Background  

The diagnosis of occult elbow fracture in children is often challenging due to equivocal or negative repeated radiographic findings.

Objective  

To evaluate the potential diagnostic role of US in children who have sustained elbow trauma with an elbow joint effusion but no fracture seen on initial radiographs.

Materials and methods  

The study included 14 consecutive children (age range 5–15 years) with elbow trauma whose elbow radiographs showed an effusion without fracture who underwent emergency imaging (within the first 72 h) with US and MRI. The aim of US was to demonstrate a lipohaemarthrosis in relation to a cortical fracture. MR imaging was used as the reference to differentiate fracture from bone or muscle contusions.

Results  

In seven children US demonstrated a lipohaemarthrosis, and MRI demonstrated a cortical fracture in all these children. Conversely, among the seven children with simple haemarthrosis seen on US, MRI did not identify a cortical fracture in six and demonstrated a cortical fracture in one.

Conclusion  

Posttrauma elbow joint effusion in children is not always related to a cortical fracture. US appears to be a reliable, accurate, widely available and effective low-cost tool in these cases. The diagnostic clue is the detection of a lipohaemarthrosis in the articular recess.