BARTON'S FRACTURES
Rim Fracture-Dislocation | Volar vs Dorsal | Carpal Subluxation
BARTON'S FRACTURE TYPES
Critical Must-Knows
- Fracture-subluxation - the carpus subluxates with the rim fragment (key distinguishing feature)
- Volar Barton = Thomas Type II Smith fracture - overlapping classification
- Shear mechanism - axial load with wrist in flexion (volar) or extension (dorsal)
- Always unstable - casting fails, surgery required for all displaced fractures
- Buttress plating - plate prevents fragment and carpus from displacing
Examiner's Pearls
- "Barton = rim fracture WITH carpal subluxation (vs die-punch = articular depression)
- "Volar Barton is more common than dorsal Barton
- "Match plate to fracture side - volar plate for volar Barton, dorsal for dorsal
- "Anatomic reduction of articular surface is critical - greater than 2mm step predicts arthritis
Clinical Imaging
Imaging Gallery
High-Yield Barton's Fracture Exam Points
Barton vs Smith vs Colles
CRITICAL EXAM DISTINCTION: Barton = rim fracture with subluxation. Smith = extra-articular with volar angulation. Colles = extra-articular with dorsal angulation. Barton is INTRA-ARTICULAR by definition.
Volar vs Dorsal Barton
Volar Barton: Volar rim fracture, carpus subluxates volarly. More common. Same as Thomas Type II Smith. Dorsal Barton: Dorsal rim fracture, carpus subluxates dorsally. Less common. Also called "reverse Barton."
Why Always Unstable
The rim fragment remains attached to the radiocarpal ligaments. When the rim fractures, the entire carpus can subluxate along with it. The intact rim acts as a ramp. No cast can prevent this displacement.
Buttress Plate Principle
The plate must be placed on the same side as the fracture to provide a buttress effect. Volar Barton = volar plate. Dorsal Barton = dorsal plate. The plate physically blocks fragment displacement.
At a Glance: Barton's vs Related Distal Radius Fractures
| Fracture Type | Key Feature | Articular | Carpal Position |
|---|---|---|---|
| Volar Barton | Volar rim fracture-subluxation | Yes - volar rim | Volar subluxation |
| Dorsal Barton | Dorsal rim fracture-subluxation | Yes - dorsal rim | Dorsal subluxation |
| Smith (Type II) | Same as volar Barton | Yes - volar rim | Volar subluxation |
| Smith (Type I/III) | Volar angulation, extra-articular | No | Neutral |
| Colles | Dorsal angulation, extra-articular | Usually no | Neutral |
| Die-punch | Articular depression (lunate fossa) | Yes - central | Neutral |
| Chauffeur's | Radial styloid fracture | Yes - lateral | Neutral |
BARTON - Key Features
Memory Hook:BARTON = Buttress plate for Articular Rim fracture where carpus and fragment go Together, requiring Operative management with No casting
VD - Volar vs Dorsal Barton
Memory Hook:The fracture and subluxation are on the SAME SIDE - Volar goes Volar, Dorsal goes Dorsal
SHEAR - Mechanism
Memory Hook:SHEAR force creates the rim fracture - hand position determines volar vs dorsal
Overview and Epidemiology
Barton's fracture is a fracture-dislocation of the distal radius involving the volar or dorsal articular rim with associated carpal subluxation. It was first described by Irish surgeon John Rhea Barton in 1838.
Key defining feature: The carpus subluxates WITH the fractured rim fragment. This distinguishes Barton's fracture from other distal radius fractures. The radiocarpal ligaments remain attached to the rim fragment, so when the rim fractures, the ligaments pull the entire carpus along with the fragment.
Terminology:
- Volar Barton: Volar rim fracture with volar carpal subluxation (more common)
- Dorsal Barton: Dorsal rim fracture with dorsal carpal subluxation (less common)
- Reverse Barton: Alternative historical name for dorsal Barton
- Thomas Type II Smith: Synonymous with volar Barton
Epidemiology:
- Accounts for 5-10% of distal radius fractures
- Volar Barton is approximately 3 times more common than dorsal Barton
- Peak incidence in young adults (20-40 years) from high-energy trauma
- Also seen in elderly with osteoporosis from low-energy falls
- No significant gender predominance
Mechanism of injury:
- Volar Barton: Axial load with wrist in flexion - shears off volar rim
- Dorsal Barton: Axial load with wrist in extension - shears off dorsal rim
- High-energy: falls from height, motor vehicle accidents, sports injuries
- Low-energy: simple falls in osteoporotic bone
John Rhea Barton
John Rhea Barton (1794-1871) was an American surgeon at Pennsylvania Hospital who described this fracture pattern in 1838. He also invented the Barton bandage and performed the first hip arthroplasty (interposition arthroplasty for hip ankylosis in 1826).
Anatomy and Pathophysiology
Distal radius articular anatomy:
The distal radius has two distinct articular rims:
- Volar rim: Stronger, with attachment of volar radiocarpal ligaments
- Dorsal rim: Thinner, with attachment of dorsal radiocarpal ligaments
Radiocarpal ligaments:
Volar ligaments (stronger):
- Radioscaphocapitate ligament
- Long radiolunate ligament
- Short radiolunate ligament
- Radioscapholunate ligament
Dorsal ligaments (weaker):
- Dorsal radiocarpal ligament
- Dorsal intercarpal ligament
Pathomechanics of Barton's fracture:
Why Barton's Fractures Are Unstable
When the rim fractures, the radiocarpal ligaments remain attached to the fragment. These ligaments connect to the proximal carpal row. Therefore, when the rim displaces, the entire carpus subluxates with it. The intact portion of the radius cannot prevent this because there is no bony block - the rim fragment acts as a "ramp" allowing the carpus to slide off.
Force transmission in volar Barton:
- Axial load applied with wrist in flexion
- Shear force concentrates at volar rim
- Volar rim fractures (oblique fracture line)
- Volar radiocarpal ligaments pull carpus volarly
- Carpus subluxates volarly with fragment
Force transmission in dorsal Barton:
- Axial load applied with wrist in extension
- Shear force concentrates at dorsal rim
- Dorsal rim fractures
- Dorsal radiocarpal ligaments pull carpus dorsally
- Carpus subluxates dorsally with fragment
The key biomechanical principle is that the carpus and rim fragment move as a single unit due to the intact ligamentous connections.
Classification Systems
Primary Classification by Rim Involved:
| Type | Rim | Subluxation | Mechanism | Frequency |
|---|---|---|---|---|
| Volar Barton | Volar | Volar | Flexion + axial load | More common (75%) |
| Dorsal Barton | Dorsal | Dorsal | Extension + axial load | Less common (25%) |
The classification is straightforward - identify which rim is fractured and confirm carpal subluxation in the same direction.
Volar Barton = Thomas Type II
Volar Barton and Thomas Type II Smith fracture describe the same injury - a volar rim fracture-subluxation. The Thomas classification for Smith fractures includes Type II as an intra-articular variant, which is identical to volar Barton.
Clinical Assessment
History:
- Mechanism (fall, position of wrist at impact)
- Energy level (high-energy vs low-energy)
- Hand dominance
- Occupation and functional demands
- Previous wrist injuries
- Medical comorbidities
Physical examination:
Clinical Examination Findings
| Finding | Volar Barton | Dorsal Barton |
|---|---|---|
| Deformity | Volar prominence, wrist appears flexed | Dorsal prominence, wrist appears extended |
| Swelling | Predominantly volar | Predominantly dorsal |
| Tenderness | Volar distal radius | Dorsal distal radius |
| Nerve at risk | Median nerve (volar) | PIN/radial sensory (dorsal) |
| Carpal position | Volarly subluxated | Dorsally subluxated |
Neurovascular assessment:
- Median nerve: Most at risk with volar Barton
- Sensation: thumb, index, middle finger palmar surface
- Motor: abductor pollicis brevis (opposition weakness)
- Acute carpal tunnel may develop
- Ulnar nerve: Assess if medial displacement
- Radial artery: Palpate at wrist
- Capillary refill: All digits
Subluxation Significance
The presence of carpal subluxation is the defining feature that distinguishes Barton's from other distal radius fractures. On examination, the carpus will be displaced in the same direction as the rim fracture. This must be confirmed on lateral radiograph.
Associated injuries to assess:
- DRUJ instability (piano key sign after reduction)
- TFCC injury
- Scapholunate ligament injury
- Ulnar styloid fracture
- Carpal fractures
Investigations
Radiographic assessment:
Standard views:
- PA view: Shows rim fragment, radial shortening, articular involvement
- Lateral view: CRITICAL - demonstrates subluxation direction and rim involved
- Oblique views: Additional fragment detail
Key radiographic features to identify:
Volar Barton:
- Volar rim fragment visible on lateral view
- Carpus subluxated volarly (anterior to radius shaft)
- Lunate may appear tilted volarly
- Volar cortex disruption on PA view
Dorsal Barton:
- Dorsal rim fragment visible on lateral view
- Carpus subluxated dorsally (posterior to radius shaft)
- Lunate may appear tilted dorsally
- Dorsal cortex disruption on PA view
Measurements to document:
- Size of rim fragment (percentage of articular surface)
- Degree of subluxation (mm of carpal translation)
- Articular step-off (mm)
- Radial height loss
- Radial inclination
CT imaging:
When to Order CT
CT is recommended for all Barton's fractures being treated surgically. It provides:
- Precise fragment size and orientation
- Detection of additional fracture lines
- Assessment of articular surface congruity
- Surgical planning for plate and screw placement
CT findings:
- Exact fragment size as percentage of joint surface
- Coronal plane fracture orientation
- Comminution assessment
- Associated carpal injuries
MRI:
- Not routine for acute Barton's fractures
- Consider if persistent pain after healing
- Evaluates TFCC and ligamentous injuries
Management Algorithm
Role of non-operative management:
Non-operative treatment is rarely appropriate for Barton's fractures due to their inherent instability. The carpal subluxation cannot be maintained with casting alone.
Potential indications (very limited):
- Truly non-displaced fracture without subluxation (rare - may not be true Barton's)
- Patient unfit for surgery with acceptable alignment
- Palliative situation
If attempted:
- Closed reduction under anesthesia
- Sugar-tong splint initially
- Long arm cast when swelling subsides
- Position: neutral rotation, slight extension (for volar), slight flexion (for dorsal)
- Weekly X-rays for first 3 weeks - high failure rate
Most surgeons consider all displaced Barton's fractures as operative injuries and proceed directly to surgical fixation.
Surgical Technique
FCR Approach for Volar Barton:
Setup:
- Supine, arm table, tourniquet
- Image intensifier available
- Regional or general anesthesia
Approach:
- Longitudinal incision over FCR tendon (6-8cm)
- Incise FCR sheath, retract FCR ulnarly (protects median nerve)
- Retract FPL radially
- Incise pronator quadratus in L-shape, elevate from radial border
- Expose fracture site directly
Reduction:
- Clear hematoma and debris from fracture
- Identify volar rim fragment
- Reduce carpus by traction and direct manipulation
- Reduce rim fragment to articular surface
- Provisional K-wire fixation
- Confirm reduction with fluoroscopy
Fixation:
- Select appropriate volar locking plate
- Position plate to support volar rim (buttress effect)
- Fix shaft first (allows plate adjustment)
- Insert distal locking screws into rim fragment
- Confirm screws capture fragment and do not penetrate joint
- Final fluoroscopy: PA, lateral, tilted lateral
Key technical points:
- Plate must extend distally enough to buttress the rim
- Balance with watershed line (too distal causes tendon problems)
- Small fragments may need specialized low-profile implants
Careful attention to plate position optimizes fixation and minimizes complications.
Complications
Complications of Barton's Fractures
| Complication | Incidence | Prevention/Management |
|---|---|---|
| Post-traumatic arthritis | 10-20% | Anatomic reduction (less than 2mm step), stable fixation |
| Malunion | Variable | Adequate fixation, early motion |
| Tendon complications | 5-15% | Appropriate plate position, low-profile dorsal implants |
| Carpal instability | 5-10% | Address associated ligament injuries |
| Median nerve injury | 5% | Careful approach, release if symptomatic |
| Stiffness | 10-20% | Early motion protocol, hand therapy |
| Hardware irritation | 10-15% | Proper plate sizing, removal if symptomatic |
| DRUJ instability | 5-10% | Address ulnar styloid, TFCC repair if needed |
Post-traumatic arthritis:
Articular Reduction Critical
Post-traumatic arthritis is the most significant long-term complication of Barton's fractures. Studies show that articular step-off greater than 2mm significantly increases the risk of symptomatic arthritis. Anatomic reduction of the articular surface is the most important factor in preventing this complication.
Tendon complications:
- Volar approach: FPL irritation/rupture if plate beyond watershed line
- Dorsal approach: EPL rupture most common, EDC irritation
- Prevention: appropriate plate position, low-profile implants, EPL transposition
Carpal instability:
- May result from associated ligament injury (not addressed)
- Or from inadequate reduction allowing chronic subluxation
- Requires ligament reconstruction if symptomatic
Stiffness:
- More common with prolonged immobilization
- Early motion protocol reduces risk
- Hand therapy essential for optimal outcomes
Postoperative Care and Rehabilitation
- Volar splint in neutral position
- Elevation and ice
- Active finger ROM immediately
- Wound check at 48-72 hours
- Edema control measures
- Remove splint, convert to removable wrist orthosis
- Begin active wrist ROM (flexion, extension, radial/ulnar deviation)
- Suture removal at 10-14 days
- Hand therapy referral
- Continue finger ROM
- Progress active ROM
- Begin forearm rotation
- Gentle passive ROM after week 4
- Edema control, scar management
- X-ray at 6 weeks to confirm healing
- Discontinue orthosis if healed
- Progressive strengthening
- Grip strengthening exercises
- Return to light activities
- Full ROM goal by 10-12 weeks
- Return to full activities
- Sport-specific rehabilitation if needed
- Consider hardware removal if symptomatic
- Final outcome assessment
Rehabilitation principles:
- Stable fixation allows early motion
- Balance protection with mobilization
- Hand therapy optimizes outcomes
- Watch for signs of complication (pain, weakness, numbness)
Early Motion
The goal of stable internal fixation is to allow early wrist motion within the first 1-2 weeks. This reduces stiffness, improves outcomes, and is a key advantage of operative management over casting.
Outcomes and Prognosis
Outcomes with operative treatment:
Modern surgical treatment of Barton's fractures produces good to excellent results in the majority of patients. Key outcome determinants include:
Favorable prognostic factors:
- Anatomic articular reduction (less than 2mm step)
- Stable fixation achieved
- Early motion protocol
- Young age
- Single fragment pattern
- No associated carpal injury
Unfavorable prognostic factors:
- Articular incongruity (greater than 2mm step)
- Comminuted fragment
- Associated carpal ligament injury
- Elderly with poor bone quality
- Delayed treatment
Functional outcomes:
- Most patients achieve functional ROM (within 20-30 degrees of normal)
- Grip strength typically recovers to 70-80% of contralateral
- Return to work: 4-8 weeks (desk), 8-12 weeks (manual)
- Return to sport: 3-4 months
Long-term considerations:
- Post-traumatic arthritis risk correlates with reduction quality
- Symptomatic arthritis may require salvage procedures (fusion, arthroplasty)
- Hardware removal in 15-20% for irritation
Evidence Base
- Barton's fractures with carpal subluxation uniformly require surgical stabilization. Buttress plating principle provides stable fixation. Anatomic reduction correlates with functional outcomes.
- Barton's fractures represent partial articular fractures with inherent instability. Volar locking plates provide excellent results for volar Barton's. Dorsal plates require careful technique to avoid extensor complications.
- Articular step greater than 2mm increases radiographic arthritis significantly. Anatomic reduction is the most important factor for long-term outcomes. Early motion protocols improve functional results.
- Classic study showing 91% incidence of radiographic arthritis with greater than 2mm articular step. Even 1-2mm incongruity associated with increased arthritis. Anatomic reduction critical.
- Plate prominence beyond critical line (watershed) associated with flexor tendon rupture. Soong grade classification for plate position. Grade 2/3 plates need close monitoring.
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
Scenario 1: Volar Barton's Fracture
"A 35-year-old man falls from a ladder onto his outstretched left hand with the wrist flexed. X-rays show a fracture of the volar rim of the distal radius with volar subluxation of the carpus. How would you manage this injury?"
Scenario 2: Dorsal Barton's Fracture
"A 28-year-old woman falls during gymnastics, landing on her outstretched hand with the wrist extended. X-rays show a fracture of the dorsal rim of the distal radius with dorsal subluxation of the carpus. How does your management differ from a volar Barton's?"
Scenario 3: Barton's vs Other Distal Radius Fractures
"An examiner shows you lateral radiographs of three different distal radius fractures and asks you to differentiate them. One shows volar angulation with no articular involvement, one shows a volar rim fracture with volar carpal subluxation, and one shows dorsal angulation. Identify each and explain the key distinguishing features."
MCQ Practice Points
Definition Question
Q: What distinguishes a Barton's fracture from other distal radius fractures? A: Barton's fracture is a rim fracture with carpal subluxation. The carpus subluxates with the rim fragment because the radiocarpal ligaments remain attached to the fragment.
Classification Question
Q: A volar Barton's fracture is synonymous with which Thomas classification? A: Thomas Type II Smith fracture. Both describe a volar rim fracture-subluxation of the distal radius.
Treatment Question
Q: What plate position is required for a dorsal Barton's fracture? A: Dorsal buttress plate. The plate must be on the same side as the fracture to provide buttress effect. A volar plate cannot buttress a dorsal rim fragment.
Mechanism Question
Q: What mechanism typically causes a volar Barton's fracture? A: Axial load with wrist in flexion. This creates a shear force that fractures the volar rim. Extension mechanism causes dorsal Barton's.
Outcome Question
Q: What articular step-off threshold is associated with increased post-traumatic arthritis? A: Greater than 2mm. Studies (Knirk and Jupiter) show significant increase in radiographic arthritis with greater than 2mm articular incongruity.
Australian Context
Epidemiology in Australia:
- Barton's fractures follow similar patterns to international data
- Seen in young adults from high-energy trauma and elderly from falls
- More common in urban trauma centers
- Sports-related injuries (skiing, cycling) contribute to younger cohort
Healthcare considerations:
- Treated at hospitals with orthopaedic capability
- May require hand surgery input for complex patterns
- Medicare rebates available for ORIF distal radius
- Public and private pathways available
Australian surgical practice:
- Modern volar locking plates widely available
- Low-profile dorsal implants from multiple manufacturers
- Fragment-specific fixation systems available
- Similar outcomes to international literature
Training relevance:
- Barton's fractures are core examination topic for Exam
- FCR and dorsal approaches are essential surgical skills
- Understanding the classification overlap (Thomas/Barton) is expected
Orthopaedic Exam Context
Barton's fractures are commonly examined because they test: (1) ability to differentiate from Smith and Colles, (2) understanding of why they are unstable, (3) knowledge of buttress plating principle, (4) surgical approach selection based on fracture type. Expect questions comparing the three fracture types and explaining treatment rationale.
BARTON'S FRACTURES
High-Yield Exam Summary
DEFINING FEATURES
- •Rim fracture (volar or dorsal) WITH carpal subluxation
- •Carpus subluxates with fragment (ligaments attached)
- •Volar Barton = Thomas Type II Smith fracture
- •Always intra-articular (partial articular AO 23-B3)
VOLAR VS DORSAL
- •Volar Barton: Volar rim + volar subluxation (3x more common)
- •Dorsal Barton: Dorsal rim + dorsal subluxation
- •Mechanism: Volar = flexed wrist, Dorsal = extended wrist
- •Plate MUST match fracture side (buttress principle)
WHY ALWAYS UNSTABLE
- •Radiocarpal ligaments remain attached to rim fragment
- •When rim fractures, ligaments pull carpus with it
- •Intact rim acts as ramp allowing subluxation
- •No cast can maintain reduction
SURGICAL TREATMENT
- •Volar Barton: FCR approach, volar buttress plate
- •Dorsal Barton: Dorsal approach, low-profile dorsal plate
- •Goal: Anatomic reduction (less than 2mm step)
- •Early motion within 1-2 weeks
COMPLICATIONS
- •Post-traumatic arthritis (greater than 2mm step = high risk)
- •Tendon complications (FPL volar, EPL dorsal)
- •Carpal instability if reduction not maintained
- •Stiffness if prolonged immobilization
EXAM DIFFERENTIALS
- •Smith: Volar angulation, NO subluxation, extra-articular (Type I/III)
- •Colles: Dorsal angulation, NO subluxation
- •Barton: Rim fracture WITH subluxation (key feature)
- •Die-punch: Articular depression, no subluxation