Which joints of the elbow are involved?
Both the radiocapitellar and ulnotrochlear joints, as well as the proximal radioulnar joint.
Is there an elbow joint effusion?
No, neither the anterior or posterior fat pads are elevated. (no "sail signs")
There is calcification within the radiocapitellar, ulnotrochlear, and proximal radioulnar joints which parallels the articular surfaces to follow the contour of the hyaline cartilage.
If one does not appreciate that this finding extends into the ulnotrochlear joint and proximal radioulnar joint, the chondrocalcinosis within the radiocapitellar joint could be mistaken for a radial head fracture in the setting of trauma. The absence of elevated fat pats mitigates this concern. In this case, the emergency department did mistakenly believe the patient had a radial head fracture based on the imaging.
Remember that the hyaline cartilage of the radial head extends circumferentially around the radial head, so chondrocalcinosis would be expected to extend similarly to anywhere around the circumference of the radial head.