Greenstick Fracture - Detailed Overview

Definition

• Tintinalli's Emergency Medicine describes it as "cortical disruption and periosteal tearing on the convex side of the bone, with an intact periosteum on the concave side of the fracture."
• Pfenninger and Fowler's Procedures for Primary Care notes it is "a level worse than a torus fracture - it involves an actual crack or disruption of one cortex and buckling of the opposite cortex."

Pathophysiology

1. Tensile stress develops on the convex (outer) side - this side fails first
2. The cortex cracks and periosteum tears on the tension (convex) side
3. Compressive stress on the concave (inner) side causes buckling without complete disruption
4. The intact periosteal hinge on the concave side stabilizes the fracture

Epidemiology & Risk Factors

• Affects almost exclusively children under 10 years (peak age 4-8 years)
• Boys slightly more affected than girls (more active/risk-taking behavior)
• Most common bones: radius, ulna (forearm), followed by tibia, fibula, humerus, clavicle
• Forearm is by far the most common site because children brace falls with an outstretched arm (FOOSH - Fall On OutStretched Hand)
• Risk factors:
  • Vitamin D deficiency / rickets (weakens cortical bone disproportionately)
  • Malnutrition
  • Physical abuse (non-accidental trauma - must be considered with inconsistent history)

Etiology / Mechanism of Injury

Clinical Features

• Localized pain (often mild-moderate, less than a complete fracture)
• Swelling and soft tissue edema at the fracture site
• Point tenderness over the bone
• Refusal to use the affected limb (especially in younger children who cannot verbalize pain)
• Visible angulation or deformity when bending is substantial

• Mild deformity - may not be dramatically apparent
• Pain on passive movement
• Neurovascular status usually intact (rare compromise given the stable nature)
• Less swelling and bruising than complete fractures

Radiology

X-ray Findings

• Fracture line visible through one cortex only (typically the convex/tension side)
• Opposite cortex shows buckling or bowing without a discrete fracture line
• No complete cortical disruption across both cortices
• Angulation of the bone at the fracture level
• Two views (AP + lateral) are mandatory - the fracture may only be visible on one projection

AP and lateral radiographs of greenstick fractures of the distal radius and ulna in a child:

Fig: AP and lateral radiographs demonstrating greenstick fractures of the distal radius and ulna. Arrows indicate the fracture lines. - Tintinalli's Emergency Medicine

Lateral radiograph of greenstick fracture of the radius after FOOSH:

Fig: Lateral radiograph following a fall on outstretched hand, demonstrating an oblique cortical fracture on the volar aspect of the radius and buckling of the dorsal cortex. - Grainger & Allison's Diagnostic Radiology

Subtle Cases

• Comparison views of the contralateral, uninjured limb are helpful in mild cases where angulation is subtle
• MRI or bone scan can detect occult greenstick fractures in the rare case where X-ray is negative but clinical suspicion is high

Differential Diagnosis

Treatment and Management

General Principles

Mild Angulation (<15°)

• Short-arm splint or cast - typically for 4-6 weeks
• Casting a few days after injury (once swelling has stabilized) reduces need for recasting due to edema
• Analgesia (paracetamol ± ibuprofen)
• Elevation of the limb initially

Significant Angulation (>15°-20°)

• Closed reduction under procedural sedation or general anaesthesia (in children)
• After reduction, a long-arm cast is applied (above elbow for forearm fractures)
• The intact periosteum on the concave side acts as a hinge and aids reduction

Reduction Technique

1. Applying traction along the long axis of the bone
2. Completing the fracture by breaking through the intact cortex (intentionally completing it) - this prevents the "spring-back" tendency
3. Then reducing and casting

Cast Immobilization Duration

• Distal radius/forearm: ~4-6 weeks
• Tibia/fibula: 6-8 weeks
• Follow-up X-rays at 1-2 weeks post-reduction to confirm maintained alignment

Surgical Management

• Closed reduction fails or cannot maintain alignment
• Severe angulation with unacceptable deformity
• Open fracture (uncommon for greenstick mechanism)

Orthopedic Referral

• Simple greenstick without angulation: orthopedic referral at follow-up is recommended but may not be emergent
• Any significant angulation: orthopedic referral at initial visit is generally recommended

Prognosis and Remodeling

• Children's bones remodel angulation over time, especially in younger children with more growth remaining
• Remodeling is most effective when deformity is in the plane of joint movement (e.g., volar-dorsal angulation at the wrist remodels well)
• Rotational deformity does NOT remodel - this must be corrected at the time of reduction
• Outcomes are generally excellent with prompt treatment

Complications

Comparison with Related Fracture Types (Pediatric Spectrum)

TORUS / BUCKLE         GREENSTICK            PLASTIC BOWING        COMPLETE FRACTURE
Axial compression      Bending force          Pure bending           High energy
Cortex buckles,        Tension side cracks,   No fracture line,      Both cortices
no crack               compression side       entire shaft bows      disrupted
                       buckles
Most stable            Stable                 Stable (but hard       Unstable
                                              to diagnose)
Immobilize 3-4 wks     Cast 4-6 wks          Reduction often        Reduction + cast
                       ± reduction            needed                 ± surgery

Summary Points

1. Greenstick = incomplete fracture exclusive to children due to pliable bone and thick periosteum
2. Mechanism: tension side cracks, compression side bends/buckles - periosteal hinge intact on concave side
3. Most common site: distal radius and ulna (FOOSH mechanism)
4. Diagnosis by 2-view X-ray - look for one-sided cortical break with angulation
5. Treatment: immobilization ± closed reduction depending on angulation degree
6. Prognosis: excellent - remodeling capacity in children corrects residual angulation (not rotation)
7. Key risk: refracture - avoid high-risk activities and ensure adequate immobilization period
8. Always consider non-accidental trauma when mechanism is inconsistent with injury