A Smith's fracture is a distal radius fracture which is typically extra-articular and associated with volar angulation. It is also known as a reverse Colles fracture. It is often caused by falling on a flexed wrist or a direct blow to the back of the wrist.
Classification
- Type 1: extra-articular
- Type 2: crosses into the dorsal articular surface
- Type 3: enters radiocarpal joint
- Volar Barton's fracture = Smith's type 3
- Both involve volar dislocation of carpus associated with intra-articular distal radius component
Epidemiology
Bimodal distribution:
- Younger patients: high-energy trauma
- Older patients: low-energy trauma or falls
- 50% intra-articular
- Radial styloid fracture; indication of higher energy
Presentation
Pain and deformity of the wrist with appropriate mechanism.
Imaging
Radiographs – wrist
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View | Measurement | Normal | Acceptable criteria |
|---|---|---|---|
AP | Radial height | 10–13mm | <5mm shortening |
Radial inclination | 21–25° | Change <5 degrees | |
Articular stepoff | Congruous | <2mm stepoff | |
Lateral | Volar tilt | 11–13° | Dorsal angulation <5° or within 20° of contralateral distal radius |
Table source: Distal radius fractures (Orthobullets)
CT scans
Important to evaluate intra-articular involvement and for surgical planning.
MRI
MRI can be useful to evaluate for soft tissue injury, such as:
- triangular fibrocartilage complex injuries
- scapholunate ligament injuries (deformity dorsal intercalated segment instability injury)
- lunotriquetral injuries (volar intercalated segmental instability injury).
Management options
- Adequate analgesia.
- Closed reduction and cast immobilisation is adequate for most non-displaced or minimally displaced extra-articular fractures.
- Where there is more significant angulation, reduction involves reducing by reversing fracture deformity with longitudinal traction and applying a long arm cast with the forearm in supination and wrist in neutral or a degree of extension.
- A sandwich or tongs-type POP slab may maintain reduced position of the fracture.
Referral and follow-up requirements
Fracture type | Urgency | Follow-up |
|---|---|---|
Non-displaced extra-articular | Non-urgent, POP dorsal slab, or sandwich slab if thought unstable | If isolated non-displaced fracture, review at fracture clinic within 1 week |
Significant displacement, encroaching or involving the articular surface | Orthopaedic review, closed reduction and POP slab | Follow up next day if orthopaedic review not available at first presentation |
Barton fracture, joint involvement, radiocarpal involvement | Orthopaedic review and advice for ORIF planning | As per orthopaedic advice |
Potential complications
- Non-union and mal-union may occur, e.g. with inadequate immobilisation, improper alignment, insufficient blood supply.
- If there is significant volar displacement, there may be a risk to the median nerve.
Patient advice
Care of temporary casts fact sheet
Resources
Smith's Fracture
Source: Wheeless' Textbook of Orthopaedics
Accessed from the Emergency Care Institute website at https://aci.health.nsw.gov.au/networks/eci/clinical/tools/smiths-fracture