Is it possible for an x-ray to not confirm a certain type of elbow fracture?

The elbow is complex: And some fractures are not seen by a routine set of xrays. Special views, ct or MRI may be needed. And you can also have a soft tissue injiry.

Occult Fractures: Any time a fracture is suspected based on signs, symptoms, mechanism of injury, and/ or any other clinical findings, but it does not show on an x-ray you should follow-up with a second x-ray in a week or two to check for an occult fracture. Cts and mris are also used sometimes, but the second x-ray can be useful at seeing new bone formation even if a fracture was not noted on the original one.