Paediatric Distal Radius Fractures

Epidemiology

Unique Paediatric Considerations

• Periosteum - thick and active; aids reduction and helps maintain it
• Remodeling potential - the distal radial physis contributes ~75% of longitudinal radial growth, giving enormous capacity to correct residual deformity, especially in younger children and in the sagittal plane (the plane of wrist motion)
• Plasticity - immature bone can deform without discrete cortical failure (plastic/bowing deformity)
• Growth plate vulnerability - the physis is the weakest point under stress; Salter-Harris injuries are common
• Remodeling is age- and plane-dependent - greater tolerance in younger children; sagittal-plane angulation corrects better than coronal or rotational deformity

Fracture Classification

Morphological Types (metaphyseal - most common)

Physeal Injuries - Salter-Harris Classification

Imaging

• Standard AP and lateral wrist radiographs are the first-line investigation
• The lateral view is critical to assess dorsal/volar angulation and DRUJ alignment
• Associated ulnar styloid fracture is common and usually requires no specific treatment
• Check for DRUJ instability (Galeazzi pattern) in shaft fractures
• CT or MRI are not routinely required but may assist with intra-articular SH III/IV fractures

Acceptable Reduction Parameters

By Age Group

• Angulation >10° in the distal third causes approximately 20° of lost pronation-supination arc
• Rotational malalignment is not corrected by remodeling - keep rotation within accepted limits
• In patients approaching skeletal maturity, near-anatomic reduction is preferred

Management

1. Torus (Buckle) Fractures

• Stable by definition; will not displace
• Treatment: removable splint or soft cast for 3-4 weeks
• No reduction required
• No routine fracture clinic follow-up needed if truly isolated torus fracture (evidence supports discharge with return-to-sport at 3-4 weeks)
• Parent education and instruction to return if concerns arise

2. Greenstick Fractures

• Conservative management; splint then short arm cast for 4-6 weeks
• Minimally displaced/undisplaced: cast without reduction
• If angulation exceeds age-appropriate limits: closed reduction under sedation or GA
• Acceptance thresholds by age:
  • Under 5 years: up to 35° lateral + 10° AP
  • 5-10 years: up to 25° lateral + 10° AP
  • Over 10 years: <20° lateral + 0° AP

3. Complete Metaphyseal Fractures

• Non-displaced or minimally displaced: below-elbow cast for 4-6 weeks
• Displaced: closed reduction and cast (below-elbow or above-elbow)
• Redisplacement risk is significant (20-35% after casting alone) - particularly in:
  • Initial displacement >50%
  • Bayonet apposition
  • Older children
  • Poor cast technique (cast index >0.8)
• K-wire fixation reduces redisplacement to 0-5% - indicated for high-risk patterns

4. Physeal (Salter-Harris) Fractures

• Undisplaced: below-elbow backslab or removable splint for 4 weeks; fracture clinic within 5 days
• Displaced: closed reduction + below-elbow backslab for 4 weeks
• Only one attempt at closed reduction - repeat attempts risk further physeal injury and growth arrest
• Reduction not advisable after ≥5 days from injury (callus formation)
• Refer to orthopaedics if closed reduction fails

• Intra-articular - require orthopaedic referral
• Usually need ORIF to restore articular congruity and physeal alignment
• Medium-to-high risk of growth disturbance

• Often missed at initial presentation (diagnosed retrospectively from growth arrest)
• Very high risk of growth disturbance

Surgical Indications

• Failed closed reduction or inability to maintain reduction in cast
• Neurovascular compromise (median nerve is most at risk - anterior interosseous nerve injury can occur)
• Open fractures
• Compartment syndrome
• SH III, IV, V fractures
• Irreducible fractures (soft tissue interposition)
• Fractures in skeletally mature adolescents where remodeling is limited

Surgical Options

Cast Technique Considerations

• Below-elbow (short arm) cast is standard for most distal metaphyseal and physeal fractures
• Above-elbow cast may be used for unstable fractures or in younger children to control rotation
• Cast index should be ≤0.7 to reduce redisplacement risk
• Adequate 3-point moulding reduces loss of reduction
• RCT evidence shows above- and below-elbow casts have similar outcomes for distal forearm fractures

Complications

Current Evidence Framework (SICOT-J 2026)

• Metaphyseal pathway: Stable fractures (torus) require minimal intervention. Displaced-but-stable fractures are managed with closed reduction and molded casting. K-wire fixation is reserved for high-risk patterns - it reduces redisplacement from 20-35% to 0-5%.
• Physeal pathway: Prioritise growth plate preservation. Intrafocal (Kapandji) K-wire pinning is preferred for unstable SH II injuries, as it provides rigid fixation while avoiding transphyseal iatrogenic injury.
• Elastic intramedullary nailing and plating carry greater implant-related morbidity and should be reserved for specific indications (irreducible, intra-articular, or near-mature fractures).
• Cast-related complications primarily reflect mechanical failure; K-wire complications are typically minor and self-limited.

Key Practical Points

1. Age matters more than angulation alone - a 7-year-old can remodel 20-25° of dorsal angulation; a 14-year-old cannot
2. One attempt at physeal reduction only - repeat manipulation significantly increases growth arrest risk
3. Torus fractures are stable - simple splinting is sufficient; no reduction needed
4. Rotational deformity does not remodel - must be corrected at time of reduction
5. Follow-up is mandatory for displaced fractures - redisplacement peaks at 1-2 weeks
6. Bayonet apposition is acceptable in children under 11 with good remodeling potential
7. Galeazzi equivalent - in children, a distal radius fracture with DRUJ disruption may manifest as a physeal injury (SH I/II of the distal ulna rather than a ligamentous injury)

• Fracture Types table - Torus, Greenstick, Complete, Plastic deformation with stability rating
• Key Paediatric Principles - remodeling, one-attempt rule, bayonet apposition, Galeazzi equivalent
• Acceptable Reduction Parameters (full-width, colour-coded) - Noonan & Price criteria across 4 age bands: sagittal/coronal angulation, rotation, bayonet apposition
• Salter-Harris Physeal Guide - all 5 types with frequency, growth disturbance risk, and ED management; HIGH/VERY HIGH risk flagged in red
• Metaphyseal Fracture Management table - torus through high-risk complete with cast type and duration

• Management Algorithm - dual-column flowchart separating Metaphyseal vs Physeal pathways with colour-coded decision boxes
• Surgical Options - K-wire (transphyseal vs Kapandji), TENS/ESIN, ORIF with specific indications
• Complications - redisplacement rates (20-35% cast vs 0-5% K-wire), growth arrest, nerve injury, compartment syndrome
• Urgent Referral Indications - highlighted red box with 8 criteria
• Footer with references (SICOT-J 2026, Noonan & Price, RCH guidelines)