"Epibasal fractures of the thumb, also called pseudo-Bennett fractures, are extra-articular two-piece fractures of the proximal first metacarpal. They are usually stable, depending on the degree of displacement, and often do not require surgery. It is important to distinguish them from intra-articular fractures (e.g. Bennett fracture-dislocation or Rolando fracture), which are usually unstable and require surgery."
"Plain films are usually sufficient to diagnose and assess epibasal fractures; however, if adequate views cannot be obtained or there is suspicion of intra-articular involvement, further assessment with CT is prudent 3."