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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
    • 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
      • often during sports or play
    • remodeling
      • remodeling greatest closer to physis and in plane of joint (wrist) motion
        • sagittal plane (flexion/extension)
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
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)  
      • typically unicortical
  • Diaphysis (20%)
    • both bone forearm fracture 
    • isolated radial shaft fracture
    • isolated ulnar shaft fracture
    • plastic deformation
      • incomplete fracture with deforming force 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 mechanism for children, often fall during play or other activity
    • 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
    • findings
      • in addition to fracture must evaluate for associated injuries
        • scapholunate joint
        • DRUJ
        • ulnar styloid
        • elbow injuries
  • CT
    • indications
      • useful characterize fracture if intra-articular
      • however use sparingly in children given concerns regarding 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
        • greenstick fracture with < 10 deg of angulation
        • torus/buckle fracture
          • studies ongoing to treat minimally displaced or torus fractures with pre-fabricated removable wrist splint, no cast
    • closed reduction under conscious sedation followed by casting
      • indications
        • greenstick fracture with > 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) 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 increasing cast index
      • follow-up
        • all forearm fractures serial radiographs should be taken every 1 to 2 weeks initially to ensure the reduction is maintained.
  • Operative
    • closed reduction and percutaneous pinning (CRPP)
      • indications
        • unstable patterns with loss of reduction in cast
        • Salter-Harris I or II fractures in the setting of NV compromise
          • CRPP reduces need for tight casting in setting with increased concern for compartment syndrome
        • any fractures unable to reduce in ED but are successfully reduced under anesthesia in the OR
    • 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 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
    • usually consists of a long arm cast (conservative approach) 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 utilize well molded short arm cast with adequate cast index instead of long arm cast initially
  • 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
      • followup 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
    • thermal injury may occur if: 
      • 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
  • 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
 

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Questions (5)

(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

11%

(272/2552)

2

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

15%

(373/2552)

3

Closed reduction and percutaneous fixation

66%

(1679/2552)

4

Closed reduction and flexible intramedullary rod fixation

4%

(96/2552)

5

Open reduction and internal fixation with a plate and screws

5%

(120/2552)

Select Answer to see Preferred Response

PREFERRED RESPONSE 3

After failed initial treatment with closed reduction and casting, displaced distal radius/forearm fractures should be treated with repeat closed reduction. Percutaneous fixation can decrease the risk of re-displacement.

Approximately 20-25% of distal radius metaphyseal fractures re-displace early after closed reduction and casting. Significant displacement can lead to poor functional and cosmetic outcomes. Indications for surgical fixation of distal forearm fractures in adolescents >10 years old include: angulation >20 degrees and rotation >30 degrees.

McLauchlan et al., in their prospective randomized, controlled trial, showed that K-wire fixation and casting was superior to closed manipulation (MUA) and casting for displaced distal radius fractures when comparing outcomes of loss of reduction and number of radiographs. Of the 33 patients in the MUA group, seven had to undergo a second procedure to correct recurrent displacement, compared to one of the 35 in the K-wire group who required exploration for recovery of a migrated pin.

Kamat et al. present a retrospective review of 1001 pediatric distal forearm fractures that required closed reduction to identify factors associated with re-displacement. They found the cast index (CI) - or ratio of sagittal (lateral) and coronal (AP) inner cast diameters - to be the only significant predictor. CI > 0.8 was associated with a significantly higher rate of displacement (26%) than CI <= 0.8 (5.6%). Previous studies have reported an ideal CI of 0.7.

Illustration A shows a distal radius fracture with dorsal displacement and apex volar angulation. Illustration B shows a distal radius fracture after closed reduction and temporary percutaneous fixation with a smooth k-wire.

Incorrect Answers:
Answer 1: The current amount of angulation is unacceptable for a child > 10 years.
Answer 2: The fracture has re-displaced once despite the first attempt at closed reduction in a well-molded cast. It is likely to re-displace and would benefit from fixation to stabilize the fracture.
Answer 4: The fracture is too distal to control the distal fragment with a flexible intramedullary rod.
Answer 5: Closed reduction will likely be sufficient to reduce the fracture. Open reduction should be reserved for cases where an adequate closed reduction cannot be achieved.

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

QID:4603
1

Hand phalanges

12%

(367/3131)

2

Femoral shaft

0%

(15/3131)

3

Clavicle

10%

(309/3131)

4

Distal radius

58%

(1808/3131)

5

Supracondylar

20%

(621/3131)

Select Answer to see Preferred Response

PREFERRED RESPONSE 4

Distal radius fractures are the most common fracture type in children less than 16-years-old.

Fractures are a common occurrence in children and adolescents. Fractures of the distal radius are the most common (22.7%), followed by fractures of the phalanges of the hand (18.9%), and fractures of the carpal/metacarpal region (8.3%). Distal radius fractures can occur in the diaphysis, metaphysis, or epiphysis. The majority are treated with closed reduction and casting.

Landin reviews the epidemiology of childhood fractures. According to his statistics, boys have a 42% risk of sustaining a fracture prior to age 16, while females have a 27% risk. Distal radius fractures were the most common, followed by hand fractures.

Illustration A shows a Salter-Harris II fracture of the distal radius with associated greenstick ulna fracture.

Incorrect Answers:
Answer 1: Fractures of the phalanges of the hand account for 18.9% of fractures.
Answer 2: Fractures of the distal femur account for 1.6% of fractures.
Answer 3: Fractures of the clavicle account for 8.1% of fractures.
Answer 5: Supracondylar fractures account for 3.3% of fractures.

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(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%

(13/1879)

2

Short arm cast immobilization

32%

(594/1879)

3

Cast index greater than 0.85

66%

(1249/1879)

4

Conscious sedation during reduction

0%

(8/1879)

5

Plaster cast immobilization

0%

(7/1879)

Select Answer to see Preferred Response

PREFERRED RESPONSE 3

Pediatric both bone forearm fractures are generally treated with closed reduction and immobilization given the innate ability of the bone to remodel. Guidelines will vary by author, but fractures at any level in children less than 9 years of age, complete displacement, 15 degrees of angulation, and 45 degrees of malrotation are acceptable. In children 9 years of age and older, 30 degrees of malrotation, 10 degrees of angulation for proximal fractures, and 15 degrees for more distal fractures are acceptable. The cast index is defined as the sagittal width of the cast divided by the coronal width. If the fracture involves the physis, repeated closed reductions are not recommended due to potential injury of the physis. Therefore it is important to recognize acceptable alignment, know the potential for remodeling at certain ages, and the importance of a well-molded cast. Webb et al conducted a prospective, randomized study of 113 children who sustained fractures of the distal forearm. Patients were randomized to long arm or short arm casting. There was no difference in fracture displacement throughout the course of treatment. Loss of reduction was associated with poorly molded casts in both groups. The average cast index of patients who lost reduction was 0.79 compared to 0.70 in patients who did not lose reduction. Patients with short arm casts missed fewer school days and experienced less difficulty with activities of daily living. An example of the cast index from Webb's article is shown in Illustration A.

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Question COMMENTS (5)

(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%

(4/409)

2

Water temperature used to dip casting material

1%

(6/409)

3

Placing the limb on a pillow during the cast curing process

7%

(28/409)

4

Fiberglass overwrapping of plaster casts

2%

(7/409)

5

Type of fracture pattern

89%

(362/409)

Select Answer to see Preferred Response

PREFERRED RESPONSE 5

Causes for thermal burns during cast application are multi-factorial.

Halanski et al. evaluated the internal and external temperature changes that occured during cast application on limb models. They found that excessively thick plaster, dip-water temperature of >24 degrees C, placing the limb on a pillow during the curing process, and fiberglass overwrapping all increase the risk for thermal injury.

Lavalette et al. in a similiar study using a glass tube filled with water to simulate an extremity found that if the temperature of the dip water was higher than 24 degrees Celsius, thickness of the cast was greater than eight ply, and if the pillow was used to limit the dissipation of heat from the cast, temperatures became high enough to cause skin burns.


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(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

70%

(628/902)

2

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

4%

(35/902)

3

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

22%

(202/902)

4

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

1%

(11/902)

5

Distal radius fracture with 25 degrees of apex-dorsal angulation

3%

(24/902)

Select Answer to see Preferred Response

PREFERRED RESPONSE 1

Noonan et al discuss the anatomy, diagnosis, treatment, and outcome in pediatric forearm and distal radius fractures in their review article. With regards to reduction and casting, the authors state that greenstick forearm fractures are usually supination injuries with apex-volar angulation (Illustration A), which can be reduced with varying degrees of forearm pronation. As a rule of thumb, most pediatric both bone fractures can be temporarily reduced by pointing the palm in the direction of the deformity. Complete both bone forearm fractures with bayonette apposition require traction to aide in reduction, and malaligned distal radius fractures can be reduced with a combination of traction, angulation, and rotation of the palm in the direction of the angulation.

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