Updated: 10/6/2018

Distal Radius Fractures - Pediatric

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Introduction
  • Epidemiology
    • incidence
      • common - forearm fractures in total account for approximately 40% of all pediatric long bone fractures
      • distal radius (and ulna) is the most common site of pediatric forearm fractures.
      • male > female (male 2-3 times more common than female)
    • demographics
      • most common during metaphyseal growth spurt
      • peak incidence occurring from: 
        • 10-12 years of age in girls
        • 12-14 years of age in boys
      • most common fracture in children under 16 years old 
  • Pathophysiology
    • mechanism
      • usually fall on an outstretched hand, extended at wrist
      • often during sports or play
    • remodeling
      • greatest closer to physis and in plane of joint (wrist) motion
        • sagittal plane (flexion/extension)
      • least for rotational deformity
Anatomy
  • Distal radius physis
    • contributes 75% growth of the radius
    • contributes 40% of entire upper extremity 
    • growth at a rate of ~ 5.25mm per year
  • Metaphyseal fracture most common, followed by physeal
Classification
  • Relation to distal physis
    • Physeal considerations 
    • Salter-Harris I     
    • Salter-Harris II     
    • Salter-Harris III   
    • Salter-Harris IV  
    • Salter-Harris V
  • Metaphysis (distal) (62%)
    • complete (Distal Radius fracture) 
      • apex volar (Colles' fracture) 
      • apex dorsal (Smith's fracture)
    • incomplete (Torus/Buckle fracture)  
      • unicortical, non-displaced
  • Diaphysis (20%)
    • both bone forearm fracture 
    • isolated radial shaft fracture
    • isolated ulnar shaft fracture
    • plastic deformation
      • deforming force over time resulting in shape change of bone without clear fracture line
      • thought to be due to a large number of microfractures resulting from a relatively lower force over longer time compared to mechanism for complete fractures 
    • greenstick fracture
      • incomplete fracture resulting from failure along tension (convex) side
        • typically plastic deformation occurs along compression side
  • Fracture with dislocation / associated injuries
    • Monteggia fracture  
      • ulnar shaft fracture with radiocapitellar dislocation
    • Galeazzi fracture  
      • radius fracture (typically distal 1/3) with associated DRUJ injury, often dislocation
Presentation
  • History
    • wide range of mechanisms for children, often fall during play or other activity, outstretched hand
    • rule out child abuse
      • mechanism or history appears inconsistent with injury
      • multiple injuries, especially different ages
      • child's affect
      • grip marks/ecchymosis
  • Symptoms
    • pain, swelling, and deformity
  • Physical exam
    • gross deformity may or may not be present
    • ecchymosis and swelling
    • inspect for puncture wounds suggesting open fracture
    • although uncommon, compartment syndrome and neurovascular injury should be evaluated for in all forearm fractures.
Imaging
  • Radiographs
    • recommended views
      • AP and lateral of wrist
      • AP and lateral of forearm
      • AP and lateral of elbow if tender about elbow, or diaphyseal fractures present
    • findings
      • in addition to fracture must evaluate for associated injuries
        • scapholunate interval
        • DRUJ (distal radio-ulnar joint)
        • ulnar styloid
        • elbow injuries
  • CT scan
    • indications
      • useful to characterize fracture if intra-articular
      • use sparingly in children given concerns of increased longitudinal effects of radiation
Treatment
 
"Classically" Acceptable Angulation for Closed Reduction in Pediatric Forearm Radius Fractures
 
(controversial with ongoing discussion)
 
Shaft / Both bone fx
Distal radius/ulna
Age Acceptable Bayonetting

Acceptable Angulations

Malrotation* Dorsal Angulation

< 9 yrs

< 1 cm

15-20°

45°

30 degrees

> 9 yrs.

< 1 cm

10°

30°

20 degrees

  • Bayonette apposition, or overlapping, of less than 1 cm, does not block rotation and is acceptable in patients less than 10 years of age.
  • General guidelines are that deformities in the plane of joint motion are more acceptable, and distal deformity (closer to distal physis) more acceptable than mid shaft.
  • The radius and ulna function as a single rotational unit. Therefore a final angulation of 10 degrees in the diaphysis can block 20-30 degrees of rotation. 
  • *Rotational deformities do not remodel and are increasingly being considered as not acceptable.
 
  • Nonoperative
    • immobilization in short arm cast for 2-3 weeks without reduction
      • indications
        • unicortical or bicortical fracture with < 10 deg of angulation
        • torus/buckle fracture
          • ongoing shift towards treating buckle fractures with pre-fabricated removable wrist splint, no cast, and limited follow-up
    • closed reduction under conscious sedation followed by casting
      • indications
        • > 10-20 degrees of angulation
        • Salter-Harris I with unacceptable alignment
        • Salter-Harris II with unacceptable alignment
      • technique (see below)
        • reduction technique determined by fracture pattern
      • acceptable criteria (see table above)
        • acceptable angulations are controversial in the orthopedic community
        • accepted angulation is defined on a case by case basis depending on
          • the age of the patient
          • location of the fracture
          • type of deformity (angulation, rotation, bayonetting)
      • outcomes
        • short-arm (SAC) vs long-arm casting (LAC)
          • good SAC (proper cast index = sagital/coronal widths close to 0.7 for good cast) considered equal to LAC for distal radius fractures
            • conservative treatment though often utilizes LAC to reduce impact of variable cast technique/quality
          • no increased risk of loss of reduction with (good) short arm vs. long arm casting 
        • cast index
          • loss of reduction is associated with poor cast index 
      • follow-up
        • all forearm fractures serial radiographs should be taken every 1 to 2 weeks initially to ensure reduction is maintained.
        • if concern for physeal injury, must follow child at least until growth seen on radiographs to confirm no growth arrest
  • Operative
    • closed reduction and percutaneous pinning (CRPP)
      • indications
        • unstable patterns unable to reduce initially, or with loss of reduction in cast at follow-up
        • Salter-Harris I or II fractures in the setting of neurovascular (NV) compromise
          • CRPP reduces need for tight casting in setting with increased concern for compartment syndrome
        • fractures unable to reduce in emergency department (ED) but successfully closed reduced under anesthesia in the operating room (OR) may be pinned for added stability
    • open reduction and internal fixation
      • indications
        • displaced Salter-Harris III and IV fractures of the distal radial physis/epiphysis unable to be closed reduced
        • irreducible fracture closed
          • often periosteum or pronator quadratus block to reduction
Treatment Techniques
  • Closed Reduction
    • timing
      • avoid delayed reduction of greater than 1 week after injury
      • for physeal injuries, generally limit to one attempt to reduce chance of growth arrest
    • reduction technique
      • gentle steady pressure for physeal reduction
      • for complete metaphyseal fractures re-create deformity to unlock fragments, then use periosteal sleeve to aid reduction
      • traction can be counter-productive due to thick periosteum
  • Casting
    • historically consisted of a long arm cast for 6 to 8 weeks with the possibility of conversion to a short arm cast after 2-4 weeks depending on the type of fracture and healing response. 
    • may cast for shorter periods, 3-4 weeks, depending on child's age and healing on imaging 
    • multiple high quality studies show fractures of distal third may be immobilized with a properly molded short arm cast.
    • special case of fratured distal radius with intact ulna: extreme ulna deviation of wrist helps keep radius fracture out to length. 
  • CRPP 
    • approach
      • avoid dorsal sensory branch of radial nerve, typically with small incision
    • reduction
      • maintain closed reduction during pinning
    • fixation
      • radial styloid pins
        • usually 1 or 2 radial styloid pins, entry just proximal to physis preferred
        • if stability demands transphyseal pin, smooth wires utilized
        • for intra-articular fractures, may pin distal to physis transversely across epiphysis 
      • dorsal pins
        • may also utilize dorsal pin, especially to restore volar tilt
        • for DRUJ injuries, or severe fractures unable to stabilize with radial pins alone, pin across ulna and DRUJ
    • postoperative considerations
      • follow-up in clinic for repeat imaging to assess healing and position
      • pin removal typically in clinic once callus formation verified on radiograph
        • may consider sedation or removal of pins in OR for children unable to tolerate in clinic
      • must immobilize radio-ulnar joints in long arm cast if stabilizing DRUJ
      • may supplement with external fixator for severe injuries
Complications
  • Casting Thermal Injury
    • risk factors for thermal injury include: 
      • dipping water temperature is > 24C (75F)
      • more than 8 layers of plaster are used
      • during cast setting, the arm is placed on a pillow. This decreases the dissipation of heat from the exothermic reaction
      • fiberglass is overwrapped over plaster
  • Cast Saw Injury
    • if bivalving or univalving cast, must ensure proper technique to avoid injury
    • extra caution if cutting cast while child is sedated or under anesthesia
    • cool saw blade frequently to ensure not overheating
  • Loss of Reduction
    • poor cast index, increased initial displacement, and incomplete reduction are all risk factors for loss of reduction
  • Malunion
    • most common complication
  • Physeal arrest
    • from initial injury or repeated/late reduction attempts
    • isolated distal radial physeal arrest can lead to ulnocarpal impaction, TFCC injuries, DRUJ injury
    • distal ulnar physis most often to arrest
  • Ulnocarpal impaction
    • from continued growth of ulna after radial arrest
  • TFCC injuries
  • Neuropathy
    • Median nerve most commonly affected
    • Uncommon in children, but must examine for acute carpal tunnel syndrome
 

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Questions (12)
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(OBQ12.134) An 11-year old boy presents to fracture clinic 1 week after sustaining a displaced metaphyseal distal radius fracture that was managed with closed reduction and cast application. While the initial post-reduction radiographs showed near anatomic alignment with a well molded cast, radiographs 1 week later show 22 degrees of apex volar angulation and dorsal re-displacement. What is the best management at this time? Review Topic

QID: 4494
1

Accept the deformity, cast change and follow-up in 3 weeks

10%

(454/4667)

2

Closed reduction and cast application, follow-up in 1 week

15%

(700/4667)

3

Closed reduction and percutaneous fixation

65%

(3033/4667)

4

Closed reduction and flexible intramedullary rod fixation

4%

(193/4667)

5

Open reduction and internal fixation with a plate and screws

6%

(266/4667)

ML 3

Select Answer to see Preferred Response

PREFERRED RESPONSE 3

(OBQ12.243) What is the most common fracture in children younger than 16-years-old? Review Topic

QID: 4603
1

Hand phalanges

12%

(449/3868)

2

Femoral shaft

0%

(19/3868)

3

Clavicle

10%

(370/3868)

4

Distal radius

60%

(2316/3868)

5

Supracondylar

18%

(700/3868)

ML 4

Select Answer to see Preferred Response

PREFERRED RESPONSE 4

(OBQ09.251) You are preparing to cast a child with a both-bone forearm fracture in the emergency room. During cast application, all of the following are directly related to the risk of thermal injury EXCEPT? Review Topic

QID: 3064
1

Layers of thickness of casting material

1%

(6/711)

2

Water temperature used to dip casting material

2%

(11/711)

3

Placing the limb on a pillow during the cast curing process

6%

(44/711)

4

Fiberglass overwrapping of plaster casts

2%

(12/711)

5

Type of fracture pattern

89%

(633/711)

ML 1

Select Answer to see Preferred Response

PREFERRED RESPONSE 5

(OBQ05.97) Isolated pronation of the forearm will most likely achieve reduction of what type of fracture in a 7-year-old boy? Review Topic

QID: 983
1

Supination injury resulting in an apex-volar greenstick both bone forearm fracture

69%

(837/1214)

2

Pronation injury resulting in an apex-dorsal greenstick both bone forearm fracture

5%

(60/1214)

3

Supination injury resulting in an apex-dorsal greenstick both bone forearm fracture

22%

(265/1214)

4

Complete both bone forearm fracture with bayonete apposition of both the radius and ulna

1%

(17/1214)

5

Distal radius fracture with 25 degrees of apex-dorsal angulation

3%

(33/1214)

ML 2

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PREFERRED RESPONSE 1

(OBQ10.196) An 8-year-old boy fell while riding his bike and landed on his outstretched arm. Radiographs are provided in Figure A. Which of the following increases the risk of displacement following closed reduction and casting? Review Topic

QID: 3289
FIGURES:
1

Long arm cast immobilization

1%

(15/2610)

2

Short arm cast immobilization

30%

(779/2610)

3

Cast index greater than 0.85

68%

(1786/2610)

4

Conscious sedation during reduction

0%

(9/2610)

5

Plaster cast immobilization

0%

(11/2610)

ML 3

Select Answer to see Preferred Response

PREFERRED RESPONSE 3
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ARTICLES (24)
CASES (9)
Topic COMMENTS (18)
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