13-E/7L Avulsion

Avulsion of/by the lateral collateral ligament

13-E/7L

The pattern of this fracture is an osseo-ligamentous avulsion of the lateral epicondyle. The classification is independent of fragment size and displacement.

This very rare fracture tends to occur in combination with elbow dislocation.

Pearl: If a medial shift is seen, consider the possibility that the elbow luxation is accompanied by a lateral epicondylar avulsion and investigate accordingly.

This fracture is only visible on an x-ray if there is a bony component, mostly seen in older children.

Additional ultrasonography and/or MRI are indicated if there is diagnostic uncertainty.

Relevant clinical features include:

  • Fat pad sign
  • Local clinical swelling
  • Local anterior tenderness
  • Painful restriction of motion

Older child (older than 6 years):

  • Around puberty the lateral epicondyle starts to ossify. Once this occurs, the ossific center can be seen on a plain x-ray
  • On this x-ray a multifragmentary avulsion and displacement of the lateral epicondyle can be seen clearly in the AP view
  • As this fragment usually is less severely displaced than the medial epicondyle, the fragment cannot usually be seen on the lateral view
  • Additional investigation, such as CT scan or MRI, is indicated if the diagnosis remains unclear after AP and lateral x-rays

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v1.0 2016-12-01