Barton Fracture

Barton fracture is an intra-articular fracture subluxation of the distal radius. A rim of the radial articular surface (volar or dorsal) breaks off as a shear fracture and the carpus subluxes with it. The volar type (volar Barton) is more common than the dorsal type.

It makes up about 1 to 2% of distal radius fractures. The mechanism is a fall on an extended and pronated wrist, which loads the dorsal rim, or a fall on a flexed wrist, which loads the volar rim. It is a high energy injury in young adults and a fragility injury in older adults.

Complications are median nerve injury and acute carpal tunnel syndrome, post-traumatic arthritis from joint incongruity, carpal subluxation and instability, malunion, stiffness, and flexor pollicis longus irritation or rupture from plates.

Pathophysiology.

The carpus pushes the radial rim fragment and then follows it into subluxation, because the volar or dorsal ligaments stay attached to the fragment. The fracture cannot be held in a cast, since the carpus slides back along the shear plane.

Wrist pain, swelling and deformity with the carpus shifted volarly or dorsally. Tenderness over the radial rim. Test the median nerve and check capillary refill. Carpal tunnel symptoms (numbness, progressive pain) suggest acute carpal tunnel syndrome. Examine the elbow, forearm and snuffbox.

• Radiographs: posteroanterior and lateral. The lateral view shows the volar or dorsal rim fragment with the carpus displaced with it.
• CT for fragment size, the articular step and comminution. It is needed for surgical planning.
• MRI is occasionally used for associated ligament injuries.

Differential diagnosis.

• Smith fracture and Colles fracture.
• Chauffeur fracture and scaphoid fracture.
• Radiocarpal dislocation and perilunate dislocation.
• Distal radioulnar joint injury.

Provisional. A closed reduction with a short arm splint holds the carpus only briefly. Elevation, finger movement and early referral.

Definitive. Surgery is nearly always required.

• Volar Barton: open reduction and fixation with a volar buttress plate through the flexor carpi radialis approach, which supports the rim and prevents carpal slippage.
• Dorsal Barton: dorsal buttress plate or fragment specific fixation (small plate or screws and Kirschner wires 1.6 mm) through a dorsal approach, protecting the extensor tendons.
• Stable fixation allows active movement at 1 to 2 weeks. A splint for 2 to 6 weeks is used.
• Cast treatment alone is limited to undisplaced fractures with a congruent joint.
• Acute carpal tunnel syndrome with failing nerve signs: carpal tunnel release at the time of surgery.

Analgesia.

• Paracetamol 1 g orally every 6 hours as needed for up to 5 to 7 days (maximum 4 g daily; 3 g daily when weight is under 50 kg, with chronic alcohol use or hepatic impairment).
• Ibuprofen 400 mg orally every 8 hours with food for up to 5 days (maximum 1200 mg daily); avoid with eGFR under 30 mL/min/1.73 m2, peptic ulcer, heart failure or anticoagulant use.
• Oral morphine 5 to 10 mg every 4 hours as needed for severe pain for up to 3 days (start 2.5 to 5 mg with age over 75 or eGFR under 30 mL/min/1.73 m2; avoid exceeding 60 mg in 24 hours without senior review); monitor sedation and respiration and prescribe a laxative.

Monitoring. Radiographs at 1 week, 2 weeks, 6 weeks and 3 months. Median nerve function at every visit. Wrist range, grip and carpal alignment at 3 months. Signs of tendon irritation from plates (pain with finger flexion) at 3 to 12 months. Post-traumatic arthritis at 1 year and later.

Referral and escalation. Refer every Barton fracture to orthopaedics (hand surgery) within 24 hours. Same day referral for open injury, acute carpal tunnel syndrome, skin compromise, or neurovascular compromise.

Special groups.

• Older adults: bone health assessment follows a fragility fracture.
• Kidney impairment: avoid ibuprofen; reduce morphine doses and extend intervals.
• Pregnancy: use paracetamol and a splint until surgery.