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