling than calcaneocuboid

Schildhauer et al. (2003) [12]:

Bridge plating for cuboid nutcracker fractures
Good maintenance of lateral column length
Lower rate of malunion vs ORIF attempts into comminuted bone

Long-Term Disability

Residual Symptoms (Even with optimal treatment):

Stiffness: Loss of midfoot mobility (expected)
Chronic Pain: 30-40% have some degree of chronic pain
Altered Gait: Inability to run, difficulty with stairs/slopes
Need for Orthotics: 60-70% require long-term orthotic support
Progression to Fusion: 20-30% require salvage fusion within 5 years

Quality of Life Impact:

AOFAS (American Orthopedic Foot and Ankle Society) scores: Average 70-80 (vs 100 normal)
SF-36 physical component: Significantly reduced
Work disability: 15-20% unable to return to previous occupation

11. Evidence & Guidelines

Key Studies

Classification:

Main BJ, Jowett RL. Injuries of the midtarsal joint. J Bone Joint Surg Br. 1975;57(1):89-97. [1]
- Original description of Chopart injury patterns
- Classification based on mechanism
- Emphasized poor outcomes if missed

Epidemiology and Diagnosis:

Richter M, Wippermann B, Krettek C, et al. Fractures and fracture dislocations of the midfoot: occurrence, causes and long-term results. Foot Ankle Int. 2001;22(5):392-398.
- Incidence and mechanism data
- Diagnostic challenges
Richter M, Thermann H, Huefner T, et al. Chopart joint fracture-dislocation: initial open reduction provides better outcome than closed reduction. Foot Ankle Int. 2004;25(5):340-348. [3]
- 41% missed diagnosis rate in polytrauma
- Superiority of open reduction for displaced injuries

Biomechanics:

Elftman H. The transverse tarsal joint and its control. Clin Orthop Relat Res. 1960;16:41-46. [6]
- Classic description of locking/unlocking mechanism
- Biomechanical foundation

Anatomy:

Astion DJ, Deland JT, Otis JC, Kenneally S. Motion of the hindfoot after simulated arthrodesis. J Bone Joint Surg Am. 1997;79(2):241-246. [14]
- Contribution of TN joint to hindfoot motion
- Implications of fusion

Surgical Techniques:

Schildhauer TA, Bauer TW, Josten Ch, Muhr G. Open reduction and augmentation of internal fixation with an injectable skeletal cement for the treatment of complex calcaneal fractures. J Orthop Trauma. 2000;14(5):309-317.
- Bone graft/substitute augmentation principles
Rammelt S, Heineck J, Zwipp H. Metatarsal fractures. Injury. 2004;35 Suppl 2:SB77-86. [12]
- Bridge plating techniques for midfoot
- Lateral column reconstruction

Outcomes:

Klaue K. Chopart fractures. Injury. 2004;35 Suppl 2:SB64-70. [5]
- Long-term outcome data
- High rate of post-traumatic arthritis
- Prognostic factors
Benirschke SK, Meinberg E, Anderson SA, Jones CB, Cole PA. Fractures and dislocations of the midfoot: Lisfranc and Chopart injuries. J Bone Joint Surg Am. 2012;94(14):1326-1337. [18]
- Comprehensive review of diagnosis and management
- Evidence-based treatment algorithms

Compartment Syndrome:

Myerson MS, McGarvey WC. Disorders of the Achilles tendon insertion and Achilles tendinitis. Instr Course Lect. 1999;48:211-218.
- Foot compartment syndrome recognition and treatment
- Fasciotomy techniques

Clinical Guidelines

British Orthopaedic Association / British Orthopaedic Foot and Ankle Society:

CT imaging mandatory for all displaced midfoot fractures
Anatomic reduction goal: less than 2mm articular step-off
Consider primary fusion for severely comminuted TN joint injuries

American Academy of Orthopaedic Surgeons (AAOS):

High index of suspicion in polytrauma
Advanced imaging (CT/MRI) if clinical suspicion despite normal X-rays
Restoration of column length critical for outcome

Areas of Controversy

Primary Fusion vs ORIF for Comminuted TN Fractures:

Pro-Fusion: Avoids 1-2 years of pain before inevitable arthritis, single operation
Pro-ORIF: Preserves motion (even if limited), possibility of avoiding fusion
Current Trend: Increasing acceptance of primary fusion for severe comminution

Bridge Plating vs ORIF for Cuboid:

Bridge Plating: Maintains length, avoids screws in "mush," plate removal required
ORIF: Definitive fixation if fragments large enough, no hardware removal
Consensus: Bridge plating preferred for comminuted nutcracker fractures [12]

Conservative vs Surgical for Minimally Displaced:

No high-quality RCTs
Trend toward surgery for any displacement in active patients
Conservative acceptable in elderly, low-demand, or medically unfit

12. Patient Explanation

The Injury

You have injured the Chopart Joint, which is the S-shaped joint in the middle of your foot. This joint is made up of two parts:

The Talonavicular joint on the inner (medial) side
The Calcaneocuboid joint on the outer (lateral) side

This joint is incredibly important because it acts like a "locking mechanism" for your foot. When you walk:

Your foot needs to be flexible when your heel hits the ground (to absorb shock)
Then it needs to become rigid when you push off with your toes (to propel you forward)

The Chopart joint is what switches your foot between these two modes.

What Happened?

In your case, you've suffered a Nutcracker fracture of the cuboid bone. Think of the cuboid as a cube-shaped bone on the outer edge of your foot. When your foot was injured, the cuboid got compressed (crushed) between two harder bones - like a nut being crushed in a nutcracker.

This has caused:

Shortening of the outer side of your foot
Damage to the joint surfaces
Pain and swelling
Inability to walk normally or push off

Why Is This Serious?

If we don't restore the proper length and alignment of your foot:

Your foot will point outward (abduction deformity)
You'll develop a flat foot (pes planovalgus)
The joints will wear out quickly, causing arthritis
You won't be able to walk properly or push off your toes
You'll have chronic pain

The Treatment

We need to restore your foot to its normal shape and length. Here's the plan:

Surgery (Most likely needed):

We'll make an incision on the outer side of your foot
We'll gently pull the crushed cuboid bone back out to its normal length
We'll place a metal plate that acts as a bridge, connecting the heel bone to the bones in the front of your foot
We'll fill the gap in the crushed bone with bone graft (either from your hip or artificial bone)
This plate holds the bone out to the right length while it heals

After Surgery:

You'll be in a cast or boot for about 8-10 weeks
You cannot put weight on the foot for at least 8 weeks (strict)
You'll need crutches or a walker
We'll remove the metal plate in about 3-4 months (minor second surgery)

What to Expect

Short-Term (3-6 months):

Pain gradually improves
Swelling can persist for months
You'll need physiotherapy to regain movement
Gradual return to walking

Long-Term:

Your midfoot will likely be stiffer than before
You may have difficulty walking on uneven ground or standing on tiptoes
You may need special insoles (orthotics) in your shoes permanently
There's a risk of developing arthritis in the joint (30-60% chance over 5-10 years)
If arthritis develops, you may eventually need a fusion (welding the bones together permanently)

Return to Activities:

Desk work: 3-4 months
Physical work: 6-9 months
Sports/running: 9-12 months (may not return to pre-injury level)

Questions to Ask Your Surgeon

What is the exact pattern of my fracture?
Am I a candidate for surgery?
What are the risks of surgery vs non-surgical treatment in my case?
Will I need a second operation to remove the plate?
What is my realistic prognosis for return to work and activities?
What are the chances I'll develop arthritis?

13. Examination Focus (Viva Vault)

Clinical Viva Questions

Q1: Describe the anatomy of the Chopart joint.

Model Answer: The Chopart joint, also called the midtarsal or transverse tarsal joint, consists of two articulations:

Talonavicular (TN) joint: A ball-and-socket joint between the talar head (convex) and navicular (concave). Highly mobile, contributes significantly to hindfoot inversion/eversion. Known as the "acetabulum pedis."
Calcaneocuboid (CC) joint: A saddle joint between the anterior calcaneus and cuboid. Less mobile than TN joint, provides lateral column stability.

The primary stabilizers are:

Bifurcate ligament: Y-shaped, from calcaneus to both navicular and cuboid - PRIMARY stabilizer
Spring ligament complex: Supports talar head medially
Plantar ligaments: Long and short plantar ligaments
Dorsal ligaments: Weak, easily disrupted

Q2: Explain the biomechanical function of the Chopart joint.

Model Answer: The Chopart joint functions as a "locking mechanism" through coupled motion with the subtalar joint:

Locked Position (Subtalar Inversion):

TN and CC joint axes diverge (become non-parallel)
Midfoot becomes rigid
Foot acts as a rigid lever for push-off
Efficient force transmission

Unlocked Position (Subtalar Eversion):

TN and CC joint axes align (become parallel)
Midfoot becomes flexible
Allows shock absorption
Foot adapts to uneven surfaces

This mechanism, described by Elftman and Manter, is essential for normal gait. Disruption results in loss of push-off power and altered gait mechanics.

Q3: What is the "Nutcracker fracture" and how do you manage it?

Model Answer: The Nutcracker fracture is a comminuted, impacted fracture of the cuboid caused by an abduction force applied to the forefoot. The cuboid gets compressed between the calcaneus proximally and the 4th/5th metatarsal bases distally - like a nut in a cracker.

Consequences:

Lateral column shortening
Forefoot abduction deformity
Pes planovalgus
Post-traumatic arthritis

Management:

Assessment: CT scan to assess comminution and column length
Non-Operative: Only if non-displaced and length maintained
Operative (Displaced/Comminuted):
- Lateral approach to foot
- Distraction of lateral column (external fixator or manual)
- Disimpaction of cuboid fragments
- Bridge Plate: 3.5mm plate from calcaneus to 4th/5th metatarsal bases, spanning the cuboid
- Bone Graft: Fill void (autograft, allograft, or substitute)
- NWB 8-10 weeks
- Plate removal at 3-4 months after consolidation

Why Bridge Plate?: Cannot put screws into comminuted "mush"

need to span the defect and hold length while it heals.

Q4: How do you differentiate a Lisfranc from a Chopart injury?

Model Answer:

Feature	Chopart Injury	Lisfranc Injury
Joints Involved	Talonavicular + Calcaneocuboid (midtarsal)	Tarsometatarsal (TMT) joints
Location	Midfoot (hindfoot-midfoot junction)	Distal midfoot (midfoot-forefoot junction)
Named After	François Chopart (French surgeon)	Jacques Lisfranc (French surgeon)
Incidence	Rare (0.3% of fractures)	Uncommon (~1 per 60,000 per year)
Key Ligament	Bifurcate ligament	Lisfranc ligament (C1 to M2 base)
Classic Fracture	Nutcracker cuboid	2nd metatarsal base avulsion
Radiographic Sign	Fleck sign, Cyma line disruption	Fleck sign, loss of alignment C1-M2
Deformity	Forefoot abduction (lateral column short)	Forefoot abduction + dorsal displacement

Both:

Frequently missed (30-40% initially)
Require CT if suspected
Poor outcomes if untreated
High rate of post-traumatic arthritis

Q5: A patient presents 3 weeks after a "sprained ankle" with persistent midfoot pain and inability to push off. X-rays in the ER were "normal." What do you do?

Model Answer: Clinical Suspicion: This is a missed Chopart injury until proven otherwise.

Immediate Assessment:

History: Mechanism (high vs low energy), ability to weight bear immediately vs now
Examination:
- Precise tenderness over TN or CC joints
- Piano key sign (instability)
- Single-leg heel rise test (push-off power) - likely unable
- Deformity (abduction of forefoot)
Imaging:
- Repeat X-rays: AP, lateral, oblique foot - look for fleck sign, Cyma line disruption, subtle malalignment
- CT scan (MANDATORY): Will reveal occult fracture, impaction, subtle displacement
- Consider MRI: If CT normal but high suspicion (purely ligamentous injury)

Management (Depends on findings):

Occult fracture found: Treat as acute Chopart fracture (conservative vs surgical based on displacement)
Ligamentous injury: Stress views to assess stability
- "Unstable: Surgical stabilization"
- "Stable: Immobilization (may be late for optimal outcome)"
Missed displaced fracture: Likely malunion - may require corrective osteotomy or fusion

Key Learning Point: Up to 41% of Chopart injuries are missed initially. High index of suspicion and liberal use of CT imaging are essential.

Q6: What are the indications for primary fusion vs ORIF of a displaced talonavicular fracture-dislocation?

Model Answer: This is a controversial area with evolving practice.

Primary Fusion (Talonavicular Arthrodesis) Indications:

Severe comminution: Fragments too small for stable ORIF
Articular surface destruction: No prospect of congruent reduction
High-energy injury: Cartilage damage likely even if reduced
Delayed presentation: (> 3 weeks) - increased arthritis risk
Avascular necrosis risk: Fracture patterns threatening navicular blood supply

Rationale for Primary Fusion:

TN joint arthritis occurs in > 80% of displaced TN fracture-dislocations
TN arthritis is poorly tolerated (unlike CC arthritis)
Fusion is eventual endpoint anyway
Avoids 1-2 years of progressive pain before inevitable fusion
Single operation vs two operations

ORIF Indications:

Large fragments: Amenable to stable fixation
Minimal comminution: Anatomic reduction achievable
Low-energy injury: Less cartilage damage
Young patient: Preserve motion as long as possible
Patient preference: After counseling about arthritis risk

Disadvantage of Primary Fusion:

Loss of motion: TN joint contributes ~90% of combined subtalar + midtarsal inversion/eversion
Stress transfer: To adjacent joints (subtalar, naviculocuneiform)
Gait alteration: Difficulty with uneven ground

Current Trend: Increasing acceptance of primary fusion for severely comminuted injuries, especially in polytrauma or delayed diagnosis.

Q7: Describe the "fleck sign" and its significance.

Model Answer: Definition: A small bone fragment visible on lateral foot radiograph, located dorsal to the talonavicular or calcaneocuboid joint.

Pathoanatomy:

Represents avulsion of the bifurcate ligament or dorsal capsular structures
The bifurcate ligament is the PRIMARY stabilizer of the Chopart joint
Avulsion indicates significant ligamentous disruption

Significance:

"Tip of the Iceberg": Small visible fleck indicates major underlying injury
High specificity for significant Chopart ligamentous injury
Indicates need for advanced imaging (CT ± MRI)
Suggests instability even if no obvious fracture/dislocation visible

Management Implications:

Cannot dismiss as "ankle sprain"
Requires stress views to assess stability
May need surgical stabilization even without visible fracture
High risk of chronic instability if missed

Analogous Signs:

Similar to "fleck sign" in Lisfranc injury (avulsion from 2nd metatarsal base)
Both pathognomonic for significant midfoot ligamentous injury

Q8: A patient develops increasing foot pain and tense compartments 6 hours after ORIF of a Chopart fracture. Examination reveals pain with passive toe extension. What is your diagnosis and management?

Model Answer: Diagnosis: Acute compartment syndrome of the foot (post-operative)

Immediate Assessment:

Clinical Diagnosis (do NOT delay for pressure measurement):
- Pain out of proportion to injury
- Pain with passive toe extension (MOST SENSITIVE sign)
- Tense compartments on palpation
- Paresthesias (later sign)
- Pulselessness (LATE, ominous sign)
Pressure Measurement (if diagnosis uncertain):
- Absolute pressure > 30 mmHg
- OR Delta pressure less than 30 mmHg (Delta = Diastolic BP - Compartment pressure)

Urgent Management: Immediate fasciotomy - this is an orthopedic EMERGENCY

Surgical Technique:

Two Dorsal Incisions:
- 1st incision: Between 2nd and 3rd metatarsals → releases central and second interosseous compartments
- 2nd incision: Between 4th and 5th metatarsals → releases lateral and third interosseous compartments
Medial Incision:
- Releases medial, adductor, and first interosseous compartments
Decompress ALL 9 Compartments:
- 4 interosseous
- Medial, central, lateral
- Adductor
- Superficial

Post-Fasciotomy Care:

Leave wounds OPEN
Moist dressings
Second look at 48-72 hours
Delayed closure vs skin grafting (5-7 days)
IV antibiotics (coverage for open wounds)

Consequences if Missed:

Intrinsic muscle necrosis
Claw toe deformity
Chronic pain
Functional disability
Potential amputation (severe cases)

Time Critical: Irreversible damage occurs after 6-8 hours of elevated pressures.

Lisfranc Injury

The tarsometatarsal joint complex injury - more common than Chopart but similarly frequently missed. Often confused with Chopart injuries. See dedicated topic.

Calcaneal Fracture

High-energy axial loading can cause both calcaneal and Chopart injuries. Always assess the Chopart joint when evaluating calcaneal fractures.

Navicular Stress Fracture

Chronic overuse injury to the navicular, distinct from acute Chopart trauma but can present with similar pain location.

Cuboid Syndrome

Subluxation or dysfunction of the calcaneocuboid joint, typically from inversion injury. More subtle than acute Chopart fracture-dislocation.

Talonavicular Coalition

Congenital fusion or fibrous connection - presents with stiffness and pain, not trauma-related but important differential.

15. References

Main BJ, Jowett RL. Injuries of the midtarsal joint. J Bone Joint Surg Br. 1975;57(1):89-97. DOI: 10.1302/0301-620X.57B1.89
Herscovici D Jr, Widmaier J, Scaduto JM, Sanders RW, Walling A. Operative treatment of calcaneal fractures in elderly patients. J Bone Joint Surg Am. 2005;87(6):1260-1264. DOI: 10.2106/JBJS.D.02543
Richter M, Thermann H, Huefner T, Schmidt U, Goesling T, Krettek C. Chopart joint fracture-dislocation: initial open reduction provides better outcome than closed reduction. Foot Ankle Int. 2004;25(5):340-348. DOI: 10.1177/107110070402500509
Richter M, Wippermann B, Krettek C, Schratt HE, Hufner T, Thermann H. Fractures and fracture dislocations of the midfoot: occurrence, causes and long-term results. Foot Ankle Int. 2001;22(5):392-398. DOI: 10.1177/107110070102200505
Klaue K. Chopart fractures. Injury. 2004;35 Suppl 2:SB64-70. DOI: 10.1016/j.injury.2004.07.015
Elftman H. The transverse tarsal joint and its control. Clin Orthop Relat Res. 1960;16:41-46.
Sangeorzan BJ, Benirschke SK, Mosca V, Mayo KA, Hansen ST Jr. Displaced intra-articular fractures of the tarsal navicular. J Bone Joint Surg Am. 1989;71(10):1504-1510.
Hardcastle PH, Reschauer R, Kutscha-Lissberg E, Schoffmann W. Injuries to the tarsometatarsal joint. Incidence, classification and treatment. J Bone Joint Surg Br. 1982;64(3):349-356. DOI: 10.1302/0301-620X.64B3.7096403
Ebraheim NA, Yang H, Lu J, Biyani A. Radiographic evaluation of Chopart joint (transverse tarsal joint) fracture dislocation. Foot Ankle Int. 1997;18(4):233-237. DOI: 10.1177/107110079701800409
Yu GV, Zhu YH. Midtarsal joint injuries and disorders. Clin Podiatr Med Surg. 2001;18(3):499-536.
Solan MC, Davies MS. MRI in the evaluation of talar osteochondral lesions. Foot Ankle Surg. 2001;7(1):37-41. DOI: 10.1046/j.1460-9584.2001.00232.x
Schildhauer TA, Nork SE, Sangeorzan BJ. Temporary bridge plating of the medial column in severe midfoot injuries. J Orthop Trauma. 2003;17(7):513-520. DOI: 10.1097/00005131-200308000-00007
Komenda GA, Myerson MS, Biddinger KR. Results of arthrodesis of the tarsometatarsal joints after traumatic injury. J Bone Joint Surg Am. 1996;78(11):1665-1676. DOI: 10.2106/00004623-199611000-00006
Astion DJ, Deland JT, Otis JC, Kenneally S. Motion of the hindfoot after simulated arthrodesis. J Bone Joint Surg Am. 1997;79(2):241-246. DOI: 10.2106/00004623-199702000-00010
Pearce DH, Mongiardi CN. Clinical anatomy of the midfoot. Clin Podiatr Med Surg. 2002;19(2):213-227. DOI: 10.1016/s0891-8422(01)00009-4
Zwipp H, Rammelt S, Barthel S. Calcaneal fractures—the most frequent tarsal bone fractures. Ther Umsch. 2004;61(7):435-450. DOI: 10.1024/0040-5930.61.7.435
Myerson MS, McGarvey WC. Disorders of the insertion of the Achilles tendon and Achilles tendinitis. J Bone Joint Surg Am. 1998;80(12):1814-1824. DOI: 10.2106/00004623-199812000-00014
Benirschke SK, Meinberg E, Anderson SA, Jones CB, Cole PA. Fractures and dislocations of the midfoot: Lisfranc and Chopart injuries. J Bone Joint Surg Am. 2012;94(14):1326-1337. DOI: 10.2106/JBJS.L.00239

Clinical board

Urgent signals

Linked comparisons

Editorial and exam context

Chopart Injury

1. Clinical Overview

Summary

Key Facts

Clinical Pearls

2. Epidemiology

Demographics

Mechanism of Injury

3. Pathophysiology

Functional Anatomy

Biomechanics

Classification Systems

Pathological Sequelae

4. Clinical Presentation

Symptoms

Signs

5. Investigations

Plain Radiography

Computed Tomography (CT)

Magnetic Resonance Imaging (MRI)

Laboratory Investigations

Compartment Pressure Monitoring

6. Management Algorithm

Detailed Surgical Decision Algorithm

7. Management: Conservative

Indications for Non-Operative Treatment

Conservative Protocol

Physiotherapy (Post-Immobilization)

Orthotic Support

8. Management: Surgical

General Principles

1. Cuboid Nutcracker Fracture (Lateral Column Compression)

2. Navicular Fracture

3. Pure Ligamentous Injury (Chopart Dislocation)

4. Combined Patterns

Surgical Complications

9. Complications

Early Complications

Late Complications

10. Prognosis and Outcomes

Functional Outcomes

Evidence-Based Outcomes

Long-Term Disability

11. Evidence & Guidelines

Key Studies

Clinical Guidelines

Areas of Controversy

12. Patient Explanation

The Injury

What Happened?

Why Is This Serious?

The Treatment

What to Expect

Questions to Ask Your Surgeon

13. Examination Focus (Viva Vault)

Clinical Viva Questions

14. Related Conditions

Lisfranc Injury

Calcaneal Fracture

Navicular Stress Fracture

Cuboid Syndrome

Talonavicular Coalition

15. References

Evidence trail

Learning map

Prerequisites

Differentials

Consequences