Barton's Fractures

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

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:

Force transmission in volar Barton:

1. Axial load applied with wrist in flexion
2. Shear force concentrates at volar rim
3. Volar rim fractures (oblique fracture line)
4. Volar radiocarpal ligaments pull carpus volarly
5. Carpus subluxates volarly with fragment

Force transmission in dorsal Barton:

1. Axial load applied with wrist in extension
2. Shear force concentrates at dorsal rim
3. Dorsal rim fractures
4. Dorsal radiocarpal ligaments pull carpus dorsally
5. 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.

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:

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

Associated injuries to assess:

• DRUJ instability (piano key sign after reduction)
• TFCC injury
• Scapholunate ligament injury
• Ulnar styloid fracture
• Carpal fractures

Differential diagnosis:

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:

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

Post-traumatic arthritis:

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

Rehabilitation principles:

• Stable fixation allows early motion
• Balance protection with mobilization
• Hand therapy optimizes outcomes
• Watch for signs of complication (pain, weakness, numbness)

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

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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

Global epidemiology

Barton's fracture is an uncommon pattern, accounting for a small proportion of the very large global burden of distal radius fractures (one of the most common fractures worldwide, with a characteristic bimodal distribution: younger patients sustaining high-energy injuries and older patients with osteoporotic fragility falls). Volar Barton's is encountered more frequently than the dorsal (reverse) variant, which is genuinely rare, with the largest published surgical series numbering only ~20 cases (Lozano-Calderón et al., PMID 16818974). The defining articular-rim-plus-subluxation pattern is consistent across populations; resource setting affects access to CT and to low-profile fragment-specific implants rather than the injury itself.

Major guidelines, side by side

The dedicated evidence base for Barton's fractures is limited to retrospective series, so guidance is largely extrapolated from the wider distal radius and partial-articular fracture literature. The strongest unifying recommendation across bodies is that displaced partial articular (rim) fractures with carpal subluxation are surgical and that fixation should be driven by fracture pattern.

Registry evidence

Major arthroplasty registries (NJR, AJRR, AOANJRR, SHAR, Norwegian, NZJR) do not track fracture-fixation implants such as distal radius plates, so there is no registry-level survivorship data specific to Barton's fixation; the evidence base is therefore confined to single-centre series and comparative cohorts (e.g. Tang et al., PMID 22868605).

Global practice variation

• Implant choice: volar locking plates are the default for volar Barton's worldwide; in limited-resource settings, non-locking buttress plates or K-wire/external-fixation constructs remain in use and still achieve union, though with modestly lower functional scores (Tang et al., PMID 22868605).
• Dorsal Barton's: managed by dorsal buttress plating where low-profile implants are available; fragment-specific or wire fixation is substituted where they are not.
• Imaging: CT for pre-operative planning is routine in high-resource centres but selectively used elsewhere; the lateral radiograph remains the universal diagnostic view.