The Dreaded Paediatric Elbow X-ray

This 6 year old girl presented to a local MIU complaining of a sore forearm after falling off a climbing frame. It was difficult to elicit the site of maximal tenderness and the following X-ray was performed:
​What does the X-ray show and how would you manage it?

​Case progression:
The child was diagnosed as having a mid-shaft ulna fracture and was placed in a back-slab and referred on to fracture clinic. The following day an eagle eyed radiologist spotted the radial head dislocation which was missed initially and the child was recalled and referred to the orthopaedic team for manipulation.
 
So, how not to miss this injury?
The key to not missing this injury is to look carefully at the radiocapitellar line. If you draw a line through the middle of the radius (on either view) this should bisect the middle of the capitellum. This is clearly not the case in the X-ray above. The images below illustrate this further:

Normal radiocapitellar line

Radial head dislocation with an abnormal radiocapitellar line

The other tip is to think of the forearm bones as a ring structure (not unlike the pelvis or the jaw). If there is a break in one place, there will nearly always be a second break or dislocation somewhere else – you can’t just break a polo mint in one place! If you see a forearm fracture, search hard for the second injury.

Dr Beth Newstead