Imaging Case of the Week 532 Answer

The main finding on the elbow x-ray is that there is a radial head dislocation.

On the AP view, the radio capitellar line aligns but the articulation appears crowded.

On the lateral view, there is a clear incongruity in the radio capitellar line suggesting a dislocated radial head.

Take home point – the radio capitellar line (a line drawn through the long axis of radius) should pass through the center of capitellum in both AP & lateral views. If not, suspect radial head dislocation.

Patients with radial head dislocation should have urgent orthopedic referral for closed reduction under sedation & image intensifier guidance.

Reference: Fundamentals of Diagnostic Radiology by Brant and Helms ,4th Edition