Supracondylar fracture

Supracondylar fractures are a classic paediatric injury which require vigilance as imaging findings can be subtle.

Simple supracondylar fractures are typically seen in younger children, and are uncommon in adults; 90% are seen in children younger than 10 years of age, with a peak age of 5-7 years 4,6. These fractures are more commonly seen in boys 4.

These injuries are almost always due to accidental trauma, such as falling from a moderate height (bed/monkey-bars) 4.

Rarely (<5%) supracondylar fractures are seen due to a fall onto the flexed elbow. They occur in older individuals and require different management and are discussed separately: see flexion supracondylar fracture 5.

Typically supracondylar fractures occur as a result of a fall on a hyper-extended elbow. They result in an extra-articular fracture line, and (when displaced) posterior displacement of the distal component.

Classification of supracondylar fractures is relatively straightforward and based on three types 6-7:

  • type I: undisplaced
  • type II: displaced with intact posterior cortex
  • type III: complete displacement

Lateral and AP radiographs are usually sufficient, and in many instances demonstrate an obvious fracture. Often, however, no fracture line can be identified. In such cases assessing for indirect signs is essential:

  • anterior fat pad sign (sail sign): the anterior fat pad is elevated by a joint effusion and appears as a lucent triangle on the lateral projection
  • posterior fat pad sign
  • anterior humeral line should intersect the middle third of the capitellum in most children 2 although, in children under 4, the anterior humeral line may pass through the anterior third without injury

After ensuring that the films are technically adequate, assessment should include:

  • a visible fracture line
    • location and especially presence of articular involvement
    • angulation (use the anterior humeral line)
    • alignment of the radius and ulna with the distal humerus
  • an invisible fracture line
    • assess for joint effusion (anterior and posterior fat pad sign)
    • if present explicitly raises the possibility of an occult supracondylar fracture and recommend re-imaging in 7-10 days
    • remember to consider other elbow trauma: radial head dislocation/pulled elbow/epicondylar fractures can all mimic an undisplaced supracondylar fracture
    • remember to assess elbow centers of ossification (CRITOE)

Although in many cases the fracture is easily seen, in some instances all that may be seen is soft tissue swelling or an anterior fat pad sign. Even in the absence of an obvious fracture, the patient needs to be treated with a cast. Repeating radiographs after inflammation has subsided may be helpful in demonstrating the fracture; this is typically done 7-10 days later.

Management depends on the type and degree of angulation 5,7.

Type I (undisplaced) fractures are stable and can be treated with cast immobilisation for approximately 3 weeks.

Type II usually require reduction (especially when angulation is more than 20 degrees). Although traditionally these fractures were treated non-operatively with cast immobilisation of the flexed arm to 120 degrees, this however dramatically increases the risk of ischaemic contracture (Volkmann contracture), as such most authors recommend percutaneous pinning (CRIF) and cast immobilisation with less than 90 degrees flexion 5,7.

Type III fractures can sometimes be treated similarly to type II (closed reduction and percutaneous pinning, CRIF) although frequently the fracture is held open by interposed soft tissues requiring open reduction 7.

There are three main complications 2-3:

Rare complication:

  • fishtail deformity due to resorption of the trochlear ossification centre (or failure of formation) due to an osteonecrosis type phenomenon
Fractures
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Article information

rID: 2130
Synonyms or Alternate Spellings:
  • Supracondylar fracture (extension)
  • Extension supracondylar fracture
  • Extension supracondylar humeral fracture
  • Extension supracondylar fractures
  • Supracondylar humeral fracture
  • Supracondylar fractures

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    Figure 1: supracondylar fracture
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    Normal alignment
    Figure 2: normal alignment of distal humerus and capitellum
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    Case 2
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    Supracondylar fra...
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    Case 8 : healing
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