Presentation
Motorcycle accident. Direct hit to the hand. Moderate soft tissue swelling on the ulnar side of the hand upon physical examination.
Patient Data
Hand radiographs revealed a fracture-dislocation of the base of the 5th metacarpal. There is subluxation of the 5th carpometacarpal joint, which is dislocated dorsally and proximally.
The fracture-dislocation of the 5th metacarpal base is called a reverse Bennett fracture-dislocation.
There is moderate soft tissue swelling on the ulnar side of the hand.
Case Discussion
A reverse Bennett fracture-dislocation describes a fracture-dislocation of the 5th metacarpal base.
Metacarpal fractures are relatively common, usually the result of an axial force, such as a fall onto the flexed wrist. Amongst the metacarpals, the 5th is the most commonly injured.
Unlike a simple undisplaced fracture of the 5th metacarpal base, a fracture-dislocation indicates that the extensor carpi ulnaris is exerting a significant pull over the metacarpal base and that the fracture is inherently unstable, demanding operative treatment
Because of this, in the presence of a 5th metacarpal fracture, it is of great importance to recognize whether there is a dislocation component or not.