CUBOID FRACTURES
Nutcracker Mechanism | Compression Injury | ORIF Required
FRACTURE PATTERNS
Critical Must-Knows
- Cuboid fractures = nutcracker mechanism - compression between calcaneus and 4th/5th metatarsals during forced plantarflexion and abduction
- Often associated with Lisfranc injuries - Cuboid fracture suggests midfoot instability, check for Lisfranc injury
- ORIF required if displaced - Prevents lateral column shortening and midfoot collapse
- Lateral column key - Cuboid is keystone of lateral column, loss of length causes lateral foot pain and midfoot instability
- Bone graft often needed - Compression mechanism causes impaction, bone loss requires grafting
Examiner's Pearls
- "Nutcracker mechanism = compression between calcaneus and metatarsals
- "Often associated with Lisfranc injuries
- "ORIF required if displaced - prevents lateral column shortening
- "Bone graft often needed for impaction
Clinical Imaging
Imaging Gallery




Critical Cuboid Fracture Exam Points
Nutcracker Mechanism
Cuboid fractures = nutcracker mechanism - Compression between calcaneus and 4th/5th metatarsals during forced plantarflexion and abduction. Causes impaction and bone loss. Often associated with Lisfranc injuries.
Lisfranc Association
Cuboid fracture suggests midfoot instability - Often associated with Lisfranc injuries. Check for Lisfranc injury if cuboid fracture present. Midfoot instability requires ORIF of both injuries.
Lateral Column Key
Cuboid is keystone of lateral column - Loss of length causes lateral column shortening and midfoot collapse. ORIF required if displaced to restore lateral column length and prevent midfoot instability.
Bone Graft Needed
Compression mechanism causes impaction - Bone loss requires bone graft to restore lateral column length. Autograft from calcaneus or iliac crest. Allograft acceptable. Prevents lateral column shortening.
Cuboid Fractures - Quick Decision Guide
| Pattern | Displacement | Treatment | Outcome |
|---|---|---|---|
| Type I | Non-displaced, isolated | Conservative (cast) | 85-90% good results |
| Type II | Displaced, isolated | ORIF | 80-85% good results |
| Type III | Part of Lisfranc injury | ORIF as part of Lisfranc | 75-85% good results |
NUTCRACKERCuboid Fracture Features
Memory Hook:NUTCRACKER: Nutcracker mechanism, Usually associated with Lisfranc, Tarsal bone, Compression injury, Restore lateral column, Abduction mechanism, Calcaneus compression, Keystone of lateral column, Examine for Lisfranc, Restore with ORIF!
ORIFTreatment Decision
Memory Hook:ORIF: ORIF Required if displaced, Restore lateral column length, Impaction requires bone graft, Fixation with screws or plate!
CHECKLisfranc Association
Memory Hook:CHECK: Cuboid fracture, High association with Lisfranc, Examine for Lisfranc, CT to assess, Key to check!
Overview and Epidemiology
Cuboid fractures are rare but important injuries involving the cuboid bone, which serves as the keystone of the lateral column. These fractures result from a nutcracker mechanism and are often associated with Lisfranc injuries.
Definition
Cuboid fracture: Fracture of the cuboid bone, which:
- Location: Lateral midfoot
- Function: Keystone of lateral column
- Mechanism: Nutcracker (compression)
- Association: Often with Lisfranc injuries
Nutcracker mechanism:
- Compression: Between calcaneus and 4th/5th metatarsals
- Forced plantarflexion and abduction: Classic mechanism
- Impaction: Causes bone loss and shortening
- Lisfranc: Often associated with midfoot instability
Epidemiology
- Incidence: Less than 1% of foot fractures
- Age: Peak 20-40 years (trauma population)
- Gender: No clear predominance
- Mechanism: High-energy trauma, forced plantarflexion and abduction
- Associated injuries: Lisfranc injuries, other midfoot trauma
Nutcracker Mechanism
Cuboid fractures = nutcracker mechanism - Compression between calcaneus and 4th/5th metatarsals during forced plantarflexion and abduction. Causes impaction and bone loss. Often associated with Lisfranc injuries - check for midfoot instability.
Anatomy and Pathophysiology
Cuboid Anatomy
Cuboid bone:
- Location: Lateral midfoot
- Function: Keystone of lateral column
- Articulations: Calcaneus (proximal), 4th/5th metatarsals (distal), navicular (medial), lateral cuneiform (medial)
- Blood supply: Branches from dorsalis pedis and lateral plantar arteries
Lateral column:
- Components: Calcaneus, cuboid, 4th/5th metatarsals
- Function: Lateral foot stability and weight bearing
- Cuboid role: Keystone, maintains lateral column length
Nutcracker mechanism:
- Compression: Between calcaneus and 4th/5th metatarsals
- Forced plantarflexion and abduction: Classic mechanism
- Impaction: Causes bone loss and shortening
Pathophysiology
Injury mechanism:
- Forced plantarflexion and abduction: Classic mechanism
- Compression: Cuboid compressed between calcaneus and metatarsals
- Impaction: Causes bone loss and lateral column shortening
- Lisfranc association: Often associated with midfoot instability
Why displacement matters:
- Lateral column shortening: Displacement causes loss of length
- Midfoot collapse: Shortening causes midfoot instability
- Arthritis risk: Malunion leads to lateral column arthritis
Why ORIF required:
- Restore length: Anatomic reduction restores lateral column length
- Prevent collapse: Prevents midfoot collapse
- Bone graft: Often needed for impaction defects
Classification Systems
Pattern-Based Classification
Type I (Non-displaced, isolated):
- Isolated cuboid fracture
- Non-displaced
- Treatment: Conservative (cast)
- Outcome: 85-90% good results
Type II (Displaced, isolated):
- Isolated cuboid fracture
- Displaced
- Treatment: ORIF
- Outcome: 80-85% good results
Type III (Part of Lisfranc injury):
- Cuboid fracture as part of Lisfranc injury
- Treatment: ORIF as part of Lisfranc
- Outcome: 75-85% good results
Pattern guides treatment approach.
Clinical Assessment
History
Symptoms:
- Lateral foot pain: Pain on lateral side of foot
- Swelling: Localised to lateral midfoot
- Difficulty weight bearing: Pain with weight bearing
- Mechanism: Forced plantarflexion and abduction
Risk factors:
- High-energy trauma
- Lisfranc injury mechanism
- Midfoot instability
Physical Examination
Inspection:
- Swelling on lateral midfoot
- Ecchymosis (may be delayed)
- Deformity (lateral column shortening if displaced)
Palpation:
- Tenderness over cuboid
- Lisfranc joint tenderness (if associated)
- Lateral column instability
Range of Motion:
- Midfoot ROM limited and painful
- Inversion/eversion painful
- Plantarflexion/dorsiflexion painful
Special tests:
- Lisfranc stress test: Check for midfoot instability
- Lateral column stress: Pain with stress
- Midfoot alignment: Check for collapse
Clinical Examination Key Point
Check for Lisfranc injury - Cuboid fractures are often associated with Lisfranc injuries. Perform Lisfranc stress test and check for midfoot instability. CT is often needed to assess both injuries.
Investigations
Standard X-ray Protocol
AP view:
- May show cuboid fracture
- Check for Lisfranc injury
Lateral view:
- May show fracture
- Assess lateral column alignment
Oblique view:
- May show fracture better
- Lisfranc joint view
Key point: CT is often needed for diagnosis and planning.
Management Algorithm



Management Pathway
Cuboid Fracture Management
CT is usually required for diagnosis - cuboid fractures are difficult to see on X-ray alone. Assess displacement, impaction, and associated Lisfranc injury. Check for lateral column shortening.
If non-displaced (less than 2mm step-off) and isolated, conservative treatment with cast and non-weight bearing for 6-8 weeks. Success rate 85-90%.
If displaced (greater than 2mm) or part of Lisfranc injury, ORIF required. Restore lateral column length. Bone graft if impaction. Success rate 80-85%.
If part of Lisfranc injury, address both injuries. Cuboid ORIF as part of Lisfranc fixation. Restore lateral column length and midfoot stability. Success rate 75-85%.
Surgical Technique
ORIF Technique
Indications:
- Displaced cuboid fractures
- Part of Lisfranc injury
- Lateral column shortening
Approach:
- Lateral approach to cuboid
- Expose cuboid
- Protect peroneal tendons
Technique:
- Exposure: Lateral approach to cuboid, expose fracture, protect peroneal tendons
- Debridement: Remove impacted bone fragments, assess bone loss
- Bone graft: Fill impaction defect with bone graft (autograft from calcaneus or iliac crest, allograft acceptable)
- Reduction: Restore lateral column length, reduce fracture anatomically
- Fixation: Screws (2.7-3.5mm) or mini-fragment plate (2.0-2.7mm)
- Verification: Confirm reduction and hardware position fluoroscopically, verify lateral column length restored
Advantages:
- Restores lateral column length
- Prevents midfoot collapse
- Allows early motion
ORIF restores lateral column length.
Complications
| Complication | Incidence | Risk Factors | Prevention/Management |
|---|---|---|---|
| Lateral column shortening | 10-15% | Impaction, inadequate reduction | Bone graft, restore length |
| Midfoot collapse | 10-15% | Lateral column shortening | Restore length, adequate fixation |
| Missed Lisfranc | 20-30% | Focus on cuboid only | Always check for Lisfranc |
| Nonunion | 5-10% | Displacement, inadequate fixation | Rigid fixation, bone graft |
Lateral Column Shortening
10-15% incidence (if untreated):
- Cause: Impaction, inadequate reduction, bone loss
- Prevention: Bone graft, restore length, adequate fixation
- Management: Revision ORIF with bone graft if symptomatic
Midfoot Collapse
10-15% incidence (if untreated):
- Cause: Lateral column shortening, inadequate fixation
- Prevention: Restore length, adequate fixation
- Management: Revision ORIF or midfoot fusion if severe
Postoperative Care
Immediate Postoperative
- Immobilisation: Short leg cast or boot
- Weight bearing: Non-weight bearing (6-8 weeks)
- ROM: Ankle ROM after cast removal
- PT: Midfoot ROM and strengthening
Rehabilitation Protocol
Weeks 0-6:
- Short leg cast, non-weight bearing
- Elevation to reduce swelling
- Ankle ROM exercises (if stable)
Weeks 6-8:
- CT to confirm healing
- Cast removal if healing
- Transition to walking boot
- Progressive weight bearing
Weeks 8-12:
- Full weight bearing
- Progressive activity
- Return to sport (3-4 months)
Outcomes and Prognosis
Overall Outcomes
ORIF (isolated):
- Success rate: 80-85% (union, pain relief)
- Functional outcomes: 75-80% return to pre-injury level
- Lateral column: 80-85% maintain length
ORIF (part of Lisfranc):
- Success rate: 75-85% (union, pain relief)
- Functional outcomes: 70-75% return to pre-injury level
- Lateral column: 75-80% maintain length
Conservative (non-displaced):
- Success rate: 85-90% (union, pain relief)
- Functional outcomes: 80-85% return to pre-injury level
- Lateral column: 85-90% maintain length
Long-Term Prognosis
Lateral column shortening progression:
- With proper treatment: 10-15% develop shortening
- Without treatment: 20-30% develop shortening
- Risk factors: Impaction, displacement, delayed treatment
Evidence Base
Cuboid Fractures
- Nutcracker mechanism - compression injury
- Often associated with Lisfranc injuries
- ORIF required if displaced (80-85% good results)
- Restore lateral column length
Lisfranc Association
- 20-30% associated with Lisfranc injuries
- Cuboid fracture suggests midfoot instability
- Check for Lisfranc if cuboid fracture present
- Both injuries require ORIF
Lateral Column
- Cuboid is keystone of lateral column
- Loss of length causes collapse
- ORIF restores length (80-85% good results)
- Bone graft often needed
Bone Graft
- Compression causes impaction and bone loss
- Bone graft required to restore length
- Autograft from calcaneus or iliac crest
- Prevents lateral column shortening
Treatment Outcomes
- ORIF isolated: 80-85% good results
- ORIF Lisfranc: 75-85% good results
- Conservative: 85-90% good results
- Lateral column shortening: 10-15% with treatment
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
Scenario 1: Isolated Cuboid Fracture
"A 30-year-old patient presents with lateral foot pain after forced plantarflexion and abduction injury. CT shows displaced cuboid fracture with 3mm displacement and impaction. No associated Lisfranc injury."
Scenario 2: Cuboid with Lisfranc Injury
"A 35-year-old patient has a cuboid fracture as part of a Lisfranc injury. The examiner asks you to explain how you manage both injuries."
MCQ Practice Points
Nutcracker Mechanism
Q: What is the nutcracker mechanism for cuboid fractures? A: Compression between calcaneus and 4th/5th metatarsals - During forced plantarflexion and abduction. Causes impaction and bone loss. Often associated with Lisfranc injuries.
Lisfranc Association
Q: Why are cuboid fractures often associated with Lisfranc injuries? A: Cuboid fracture suggests midfoot instability - 20-30% of cuboid fractures are associated with Lisfranc injuries. Check for Lisfranc injury if cuboid fracture present. Both injuries require ORIF.
Lateral Column
Q: Why is the cuboid important for lateral column stability? A: Cuboid is keystone of lateral column - Loss of length causes lateral column shortening and midfoot collapse. ORIF required if displaced to restore length. Bone graft often needed for impaction.
ORIF Indications
Q: When is ORIF required for cuboid fractures? A: Displacement greater than 2mm or part of Lisfranc injury - Prevents lateral column shortening and midfoot collapse. Bone graft needed for impaction. Success rate 80-85%.
Bone Graft
Q: Why is bone graft often needed for cuboid fractures? A: Compression mechanism causes impaction and bone loss - Bone graft required to restore lateral column length. Autograft from calcaneus or iliac crest. Prevents lateral column shortening.
Australian Context
Clinical Practice
- Cuboid fractures rare but important
- Often associated with Lisfranc injuries
- ORIF standard for displaced fractures
- Bone graft often needed
Healthcare System
- ORIF covered under public system
- Public hospitals handle most cases
- Private insurance covers procedures
- High-energy trauma common
Orthopaedic Exam Relevance
Cuboid fractures are a common viva topic. Know that nutcracker mechanism (compression between calcaneus and metatarsals), often associated with Lisfranc injuries (20-30%), ORIF required if displaced (restores lateral column length), bone graft needed for impaction, and cuboid is keystone of lateral column. Be prepared to discuss the nutcracker mechanism and Lisfranc association.
CUBOID FRACTURES
High-Yield Exam Summary
Key Concepts
- •Nutcracker mechanism = compression between calcaneus and 4th/5th metatarsals
- •Often associated with Lisfranc injuries (20-30%)
- •Cuboid is keystone of lateral column
- •ORIF required if displaced (restores lateral column length)
Classification
- •Type I: Non-displaced, isolated - conservative (85-90% good results)
- •Type II: Displaced, isolated - ORIF (80-85% good results)
- •Type III: Part of Lisfranc injury - ORIF as part of Lisfranc (75-85% good results)
- •Displacement threshold: Greater than 2mm requires ORIF
Treatment
- •Non-displaced, isolated: Conservative (cast, NWB 6-8 weeks)
- •Displaced, isolated: ORIF with bone graft if impaction (80-85% good results)
- •Part of Lisfranc: ORIF as part of Lisfranc fixation (75-85% good results)
- •Displacement greater than 2mm: ORIF required
Surgical Technique
- •Lateral approach: Protect peroneal tendons
- •Debride impacted bone, assess bone loss
- •Bone graft: Fill impaction defect (autograft from calcaneus or iliac crest)
- •Fixation: Screws (2.7-3.5mm) or mini-fragment plate (2.0-2.7mm)
- •Restore lateral column length
- •Verify reduction fluoroscopically
Complications
- •Lateral column shortening: 10-15% if untreated (prevent with bone graft, restore length)
- •Midfoot collapse: 10-15% if untreated (prevent with adequate fixation)
- •Missed Lisfranc: 20-30% (prevent by always checking for Lisfranc)
- •Nonunion: 5-10% (prevent with rigid fixation, bone graft)