Smith's Fractures

Smith's fracture is a distal radius fracture with volar angulation of the distal fragment (apex dorsal). It was first described by Irish surgeon Robert William Smith in 1847, 33 years after Abraham Colles described the dorsally angulated variant.

Distal radius anatomy relevant to Smith fractures:

The distal radius has several key features:

• Volar tilt: Normal volar tilt is 10-15 degrees (palmar inclination)
• Radial inclination: Normal is 22-23 degrees
• Radial height: Normal is 11-12mm
• Ulnar variance: Usually neutral to slightly negative

Ligamentous attachments:

• Volar radiocarpal ligaments (radioscaphocapitate, long radiolunate, short radiolunate) are strong
• These ligaments remain attached to the distal fragment
• They pull the fragment volarly, creating the characteristic deformity
• This explains why Smith fractures are inherently unstable

Pathomechanics of Smith fracture:

History:

• Mechanism (FOOSH with flexed wrist, direct blow, high-energy trauma)
• Hand dominance
• Occupation and functional demands
• Previous wrist injuries
• Medical comorbidities (diabetes, osteoporosis)

Physical examination:

Neurovascular assessment:

• Median nerve: Most at risk due to volar displacement
  • Sensation in thumb, index, middle finger
  • Motor: abductor pollicis brevis (APB)
  • Carpal tunnel symptoms may develop acutely
• Radial artery: Palpate at anatomical snuffbox and wrist
• Capillary refill: Assess all digits

Associated injuries to assess:

• Scapholunate ligament injury
• TFCC injury
• DRUJ instability
• Carpal fractures (especially scaphoid)
• Ulnar styloid fracture

Differential diagnosis:

The volar-prominence deformity and a distal radius injury on plain films can mimic several patterns. The single most discriminating step is the lateral radiograph (direction of angulation) and whether the fracture is articular.

Radiographic assessment:

View larger

Flexor tendon complications:

Rehabilitation principles:

• Early ROM prevents stiffness
• Volar plate allows early mobilization
• Strengthening delayed until fracture healed (6 weeks)
• Hand therapy optimizes outcomes
• Patient education on activity restrictions

Outcomes with modern treatment:

Volar locked plating of Smith fractures produces excellent results in most patients. Functional outcomes are comparable to or better than historical non-operative management.

Global epidemiology:

Distal radius fractures are among the commonest fractures worldwide, with a bimodal age distribution - a peak in children and young adults from higher-energy mechanisms and a larger peak in older (predominantly female, osteoporotic) patients from low-energy falls. Prevalence has risen over four decades in both groups. Smith (volar-displacing) fractures are far less common than the dorsally displacing Colles pattern, but the volar pattern is over-represented among younger, higher-energy injuries (sport, motorcycle, direct dorsal blow), which is why mechanism shapes the demographic. The figures below are PubMed-verifiable population data, not country-specific framing.

Major guidelines, side by side:

There is no Smith-specific international guideline; recommendations come from the broader distal radius literature and society guidance. The unifying message across bodies is that an unstable, displaced, volarly translating distal radius fracture is poorly controlled by cast alone and is a strong indication for fixation, while low-demand elderly extra-articular fractures may be managed conservatively.

Registry and trial evidence:

National joint registries (NJR, AJRR, AOANJRR, SHAR and others) primarily capture arthroplasty rather than fracture fixation, so distal radius implant-survival data come chiefly from trials and large cohorts rather than registries. The key high-level evidence is therefore:

• Arora 2011 RCT - volar plating gives better early function, grip strength and radiographic restoration than casting in patients 65 and older, but equivalent patient-rated outcomes at 12 months with more complications; this is the central plate-versus-cast trial.
• Soong 2011 - defined the watershed-line plate-prominence grading that governs flexor tendon rupture risk and is now a global benchmark for plate position.
• Handoll & Elliott 2015 Cochrane - no rehabilitation regimen is clearly superior; coached home exercise after stable plating performs at least as well as routine supervised physiotherapy.

Global practice variation:

• High-resource settings: volar locking plate fixation is the default for displaced/unstable Smith and volar-shear (Thomas II) fractures, enabling early motion.
• Limited-resource settings: closed reduction with sugar-tong/cast or K-wire fixation remains common where locking plates or image intensifiers are scarce; for a truly unstable volar-shear pattern this carries a higher redisplacement risk, so buttress fixation is prioritised when available.
• Older, low-demand patients: more variation - acceptance of a degree of malunion in exchange for avoiding surgery is reasonable for extra-articular patterns, but volar-shear instability with carpal translation still favours fixation in any setting.

Implant note (vendor-neutral):

Multiple anatomically pre-contoured volar locking plate systems are available worldwide, with fragment-specific options for complex articular patterns. The principle (a fixed-angle buttress proximal to the watershed line) matters far more than the manufacturer.