Reverse Bennett Fracture

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"Because the fracture-dislocation of the base of the fifth metacarpal is pathologically and radiographically similar to the Bennett fracture of the thumb metacarpal, it is referred to as a "reversed Bennett", "ulnar Bennett", or "Tenneb" (Bennett spelled backwards) fracture". In further analogy with the Bennett Fracture, the large distal fragment of the base of the fifth metacarpal is proximally retracted by the flexor and extensor carpi ulnaris muscles, and open reduction and internal fixation are recommended to reduce and stabilise the fracture fragments. (J. Harris, W. Harris and R. Novelline, The Radiology of Emergency Medicine, 3rd ed, Williams and Wilkins, 1993, p452 - 455).

Reverse Bennett Fracture

Case 1

metacarpal base fracture-dislocationThis patient presented to the Emergency Department following a fight. His right hand was very painful and he had an abnormal prominence dorsally along the ulnar aspect in the region of the base of his 5th metacarpal (arrowed).
metacarpal base fracture-dislocationThe patient's right metacarpophalangeal joint demonstrated an abnormal lack of prominence.
base 5th metacarpal fracture dislocationThe PA hand image demonstrates a fracture dislocation of the base of the 5th metacarpal with ulnar displacement.
base 5th metacarpal fracture dislocationThe oblique hand image demonstrates dorsal displacement of the dislocated 5th metacarpal. There is also a small bony fragment demonstrated at the base of the 5th metacarpal adjacent to the cortex of the hamate ? donor site
base 5th metacarpal fracture dislocationThe lateral hand image demonstrates the angular displacement of the 5th metacarpal base.

The fracture-dislocation was reduced with local pain relief and reimaged before the patient was taken to the operating theatre for K-wiring under image intensifier control.